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Sample records for gps navigation system

  1. 78 FR 68861 - Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ...Certain Navigation Products, Including GPS Devices, Navigation and Display Systems...certain navigation products, including GPS devices, navigation and display systems...certain navigation products, including GPS devices, navigation and display...

  2. 78 FR 68861 - Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ... COMMISSION Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems... and display systems, radar systems, navigational aids, mapping systems and related software by reason... products, including GPS devices, navigation and display systems, radar systems, navigational aids,...

  3. GPS Supplemental Navigation Systems for Use During the Transition to a Sole-Means-GPS

    E-print Network

    Stanford University

    GPS Supplemental Navigation Systems for Use During the Transition to a Sole-Means-GPS National vehicle navigation and control. He is a co- author of two control system text books. Per Enge, Ph Radio Navigation Plan presents a plan that includes phasing out of existing radio-navigation aids

  4. Autonomous navigation system based on GPS and magnetometer data

    NASA Technical Reports Server (NTRS)

    Julie, Thienel K. (Inventor); Richard, Harman R. (Inventor); Bar-Itzhack, Itzhack Y. (Inventor)

    2004-01-01

    This invention is drawn to an autonomous navigation system using Global Positioning System (GPS) and magnetometers for low Earth orbit satellites. As a magnetometer is reliable and always provides information on spacecraft attitude, rate, and orbit, the magnetometer-GPS configuration solves GPS initialization problem, decreasing the convergence time for navigation estimate and improving the overall accuracy. Eventually the magnetometer-GPS configuration enables the system to avoid costly and inherently less reliable gyro for rate estimation. Being autonomous, this invention would provide for black-box spacecraft navigation, producing attitude, orbit, and rate estimates without any ground input with high accuracy and reliability.

  5. 76 FR 72442 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-23

    ...No. 337-TA-814] Certain Automotive GPS Navigation Systems, Components Thereof...after importation of certain automotive GPS navigation systems, components thereof...after importation of certain automotive GPS navigation systems, components...

  6. 76 FR 66750 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ...COMMISSION [DN 2850] Certain Automotive GPS Navigation Systems, Components Thereof...complaint entitled In Re Certain Automotive GPS Navigation Systems, Components Thereof...after importation of certain automotive gps navigation systems, components...

  7. Investigation and evaluation of shuttle/GPS navigation system

    NASA Technical Reports Server (NTRS)

    Nilsen, P. W.

    1977-01-01

    Iterative procedures were used to analyze the performance of two preliminary shuttle/GPS navigation system configurations: an early OFT experimental system and a more sophisticated system which consolidates several separate navigation functions thus permitting net cost savings from decreased shuttle avionics weight and power consumption, and from reduced ground data processing. The GPS system can provide on-orbit navigation accuracy an order of magnitude better than the baseline system, with very adequate link margins. The worst-case link margin is 4.3 dB. This link margin accounts for shuttle RF circuit losses which were minimized under the constraints of program schedule and environmental limitations. Implicit in the link analyses are the location trade-offs for preamplifiers and antennas.

  8. High accuracy autonomous navigation using the global positioning system (GPS)

    NASA Technical Reports Server (NTRS)

    Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul

    1997-01-01

    The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.

  9. 77 FR 13350 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-06

    ...COMMISSION [Investigation No. 337-TA-814] Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing...within the United States after importation of certain automotive GPS navigation systems, components thereof, and products...

  10. 77 FR 35428 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ...COMMISSION [Investigation No. 337-TA-814] Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing...within the United States after importation of certain automotive GPS navigation systems, components thereof, and products...

  11. Navstar GPS and GLONASS. Global satellite navigation systems

    NASA Astrophysics Data System (ADS)

    Daly, P.

    Both the Navstar GPS and GLONASS satellite navigation systems developed respectively by the U.S.A. and the Soviet Union are now planned to become operational by 1995. Both systems are capable of providing the civil community with high-precision position-fixes and/or timing references on a continuous, world-wide basis. Already both systems have several satellites in orbit in order for pre-operational testing to be conducted. The paper discusses (i) the widely-differing launch histories of both systems, (ii) developments in planned use of orbits, (iii) the deliberate degradation of accuracy by the use of selective availability, (iv) progress in plans to provide a joint Navstar GPS/GLONASS civil satellite navigation system possibly integrated with other satellite ranging systems and (v) current status of both systems.

  12. Flight evaluation of differential GPS aided inertial navigation systems

    NASA Technical Reports Server (NTRS)

    Mcnally, B. David; Paielli, Russell A.; Bach, Ralph E., Jr.; Warner, David N., Jr.

    1992-01-01

    Algorithms are described for integration of Differential Global Positioning System (DGPS) data with Inertial Navigation System (INS) data to provide an integrated DGPS/INS navigation system. The objective is to establish the benefits that can be achieved through various levels of integration of DGPS with INS for precision navigation. An eight state Kalman filter integration was implemented in real-time on a twin turbo-prop transport aircraft to evaluate system performance during terminal approach and landing operations. A fully integrated DGPS/INS system is also presented which models accelerometer and rate-gyro measurement errors plus position, velocity, and attitude errors. The fully integrated system was implemented off-line using range-domain (seventeen-state) and position domain (fifteen-state) Kalman filters. Both filter integration approaches were evaluated using data collected during the flight test. Flight-test data consisted of measurements from a 5 channel Precision Code GPS receiver, a strap-down Inertial Navigation Unit (INU), and GPS satellite differential range corrections from a ground reference station. The aircraft was laser tracked to determine its true position. Results indicate that there is no significant improvement in positioning accuracy with the higher levels of DGPS/INS integration. All three systems provided high-frequency (e.g., 20 Hz) estimates of position and velocity. The fully integrated system provided estimates of inertial sensor errors which may be used to improve INS navigation accuracy should GPS become unavailable, and improved estimates of acceleration, attitude, and body rates which can be used for guidance and control. Precision Code DGPS/INS positioning accuracy (root-mean-square) was 1.0 m cross-track and 3.0 m vertical. (This AGARDograph was sponsored by the Guidance and Control Panel.)

  13. Evaluation of Mobile Phone Interference With Aircraft GPS Navigation Systems

    NASA Technical Reports Server (NTRS)

    Pace, Scott; Oria, A. J.; Guckian, Paul; Nguyen, Truong X.

    2004-01-01

    This report compiles and analyzes tests that were conducted to measure cell phone spurious emissions in the Global Positioning System (GPS) radio frequency band that could affect the navigation system of an aircraft. The cell phone in question had, as reported to the FAA (Federal Aviation Administration), caused interference to several GPS receivers on-board a small single engine aircraft despite being compliant with data filed at the time with the FCC by the manufacturer. NASA (National Aeronautics and Space Administration) and industry tests show that while there is an emission in the 1575 MHz GPS band due to a specific combination of amplifier output impedance and load impedance that induces instability in the power amplifier, these spurious emissions (i.e., not the intentional transmit signal) are similar to those measured on non-intentionally transmitting devices such as, for example, laptop computers. Additional testing on a wide sample of different commercial cell phones did not result in any emission in the 1575 MHz GPS Band above the noise floor of the measurement receiver.

  14. 77 FR 13350 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-06

    ... complaint filed by Beacon Navigation GmbH of Zug, Switzerland (``Beacon''). 76 FR 72443 (Nov. 23, 2011). The... Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same; Determination... importation of certain automotive GPS navigation systems, components thereof, and products containing the...

  15. DESIGN OF A DOPPLER-AIDED GPS NAVIGATION SYSTEM FOR WEAK SIGNALS CAUSED BY STRONG IONOSPHERIC

    E-print Network

    Stanford University

    SCINTILLATION A DISSERTATION SUBMITTED TO THE DEPARTMENT OF AERONAUTICS AND ASTRONAUTICS AND THE COMMITTEE OF PHILOSOPHY Tsung-Yu Chiou May 2010 #12;Abstract The fundamental tasks of a Global Positioning System (GPS the interference due to ionospheric scintillation on the GPS receiver used in aviation navigation. Using GPS

  16. Autonomous reconfigurable GPS/INS navigation and pointing system for rendezvous and docking

    NASA Technical Reports Server (NTRS)

    Upadhyay, T. N.; Cotterill, S.; Deaton, A. W.

    1992-01-01

    This paper describes the development of an autonomous integrated spacecraft navigation system which provides multiple modes of navigation, including relative and absolute navigation. The system provides attitude information from GPS or INS, or by tightly integrating the two systems. Interferometric GPS techniques are used when multiple antennas and integrated Doppler measurements are available. An important aspect of this research is the autonomously reconfigurable Kalman filter, controlled by an embedded knowledge base, designed to respond to component degradation and changes in mission goals.

  17. The Performance Analysis of a Real-Time Integrated INS/GPS Vehicle Navigation System with Abnormal GPS Measurement Elimination

    PubMed Central

    Chiang, Kai-Wei; Duong, Thanh Trung; Liao, Jhen-Kai

    2013-01-01

    The integration of an Inertial Navigation System (INS) and the Global Positioning System (GPS) is common in mobile mapping and navigation applications to seamlessly determine the position, velocity, and orientation of the mobile platform. In most INS/GPS integrated architectures, the GPS is considered to be an accurate reference with which to correct for the systematic errors of the inertial sensors, which are composed of biases, scale factors and drift. However, the GPS receiver may produce abnormal pseudo-range errors mainly caused by ionospheric delay, tropospheric delay and the multipath effect. These errors degrade the overall position accuracy of an integrated system that uses conventional INS/GPS integration strategies such as loosely coupled (LC) and tightly coupled (TC) schemes. Conventional tightly coupled INS/GPS integration schemes apply the Klobuchar model and the Hopfield model to reduce pseudo-range delays caused by ionospheric delay and tropospheric delay, respectively, but do not address the multipath problem. However, the multipath effect (from reflected GPS signals) affects the position error far more significantly in a consumer-grade GPS receiver than in an expensive, geodetic-grade GPS receiver. To avoid this problem, a new integrated INS/GPS architecture is proposed. The proposed method is described and applied in a real-time integrated system with two integration strategies, namely, loosely coupled and tightly coupled schemes, respectively. To verify the effectiveness of the proposed method, field tests with various scenarios are conducted and the results are compared with a reliable reference system. PMID:23955434

  18. The performance analysis of a real-time integrated INS/GPS vehicle navigation system with abnormal GPS measurement elimination.

    PubMed

    Chiang, Kai-Wei; Duong, Thanh Trung; Liao, Jhen-Kai

    2013-01-01

    The integration of an Inertial Navigation System (INS) and the Global Positioning System (GPS) is common in mobile mapping and navigation applications to seamlessly determine the position, velocity, and orientation of the mobile platform. In most INS/GPS integrated architectures, the GPS is considered to be an accurate reference with which to correct for the systematic errors of the inertial sensors, which are composed of biases, scale factors and drift. However, the GPS receiver may produce abnormal pseudo-range errors mainly caused by ionospheric delay, tropospheric delay and the multipath effect. These errors degrade the overall position accuracy of an integrated system that uses conventional INS/GPS integration strategies such as loosely coupled (LC) and tightly coupled (TC) schemes. Conventional tightly coupled INS/GPS integration schemes apply the Klobuchar model and the Hopfield model to reduce pseudo-range delays caused by ionospheric delay and tropospheric delay, respectively, but do not address the multipath problem. However, the multipath effect (from reflected GPS signals) affects the position error far more significantly in a consumer-grade GPS receiver than in an expensive, geodetic-grade GPS receiver. To avoid this problem, a new integrated INS/GPS architecture is proposed. The proposed method is described and applied in a real-time integrated system with two integration strategies, namely, loosely coupled and tightly coupled schemes, respectively. To verify the effectiveness of the proposed method, field tests with various scenarios are conducted and the results are compared with a reliable reference system. PMID:23955434

  19. Development of a GPS/INS/MAG navigation system and waypoint navigator for a VTOL UAV

    NASA Astrophysics Data System (ADS)

    Meister, Oliver; Mönikes, Ralf; Wendel, Jan; Frietsch, Natalie; Schlaile, Christian; Trommer, Gert F.

    2007-04-01

    Unmanned aerial vehicles (UAV) can be used for versatile surveillance and reconnaissance missions. If a UAV is capable of flying automatically on a predefined path the range of possible applications is widened significantly. This paper addresses the development of the integrated GPS/INS/MAG navigation system and a waypoint navigator for a small vertical take-off and landing (VTOL) unmanned four-rotor helicopter with a take-off weight below 1 kg. The core of the navigation system consists of low cost inertial sensors which are continuously aided with GPS, magnetometer compass, and a barometric height information. Due to the fact, that the yaw angle becomes unobservable during hovering flight, the integration with a magnetic compass is mandatory. This integration must be robust with respect to errors caused by the terrestrial magnetic field deviation and interferences from surrounding electronic devices as well as ferrite metals. The described integration concept with a Kalman filter overcomes the problem that erroneous magnetic measurements yield to an attitude error in the roll and pitch axis. The algorithm provides long-term stable navigation information even during GPS outages which is mandatory for the flight control of the UAV. In the second part of the paper the guidance algorithms are discussed in detail. These algorithms allow the UAV to operate in a semi-autonomous mode position hold as well an complete autonomous waypoint mode. In the position hold mode the helicopter maintains its position regardless of wind disturbances which ease the pilot job during hold-and-stare missions. The autonomous waypoint navigator enable the flight outside the range of vision and beyond the range of the radio link. Flight test results of the implemented modes of operation are shown.

  20. Autonomous reconfigurable GPS/INS navigation and pointing system for rendezvous and docking

    NASA Technical Reports Server (NTRS)

    Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. Wayne

    1991-01-01

    This paper describes the results of an integrated navigation and pointing system software development effort sponsored by the NASA MSFC through a SBIR Phase 2 Program. The integrated Global Positioning System (GPS)/Inertial Navigation System (INS) implements an autonomous navigation filter that is reconfigurable in real-time to accommodate mission contingencies. An onboard expert system monitors the spacecraft status and reconfigures the navigation filter accordingly, to optimize the system performance. The navigation filter is a multi-mode Kalman filter to estimate the spacecraft position, velocity, and attitude. Three different GPS-based attitude determination techniques, namely, velocity vector matching, attitude vector matching, and interferometric processing, are implemented to encompass different mission contingencies. The integrated GPS/INS navigation filter will use any of these techniques depending on the mission phase and the state of the sensors. The first technique, velocity vector matching, uses the GPS velocity measurement to estimate the INS velocity errors and exploits the correlation between INS velocity and attitude errors to estimate the attitude. The second technique, attitude vector matching, uses INS gyro measurements and GPS carrier phase (integrated Doppler) measurements during a spacecraft rotation maneuver to determine the attitude. Both of these techniques require only one GPS antenna onboard to determine the spacecraft attitude. The third technique, interferometric processing, requires use of multiple GPS antennae. In order to determine 3-axis body attitude, three GPS antennae (2 no-coplanor baselines) are required.

  1. Modular Software for Spacecraft Navigation Using the Global Positioning System (GPS)

    NASA Technical Reports Server (NTRS)

    Truong, S. H.; Hartman, K. R.; Weidow, D. A.; Berry, D. L.; Oza, D. H.; Long, A. C.; Joyce, E.; Steger, W. L.

    1996-01-01

    The Goddard Space Flight Center Flight Dynamics and Mission Operations Divisions have jointly investigated the feasibility of engineering modular Global Positioning SYSTEM (GPS) navigation software to support both real time flight and ground postprocessing configurations. The goals of this effort are to define standard GPS data interfaces and to engineer standard, reusable navigation software components that can be used to build a broad range of GPS navigation support applications. The paper discusses the GPS modular software (GMOD) system and operations concepts, major requirements, candidate software architecture, feasibility assessment and recommended software interface standards. In additon, ongoing efforts to broaden the scope of the initial study and to develop modular software to support autonomous navigation using GPS are addressed,

  2. Integrated GPS/INS navigation system design for autonomous spacecraft rendezvous

    NASA Astrophysics Data System (ADS)

    Gaylor, David Edward

    2003-10-01

    The goal of the NASA Space Launch Initiative (SLI) program is to advance the technologies for the next generation reusable launch vehicle (RLV). The SLI program has identified automated rendezvous and docking as an area requiring further research and development. Currently, the Space Shuttle uses a partially manual system for rendezvous, but a fully automated system could be safer and more reliable. Previous studies have shown that it is feasible to use the Global Positioning System (GPS) for spacecraft navigation during rendezvous with the International Space Station (ISS). However, these studies have not accounted for the effects of GPS signal blockage and multipath in the vicinity of the ISS, which make a GPS-only navigation system less accurate and reliable. One possible solution is to combine GPS with an inertial navigation system (INS). The integration of GPS and INS can be achieved using a Kalman filter. GPS/INS systems have been used in aircraft for many years and have also been used in launch vehicles. However, the performance of GPS/INS systems in orbit and during spacecraft rendezvous has not been characterized. The primary objective of this research is to evaluate the ability of an integrated GPS/INS to provide accurate navigation solutions during a rendezvous scenario where the effects of ISS signal blockage, multipath and delta-v maneuvers degrade GPS-only navigation. In order to accomplish this, GPS-only and GPS/INS Kalman filters have been developed for both absolute and relative navigation, as well as a new statistical multipath model for spacecraft operating near the ISS. Several factors that affect relative navigation performance were studied, including: filter tuning, GPS constellation geometry, rendezvous approach direction, and inertial sensor performance. The results showed that each of these factors has a large impact on relative navigation performance. Finally, it has been demonstrated that a GPS/INS system based on medium accuracy aircraft avionics-grade inertial sensors does not provide adequate relative navigation performance for rendezvous with the ISS unless accelerometer thresholding is used. However, the use of state-of-the-art inertial navigation sensors provides relative position accuracy which is adequate for rendezvous with ISS if an additional rendezvous sensor is included.

  3. FPGA-Based Real-Time Embedded System for RISS/GPS Integrated Navigation

    PubMed Central

    Abdelfatah, Walid Farid; Georgy, Jacques; Iqbal, Umar; Noureldin, Aboelmagd

    2012-01-01

    Navigation algorithms integrating measurements from multi-sensor systems overcome the problems that arise from using GPS navigation systems in standalone mode. Algorithms which integrate the data from 2D low-cost reduced inertial sensor system (RISS), consisting of a gyroscope and an odometer or wheel encoders, along with a GPS receiver via a Kalman filter has proved to be worthy in providing a consistent and more reliable navigation solution compared to standalone GPS receivers. It has been also shown to be beneficial, especially in GPS-denied environments such as urban canyons and tunnels. The main objective of this paper is to narrow the idea-to-implementation gap that follows the algorithm development by realizing a low-cost real-time embedded navigation system capable of computing the data-fused positioning solution. The role of the developed system is to synchronize the measurements from the three sensors, relative to the pulse per second signal generated from the GPS, after which the navigation algorithm is applied to the synchronized measurements to compute the navigation solution in real-time. Employing a customizable soft-core processor on an FPGA in the kernel of the navigation system, provided the flexibility for communicating with the various sensors and the computation capability required by the Kalman filter integration algorithm. PMID:22368460

  4. Error Analysis System for Spacecraft Navigation Using the Global Positioning System (GPS)

    NASA Technical Reports Server (NTRS)

    Truong, S. H.; Hart, R. C.; Hartman, K. R.; Tomcsik, T. L.; Searl, J. E.; Bernstein, A.

    1997-01-01

    The Flight Dynamics Division (FDD) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) is currently developing improved space-navigation filtering algorithms to use the Global Positioning System (GPS) for autonomous real-time onboard orbit determination. In connection with a GPS technology demonstration on the Small Satellite Technology Initiative (SSTI)/Lewis spacecraft, FDD analysts and programmers have teamed with the GSFC Guidance, Navigation, and Control Branch to develop the GPS Enhanced Orbit Determination Experiment (GEODE) system. The GEODE system consists of a Kalman filter operating as a navigation tool for estimating the position, velocity, and additional states required to accurately navigate the orbiting Lewis spacecraft by using astrodynamic modeling and GPS measurements from the receiver. A parallel effort at the FDD is the development of a GPS Error Analysis System (GEAS) that will be used to analyze and improve navigation filtering algorithms during development phases and during in-flight calibration. For GEAS, the Kalman filter theory is extended to estimate the errors in position, velocity, and other error states of interest. The estimation of errors in physical variables at regular intervals will allow the time, cause, and effect of navigation system weaknesses to be identified. In addition, by modeling a sufficient set of navigation system errors, a system failure that causes an observed error anomaly can be traced and accounted for. The GEAS software is formulated using Object Oriented Design (OOD) techniques implemented in the C++ programming language on a Sun SPARC workstation. The Phase 1 of this effort is the development of a basic system to be used to evaluate navigation algorithms implemented in the GEODE system. This paper presents the GEAS mathematical methodology, systems and operations concepts, and software design and implementation. Results from the use of the basic system to evaluate navigation algorithms implemented on GEODE are also discussed. In addition, recommendations for generalization of GEAS functions and for new techniques to optimize the accuracy and control of the GPS autonomous onboard navigation are presented.

  5. 76 FR 50808 - Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ...intent to cancel Technical Standard Order (TSO)- C129a, Airborne Supplemental Navigation...notice announces the FAA's intent to cancel TSO-C129a, Airborne Supplemental Navigation...System (GPS). The effect of the cancelled TSO will result in no new TSO-C129a...

  6. A Self-Tuning Kalman Filter for Autonomous Navigation Using the Global Positioning System (GPS)

    NASA Technical Reports Server (NTRS)

    Truong, Son H.

    1999-01-01

    Most navigation systems currently operated by NASA are ground-based, and require extensive support to produce accurate results. Recently developed systems that use Kalman filter and GPS (Global Positioning Systems) data for orbit determination greatly reduce dependency on ground support, and have potential to provide significant economies for NASA spacecraft navigation. These systems, however, still rely on manual tuning from analysts. A sophisticated neuro-fuzzy component fully integrated with the flight navigation system can perform the self-tuning capability for the Kalman filter and help the navigation system recover from estimation errors in real time.

  7. A Self-Tuning Kalman Filter for Autonomous Navigation using the Global Positioning System (GPS)

    NASA Technical Reports Server (NTRS)

    Truong, S. H.

    1999-01-01

    Most navigation systems currently operated by NASA are ground-based, and require extensive support to produce accurate results. Recently developed systems that use Kalman filter and GPS data for orbit determination greatly reduce dependency on ground support, and have potential to provide significant economies for NASA spacecraft navigation. These systems, however, still rely on manual tuning from analysts. A sophisticated neuro-fuzzy component fully integrated with the flight navigation system can perform the self-tuning capability for the Kalman filter and help the navigation system recover from estimation errors in real time.

  8. Autonomous reconfigurable GPS/INS navigation and pointing system for rendezvous and docking

    NASA Technical Reports Server (NTRS)

    Upadhyay, Triveni M.

    1991-01-01

    The briefing describes work using the Global Positioning System to determine position of spacecraft and the development of computer tools to utilize these position determinations to enable autonomous rendezvous. Using GPS data in conjunction with Inertial Navigation Systems (INS) provides the capability for absolute spacecraft navigation, navigation of one spacecraft relative to another, and attitude determination. Some results presented are based on limited observations, though simulation results are documented. A GPS/INS navigation flight experiment could provide a platform for evaluating approaches for autonomous operation and reconfigurability of the navigation and attitude determination subsystem for future space vehicles. Current emphasis is on the development and demonstration of an Onboard Mission Manager (OMM) and a Multi-Mode Navigation Kalman filter. Sensor data will be handed over to the OMM, which will determine the appropriate response and generate commands for the Kalman filter to use to reconfigure itself. Global Positioning System measurements and INS data will be processed in the integrated navigation filter and used to compute errors in position, velocity, and attitude. Inertial Navigation Systems instrument errors (biases, scale factors, etc.) also can be estimated. The OMM then will use a knowledge base to determine appropriate system response. The GPS is good for missions that have attitude pointing accuracy requirements within the 100 to 200 arcsecond range.

  9. GPS Navigation for Outdoor and Indoor Environments

    E-print Network

    Abidi, Mongi A.

    GPS Navigation for Outdoor and Indoor Environments Project in Lieu of Thesis presented of this would matter. #12;i ABSTRACT The Global Positioning System (GPS) is an accurate positioning system. The GPS has an accuracy that varies from 4mm up to 11m. This project in lieu of thesis investigates

  10. Map Matching and Heuristic Elimination of Gyro Drift for Personal Navigation Systems in GPS-denied Conditions

    E-print Network

    Borenstein, Johann

    of determining and maintaining positional information for a person traveling on foot. Pedestrian Tracking SystemsMap Matching and Heuristic Elimination of Gyro Drift for Personal Navigation Systems in GPS reduction of heading errors in inertial navigation systems used under GPS-denied conditions. Presumably

  11. A DME Based Area Navigation Systems for GPS/WAAS Interference Mitigation In General Aviation Applications

    E-print Network

    Stanford University

    A DME Based Area Navigation Systems for GPS/WAAS Interference Mitigation In General Aviation, Stanford University Abstract The Federal Aviation Administration is leading the National Airspace System aviation aircraft to the complex commercial jet-liners. This trans- formation of the National Airspace

  12. Space shuttle navigation analysis. Volume 1: GPS aided navigation

    NASA Technical Reports Server (NTRS)

    Matchett, G. A.; Vogel, M. A.; Macdonald, T. J.

    1980-01-01

    Analytical studies related to space shuttle navigation are presented. Studies related to the addition of NAVSTAR Global Positioning System user equipment to the shuttle avionics suite are presented. The GPS studies center about navigation accuracy covariance analyses for both developmental and operational phases of GPS, as well as for various orbiter mission phases.

  13. Adaptive Resampling Particle Filters for GPS Carrier-Phase Navigation and Collision Avoidance System

    NASA Astrophysics Data System (ADS)

    Hwang, Soon Sik

    This dissertation addresses three problems: 1) adaptive resampling technique (ART) for Particle Filters, 2) precise relative positioning using Global Positioning System (GPS) Carrier-Phase (CP) measurements applied to nonlinear integer resolution problem for GPS CP navigation using Particle Filters, and 3) collision detection system based on GPS CP broadcasts. First, Monte Carlo filters, called Particle Filters (PF), are widely used where the system is non-linear and non-Gaussian. In real-time applications, their estimation accuracies and efficiencies are significantly affected by the number of particles and the scheduling of relocating weights and samples, the so-called resampling step. In this dissertation, the appropriate number of particles is estimated adaptively such that the error of the sample mean and variance stay in bounds. These bounds are given by the confidence interval of a normal probability distribution for a multi-variate state. Two required number of samples maintaining the mean and variance error within the bounds are derived. The time of resampling is determined when the required sample number for the variance error crosses the required sample number for the mean error. Second, the PF using GPS CP measurements with adaptive resampling is applied to precise relative navigation between two GPS antennas. In order to make use of CP measurements for navigation, the unknown number of cycles between GPS antennas, the so called integer ambiguity, should be resolved. The PF is applied to this integer ambiguity resolution problem where the relative navigation states estimation involves nonlinear observations and nonlinear dynamics equation. Using the PF, the probability density function of the states is estimated by sampling from the position and velocity space and the integer ambiguities are resolved without using the usual hypothesis tests to search for the integer ambiguity. The ART manages the number of position samples and the frequency of the resampling step for real-time kinematics GPS navigation. The experimental results demonstrate the performance of the ART and the insensitivity of the proposed approach to GPS CP cycle-slips. Third, the GPS has great potential for the development of new collision avoidance systems and is being considered for the next generation Traffic alert and Collision Avoidance System (TCAS). The current TCAS equipment, is capable of broadcasting GPS code information to nearby airplanes, and also, the collision avoidance system using the navigation information based on GPS code has been studied by researchers. In this dissertation, the aircraft collision detection system using GPS CP information is addressed. The PF with position samples is employed for the CP based relative position estimation problem and the same algorithm can be used to determine the vehicle attitude if multiple GPS antennas are used. For a reliable and enhanced collision avoidance system, three dimensional trajectories are projected using the estimates of the relative position, velocity, and the attitude. It is shown that the performance of GPS CP based collision detecting algorithm meets the accuracy requirements for a precise approach of flight for auto landing with significantly less unnecessary collision false alarms and no miss alarms.

  14. Autonomous Navigation of the SSTI/Lewis Spacecraft Using the Global Positioning System (GPS)

    NASA Technical Reports Server (NTRS)

    Hart, R. C.; Long, A. C.; Lee, T.

    1997-01-01

    The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) is pursuing the application of Global Positioning System (GPS) technology to improve the accuracy and economy of spacecraft navigation. High-accuracy autonomous navigation algorithms are being flight qualified in conjunction with GSFC's GPS Attitude Determination Flyer (GADFLY) experiment on the Small Satellite Technology Initiative (SSTI) Lewis spacecraft, which is scheduled for launch in 1997. Preflight performance assessments indicate that these algorithms can provide a real-time total position accuracy of better than 10 meters (1 sigma) and velocity accuracy of better than 0.01 meter per second (1 sigma), with selective availability at typical levels. This accuracy is projected to improve to the 2-meter level if corrections to be provided by the GPS Wide Area Augmentation System (WAAS) are included.

  15. Space Shuttle Navigation in the GPS Era

    NASA Technical Reports Server (NTRS)

    Goodman, John L.

    2001-01-01

    The Space Shuttle navigation architecture was originally designed in the 1970s. A variety of on-board and ground based navigation sensors and computers are used during the ascent, orbit coast, rendezvous, (including proximity operations and docking) and entry flight phases. With the advent of GPS navigation and tightly coupled GPS/INS Units employing strapdown sensors, opportunities to improve and streamline the Shuttle navigation process are being pursued. These improvements can potentially result in increased safety, reliability, and cost savings in maintenance through the replacement of older technologies and elimination of ground support systems (such as Tactical Air Control and Navigation (TACAN), Microwave Landing System (MLS) and ground radar). Selection and missionization of "off the shelf" GPS and GPS/INS units pose a unique challenge since the units in question were not originally designed for the Space Shuttle application. Various options for integrating GPS and GPS/INS units with the existing orbiter avionics system were considered in light of budget constraints, software quality concerns, and schedule limitations. An overview of Shuttle navigation methodology from 1981 to the present is given, along with how GPS and GPS/INS technology will change, or not change, the way Space Shuttle navigation is performed in the 21 5 century.

  16. GPS navigation experiment using high precision GPS timing receivers

    NASA Technical Reports Server (NTRS)

    Buisson, J. A.; Oaks, O. J.; Lister, M. J.; Wardrip, S. C.; Leschiutta, S.; Galliano, P. G.; Cordara, D.; Pettiti, V.; Detoma, E.; Dachel, P.

    1985-01-01

    Global Positioning System (GPS) Time Transfer receivers were developed by the Naval Research Laboratory (NRL) to provide synchronization for the NASA Global Laser Tracking Network (GLTN). The capabilities of the receiver are being expanded mainly through software modification to: Demonstrate the position location capabilities of a single channel receiver unsign the GPS C/A code; and Demonstrate the time/navigation capability of the receiver onboard a moving platform, by sequential tracking of GPS satellites.

  17. The impact of sub-auroral polarization streams on GPS-based navigation systems

    NASA Astrophysics Data System (ADS)

    Basu, Su.; Basu, S.; Makela, J.; Doherty, P.; Wright, J.; Rich, F.

    Analysis of GPS phase fluctuations in conjunction with regional total electron content TEC maps in-situ measurements of sub-auroral polarization streams SAPS from several DMSP spacecraft supported by ionosonde measurements and TIMED GUVI images obtained during the intense magnetic storm of November 8 2004 have indicated the tremendous impact of large ionospheric velocities on GPS-based navigation systems within the mid-latitude region in the North American sector The major difference between this superstorm and the others observed during the October-November 2003 events is the absence of appreciable storm-enhanced density gradients with the mid-latitude region being entirely engulfed by either the auroral oval or the ionospheric trough within which the SAPS were confined during the local dusk to nighttime hours This shows that it is possible to disable GPS-based navigation systems for more than ten hours even in the absence of appreciable TEC gradients provided an intense flow channel is present in the ionosphere during nighttime hours

  18. Integrating GPS, GYRO, vehicle speed sensor, and digital map to provide accurate and real-time position in an intelligent navigation system

    NASA Astrophysics Data System (ADS)

    Li, Qingquan; Fang, Zhixiang; Li, Hanwu; Xiao, Hui

    2005-10-01

    The global positioning system (GPS) has become the most extensively used positioning and navigation tool in the world. Applications of GPS abound in surveying, mapping, transportation, agriculture, military planning, GIS, and the geosciences. However, the positional and elevation accuracy of any given GPS location is prone to error, due to a number of factors. The applications of Global Positioning System (GPS) positioning is more and more popular, especially the intelligent navigation system which relies on GPS and Dead Reckoning technology is developing quickly for future huge market in China. In this paper a practical combined positioning model of GPS/DR/MM is put forward, which integrates GPS, Gyro, Vehicle Speed Sensor (VSS) and digital navigation maps to provide accurate and real-time position for intelligent navigation system. This model is designed for automotive navigation system making use of Kalman filter to improve position and map matching veracity by means of filtering raw GPS and DR signals, and then map-matching technology is used to provide map coordinates for map displaying. In practical examples, for illustrating the validity of the model, several experiments and their results of integrated GPS/DR positioning in intelligent navigation system will be shown for the conclusion that Kalman Filter based GPS/DR integrating position approach is necessary, feasible and efficient for intelligent navigation application. Certainly, this combined positioning model, similar to other model, can not resolve all situation issues. Finally, some suggestions are given for further improving integrated GPS/DR/MM application.

  19. a New Survey on Self-Tuning Integrated Low-Cost Gps/ins Vehicle Navigation System in Harsh Environment

    NASA Astrophysics Data System (ADS)

    Navidi, N.; Landry, R., Jr.

    2015-08-01

    Nowadays, Global Positioning System (GPS) receivers are aided by some complementary radio navigation systems and Inertial Navigation Systems (INS) to obtain more accuracy and robustness in land vehicular navigation. Extended Kalman Filter (EKF) is an acceptable conventional method to estimate the position, the velocity, and the attitude of the navigation system when INS measurements are fused with GPS data. However, the usage of the low-cost Inertial Measurement Units (IMUs) based on the Micro-Electro-Mechanical Systems (MEMS), for the land navigation systems, reduces the precision and stability of the navigation system due to their inherent errors. The main goal of this paper is to provide a new model for fusing low-cost IMU and GPS measurements. The proposed model is based on EKF aided by Fuzzy Inference Systems (FIS) as a promising method to solve the mentioned problems. This model considers the parameters of the measurement noise to adjust the measurement and noise process covariance. The simulation results show the efficiency of the proposed method to reduce the navigation system errors compared with EKF.

  20. 76 FR 50808 - Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... Federal Aviation Administration Airborne Supplemental Navigation Equipment Using the Global Positioning... Technical Standard Order (TSO)- C129a, Airborne Supplemental Navigation Equipment Using the Global... cancel TSO-C129a, Airborne Supplemental Navigation Equipment Using the Global Positioning System...

  1. Definition study of land/sea civil user navigational location monitoring systems for NAVSTAR GPS: User requirements and systems concepts

    NASA Technical Reports Server (NTRS)

    Devito, D. M.

    1981-01-01

    A low-cost GPS civil-user mobile terminal whose purchase cost is substantially an order of magnitude less than estimates for the military counterpart is considered with focus on ground station requirements for position monitoring of civil users requiring this capability and the civil user navigation and location-monitoring requirements. Existing survey literature was examined to ascertain the potential users of a low-cost NAVSTAR receiver and to estimate their number, function, and accuracy requirements. System concepts are defined for low cost user equipments for in-situ navigation and the retransmission of low data rate positioning data via a geostationary satellite to a central computing facility.

  2. A Substitute Vision System for Providing 3D Perception and GPS Navigation via Electro-Tactile Stimulation

    E-print Network

    Ward, Koren

    A Substitute Vision System for Providing 3D Perception and GPS Navigation via Electro by extracting a depth map from stereo cameras by measuring the disparity between the stereo images. This range the potential that this form of 3D environment perception has at enabling the user to achieve localisation

  3. ION GNSS 2006, Fort Worth TX, 26-29 September 2006 1/14 Integrated GPS/INS System for Pedestrian Navigation in a

    E-print Network

    Calgary, University of

    Navigation in a Signal Degraded Environment S. Godha, G. Lachapelle, and M. E. Cannon Positioning Location and Navigation Group (PLAN) Department of Geomatics Engineering, Schulich School of Engineering University research is focused on integrated IMU/GPS navigation systems for pedestrian and vehicular navigation. Dr

  4. INS/GPS/LiDAR Integrated Navigation System for Urban and Indoor Environments Using Hybrid Scan Matching Algorithm

    PubMed Central

    Gao, Yanbin; Liu, Shifei; Atia, Mohamed M.; Noureldin, Aboelmagd

    2015-01-01

    This paper takes advantage of the complementary characteristics of Global Positioning System (GPS) and Light Detection and Ranging (LiDAR) to provide periodic corrections to Inertial Navigation System (INS) alternatively in different environmental conditions. In open sky, where GPS signals are available and LiDAR measurements are sparse, GPS is integrated with INS. Meanwhile, in confined outdoor environments and indoors, where GPS is unreliable or unavailable and LiDAR measurements are rich, LiDAR replaces GPS to integrate with INS. This paper also proposes an innovative hybrid scan matching algorithm that combines the feature-based scan matching method and Iterative Closest Point (ICP) based scan matching method. The algorithm can work and transit between two modes depending on the number of matched line features over two scans, thus achieving efficiency and robustness concurrently. Two integration schemes of INS and LiDAR with hybrid scan matching algorithm are implemented and compared. Real experiments are performed on an Unmanned Ground Vehicle (UGV) for both outdoor and indoor environments. Experimental results show that the multi-sensor integrated system can remain sub-meter navigation accuracy during the whole trajectory. PMID:26389906

  5. INS/GPS/LiDAR Integrated Navigation System for Urban and Indoor Environments Using Hybrid Scan Matching Algorithm.

    PubMed

    Gao, Yanbin; Liu, Shifei; Atia, Mohamed M; Noureldin, Aboelmagd

    2015-01-01

    This paper takes advantage of the complementary characteristics of Global Positioning System (GPS) and Light Detection and Ranging (LiDAR) to provide periodic corrections to Inertial Navigation System (INS) alternatively in different environmental conditions. In open sky, where GPS signals are available and LiDAR measurements are sparse, GPS is integrated with INS. Meanwhile, in confined outdoor environments and indoors, where GPS is unreliable or unavailable and LiDAR measurements are rich, LiDAR replaces GPS to integrate with INS. This paper also proposes an innovative hybrid scan matching algorithm that combines the feature-based scan matching method and Iterative Closest Point (ICP) based scan matching method. The algorithm can work and transit between two modes depending on the number of matched line features over two scans, thus achieving efficiency and robustness concurrently. Two integration schemes of INS and LiDAR with hybrid scan matching algorithm are implemented and compared. Real experiments are performed on an Unmanned Ground Vehicle (UGV) for both outdoor and indoor environments. Experimental results show that the multi-sensor integrated system can remain sub-meter navigation accuracy during the whole trajectory. PMID:26389906

  6. Dual RF Astrodynamic GPS Orbital Navigator Satellite

    NASA Technical Reports Server (NTRS)

    Kanipe, David B.; Provence, Robert Steve; Straube, Timothy M.; Reed, Helen; Bishop, Robert; Lightsey, Glenn

    2009-01-01

    Dual RF Astrodynamic GPS Orbital Navigator Satellite (DRAGONSat) will demonstrate autonomous rendezvous and docking (ARD) in low Earth orbit (LEO) and gather flight data with a global positioning system (GPS) receiver strictly designed for space applications. ARD is the capability of two independent spacecraft to rendezvous in orbit and dock without crew intervention. DRAGONSat consists of two picosatellites (one built by the University of Texas and one built by Texas A and M University) and the Space Shuttle Payload Launcher (SSPL); this project will ultimately demonstrate ARD in LEO.

  7. Autonomous Relative Navigation for Formation-Flying Satellites Using GPS

    NASA Technical Reports Server (NTRS)

    Gramling, Cheryl; Carpenter, J. Russell; Long, Anne; Kelbel, David; Lee, Taesul

    2000-01-01

    The Goddard Space Flight Center is currently developing advanced spacecraft systems to provide autonomous navigation and control of formation flyers. This paper discusses autonomous relative navigation performance for a formation of four eccentric, medium-altitude Earth-orbiting satellites using Global Positioning System (GPS) Standard Positioning Service (SPS) and "GPS-like " intersatellite measurements. The performance of several candidate relative navigation approaches is evaluated. These analyses indicate that an autonomous relative navigation position accuracy of 1meter root-mean-square can be achieved by differencing high-accuracy filtered solutions if only measurements from common GPS space vehicles are used in the independently estimated solutions.

  8. Autonomous Navigation Improvements for High-Earth Orbiters Using GPS

    NASA Technical Reports Server (NTRS)

    Long, Anne; Kelbel, David; Lee, Taesul; Garrison, James; Carpenter, J. Russell; Bauer, F. (Technical Monitor)

    2000-01-01

    The Goddard Space Flight Center is currently developing autonomous navigation systems for satellites in high-Earth orbits where acquisition of the GPS signals is severely limited This paper discusses autonomous navigation improvements for high-Earth orbiters and assesses projected navigation performance for these satellites using Global Positioning System (GPS) Standard Positioning Service (SPS) measurements. Navigation performance is evaluated as a function of signal acquisition threshold, measurement errors, and dynamic modeling errors using realistic GPS signal strength and user antenna models. These analyses indicate that an autonomous navigation position accuracy of better than 30 meters root-mean-square (RMS) can be achieved for high-Earth orbiting satellites using a GPS receiver with a very stable oscillator. This accuracy improves to better than 15 meters RMS if the GPS receiver's signal acquisition threshold can be reduced by 5 dB-Hertz to track weaker signals.

  9. Position, Navigation, and Timing: GPS Scientific Applications

    NASA Technical Reports Server (NTRS)

    Neilan, Ruth E.

    2008-01-01

    This slide presentation reviews the development and deployment of the Global Positioning System (GPS). This presentation also includes measuring space and time, GPS as a tool for science, development of high precision JPL GPS receivers, and technology and applications developments.

  10. DARPA looks beyond GPS for positioning, navigating, and timing

    SciTech Connect

    Kramer, David

    2014-10-01

    Cold-atom interferometry, microelectromechanical systems, signals of opportunity, and atomic clocks are some of the technologies the defense agency is pursuing to provide precise navigation when GPS is unavailable.

  11. Large magnetic storm-induced nighttime ionospheric flows at midlatitudes and their impacts on GPS-based navigation systems

    NASA Astrophysics Data System (ADS)

    Basu, Su.; Basu, S.; Makela, J. J.; MacKenzie, E.; Doherty, P.; Wright, J. W.; Rich, F.; Keskinen, M. J.; Sheehan, R. E.; Coster, A. J.

    2008-03-01

    Analysis of GPS phase fluctuations in conjunction with regional total electron content (TEC) maps, in situ measurements of subauroral polarization streams (SAPS) and auroral convection from several Defense Meteorological Satellite Program spacecraft, and dynasonde measurements at the Bear Lake Observatory obtained during the intense magnetic storm of 7-8 November 2004 have indicated the serious impact of large ionospheric velocities on GPS-based navigation systems within the midlatitude region in the North American sector. The major difference between this superstorm and the others observed during the earlier October-November 2003 events is the absence of appreciable storm-enhanced density gradients, with the midlatitude region being enveloped by either the auroral oval or the ionospheric trough within which the SAPS were confined during the local dusk to nighttime hours. This shows that it is possible to disable GPS-based navigation systems for many hours even in the absence of appreciable TEC gradients, provided an intense flow channel is present in the ionosphere during nighttime hours. The competing effects of irregularity amplitude ?N/N, the background F region density, and the magnitude of SAPS or auroral convection are discussed in establishing the extent of the region of impact on such systems.

  12. Design and implementation of embedded GPS navigation software

    NASA Astrophysics Data System (ADS)

    Zeng, Zhe; Li, Zhong-Hua; Zhu, Cai-Lian

    2004-06-01

    A navigation software, which provides positioning and navigation service based on GPS technique, is introduced. This software is designed and realized under the environment of the embedded operating system WindowsCE and can be widely applied to the systems such as ITS (intelligent transportation systems) and LBS (location based services).

  13. NAVIGATION PERFORMANCE IN HIGH EARTH ORBITS USING NAVIGATOR GPS RECEIVER

    NASA Technical Reports Server (NTRS)

    Bamford, William; Naasz, Bo; Moreau, Michael C.

    2006-01-01

    NASA GSFC has developed a GPS receiver that can acquire and track GPS signals with sensitivity significantly lower than conventional GPS receivers. This opens up the possibility of using GPS based navigation for missions in high altitude orbit, such as Geostationary Operational Environmental Satellites (GOES) in a geostationary orbit, and the Magnetospheric MultiScale (MMS) Mission, in highly eccentric orbits extending to 12 Earth radii and higher. Indeed much research has been performed to study the feasibility of using GPS navigation in high Earth orbits and the performance achievable. Recently, GSFC has conducted a series of hardware in-the-loop tests to assess the performance of this new GPS receiver in various high Earth orbits of interest. Tracking GPS signals to down to approximately 22-25 dB-Hz, including signals from the GPS transmitter side-lobes, steady-state navigation performance in a geostationary orbit is on the order of 10 meters. This paper presents the results of these tests, as well as sensitivity analysis to such factors as ionosphere masks, use of GPS side-lobe signals, and GPS receiver sensitivity.

  14. Method and apparatus for relative navigation using reflected GPS signals

    NASA Technical Reports Server (NTRS)

    Cohen, Ian R. (Inventor); Boegner, Jr., Gregory J. (Inventor)

    2010-01-01

    A method and system to passively navigate an orbiting moving body towards an orbiting target using reflected GPS signals. A pair of antennas is employed to receive both direct signals from a plurality of GPS satellites and a second antenna to receive GPS signals reflected off an orbiting target. The direct and reflected signals are processed and compared to determine the relative distance and position of the orbiting moving body relative to the orbiting target.

  15. Autonomous GPS/INS navigation experiment for Space Transfer Vehicle

    NASA Technical Reports Server (NTRS)

    Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. W.

    1993-01-01

    An experiment to validate the concept of developing an autonomous integrated spacecraft navigation system using on board Global Positioning System (GPS) and Inertial Navigation System (INS) measurements is described. The feasibility of integrating GPS measurements with INS measurements to provide a total improvement in spacecraft navigation performance, i.e. improvement in position, velocity and attitude information, was previously demonstrated. An important aspect of this research is the automatic real time reconfiguration capability of the system designed to respond to changes in a spacecraft mission under the control of an expert system.

  16. Next Generation GPS Ground Control Segment (OCX) Navigation Design

    NASA Technical Reports Server (NTRS)

    Bertiger, Willy; Bar-Sever, Yoaz; Harvey, Nate; Miller, Kevin; Romans, Larry; Weiss, Jan; Doyle, Larry; Solorzano, Tara; Petzinger, John; Stell, Al

    2010-01-01

    In February 2010, a Raytheon-led team was selected by The Air Force to develop, implement, and operate the next generation GPS ground control segment (OCX). To meet and exceed the demanding OCX navigation performance requirements, the Raytheon team partnered with ITT (Navigation lead) and JPL to adapt major elements of JPL's navigation technology, proven in the operations of the Global Differential GPS (GDGPS) System. Key design goals for the navigation subsystem include accurate ephemeris and clock accuracy (user range error), ease of model upgrades, and a smooth and safe transition from the legacy system to OCX.We will describe key elements of the innovative architecture of the OCX navigation subsystem,and demonstrate the anticipated performance of the system through high fidelity simulations withactual GPS measurements.

  17. Precise positioning with current multi-constellation Global Navigation Satellite Systems: GPS, GLONASS, Galileo and BeiDou

    PubMed Central

    Li, Xingxing; Zhang, Xiaohong; Ren, Xiaodong; Fritsche, Mathias; Wickert, Jens; Schuh, Harald

    2015-01-01

    The world of satellite navigation is undergoing dramatic changes with the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs). At the moment more than 70 satellites are already in view, and about 120 satellites will be available once all four systems (BeiDou + Galileo + GLONASS + GPS) are fully deployed in the next few years. This will bring great opportunities and challenges for both scientific and engineering applications. In this paper we develop a four-system positioning model to make full use of all available observations from different GNSSs. The significant improvement of satellite visibility, spatial geometry, dilution of precision, convergence, accuracy, continuity and reliability that a combining utilization of multi-GNSS brings to precise positioning are carefully analyzed and evaluated, especially in constrained environments. PMID:25659949

  18. Precise positioning with current multi-constellation Global Navigation Satellite Systems: GPS, GLONASS, Galileo and BeiDou.

    PubMed

    Li, Xingxing; Zhang, Xiaohong; Ren, Xiaodong; Fritsche, Mathias; Wickert, Jens; Schuh, Harald

    2015-01-01

    The world of satellite navigation is undergoing dramatic changes with the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs). At the moment more than 70 satellites are already in view, and about 120 satellites will be available once all four systems (BeiDou + Galileo + GLONASS + GPS) are fully deployed in the next few years. This will bring great opportunities and challenges for both scientific and engineering applications. In this paper we develop a four-system positioning model to make full use of all available observations from different GNSSs. The significant improvement of satellite visibility, spatial geometry, dilution of precision, convergence, accuracy, continuity and reliability that a combining utilization of multi-GNSS brings to precise positioning are carefully analyzed and evaluated, especially in constrained environments. PMID:25659949

  19. An Integrated Navigation System using GPS Carrier Phase for Real-Time Airborne Synthetic Aperture Radar (SAR)

    SciTech Connect

    Fellerhoff, J. Rick; Kim, Theodore J.; Kohler, Stewart M.

    1999-06-24

    A Synthetic Aperture Radar (SAR) requires accu- rate measurement of the motion of the imaging plat- form to produce well-focused images with minimal absolute position error. The motion measurement (MoMeas) system consists of a inertial measurement unit (IMU) and a P-code GPS receiver that outputs corrected ephemeris, L1 & L2 pseudoranges, and L1 & L2 carrier phase measurements. The unknown initial carrier phase biases to the GPS satellites are modeled as states in an extended Kalman filter and the resulting integrated navigation solution has po- sition errors that change slowly with time. Position error drifts less than 1- cm/sec have been measured from the SAR imagery for various length apertures.

  20. Operational Use of GPS Navigation for Space Shuttle Entry

    NASA Technical Reports Server (NTRS)

    Goodman, John L.; Propst, Carolyn A.

    2008-01-01

    The STS-118 flight of the Space Shuttle Endeavour was the first shuttle mission flown with three Global Positioning System (GPS) receivers in place of the three legacy Tactical Air Navigation (TACAN) units. This marked the conclusion of a 15 year effort involving procurement, missionization, integration, and flight testing of a GPS receiver and a parallel effort to formulate and implement shuttle computer software changes to support GPS. The use of GPS data from a single receiver in parallel with TACAN during entry was successfully demonstrated by the orbiters Discovery and Atlantis during four shuttle missions in 2006 and 2007. This provided the confidence needed before flying the first all GPS, no TACAN flight with Endeavour. A significant number of lessons were learned concerning the integration of a software intensive navigation unit into a legacy avionics system. These lessons have been taken into consideration during vehicle design by other flight programs, including the vehicle that will replace the Space Shuttle, Orion.

  1. Integrated INS/GPS Navigation from a Popular Perspective

    NASA Technical Reports Server (NTRS)

    Omerbashich, Mensur

    2002-01-01

    Inertial navigation, blended with other navigation aids, Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relatively new concepts based upon using Differential GPS (DGPS) blended with Inertial (and visual) Navigation Sensors (INS) offer the possibility of low cost, autonomous aircraft landing. The FAA has decided to implement the system in a sophisticated form as a new standard navigation tool during this decade. There have been a number of new inertial sensor concepts in the recent past that emphasize increased accuracy of INS/GPS versus INS and reliability of navigation, as well as lower size and weight, and higher power, fault tolerance, and long life. The principles of GPS are not discussed; rather the attention is directed towards general concepts and comparative advantages. A short introduction to the problems faced in kinematics is presented. The intention is to relate the basic principles of kinematics to probably the most used navigation method in the future-INS/GPS. An example of the airborne INS is presented, with emphasis on how it works. The discussion of the error types and sources in navigation, and of the role of filters in optimal estimation of the errors then follows. The main question this paper is trying to answer is 'What are the benefits of the integration of INS and GPS and how is this, navigation concept of the future achieved in reality?' The main goal is to communicate the idea about what stands behind a modern navigation method.

  2. Navstar Global Positioning System /GPS/

    NASA Astrophysics Data System (ADS)

    Reynolds, J. W.

    The space-based navigation and time-transfer Navstar Global Positioning System (GPS) provides full time and precise global navigation support for civil and military systems. Prototype equipment tests have shown the GPS to be capable of navigation accuracies an order of magnitude greater than those of existing navigation systems, and bombing accuracies five times better than the best bombing system extant. Attentionis given to the GPS development status and to U.S. Air Force, Navy and Army in-orbit testing and evaluation objectives. When the full 18-satellite GPS constellation is operational, by the end of 1988, 30,000 users will be equipped with receivers, and aircraft, ships, land vehicles and foot soldiers will be able to use the system in order to maximize the coordination of forces. Because the system is passive at the level of the receiver, there will be no danger of betraying one's own positions.

  3. Airborne gravimetry, altimetry, and GPS navigation errors

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L.

    1992-01-01

    Proper interpretation of airborne gravimetry and altimetry requires good knowledge of aircraft trajectory. Recent advances in precise navigation with differential GPS have made it possible to measure gravity from the air with accuracies of a few milligals, and to obtain altimeter profiles of terrain or sea surface correct to one decimeter. These developments are opening otherwise inaccessible regions to detailed geophysical mapping. Navigation with GPS presents some problems that grow worse with increasing distance from a fixed receiver: the effect of errors in tropospheric refraction correction, GPS ephemerides, and the coordinates of the fixed receivers. Ionospheric refraction and orbit error complicate ambiguity resolution. Optimal navigation should treat all error sources as unknowns, together with the instantaneous vehicle position. To do so, fast and reliable numerical techniques are needed: efficient and stable Kalman filter-smoother algorithms, together with data compression and, sometimes, the use of simplified dynamics.

  4. Loosely Coupled GPS-Aided Inertial Navigation System for Range Safety

    NASA Technical Reports Server (NTRS)

    Heatwole, Scott; Lanzi, Raymond J.

    2010-01-01

    The Autonomous Flight Safety System (AFSS) aims to replace the human element of range safety operations, as well as reduce reliance on expensive, downrange assets for launches of expendable launch vehicles (ELVs). The system consists of multiple navigation sensors and flight computers that provide a highly reliable platform. It is designed to ensure that single-event failures in a flight computer or sensor will not bring down the whole system. The flight computer uses a rules-based structure derived from range safety requirements to make decisions whether or not to destroy the rocket.

  5. Vibrotactile Feedback in Steering Wheel Reduces Navigation Errors during GPS-Guided Car Driving

    E-print Network

    Basdogan, Cagatay

    Vibrotactile Feedback in Steering Wheel Reduces Navigation Errors during GPS-Guided Car Driving feedback displayed through the steering wheel of a car can reduce the perceptual and cognitive load with the GPS-based voice commands. KEYWORDS: vibrotactile, haptics, car navigation systems, GPS, steering wheel

  6. Reconstruction of KOMPSAT-l GPS navigation solutions using GPS data generation and preprocessing program

    NASA Astrophysics Data System (ADS)

    Lee, Byoung-Sun; Lee, Jeong-Sook; Kim, Jae-Hoon; Lee, Seong-Pal; Yoon, Jae-Cheol; Roh, Kyoung-Min; Park, Eun-Seo; Choi, Kyu-Hong

    2004-04-01

    GPS navigation solutions and GPS-related telemetry points are analyzed using one-day playback data from the KOMPSAT-1 Spacecraft. Then, the GPS navigation solutions are reconstructed using simulated GPS raw measurements such as pseudo-ranges between the KOMPSAT-1 and GPS satellites constellation. GPS data generation and preprocessing computer programs are developed and used for the generation of the GPS raw measurement and reconstruction of the GPS navigation solutions. The playback GPS data and the reconstructed data are compared with each other.

  7. Geomagnetic storms, super-storms, and their impacts on GPS-based navigation systems

    NASA Astrophysics Data System (ADS)

    Astafyeva, E.; Yasyukevich, Yu.; Maksikov, A.; Zhivetiev, I.

    2014-07-01

    Using data of GPS receivers located worldwide, we analyze the quality of GPS performance during four geomagnetic storms of different intensity: two super-storms and two intense storms. We show that during super-storms the density of GPS Losses-of-Lock (LoL) increases up to 0.25% at L1 frequency and up to 3% at L2 frequency, and up to 0.15% (at L1) and 1% (at L2) during less intense storms. Also, depending on the intensity of the storm time ionospheric disturbances, the total number of total electron content (TEC) slips can exceed from 4 to 40 times the quiet time level. Both GPS LoL and TEC slips occur during abrupt changes of SYM-H index of geomagnetic activity, i.e., during the main phase of geomagnetic storms and during development of ionospheric storms. The main contribution in the total number of GPS LoL was found to be done by GPS sites located at low and high latitudes, whereas the area of numerous TEC slips seemed to mostly correspond to the boundary of the auroral oval, i.e., region with intensive ionospheric irregularities. Our global maps of TEC slips show where the regions with intense irregularities of electron density occur during geomagnetic storms and will let us in future predict appearance of GPS errors for geomagnetically disturbed conditions.

  8. A LEAPFROG NAVIGATION SYSTEM A DISSERTATION

    E-print Network

    Stanford University

    A LEAPFROG NAVIGATION SYSTEM A DISSERTATION SUBMITTED TO THE DEPARTMENT OF AERONAUTICS and places where conventional navigation systems, such as the Global Positioning System (GPS), are unavailable due to anything from temporary signal occultations to lack of navigation system infrastructure

  9. Optimization Algorithm for Kalman Filter Exploiting the Numerical Characteristics of SINS/GPS Integrated Navigation Systems.

    PubMed

    Hu, Shaoxing; Xu, Shike; Wang, Duhu; Zhang, Aiwu

    2015-01-01

    Aiming at addressing the problem of high computational cost of the traditional Kalman filter in SINS/GPS, a practical optimization algorithm with offline-derivation and parallel processing methods based on the numerical characteristics of the system is presented in this paper. The algorithm exploits the sparseness and/or symmetry of matrices to simplify the computational procedure. Thus plenty of invalid operations can be avoided by offline derivation using a block matrix technique. For enhanced efficiency, a new parallel computational mechanism is established by subdividing and restructuring calculation processes after analyzing the extracted "useful" data. As a result, the algorithm saves about 90% of the CPU processing time and 66% of the memory usage needed in a classical Kalman filter. Meanwhile, the method as a numerical approach needs no precise-loss transformation/approximation of system modules and the accuracy suffers little in comparison with the filter before computational optimization. Furthermore, since no complicated matrix theories are needed, the algorithm can be easily transplanted into other modified filters as a secondary optimization method to achieve further efficiency. PMID:26569247

  10. GPS compound eye attitude and navigation sensor and method

    NASA Technical Reports Server (NTRS)

    Quinn, David A. (Inventor)

    2003-01-01

    The present invention is a GPS system for navigation and attitude determination, comprising a sensor array including a convex hemispherical mounting structure having a plurality of mounting surfaces, and a plurality of antennas mounted to the mounting surfaces for receiving signals from space vehicles of a GPS constellation. The present invention also includes a receiver for collecting the signals and making navigation and attitude determinations. In an alternate embodiment the present invention may include two opposing convex hemispherical mounting structures, each of the mounting structures having a plurality of mounting surfaces, and a plurality of antennas mounted to the mounting surfaces.

  11. GPS Auto-Navigation Design for Unmanned Air Vehicles

    NASA Technical Reports Server (NTRS)

    Nilsson, Caroline C. A.; Heinzen, Stearns N.; Hall, Charles E., Jr.; Chokani, Ndaona

    2003-01-01

    A GPS auto-navigation system is designed for Unmanned Air Vehicles. The objective is to enable the air vehicle to be used as a test-bed for novel flow control concepts. The navigation system uses pre-programmed GPS waypoints. The actual GPS position, heading, and velocity are collected by the flight computer, a PC104 system running in Real-Time Linux, and compared with the desired waypoint. The navigator then determines the necessity of a heading correction and outputs the correction in the form of a commanded bank angle, for a level coordinated turn, to the controller system. This controller system consists of 5 controller! (pitch rate PID, yaw damper, bank angle PID, velocity hold, and altitude hold) designed for a closed loop non-linear aircraft model with linear aerodynamic coefficients. The ability and accuracy of using GPS data, is validated by a GPS flight. The autopilots are also validated in flight. The autopilot unit flight validations show that the designed autopilots function as designed. The aircraft model, generated on Matlab SIMULINK is also enhanced by the flight data to accurately represent the actual aircraft.

  12. GPS receiver architecture for autonomous navigation in high earth orbits

    NASA Astrophysics Data System (ADS)

    Moreau, Michael Christopher

    2001-07-01

    This dissertation develops the systems level design of a Global Positioning System (GPS) receiver for high Earth orbit (HEO) satellite missions. The prospect of using GPS for autonomous navigation of satellites in highly eccentric and geosynchronous orbits has long been considered, with the goal of increasing spacecraft autonomy and reducing operations costs for these missions. While GPS has been used extensively for navigation of satellites in low Earth orbits (LEO), existing GPS receivers are not capable of functioning well at higher altitudes, where GPS signal availability is extremely limited. The primary emphasis is the development of algorithms and methods to add HEO capabilities to existing GPS receiver hardware; in particular, optimization of the receiver algorithms for space, and for the weak signals present in HEO. Software simulation tools have been developed and used to model aspects of the GPS signal geometries, dynamics, and power levels. At low altitudes, geometries and signal levels are favorable; however, dynamics are extremely high. At high altitudes, power levels are weaker and geometries are poorer, but the dynamics are more manageable. Improved algorithms governing satellite selection, signal acquisition, and the overall design of the tracking loops are presented. Adaptability to highly variable operating conditions is a key design feature of the algorithms in a HEO receiver. Preliminary steps have been taken to implement these concepts in the PiVoT GPS receiver being developed by NASA Goddard Space Flight Center (GSFC). These steps to optimize the performance of the receiver for space are expected to improve overall navigation performance by increasing the sensitivity of the receiver to track weaker GPS signals between 28 to 35 dB-Hz. Preliminary test results conducted with a hardware GPS simulator and the PiVoT GPS receiver are presented. The limiting altitude for GPS tracking is highly dependant on the capabilities of the receiver, the antenna configurations, and the pointing constraints of the spacecraft. For a conventional GPS receiver with a tracking threshold of 33 to 35 dB-HZ, this limit is approximately 25 to 30 Earth radii. Some of the weak signal tracking techniques discussed in this dissertation could extend this limit to perhaps 40 to 50 Earth radii.

  13. Augmentation of GPS for Ship Navigation in Constricted Water Ways

    E-print Network

    Calgary, University of

    in the Marine Technical and Support Services Directorate of the Canadian Coast Guard. At present he for ship navigation in constricted water ways. INTRODUCTION Both the Canadian Coast Guard (CCG) and United States Coast Guard (USCG) are completing work on their public marine Differential GPS (DGPS) systems

  14. GPS-aided inertial technology and navigation-based photogrammetry for aerial mapping the San Andreas fault system

    USGS Publications Warehouse

    Sanchez, Richard D.; Hudnut, Kenneth W.

    2004-01-01

    Aerial mapping of the San Andreas Fault System can be realized more efficiently and rapidly without ground control and conventional aerotriangulation. This is achieved by the direct geopositioning of the exterior orientation of a digital imaging sensor by use of an integrated Global Positioning System (GPS) receiver and an Inertial Navigation System (INS). A crucial issue to this particular type of aerial mapping is the accuracy, scale, consistency, and speed achievable by such a system. To address these questions, an Applanix Digital Sensor System (DSS) was used to examine its potential for near real-time mapping. Large segments of vegetation along the San Andreas and Cucamonga faults near the foothills of the San Bernardino and San Gabriel Mountains were burned to the ground in the California wildfires of October-November 2003. A 175 km corridor through what once was a thickly vegetated and hidden fault surface was chosen for this study. Both faults pose a major hazard to the greater Los Angeles metropolitan area and a near real-time mapping system could provide information vital to a post-disaster response.

  15. 77 FR 35428 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... Beacon Navigation GmbH of Zug, Switzerland (``Beacon''). 76 FR 72443 (Nov. 23, 2011). The complaint... Company from the investigation and replace it with General Motors LLC of Detroit, Michigan. 77 FR 13350... Corporation of Hamamatsu City, Japan; American Suzuki Motor Corporation of Brea, California; Jaguar Land...

  16. GPS/MEMS IMU/Microprocessor Board for Navigation

    NASA Technical Reports Server (NTRS)

    Gender, Thomas K.; Chow, James; Ott, William E.

    2009-01-01

    A miniaturized instrumentation package comprising a (1) Global Positioning System (GPS) receiver, (2) an inertial measurement unit (IMU) consisting largely of surface-micromachined sensors of the microelectromechanical systems (MEMS) type, and (3) a microprocessor, all residing on a single circuit board, is part of the navigation system of a compact robotic spacecraft intended to be released from a larger spacecraft [e.g., the International Space Station (ISS)] for exterior visual inspection of the larger spacecraft. Variants of the package may also be useful in terrestrial collision-detection and -avoidance applications. The navigation solution obtained by integrating the IMU outputs is fed back to a correlator in the GPS receiver to aid in tracking GPS signals. The raw GPS and IMU data are blended in a Kalman filter to obtain an optimal navigation solution, which can be supplemented by range and velocity data obtained by use of (l) a stereoscopic pair of electronic cameras aboard the robotic spacecraft and/or (2) a laser dynamic range imager aboard the ISS. The novelty of the package lies mostly in those aspects of the design of the MEMS IMU that pertain to controlling mechanical resonances and stabilizing scale factors and biases.

  17. Ultra-tightly Coupled GPS/Vehicle Sensor Integration for Land Vehicle Navigation

    E-print Network

    Calgary, University of

    Ultra-tightly Coupled GPS/Vehicle Sensor Integration for Land Vehicle Navigation TAO LI, MARK G, and attitude information. This paper investigates an ultra-tight integration strategy to fuse GPS and a vehicle vehicles can be used to further improve navigation accuracy and system redun- dancy [16]. To integrate

  18. Operational considerations of using GPS for spacecraft navigation

    NASA Technical Reports Server (NTRS)

    Hart, Roger C.; Hartman, Kathy R.

    1995-01-01

    The Flight Dynamics Facility (FDF) at the NASA Goddard Space Flight Center (GSFC) has provided operational spacecraft orbit support for many years, currently generating orbit products for about 20 satellites. To date, operational orbit determination in the FDF has been performed on the ground using data from ground-based or space-based tracking systems. Current development of spaceborne Global Positioning System (GPS) receivers is projected to have a significant effect on the support needed for operational satellite navigation. This paper identifies the functions performed in spacecraft navigation and examines and quantifies how the functions and support levels will be affected as onboard GPS receivers are implemented on spacecraft. Cases are considered spacecraft using or not using NASA ground and space networks resources.

  19. 76 FR 39896 - In the Matter of Certain GPS Navigation Products, Components Thereof, and Related Software...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ...337-TA-783] In the Matter of Certain GPS Navigation Products, Components Thereof...United States after importation of certain GPS navigation products, components thereof...United States after importation of certain GPS navigation products, components...

  20. Absolute and relative satellite-to-satellite navigation using GPS

    NASA Astrophysics Data System (ADS)

    Binning, Patrick William

    This dissertation describes the methods and implementation of extended Kalman filtering, backwards smoothing and carrier phase integer ambiguity resolution for the problem of absolute satellite orbit determination and satellite to satellite relative navigation while using measurements from the Global Positioning System (GPS). All data are considered to be taken from both frequencies of the GPS constellation. Also, the data is considered to be free from the effects of Selective Availability (SA) although this feature is briefly addressed. The absolute navigation techniques are applied to actual data obtained from the TOPEX/Poseidon satellite as well as simulated data. The algorithms are used to estimate the position, velocity, clock offset, and frequency offset. The simulated data are derived from two sources: a software simulator, and a Northern Telecom GPS signal simulator used in conjunction with an Allen Osborne Associates TurboRogue receiver. Four algorithms are presented in the area of relative satellite to satellite navigation. These can be separated into two categories: those that base the relative state update using only the GPS pseudorange, and those that base the relative state update on the GPS carrier phase only. There are three pseudorange techniques investigated. The first involves straight differencing of two absolute estimates when using the pseudoranges from all observable GPS satellites from each receiver. The second involves using a correlated process noise matrix while processing simultaneous pseudoranges from common view GPS satellites. The relative state for this process is then the difference of the two absolute states. The measurements for both user spacecraft must be taken at the same instant in time for this process to work. A measurement interpolation algorithm is presented in order to solve this problem. The third pseudorange method is the first to estimate the relative state explicitly by employing the single difference pseudorange measurement. The carrier phase technique shows the highest accuracy for relative state estimation. The algorithm in this dissertation utilizes the widelane carrier phase combination of GPS observables. The single difference is then taken between two simultaneous widelane carrier phase measurements. Inherent in this process is the need to determine the widelane integer. A robust algorithm is presented which allows this problem to be solved. The relative navigation algorithms are applied to software and hardware simulated data. A unique aspect of this research involves using a Northern Telecom GPS RF signal generator with an Allen Osborne Associates TurboRogue receiver to simulate measurements from 2 coorbiting receivers. In addition, a software simulator is developed which allows more control over the simulation errors. The absolute navigation 1sigma position errors are 50 cm for a smoothed solution using precise GPS information and 3 to 7 meters when using the broadcast navigation parameters. The most precise pseudorange relative technique demonstrates 1sigma position errors of between 10 cm and 25 cm. The carrier phase technique shows 1sigma position errors on the order of 1.5 cm to 3.0 cm. These statistics are derived from 24 software simulations as well as 20 hardware simulations. A discussion of the cumulative results as well as individual test cases is presented.

  1. GPS Navigation for the Magnetospheric Multi-Scale Mission

    NASA Technical Reports Server (NTRS)

    Bamford, William; Mitchell, Jason; Southward, Michael; Baldwin, Philip; Winternitz, Luke; Heckler, Gregory; Kurichh, Rishi; Sirotzky, Steve

    2009-01-01

    In 2014. NASA is scheduled to launch the Magnetospheric Multiscale Mission (MMS), a four-satellite formation designed to monitor fluctuations in the Earth's magnetosphere. This mission has two planned phases with different orbits (1? x 12Re and 1.2 x 25Re) to allow for varying science regions of interest. To minimize ground resources and to mitigate the probability of collisions between formation members, an on-board orbit determination system consisting of a Global Positioning System (GPS) receiver and crosslink transceiver was desired. Candidate sensors would be required to acquire GPS signals both below and above the constellation while spinning at three revolutions-per-minute (RPM) and exchanging state and science information among the constellation. The Intersatellite Ranging and Alarm System (IRAS), developed by Goddard Space Flight Center (GSFC) was selected to meet this challenge. IRAS leverages the eight years of development GSFC has invested in the Navigator GPS receiver and its spacecraft communication expertise, culminating in a sensor capable of absolute and relative navigation as well as intersatellite communication. The Navigator is a state-of-the-art receiver designed to acquire and track weak GPS signals down to -147dBm. This innovation allows the receiver to track both the main lobe and the much weaker side lobe signals. The Navigator's four antenna inputs and 24 tracking channels, together with customized hardware and software, allow it to seamlessly maintain visibility while rotating. Additionally, an extended Kalman filter provides autonomous, near real-time, absolute state and time estimates. The Navigator made its maiden voyage on the Space Shuttle during the Hubble Servicing Mission, and is scheduled to fly on MMS as well as the Global Precipitation Measurement Mission (GPM). Additionally, Navigator's acquisition engine will be featured in the receiver being developed for the Orion vehicle. The crosslink transceiver is a 1/4 Watt transmitter utilizing a TDMA schedule to distribute a science quality message to all constellation members every ten seconds. Additionally the system generates one-way range measurements between formation members which is used as input to the Kalman filter. In preparation for the MMS Preliminary Design Review (PDR), the Navigator was required to pass a series of Technology Readiness Level (TRL) tests to earn the necessary TRL-6 classification. The TRL-6 level is achieved by demonstrating a prototype unit in a relevant end-to-end environment. The IRAS unit was able to meet all requirements during the testing phase, and has thus been TRL-6 qualified

  2. Single-Frequency GPS Relative Navigation in a High Ionosphere Orbital Environment

    NASA Technical Reports Server (NTRS)

    Conrad, Patrick R.; Naasz, Bo J.

    2007-01-01

    The Global Positioning System (GPS) provides a convenient source for space vehicle relative navigation measurements, especially for low Earth orbit formation flying and autonomous rendezvous mission concepts. For single-frequency GPS receivers, ionospheric path delay can be a significant error source if not properly mitigated. In particular, ionospheric effects are known to cause significant radial position error bias and add dramatically to relative state estimation error if the onboard navigation software does not force the use of measurements from common or shared GPS space vehicles. Results from GPS navigation simulations are presented for a pair of space vehicles flying in formation and using GPS pseudorange measurements to perform absolute and relative orbit determination. With careful measurement selection techniques relative state estimation accuracy to less than 20 cm with standard GPS pseudorange processing and less than 10 cm with single-differenced pseudorange processing is shown.

  3. Presented at Institute of Navigation GPS2002 (September 24-27, 2002, Portland, OR) 1 Fault Detection Methods And Testing

    E-print Network

    Calgary, University of

    Presented at Institute of Navigation GPS2002 (September 24-27, 2002, Portland, OR) 1 Fault at the same institution. He has previous experience in GPS related R&D at NovAtel Inc. and Trimble Navigation and measure the impact of undetected faults in a navigation system. Fault detection methods and testing

  4. Passive GPS-Free Navigation for Small UAVs Jack Langelaan

    E-print Network

    Langelaan, Jack W.

    Passive GPS-Free Navigation for Small UAVs Jack Langelaan Steve Rock Department of Aeronautics-free navigation of a small Unmanned Aerial Vehicle with a minimal sensor suite (limited to an inertial measurement unit and a monocular camera) is presented. The navigation task is cast as a Simul- taneous Localization

  5. Navigation in GPS Challenged Environments Based Upon Ranging Imagery

    NASA Astrophysics Data System (ADS)

    Markiel, J. N. Nikki

    The ability of living creatures to navigate their environment is one of the great mysteries of life. Humans, even from an early age, can acquire data about their surroundings, determine whether objects are movable or fixed, and identify open space, separate static and non-static objects, and move towards another location with minimal effort, in infinitesimal time spans. Over extended time periods humans can recall the location of objects and duplicate navigation tasks based purely on relative positioning of landmarks. Our ability to emulate this complex process in autonomous vehicles remains incomplete, despite significant research efforts over the past half century. Autonomous vehicles rely on a variety of electronic sensors to acquire data about their environment; the challenge is to transform that data into information supporting the objective of navigation. Historically, much of the sensor data was limited to the two dimensional (2D) instance; recent technological developments such as Laser Ranging and 3D Sonar are extending data collection to full three dimensional (3D) acquisition. The objective of this dissertation is the development of an algorithm to support the transformation of 3D ranging data into a navigation solution within unknown environments, and in the presence of dynamically moving objects. The algorithm reflects one of the very first attempts to leverage the 3D ranging technology for the purpose of autonomous navigation, and provides a system which enables the ability to complete the following objectives: • Separation of static and non-static elements in the environment. • Navigation based upon the range measurements of static elements. This research extends the body of knowledge in three primary topics. 1) The first is the development of a general method to identify n features in an initial data set from m features in a subsequent data set, given that both data sets are acquired via 3D ranging sensors. Accomplishing this objective, particularly with respect to 2D datasets, has long been a difficult proposition when attempting to link overlapping data sets. 2) Secondly, an innovative methodology to segment a set of discrete 3D range measurements is presented. 3) Finally, the research develops a methodology to support navigation in environments previously infeasible for autonomous vehicles due to lack of position updates. This problem is well known in the navigation field; while Global Positioning Systems (GPS) provide excellent positional information, their signals can become unavailable in a wide variety of conditions. Current research in robotic manipulation rarely addresses the concept of operations within an unknown environment, and virtually never attempts navigation in the presence of non-static objects. The ability to extend the navigation solution beyond these limitations extends the possibilities for autonomous navigation and advances the field of navigation. The current algorithm cannot provide a navigation solution for an indefinite time period; it can extend the feasible extent of navigation without benefit of GPS positioning. While this research could not possibly claim to solve the problem of autonomous navigation, it represents an important step towards the vision of developing a machine to emulate cognitive navigation.

  6. Chances of GPS-satellite-navigation for aerial photogrammetry

    NASA Astrophysics Data System (ADS)

    Hartl, Philipp; Wehr, Aloys

    1986-11-01

    The 'Global Positioning System (GPS)' offers excellent possibilities for both survey navigation and camera orientation, which can be of great importance for the future. A general review is given of the advantages accompanied with it. Then the methods of the precise positioning and attitude determination are explained, which are based upon the carrier phase measurement. For the attitude determination the coordinate transformations are described, which allow to derive the orientation data from the interferometric measurement data. In principle, one can achieve relative accuracies of better than one meter rms for three-dimensional positioning during flight and of much better than one arcmin in attitude.

  7. A LEO Satellite Navigation Algorithm Based on GPS and Magnetometer Data

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Bar-Itzhack, Itzhack; Harman, Rick; Bauer, Frank H. (Technical Monitor)

    2000-01-01

    The Global Positioning System (GPS) has become a standard method for low cost onboard satellite orbit determination. The use of a GPS receiver as an attitude and rate sensor has also been developed in the recent past. Additionally, focus has been given to attitude and orbit estimation using the magnetometer, a low cost, reliable sensor. Combining measurements from both GPS and a magnetometer can provide a robust navigation system that takes advantage of the estimation qualities of both measurements. Ultimately a low cost, accurate navigation system can result, potentially eliminating the need for more costly sensors, including gyroscopes.

  8. Autonomous GPS/INS navigation experiment for Space Transfer Vehicle (STV)

    NASA Technical Reports Server (NTRS)

    Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. Wayne

    1991-01-01

    An experiment to validate the concept of developing an autonomous integrated spacecraft navigation system using on board Global Positioning System (GPS) and Inertial Navigation System (INS) measurements is described. The feasibility of integrating GPS measurements with INS measurements to provide a total improvement in spacecraft navigation performance, i.e. improvement in position, velocity and attitude information, was previously demonstrated. An important aspect of this research is the automatic real time reconfiguration capability of the system designed to respond to changes in a spacecraft mission under the control of an expert system.

  9. Institute of Navigation GPS-99/Nashville/September 13-17, 1999 1 PSEUDOLITE-BASED INVERTED GPS

    E-print Network

    Calgary, University of

    Institute of Navigation GPS-99/Nashville/September 13-17, 1999 1 PSEUDOLITE-BASED INVERTED GPS at the University of Calgary. She has been involved with GPS research since 1984 and has published numerous papers on static and kinematic GPS positioning. She is also the author of several GPS related software programs. Dr

  10. A Leo Satellite Navigation Algorithm Based on GPS and Magnetometer Data

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Harman, Rick; Bar-Itzhack, Itzhack

    2001-01-01

    The Global Positioning System (GPS) has become a standard method for low cost onboard satellite orbit determination. The use of a GPS receiver as an attitude and rate sensor has also been developed in the recent past. Additionally, focus has been given to attitude and orbit estimation using the magnetometer, a low cost, reliable sensor. Combining measurements from both GPS and a magnetometer can provide a robust navigation system that takes advantage of the estimation qualities of both measurements. Ultimately, a low cost, accurate navigation system can result, potentially eliminating the need for more costly sensors, including gyroscopes. This work presents the development of a technique to eliminate numerical differentiation of the GPS phase measurements and also compares the use of one versus two GPS satellites.

  11. Navigation accuracy and interference rejection for GPS adaptive antenna arrays

    NASA Astrophysics Data System (ADS)

    de Lorenzo, David S.

    2007-12-01

    The classic problem in signal processing is to enhance signal while suppressing noise. In this investigation, the signal is timing information from satellites of the Global Positioning System (GPS). The noise originates from jammers at disparate locations. The first step in the solution is to develop a software receiver that implements an adaptive directional antenna array which points (electronically) to individual GPS satellites while suppressing jammers. This software receiver and the associated space-time adaptive algorithms represent a robust and efficient architecture for follow-on hardware implementation. The second step is to analyze the tradeoff between allocating resources to reject radio frequency interference and allocating resources to mitigate measurement biases in the GPS timing information. This analysis leads to deterministic corrections that reduce navigation biases to acceptable levels while preserving the interference rejection capabilities of the adaptive array. The final step is experimental verification by exercising the software receiver with operational hardware in the loop. This investigation demonstrates that adaptive antenna arrays can enable systems that meet the aggressive accuracy and integrity requirements for piloted and autonomous aircraft landing while simultaneously providing significant attenuation of radio frequency interference.

  12. Indoor/Outdoor Seamless Positioning Using Lighting Tags and GPS Cellular Phones for Personal Navigation

    NASA Astrophysics Data System (ADS)

    Namie, Hiromune; Morishita, Hisashi

    The authors focused on the development of an indoor positioning system which is easy to use, portable and available for everyone. This system is capable of providing the correct position anywhere indoors, including onboard ships, and was invented in order to evaluate the availability of GPS indoors. Although the performance of GPS is superior outdoors, there has been considerable research regarding indoor GPS involving sensitive GPS, pseudolites (GPS pseudo satellite), RFID (Radio Frequency IDentification) tags, and wireless LAN .However, the positioning rate and the precision are not high enough for general use, which is the reason why these technologies have not yet spread to personal navigation systems. In this regard, the authors attempted to implement an indoor positioning system using cellular phones with built-in GPS and infrared light data communication functionality, which are widely used in Japan. GPS is becoming increasingly popular, where GPGGS sentences of the NMEA outputted from the GPS receiver provide spatiotemporal information including latitude, longitude, altitude, and time or ECEF xyz coordinates. As GPS applications grow rapidly, spatiotemporal data becomes key to the ubiquitous outdoor and indoor seamless positioning services at least for the entire area of Japan, as well as to becoming familiar with satellite positioning systems (e.g. GPS). Furthermore, the authors are also working on the idea of using PDAs (Personal Digital Assistants), as cellular phones with built-in GPS and PDA functionality are also becoming increasingly popular.

  13. The Global Positioning System and its application in spacecraft navigation

    NASA Technical Reports Server (NTRS)

    Van Leeuwen, A.; Rosen, E.; Carrier, L. M.

    1979-01-01

    The paper presents an overview of the Global Positioning System (GPS) as well as a discussion of the user system parameters govering the design of a low-earth-orbit spacecraft GPS navigation system. A specific application, the Space Shuttle orbiter GPS navigation system, is discussed with particular attention given to its receiver/processor.

  14. Optimising the Integration of Terrain Referenced Navigation with INS and GPS

    NASA Astrophysics Data System (ADS)

    Groves, Paul D.; Handley, Robin J.; Runnalls, Andrew R.

    2006-01-01

    The benefits of integrated INS/GPS systems are well known. However, the knowledge required to jam GPS is becoming public and the hardware to achieve this is basic. When GPS data are unavailable and a low grade INS is used, navigation accuracy quickly degrades to an unacceptable level. The addition of one or more terrain referenced navigation (TRN) systems to an integrated INS/GPS navigation system enables the INS to be calibrated during GPS outages, increasing the robustness of the overall navigation solution. TRN techniques are compared and integration architectures are reviewed. For the initial studies of INS/GPS/TRN integration, radar altimeter based terrain contour navigation (TCN) with a batch processing algorithm is used in conjunction with a centralised integration filter. Four different approaches for using these TCN fixes to calibrate the INS are compared. These are a best fix method, a weighted fix method using a probabilistic data association filter (PDAF) and single and multi-hypothesis versions of the Iterative Gaussian Mixture Approximation of the Posterior (IGMAP) method. Simulation results are presented showing that the single hypothesis IGMAP technique offers the best balance between accuracy, robustness and processing efficiency.

  15. GPS system simulation methodology

    NASA Technical Reports Server (NTRS)

    Ewing, Thomas F.

    1993-01-01

    The following topics are presented: background; Global Positioning System (GPS) methodology overview; the graphical user interface (GUI); current models; application to space nuclear power/propulsion; and interfacing requirements. The discussion is presented in vugraph form.

  16. Sole means navigation and integrity through hybrid Loran-C and NAVSTAR GPS

    NASA Technical Reports Server (NTRS)

    Vangraas, Frank

    1990-01-01

    A sole means navigation system does not only call for integrity, but also for coverage, reliability, availability and accuracy. Even though ground monitored GPS will provide integrity, availability is still not sufficient. One satellite outage can affect a large service area for several hours per day. The same holds for differential GPS; a total satellite outage cannot be corrected for. To obtain sufficient coverage, extra measurements are needed, either in the form of extra GPS satellites (expensive) or through redundant measurements from other systems. LORAN-C is available and will, hybridized with GPS, result in a system that has the potential to satisfy the requirements for a sole means navigation system for use in the continental United States. Assumptions are made about the qualification sole means, mainly based on current sole means systems such as VOR/DME. In order to allow for system design that will satisfy sole means requirements, it is recommended that a definition of a sole means navigation system be established. This definition must include requirements for availability, reliability, and integrity currently not specified. In addition to the definition of a sole means navigation system, certification requirements must be established for hybrid navigation systems. This will allow for design and production of a new generation of airborne navigation systems that will reduce overall system costs and simplify training procedures.

  17. Proceedings of NTM 2004 Conference (Session E3), San Diego, CA, January 26-28, The Institute of Navigation. 1 Kinematic Azimuth Alignment of INS using GPS

    E-print Network

    Calgary, University of

    of Navigation. 1 Kinematic Azimuth Alignment of INS using GPS Velocity Information A. O. Salycheva and M is on the integration of GPS with medium accuracy inertial navigation systems. Dr. M. Elizabeth Cannon is Professor of Geomatics Engineering at the University of Calgary. She has been involved in GPS research and development

  18. INL Autonomous Navigation System

    Energy Science and Technology Software Center (ESTSC)

    2005-03-30

    The INL Autonomous Navigation System provides instructions for autonomously navigating a robot. The system permits high-speed autonomous navigation including obstacle avoidance, waypoing navigation and path planning in both indoor and outdoor environments.

  19. 77 FR 16860 - Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ...TRADE COMMISSION [Investigation No. 337-TA-783] Certain GPS Navigation Products, Components Thereof, and Related Software...and sale within the United States after importation of certain GPS navigation products, components thereof, and related...

  20. SPACECRAFT NAVIGATION USING THE MODERNIZED GLOBAL POSITIONING SYSTEM SIGNAL

    E-print Network

    Lightsey, Glenn

    SPACECRAFT NAVIGATION USING THE MODERNIZED GLOBAL POSITIONING SYSTEM SIGNAL E. G. Lightsey and R. B. Harris ABSTRACT Navigation is examined using information that is presently known about the modernized GPS The utility of the Global Positioning System (GPS) for spacecraft navigation and timing has been widely

  1. Onboard Pseudolite Augmentation System for Relative Navigation

    E-print Network

    Onboard Pseudolite Augmentation System for Relative Navigation Tob e Corazzini and Jonathan P. How GPS satel- lites, the available signals can be augmented with pseu- dolites onboard the vehicles presents an alternative approach of mounting a GPS transceiver system onboard each of the vehicles

  2. Navigating the human hippocampus without a GPS.

    PubMed

    Zucker, Halle R; Ranganath, Charan

    2015-06-01

    The award of the Nobel Prize to Professors John O'Keefe, May-Britt Moser, and Edvard Moser brings global recognition to one of the most significant success stories in modern neuroscience. Here, we consider how their findings, along with related studies of spatial cognition in rodents, have informed our understanding of the human hippocampus. Rather than identifying a "GPS" in the brain, we emphasize that these researchers helped to establish a fundamental role for cortico-hippocampal networks in the guidance of behavior based on a representation of the current place, time, and situation. We conclude by highlighting the major questions that remain to be addressed in future research. PMID:25788106

  3. GPS-based relative navigation for the Proba-3 formation flying mission

    NASA Astrophysics Data System (ADS)

    Ardaens, Jean-Sébastien; D'Amico, Simone; Cropp, Alexander

    2013-10-01

    The primary objective of the Proba-3 mission is to build a solar coronagraph composed of two satellites flying in close formation on a high elliptical orbit and tightly controlled at apogee. Both spacecraft will embark a low-cost GPS receiver, originally designed for low-Earth orbits, to support the mission operations and planning during the perigee passage, when the GPS constellation is visible. The paper demonstrates the possibility of extending the utilization range of the GPS-based navigation system to serve as sensor for formation acquisition and coarse formation keeping. The results presented in the paper aim at achieving an unprecedented degree of realism using a high-fidelity simulation environment with hardware-in-the-loop capabilities. A modified version of the flight-proven PRISMA navigation system, composed of two single-frequency Phoenix GPS receivers and an advanced real-time onboard navigation filter, has been retained for this analysis. For several-day long simulations, the GPS receivers are replaced by software emulation to accelerate the simulation process. Special attention has been paid to the receiver link budget and to the selection of a proper attitude profile. Overall the paper demonstrates that, despite a limited GPS tracking time, the onboard navigation filter gets enough measurements to perform a relative orbit determination accurate at the centimeter level at perigee. Afterwards, the orbit prediction performance depends mainly on the quality of the onboard modeling of the differential solar radiation pressure acting on the satellites. When not taken into account, this perturbation is responsible for relative navigation errors at apogee up to 50 m. The errors can be reduced to only 10 m if the navigation filter is able to model this disturbance with 70% fidelity.

  4. GPS World, Innovation: Autonomous Navigation at High Earth Orbits

    NASA Technical Reports Server (NTRS)

    Bamford, William; Winternitz, Luke; Hay, Curtis

    2005-01-01

    Calculating a spacecraft's precise location at high orbital altitudes-22,000 miles (35,800 km) and beyond-is an important and challenging problem. New and exciting opportunities become possible if satellites are able to autonomously determine their own orbits. First, the repetitive task of periodically collecting range measurements from terrestrial antennas to high altitude spacecraft becomes less important-this lessens competition for control facilities and saves money by reducing operational costs. Also, autonomous navigation at high orbital altitudes introduces the possibility of autonomous station keeping. For example, if a geostationary satellite begins to drift outside of its designated slot it can make orbit adjustments without requiring commands from the ground. Finally, precise onboard orbit determination opens the door to satellites flying in formation-an emerging concept for many scientific space applications. The realization of these benefits is not a trivial task. While the navigation signals broadcast by GPS satellites are well suited for orbit and attitude determination at lower altitudes, acquiring and using these signals at geostationary (GEO) and highly elliptical orbits is much more difficult. The light blue trace describes the GPS orbit at approximately 12,550 miles (20,200 km) altitude. GPS satellites were designed to provide navigation signals to terrestrial users-consequently the antenna array points directly toward the earth. GEO and HE0 orbits, however, are well above the operational GPS constellation, making signal reception at these altitudes more challenging. The nominal beamwidth of a Block II/IIA GPS satellite antenna array is approximately 42.6 degrees. At GEO and HE0 altitudes, most of these primary beam transmissions are blocked by the Earth, leaving only a narrow region of nominal signal visibility near opposing limbs of the earth. This region is highlighted in gray. If GPS receivers at GEO and HE0 orbits were designed to use these higher power signals only, precise orbit determination would not be practical. Fortunately, the GPS satellite antenna array also produces side lobe signals at much lower power levels. NASA has designed and tested the Navigator, a new GPS receiver that can acquire and track these weaker signals, thereby dramatically increasing the signal visibility at these altitudes. While using much weaker signals is a fundamental requirement for a high orbital altitude GPS receiver, it is certainly not the only challenge. There are other unique characteristics of this application that must also be considered. For example, Position Dilution of Precision (PDOP) figures are much higher at GEO and HE0 altitudes because visible GPS satellites are concentrated in a much smaller area with respect to the spacecraft antenna. These poor PDOP values contribute considerable error to the point solutions calculated by the spacecraft GPS receiver. Finally, spacecraft GPS receivers must be designed to withstand a variety of extreme environmental conditions. Variations in acceleration between launch and booster separation are extreme. Temperature gradients in the space environment are also severe. Furthermore, radiation effects are a major concern-spacecraft-borne GPS receivers must be designed with radiation-hardened electronics to guard against this phenomenon, otherwise they simply will not work. Perhaps most importantly, there are no opportunities to repair or modify any space-borne GPS receiver after it has been launched. Great care must be taken to ensure all performance characteristics have been analyzed prior to liftoff.

  5. Development And Test of A Digitally Steered Antenna Array for The Navigator GPS Receiver

    NASA Technical Reports Server (NTRS)

    Pinto, Heitor David; Valdez, Jennifer E.; Winternitz, Luke M. B.; Hassouneh, Munther A.; Price, Samuel R.

    2012-01-01

    Global Positioning System (GPS)-based navigation has become common for low-Earth orbit spacecraft as the signal environment is similar to that on the Earth s surface. The situation changes abruptly, however, for spacecraft whose orbital altitudes exceed that of the GPS constellation. Visibility is dramatically reduced and signals that are present may be very weak and more susceptible to interference. GPS receivers effective at these altitudes require increased sensitivity, which often requires a high-gain antenna. Pointing such an antenna can pose a challenge. One efficient approach to mitigate these problems is the use of a digitally steered antenna array. Such an antenna can optimally allocate gain toward desired signal sources and away from interferers. This paper presents preliminary results in the development and test of a digitally steered antenna array for the Navigator GPS research program at NASA s Goddard Space Flight Center. In particular, this paper highlights the development of an array and front-end electronics, the development and test of a real-time software GPS receiver, and implementation of three beamforming methods for combining the signals from the array. Additionally, this paper discusses the development of a GPS signal simulator which produces digital samples of the GPS L1C/A signals as they would be received by an arbitrary antenna array configuration. The simulator models transmitter and receiver dynamics, near-far and multipath interference, and has been a critical component in both the development and test of the GPS receiver. The GPS receiver system was tested with real and simulated GPS signals. Preliminary results show that performance improvement was achieved in both the weak signal and interference environments, matching analytical predictions. This paper summarizes our initial findings and discusses the advantages and limitations of the antenna array and the various beamforming methods.

  6. Networked differential GPS system

    NASA Technical Reports Server (NTRS)

    Mueller, K. Tysen (Inventor); Loomis, Peter V. W. (Inventor); Kalafus, Rudolph M. (Inventor); Sheynblat, Leonid (Inventor)

    1994-01-01

    An embodiment of the present invention relates to a worldwide network of differential GPS reference stations (NDGPS) that continually track the entire GPS satellite constellation and provide interpolations of reference station corrections tailored for particular user locations between the reference stations Each reference station takes real-time ionospheric measurements with codeless cross-correlating dual-frequency carrier GPS receivers and computes real-time orbit ephemerides independently. An absolute pseudorange correction (PRC) is defined for each satellite as a function of a particular user's location. A map of the function is constructed, with iso-PRC contours. The network measures the PRCs at a few points, so-called reference stations and constructs an iso-PRC map for each satellite. Corrections are interpolated for each user's site on a subscription basis. The data bandwidths are kept to a minimum by transmitting information that cannot be obtained directly by the user and by updating information by classes and according to how quickly each class of data goes stale given the realities of the GPS system. Sub-decimeter-level kinematic accuracy over a given area is accomplished by establishing a mini-fiducial network.

  7. Results from Navigator GPS Flight Testing for the Magnetospheric MultiScale Mission

    NASA Technical Reports Server (NTRS)

    Lulich, Tyler D.; Bamford, William A.; Wintermitz, Luke M. B.; Price, Samuel R.

    2012-01-01

    The recent delivery of the first Goddard Space Flight Center (GSFC) Navigator Global Positioning System (GPS) receivers to the Magnetospheric MultiScale (MMS) mission spacecraft is a high water mark crowning a decade of research and development in high-altitude space-based GPS. Preceding MMS delivery, the engineering team had developed receivers to support multiple missions and mission studies, such as Low Earth Orbit (LEO) navigation for the Global Precipitation Mission (GPM), above the constellation navigation for the Geostationary Operational Environmental Satellite (GOES) proof-of-concept studies, cis-Lunar navigation with rapid re-acquisition during re-entry for the Orion Project and an orbital demonstration on the Space Shuttle during the Hubble Servicing Mission (HSM-4).

  8. NASA's GPS tracking system for Aristoteles

    NASA Astrophysics Data System (ADS)

    Davis, E. S.; Hajj, G.; Kursinski, E. R.; Kyriacou, C.; Meehan, T. K.; Melbourne, William G.; Neilan, R. E.; Young, L. E.; Yunck, Thomas P.

    1991-12-01

    NASA 's Global Positioning System (GPS) tracking system for Artistoteles receivers and a GPS flight receiver aboard Aristoteles is described. It will include a global network of GPS ground receivers and a GPS flight receiver aboard Aristoteles. The flight receiver will operate autonomously; it will provide real time navigation solutions for Aristoteles and tracking data needed by ESOC for operational control of the satellite. The GPS flight and ground receivers will currently and continuously track all visible GPS satellites. These observations will yield high accuracy differential positions and velocities of Aristoteles in a terrestrial frame defined by the locations of the globally distributed ground work. The precise orbits and tracking data will be made available to science investigators as part of the geophysical data record. The characteristics of the GPS receivers, both flight and ground based, that NASA will be using to support Aristoteles are described. The operational aspects of the overall tracking system, including the data functions and the resulting data products are summarized. The expected performance of the tracking system is compared to Aristoteles requirements and the need to control key error sources such as multipath is identified.

  9. Benefits of Combined GPS/GLONASS with Low-Cost MEMS IMUs for Vehicular Urban Navigation

    PubMed Central

    Angrisano, Antonio; Petovello, Mark; Pugliano, Giovanni

    2012-01-01

    The integration of Global Navigation Satellite Systems (GNSS) with Inertial Navigation Systems (INS) has been very actively researched for many years due to the complementary nature of the two systems. In particular, during the last few years the integration with micro-electromechanical system (MEMS) inertial measurement units (IMUs) has been investigated. In fact, recent advances in MEMS technology have made possible the development of a new generation of low cost inertial sensors characterized by small size and light weight, which represents an attractive option for mass-market applications such as vehicular and pedestrian navigation. However, whereas there has been much interest in the integration of GPS with a MEMS-based INS, few research studies have been conducted on expanding this application to the revitalized GLONASS system. This paper looks at the benefits of adding GLONASS to existing GPS/INS(MEMS) systems using loose and tight integration strategies. The relative benefits of various constraints are also assessed. Results show that when satellite visibility is poor (approximately 50% solution availability) the benefits of GLONASS are only seen with tight integration algorithms. For more benign environments, a loosely coupled GPS/GLONASS/INS system offers performance comparable to that of a tightly coupled GPS/INS system, but with reduced complexity and development time. PMID:22666079

  10. Robust Real-Time Wide-Area Differential GPS Navigation

    NASA Technical Reports Server (NTRS)

    Yunck, Thomas P. (Inventor); Bertiger, William I. (Inventor); Lichten, Stephen M. (Inventor); Mannucci, Anthony J. (Inventor); Muellerschoen, Ronald J. (Inventor); Wu, Sien-Chong (Inventor)

    1998-01-01

    The present invention provides a method and a device for providing superior differential GPS positioning data. The system includes a group of GPS receiving ground stations covering a wide area of the Earth's surface. Unlike other differential GPS systems wherein the known position of each ground station is used to geometrically compute an ephemeris for each GPS satellite. the present system utilizes real-time computation of satellite orbits based on GPS data received from fixed ground stations through a Kalman-type filter/smoother whose output adjusts a real-time orbital model. ne orbital model produces and outputs orbital corrections allowing satellite ephemerides to be known with considerable greater accuracy than from die GPS system broadcasts. The modeled orbits are propagated ahead in time and differenced with actual pseudorange data to compute clock offsets at rapid intervals to compensate for SA clock dither. The orbital and dock calculations are based on dual frequency GPS data which allow computation of estimated signal delay at each ionospheric point. These delay data are used in real-time to construct and update an ionospheric shell map of total electron content which is output as part of the orbital correction data. thereby allowing single frequency users to estimate ionospheric delay with an accuracy approaching that of dual frequency users.

  11. A LEO Satellite Navigation Algorithm Based on GPS and Magnetometer Data

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Bar-Itzhack, Itzhack Y.; Harman, Rick

    2000-01-01

    The Global Position System (GPS) has become a standard method for low cost onboard satellite orbit determination. The use of GPS as an attitude and rate sensor has also been developed in the recent past. Additionally, focus has been given to attitude and orbit estimation using the magnetometer, a low cost, reliable sensor. Combining measurements from both GPS and a magnetometer can provide a robust navigation system which takes advantage of the estimation qualities of both measurements. Ultimately a low cost, accurate navigation system can result, potentially eliminating the need for more costly sensors, including gyroscopes. This work presents the development and preliminary testing of a unified navigation algorithm which produces estimates of attitude, angular rate, position, and velocity for a low earth orbit (LEO) spacecraft. The system relies on GPS phase, range, and range rate data as well as magnetometer data. The algorithm used is an extended Kalman filter (EKF) developed to provide LEO attitude, orbit, and rate estimates using magnetometer and sun sensor data. Incorporating sun sensor data into the EKF improved the attitude and rate estimates. For many LEO spacecraft the sun data is available during only a portion of the orbit. However, GPS data is available continuously throughout the orbit. GPS can produce accurate orbit estimates and combining GPS and magnetometer data improves the attitude and rate estimates. The magnetometer based EKF can converge from large initial errors in position, velocity, and 3 attitude . Combining the magnetometer and GPS data into a single EKF will provide a more robust and accurate system. The EKF is based on an existing EKF. The GPS measurement models for phase, range, and range rate are incorporated into the existing structure of the filter. The original EKF produced the orbit estimates in terms of Keplerian elements. Due to the nature of the GPS measurements and ease of computation, the orbit estimates are converted to the Cartesian position and velocity. The measurement model for the magnetometer is adjusted for this change in the state and the measurements. Preliminary test results based on simulated GPS and magnetometer data are included.

  12. Applications of Clocks to Space Navigation & "Planetary GPS"

    NASA Technical Reports Server (NTRS)

    Lichten, Stephen M.

    2004-01-01

    The ability to fly atomic clocks on GPS satellites has profoundly defined the capabilities and limitations of GPS in near-Earth applications. It is likely that future infrastructure for Lunar and Mars applications will be constrained by financial factors. The development of a low cost, small, high performance space clock -- or ultrahigh performance space clocks -- could revolutionize and drive the entire approach to GPS-like systems at the Moon (or Mars), and possibly even change the future of GPS at Earth. Many system trade studies are required. The performance of future GPS-like tracking systems at the Moon or Mars will depend critically on clock performance, availability of inertial sensors, and constellation coverage. Example: present-day GPS carry 10(exp -13) clocks and require several updates per day. With 10(exp -15) clocks, a constellation at Mars could operate autonomously with updates just once per month. Use of GPS tracking at the Moon should be evaluated in a technical study.

  13. RANGE - Robust autonomous navigation in GPS-denied environments

    E-print Network

    Bachrach, Abraham Galton

    This video highlights our system that enables a Micro Aerial Vehicle (MAV) to autonomously explore and map unstructured and unknown GPS-denied environments. While mapping and exploration solutions are now well-established ...

  14. GPS/Galileo navigation in GTO/GEO orbit

    NASA Astrophysics Data System (ADS)

    Marmet, François-Xavier; Maureau, Jerome; Calaprice, Massimiliano; Aguttes, Jean Paul

    2015-12-01

    The development of electrically propelled geostationary platforms, together with alternative strategies to reach geostationary orbit, increase the interest for autonomous satellite localization and particularly GNSS navigation for high altitude orbits. It is known that GNSS navigation in GTO/GEO is much more difficult than in LEO since the GNSS receiver is often or permanently at an altitude greater than the altitude of the GNSS constellations, making the GNSS signals drastically less available and weaker. This work is about GPS and Galileo navigation on GEO and GTO orbits, with revised hypotheses compared to studies sometimes more than 15 years old. Moreover, the study goes beyond GNSS geometrical visibility by dealing with operating thresholds and showing the sensitivity to key GNSS receiver thresholds and simulation hypotheses. Comprehensive simulation results and analyses come along with a discussion of the operational benefits of using GPS and Galileo navigation. These data eventually set the ground for a discussion of the key technical options (number and antenna types, GNSS function architecture, signal processing algorithms, orbital filter…). It is shown that using GNSS for GTOGEO orbits is feasible, even considering current spaceborne receivers state-of-the-art, and provides most of the acclaimed benefits of GNSS in LEO, among them more accurate spacecraft localization, precise onboard absolute time and increased autonomy.

  15. A New Centimeter-Level Real-Time Global Navigation and Positioning Capability with GPS

    NASA Technical Reports Server (NTRS)

    Bar-Sever, Yoaz

    2001-01-01

    NASA/JPL has developed a new, precise, global, GPS-based capability for real-time terrestrial and space platform navigation. It has been demonstrated on Earth's surface and is 10 times more accurate than other real-time GPS-based systems. The new system poses certain advantages for Earth science remote sensing, including: the onboard generation of science data products in real-time, sensor control and reduction of data transmission bandwidth, improved environmental forecasting, autonomous and intelligent platform control, operations cost savings, and technology transfer and commercial partnership opportunities. The system's measurement capabilities and applications, demonstrated orbit accuracies, and precision LEO and spacecraft positioning and timing are highlighted.

  16. Autonomous integrated GPS/INS navigation experiment for OMV. Phase 1: Feasibility study

    NASA Technical Reports Server (NTRS)

    Upadhyay, Triveni N.; Priovolos, George J.; Rhodehamel, Harley

    1990-01-01

    The phase 1 research focused on the experiment definition. A tightly integrated Global Positioning System/Inertial Navigation System (GPS/INS) navigation filter design was analyzed and was shown, via detailed computer simulation, to provide precise position, velocity, and attitude (alignment) data to support navigation and attitude control requirements of future NASA missions. The application of the integrated filter was also shown to provide the opportunity to calibrate inertial instrument errors which is particularly useful in reducing INS error growth during times of GPS outages. While the Orbital Maneuvering Vehicle (OMV) provides a good target platform for demonstration and for possible flight implementation to provide improved capability, a successful proof-of-concept ground demonstration can be obtained using any simulated mission scenario data, such as Space Transfer Vehicle, Shuttle-C, Space Station.

  17. GPS Cycle Slip Detection Considering Satellite Geometry Based on TDCP/INS Integrated Navigation.

    PubMed

    Kim, Younsil; Song, Junesol; Kee, Changdon; Park, Byungwoon

    2015-01-01

    This paper presents a means of carrier phase cycle slip detection for an inertial-aided global positioning system (GPS), which is based on consideration of the satellite geometry. An integrated navigation solution incorporating a tightly coupled time differenced carrier phase (TDCP) and inertial navigation system (INS) is used to detect cycle slips. Cycle-slips are detected by comparing the satellite-difference (SD) and time-difference (TD) carrier phase measurements obtained from the GPS satellites with the range estimated by the integrated navigation solution. Additionally the satellite geometry information effectively improves the range estimation performance without a hardware upgrade. And the covariance obtained from the TDCP/INS filter is used to compute the threshold for determining cycle slip occurrence. A simulation and the results of a vehicle-based experiment verify the cycle slip detection performance of the proposed algorithm. PMID:26437412

  18. GPS Cycle Slip Detection Considering Satellite Geometry Based on TDCP/INS Integrated Navigation

    PubMed Central

    Kim, Younsil; Song, Junesol; Kee, Changdon; Park, Byungwoon

    2015-01-01

    This paper presents a means of carrier phase cycle slip detection for an inertial-aided global positioning system (GPS), which is based on consideration of the satellite geometry. An integrated navigation solution incorporating a tightly coupled time differenced carrier phase (TDCP) and inertial navigation system (INS) is used to detect cycle slips. Cycle-slips are detected by comparing the satellite-difference (SD) and time-difference (TD) carrier phase measurements obtained from the GPS satellites with the range estimated by the integrated navigation solution. Additionally the satellite geometry information effectively improves the range estimation performance without a hardware upgrade. And the covariance obtained from the TDCP/INS filter is used to compute the threshold for determining cycle slip occurrence. A simulation and the results of a vehicle-based experiment verify the cycle slip detection performance of the proposed algorithm. PMID:26437412

  19. GPS(global positioning system) , , . D. Patterson GPS(Global Positioning

    E-print Network

    Cho, Sung-Bae

    . . . GPS(global positioning system) , , , , [1]. , . . . . D. Patterson GPS(Global Positioning System) GPS [2]. D. Ashbrook GPS k-means [3]. . . GPS . GPS 10m . SOM(self-organizing map) . SOM GPS . . 1 . , . RSOM(recurrent SOM) . SOM . RSOM SOM [4]. SOM . GPS . #12;GPS Sensor Train SOM Build Local

  20. Meta-image navigation augmenters for GPS denied mountain navigation of small UAS

    NASA Astrophysics Data System (ADS)

    Wang, Teng; ?elik, Koray; Somani, Arun K.

    2014-06-01

    We present a novel approach to use mountain drainage patterns for GPS-Denied navigation of small unmanned aerial systems (UAS) such as the ScanEagle, utilizing a down-looking fixed focus monocular imager. Our proposal allows extension of missions to GPS-denied mountain areas, with no assumption of human-made geographic objects. We leverage the analogy between mountain drainage patterns, human arteriograms, and human fingerprints, to match local drainage patterns to Graphics Processing Unit (GPU) rendered parallax occlusion maps of geo-registered radar returns (GRRR). Details of our actual GPU algorithm is beyond the subject of this paper, and is planned as a future paper. The matching occurs in real-time, while GRRR data is loaded on-board the aircraft pre-mission, so as not to require a scanning aperture radar during the mission. For recognition purposes, we represent a given mountain area with a set of spatially distributed mountain minutiae, i.e., details found in the drainage patterns, so that conventional minutiae-based fingerprint matching approaches can be used to match real-time camera image against template images in the training set. We use medical arteriography processing techniques to extract the patterns. The minutiae-based representation of mountains is achieved by first exposing mountain ridges and valleys with a series of filters and then extracting mountain minutiae from these ridges/valleys. Our results are experimentally validated on actual terrain data and show the effectiveness of minutiae-based mountain representation method. Furthermore, we study how to select landmarks for UAS navigation based on the proposed mountain representation and give a set of examples to show its feasibility. This research was in part funded by Rockwell Collins Inc.

  1. Landsat/4/Global Positioning System navigation results

    NASA Technical Reports Server (NTRS)

    Heuberger, H.; Church, L.

    1984-01-01

    An experimental GPSPAC flown on the Landsat-4 spacecraft was the first spaceborne navigation system to use the NAVSTAR Global Position System (GPS). In order to validate the accuracy and reliability of GPSPAC orbit solutions, definitive Landsat-4 ephemerides, derived from ground based tracking data, were generated and compared with GPSPAC estimates. In addition, Landsat-4 orbital solutions were reconstructed from raw GPS measurement data with a GPSPAC navigation simulator program using different Kalman filter constants. Ephemeris comparisons and simulator results are presented, as well as recommendations for the navigation filter.

  2. A state dynamics method for integrated GPS/INS navigation and its application to aircraft precision approach

    NASA Astrophysics Data System (ADS)

    Chan, Fang-Cheng

    In recent years, GPS navigation systems have found widespread use in many diverse applications. The achievements of GPS navigation systems in positioning and navigation services have been nothing short of extraordinary. With the use of carrier phase measurements and Differential GPS (DGPS), centimeter-level performance is achievable today. Therefore, the principal issues for modern navigation are not related to accuracy per se, but robustness. Unfortunately in this regard, all radionavigation systems are subject to Radio Frequency Interference (RFI). In response, this research is focused on the development of interference-robust navigation systems for aviation applications. A new dual-frequency Carrier-phase DGPS (CDGPS) architecture has been developed in this research and its performance was evaluated relative to the requirements for a unique shipboard landing application. RFI vulnerability was addressed for this application by directly incorporating a single frequency architecture as a back-up in the event of hostile jamming on one frequency. For critical civil aviation applications without access to dual frequency GPS signals, a novel method for tightly-coupling GPS and Inertial Navigation Sensors (INS) was developed to address the signal vulnerability issue. The new hybrid navigation system, based on the direct fusion of GPS and INS using state dynamics, is a mathematically rigorous approach, yet it is more direct and simpler to implement than existing GPS/INS integration schemes. The hybrid navigation system was validated with flight data, and predicted system performance was evaluated using a covariance analysis method. Necessary conditions on INS sensor and gravity model quality were derived to ensure that the hybrid system performance is compliant with navigation requirements for aircraft precision approach and landing. In addition, a new fault detection algorithm, based on integrated Kalman filter innovations, was developed and evaluated against other existing GPS fault detection methods and radar altimeter detection technique. It is shown that the new algorithm outperforms existing methods in the detection of slowly developing ranging errors, such as those caused by ionospheric and tropospheric anomalies. It is also demonstrated that the radar detection technique can provide a significant benefit to navigation system integrity.

  3. Application of aircraft navigation sensors to enhanced vision systems

    NASA Technical Reports Server (NTRS)

    Sweet, Barbara T.

    1993-01-01

    In this presentation, the applicability of various aircraft navigation sensors to enhanced vision system design is discussed. First, the accuracy requirements of the FAA for precision landing systems are presented, followed by the current navigation systems and their characteristics. These systems include Instrument Landing System (ILS), Microwave Landing System (MLS), Inertial Navigation, Altimetry, and Global Positioning System (GPS). Finally, the use of navigation system data to improve enhanced vision systems is discussed. These applications include radar image rectification, motion compensation, and image registration.

  4. Simulation of a navigator algorithm for a low-cost GPS receiver

    NASA Technical Reports Server (NTRS)

    Hodge, W. F.

    1980-01-01

    The analytical structure of an existing navigator algorithm for a low cost global positioning system receiver is described in detail to facilitate its implementation on in-house digital computers and real-time simulators. The material presented includes a simulation of GPS pseudorange measurements, based on a two-body representation of the NAVSTAR spacecraft orbits, and a four component model of the receiver bias errors. A simpler test for loss of pseudorange measurements due to spacecraft shielding is also noted.

  5. An Integrated UAV Navigation System Based on Aerial Image Matching.

    E-print Network

    Doherty, Patrick

    An Integrated UAV Navigation System Based on Aerial Image Matching. Gianpaolo Conte and Patrick Vehicle (UAV) navigation system in case of GPS failure. A vision based navigation system which com- bines inertial sensors, visual odometer and registration of a UAV on-board video to a given geo-referenced aerial

  6. Testing the Preliminary X-33 Navigation System

    NASA Technical Reports Server (NTRS)

    Lomas, James J.; Mitchell, Daniel W.; Freestone, Todd M.; Lee, Charles; Lessman, Craig; Foster, Lee D. (Technical Monitor)

    2001-01-01

    The X-33 Reusable Launch Vehicle (RLV) must meet the demanding requirements of landing autonomously on a narrow landing strip following a flight that reaches an altitude of up to 200,000 feet and a speed in excess of Mach 9 with significant in-flight energy bleed-off maneuvers. To execute this flight regimen a highly reliable avionics system has been designed that includes three LN-100G Inertial Navigation System/Global Positioning System (INS/GPS) units as the primary navigation system for the X-33. NASA's Marshall Space Flight Center (MSFC) tested an INS/GPS system in real-time simulations to determine the ability of this navigation suite to meet the in flight and autonomous landing requirements of the X-33 RLV. A total of sixty-one open loop tests were performed to characterize the navigation accuracy of the LN-100G. Twenty-seven closed-loop tests were also performed to evaluate the performance of the X-33 Guidance, Navigation and Control (GN&C) algorithms with the real navigation hardware. These closed-loop tests were also designed to expose any integration or operational issues with the real-time X-33 vehicle simulation. Dynamic road tests of the INS/GPS were conducted by Litton to assess the performance of differential and nondifferential INS/GPS hybrid navigation solutions. The results of the simulations and road testing demonstrate that this novel solution is capable of meeting the demanding requirements of take-off, in-flight navigation, and autonomous landing of the X-33 RLV. This paper describes the test environment developed to stimulate the LN-100G and discusses the results of this test effort. This paper also presents recommendations for a navigation system suitable to an operational RLV system.

  7. 77 FR 16860 - Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ..., 6,865,452, and 7,209,070. 76 FR 39896 (July 7, 2011). The notice of investigation named as... Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of Investigation on... within the United States after importation of certain GPS navigation products, components thereof,...

  8. 76 FR 39896 - In the Matter of Certain GPS Navigation Products, Components Thereof, and Related Software...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-07

    ... COMMISSION In the Matter of Certain GPS Navigation Products, Components Thereof, and Related Software; Notice... importation, and the sale within the United States after importation of certain GPS navigation products... States, the sale for importation, or the sale within the United States after importation of certain...

  9. GPS World | November2011 www.gpsworld.com44 INNOVATION | System Design & Test

    E-print Network

    Stanford University

    GPS World | November2011 www.gpsworld.com44 INNOVATION | System Design & Test T he Navstar Global Positioning System is so far the most widely used space-based positioning, navigation, and timing system. GPS to at least four GPS sat- ellites in view, as well as the position and clock data for these satellites

  10. GPS navigation algorithms for Autonomous Airborne Refueling of Unmanned Air Vehicles

    NASA Astrophysics Data System (ADS)

    Khanafseh, Samer Mahmoud

    Unmanned Air Vehicles (UAVs) have recently generated great interest because of their potential to perform hazardous missions without risking loss of life. If autonomous airborne refueling is possible for UAVs, mission range and endurance will be greatly enhanced. However, concerns about UAV-tanker proximity, dynamic mobility and safety demand that the relative navigation system meets stringent requirements on accuracy, integrity, and continuity. In response, this research focuses on developing high-performance GPS-based navigation architectures for Autonomous Airborne Refueling (AAR) of UAVs. The AAR mission is unique because of the potentially severe sky blockage introduced by the tanker. To address this issue, a high-fidelity dynamic sky blockage model was developed and experimentally validated. In addition, robust carrier phase differential GPS navigation algorithms were derived, including a new method for high-integrity reacquisition of carrier cycle ambiguities for recently-blocked satellites. In order to evaluate navigation performance, world-wide global availability and sensitivity covariance analyses were conducted. The new navigation algorithms were shown to be sufficient for turn-free scenarios, but improvement in performance was necessary to meet the difficult requirements for a general refueling mission with banked turns. Therefore, several innovative methods were pursued to enhance navigation performance. First, a new theoretical approach was developed to quantify the position-domain integrity risk in cycle ambiguity resolution problems. A mechanism to implement this method with partially-fixed cycle ambiguity vectors was derived, and it was used to define tight upper bounds on AAR navigation integrity risk. A second method, where a new algorithm for optimal fusion of measurements from multiple antennas was developed, was used to improve satellite coverage in poor visibility environments such as in AAR. Finally, methods for using data-link extracted measurements as an additional inter-vehicle ranging measurement were also introduced. The algorithms and methods developed in this work are generally applicable to realize high-performance GPS-based navigation in partially obstructed environments. Navigation performance for AAR was quantified through covariance analysis, and it was shown that the stringent navigation requirements for this application are achievable. Finally, a real-time implementation of the algorithms was developed and successfully validated in autopiloted flight tests.

  11. HaptiGo Tactile Navigation System 

    E-print Network

    Regmi, Sarin

    2012-04-22

    developed a navigation system, HaptiGo, which uses a tactile harness controlled by an Android application to communicate directions. The use of a smartphone to provide GPS and compass information allows for a more compact and user-friendly system...

  12. Autonomous satellite navigation with the Global Positioning System

    NASA Technical Reports Server (NTRS)

    Fuchs, A. J.; Wooden, W. H., II; Long, A. C.

    1977-01-01

    This paper discusses the potential of using the Global Positioning System (GPS) to provide autonomous navigation capability to NASA satellites in the 1980 era. Some of the driving forces motivating autonomous navigation are presented. These include such factors as advances in attitude control systems, onboard science annotation, and onboard gridding of imaging data. Simulation results which demonstrate baseline orbit determination accuracies using GPS data on Seasat, Landsat-D, and the Solar Maximum Mission are presented. Emphasis is placed on identifying error sources such as GPS time, GPS ephemeris, user timing biases, and user orbit dynamics, and in a parametric sense on evaluating their contribution to the orbit determination accuracies.

  13. Introduction to Global Navigation Satellite System

    NASA Technical Reports Server (NTRS)

    Moreau, Michael

    2005-01-01

    This viewgraph presentation reviews the fundamentals of satellite navigation, and specifically how GPS works. It presents an overview and status of Global Positioning System, for both the current GPS, and plans to modernize it in the future. There is also a overview and status of other Global Navigation Satellite System (GNSS), specifically GLONASS, Galileo, and QZSS. There is also a review of Satellite based time transfer techniques. The topic is of interest to the Time and Frequency Community, because the Global Positioning system has become the primary system for distributing Time and frequency globally, and because it allows users to synchronize clocks and calibrate and control oscillators in any location that has a GPS antenna.

  14. Abstract--There is an increasing demand for use of the Global Positioning System (GPS) to navigate or track objects in the

    E-print Network

    Washington at Seattle, University of

    in position calculation. Multipath propagation of GPS signals is one of the main sources of GPS errors and phase significantly. The magnitude of pseudorange error caused by multipath propagations can be as high and branches, can reflect GPS signals and result in large position errors. Canopies in the forest will also

  15. Abstract--There is an increasing demand for use of the Global Positioning System (GPS) to navigate or track objects in the

    E-print Network

    Wang, Yinhai

    . Multipath propagation of GPS signals is one of the main sources of GPS errors in the forest. Objects near. The magnitude of pseudorange error caused by multipath propagations can be as high as 230~260 feet [1]. Another and branches, can reflect GPS signals and result in large position errors. Canopies in the forest will also

  16. A navigation algorithm for single channel low-cost GPS receiver

    NASA Technical Reports Server (NTRS)

    Parsiani, H.; Noe, P. S.; Rhyne, V. T.; Painter, J. H.

    1979-01-01

    A sequential navigation algorithm for a navigator using the Global Positioning System satellites is developed and tested for both noise-free and noisy system models. Data from a six-hour flight from California to Hawaii (C5A aircraft) simulates a true user to test the accuracy of the user's position for a sequential navigation system. For error reduction in the user's position in the sequential navigation system (considering 100 m as a maximum average error tolerated by any low-cost GPS user) an analysis of error sources in the sequential system has led to the use of range-ephemeris rate to translate ranges to a common point in time and to use velocity aiding at the time of a satellite disappearance. To reduce the user's position and velocity errors in a noisy navigation system an 'alpha-beta' two-pole filter is implemented whose optimum alpha is obtained experimentally. A user's position error of 73 m at noise range error of 30.48 (1sigma) is achieved.

  17. LEAPFROG NAVIGATION SYSTEM Guttorm R. Opshaug

    E-print Network

    Stanford University

    progresses, all units take turns acting as fixed or mobile stations, and the entire group can leapfrog groups work on self-configuring navigation systems. The Mars Rover project at Stanford University use GPS of a rover and 3 fixed stations [2]. A group at Worchester Polytechnic Institute has suggested a real

  18. Tightly Coupled Low Cost 3D RISS/GPS Integration Using a Mixture Particle Filter for Vehicular Navigation

    PubMed Central

    Georgy, Jacques; Noureldin, Aboelmagd

    2011-01-01

    Satellite navigation systems such as the global positioning system (GPS) are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS)-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF). Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF) was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D) reduced inertial sensors system (RISS) with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle’s odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s) even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift, which are loosely-coupled updates, a hybrid loosely/tightly coupled solution is proposed. This solution is suitable for downtown environments because of the long natural outages or degradation of GPS. The performance of the proposed 3D Navigation solution using Mixture PF for 3D RISS/GPS integration is examined by road test trajectories in a land vehicle and compared to the KF counterpart. PMID:22163846

  19. Tightly coupled low cost 3D RISS/GPS integration using a mixture particle filter for vehicular navigation.

    PubMed

    Georgy, Jacques; Noureldin, Aboelmagd

    2011-01-01

    Satellite navigation systems such as the global positioning system (GPS) are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS)-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF). Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF) was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D) reduced inertial sensors system (RISS) with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle's odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s) even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift, which are loosely-coupled updates, a hybrid loosely/tightly coupled solution is proposed. This solution is suitable for downtown environments because of the long natural outages or degradation of GPS. The performance of the proposed 3D Navigation solution using Mixture PF for 3D RISS/GPS integration is examined by road test trajectories in a land vehicle and compared to the KF counterpart. PMID:22163846

  20. An Effective Approach to Improving Low-Cost GPS Positioning Accuracy in Real-Time Navigation

    PubMed Central

    Islam, Md. Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4–10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679

  1. An effective approach to improving low-cost GPS positioning accuracy in real-time navigation.

    PubMed

    Islam, Md Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4-10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679

  2. Institute of Navigation National Technical Meeting/San Diego/January 25-27, 1999 1 Real-Time GPS Reference Network Carrier

    E-print Network

    Calgary, University of

    Reference Network Carrier Phase Ambiguity Resolution H. Sun, Kvaerner Marine Automation M.E. Cannon related to GPS and integrated GPS/INS systems. She is a Past President of the Institute of Navigation. Tor that occurs as a function of distance. A network of reference stations can however be used to model errors

  3. A New Indoor Positioning System Architecture Using GPS Signals.

    PubMed

    Xu, Rui; Chen, Wu; Xu, Ying; Ji, Shengyue

    2015-01-01

    The pseudolite system is a good alternative for indoor positioning systems due to its large coverage area and accurate positioning solution. However, for common Global Positioning System (GPS) receivers, the pseudolite system requires some modifications of the user terminals. To solve the problem, this paper proposes a new pseudolite-based indoor positioning system architecture. The main idea is to receive real-world GPS signals, repeat each satellite signal and transmit those using indoor transmitting antennas. The transmitted GPS-like signal can be processed (signal acquisition and tracking, navigation data decoding) by the general receiver and thus no hardware-level modification on the receiver is required. In addition, all Tx can be synchronized with each other since one single clock is used in Rx/Tx. The proposed system is simulated using a software GPS receiver. The simulation results show the indoor positioning system is able to provide high accurate horizontal positioning in both static and dynamic situations. PMID:25938199

  4. A New Indoor Positioning System Architecture Using GPS Signals

    PubMed Central

    Xu, Rui; Chen, Wu; Xu, Ying; Ji, Shengyue

    2015-01-01

    The pseudolite system is a good alternative for indoor positioning systems due to its large coverage area and accurate positioning solution. However, for common Global Positioning System (GPS) receivers, the pseudolite system requires some modifications of the user terminals. To solve the problem, this paper proposes a new pseudolite-based indoor positioning system architecture. The main idea is to receive real-world GPS signals, repeat each satellite signal and transmit those using indoor transmitting antennas. The transmitted GPS-like signal can be processed (signal acquisition and tracking, navigation data decoding) by the general receiver and thus no hardware-level modification on the receiver is required. In addition, all Tx can be synchronized with each other since one single clock is used in Rx/Tx. The proposed system is simulated using a software GPS receiver. The simulation results show the indoor positioning system is able to provide high accurate horizontal positioning in both static and dynamic situations. PMID:25938199

  5. Integration of the B-52G Offensive Avionics System (OAS) with the Global Positioning System (GPS)

    NASA Astrophysics Data System (ADS)

    Foote, A. L.; Pluntze, S. C.

    Integration of the B-52G OAS with the GPS has been accomplished by modification of existing OAS software. GPS derived position and velocity data are used to enhance the quality of the OAS inertial and dead reckoning navigation systems. The engineering design and the software development process used to implement this design are presented.

  6. Autocalibrating vision guided navigation of unmanned air vehicles via tactical monocular cameras in GPS denied environments

    NASA Astrophysics Data System (ADS)

    Celik, Koray

    This thesis presents a novel robotic navigation strategy by using a conventional tactical monocular camera, proving the feasibility of using a monocular camera as the sole proximity sensing, object avoidance, mapping, and path-planning mechanism to fly and navigate small to medium scale unmanned rotary-wing aircraft in an autonomous manner. The range measurement strategy is scalable, self-calibrating, indoor-outdoor capable, and has been biologically inspired by the key adaptive mechanisms for depth perception and pattern recognition found in humans and intelligent animals (particularly bats), designed to assume operations in previously unknown, GPS-denied environments. It proposes novel electronics, aircraft, aircraft systems, systems, and procedures and algorithms that come together to form airborne systems which measure absolute ranges from a monocular camera via passive photometry, mimicking that of a human-pilot like judgement. The research is intended to bridge the gap between practical GPS coverage and precision localization and mapping problem in a small aircraft. In the context of this study, several robotic platforms, airborne and ground alike, have been developed, some of which have been integrated in real-life field trials, for experimental validation. Albeit the emphasis on miniature robotic aircraft this research has been tested and found compatible with tactical vests and helmets, and it can be used to augment the reliability of many other types of proximity sensors.

  7. Shuttle Global Positioning (GPS) System design study

    NASA Technical Reports Server (NTRS)

    Nilsen, P.; Huth, G. K.

    1980-01-01

    Investigations of certain aspects and problems of the shuttle global positioning system GPS, are presented. Included are: test philosophy and test outline; development of a phase slope specification for the shuttle GPS antenna; an investigation of the shuttle jamming vulnerability; and an expression for the GPS signal to noise density ratio for the thermal protection system.

  8. IMU/GPS System Provides Position and Attitude Data

    NASA Technical Reports Server (NTRS)

    Lin, Ching Fang

    2006-01-01

    A special navigation system is being developed to provide high-quality information on the position and attitude of a moving platform (an aircraft or spacecraft), for use in pointing and stabilization of a hyperspectral remote-sensing system carried aboard the platform. The system also serves to enable synchronization and interpretation of readouts of all onboard sensors. The heart of the system is a commercially available unit, small enough to be held in one hand, that contains an integral combination of an inertial measurement unit (IMU) of the microelectromechanical systems (MEMS) type, Global Positioning System (GPS) receivers, a differential GPS subsystem, and ancillary data-processing subsystems. The system utilizes GPS carrier-phase measurements to generate time data plus highly accurate and continuous data on the position, attitude, rotation, and acceleration of the platform. Relative to prior navigation systems based on IMU and GPS subsystems, this system is smaller, is less expensive, and performs better. Optionally, the system can easily be connected to a laptop computer for demonstration and evaluation. In addition to airborne and spaceborne remote-sensing applications, there are numerous potential terrestrial sensing, measurement, and navigation applications in diverse endeavors that include forestry, environmental monitoring, agriculture, mining, and robotics.

  9. Onboard Navigation Systems Characteristics

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The space shuttle onboard navigation systems characteristics are described. A standard source of equations and numerical data for use in error analyses and mission simulations related to space shuttle development is reported. The sensor characteristics described are used for shuttle onboard navigation performance assessment. The use of complete models in the studies depend on the analyses to be performed, the capabilities of the computer programs, and the availability of computer resources.

  10. High accuracy integrated global positioning system/inertial navigation system LDRD: Final report

    SciTech Connect

    Owen, T.E.; Meindl, M.A.; Fellerhoff, J.R.

    1997-03-01

    This report contains the results of a Sandia National Laboratories Directed Research and Development (LDRD) program to investigate the integration of Global Positioning System (GPS) and inertial navigation system (INS) technologies toward the goal of optimizing the navigational accuracy of the combined GPSANS system. The approach undertaken is to integrate the data from an INS, which has long term drifts, but excellent short term accuracy, with GPS carrier phase signal information, which is accurate to the sub-centimeter level, but requires continuous tracking of the GPS signals. The goal is to maintain a sub-meter accurate navigation solution while the vehicle is in motion by using the GPS measurements to estimate the INS navigation errors and then using the refined INS data to aid the GPS carrier phase cycle slip detection and correction and bridge dropouts in the GPS data. The work was expanded to look at GPS-based attitude determination, using multiple GPS receivers and antennas on a single platform, as a possible navigation aid. Efforts included not only the development of data processing algorithms and software, but also the collection and analysis of GPS and INS flight data aboard a Twin Otter aircraft. Finally, the application of improved navigation system accuracy to synthetic aperture radar (SAR) target location is examined.

  11. GPS Navigation Solutions by Analogue Neural Network Least-Squares Processors

    NASA Astrophysics Data System (ADS)

    Jwo, Dah-Jing

    2005-01-01

    The solution for the receiver's position and clock bias using four or more GPS pseudorange measurements involve nonlinear quadratic equations. One of the popular techniques attempts to linearise the equations and solve them by the least-squares (LS) scheme based on an iterative gradient approach. For real-time applications when the solution is to be obtained within a time of the order of a hundred nanoseconds, a digital computer often cannot comply with the desired computation time, or its use is too expensive. In this paper, two ordinary differential equation formulation schemes and corresponding circuits of neuron-like analog processors will be employed for GPS navigation processing. The circuits of simple neuron-like analog processors are employed essentially for solving systems of linear equations based on the criterion of mean square error minimization, which is commonly utilized for determining positioning solutions in the GPS receivers. Experiments on single epoch and thereafter dynamic positioning will be conducted by computer simulation to validate the usefulness of the proposed scheme. The solutions will be assessed and compared to those provided by the conventional method in which pseudo-inverse matrix calculation by digital computer is involved.

  12. GPS-Based Navigation And Orbit Determination for the AMSAT AO-40 Satellite

    NASA Technical Reports Server (NTRS)

    Davis, George; Moreau, Michael; Carpenter, Russell; Bauer, Frank

    2002-01-01

    The AMSAT OSCAR-40 (AO-40) spacecraft occupies a highly elliptical orbit (HEO) to support amateur radio experiments. An interesting aspect of the mission is the attempted use of GPS for navigation and attitude determination in HEO. Previous experiences with GPS tracking in such orbits have demonstrated the ability to acquire GPS signals, but very little data were produced for navigation and orbit determination studies. The AO-40 spacecraft, flying two Trimble Advanced Navigation Sensor (TANS) Vector GPS receivers for signal reception at apogee and at perigee, is the first to demonstrate autonomous tracking of GPS signals from within a HEO with no interaction from ground controllers. Moreover, over 11 weeks of total operations as of June 2002, the receiver has returned a continuous stream of code phase, Doppler, and carrier phase measurements useful for studying GPS signal characteristics and performing post-processed orbit determination studies in HEO. This paper presents the initial efforts to generate AO-40 navigation solutions from pseudorange data reconstructed from the TANS Vector code phase, as well as to generate a precise orbit solution for the AO-40 spacecraft using a batch filter.

  13. Navigating the Return Trip from the Moon Using Earth-Based Ground Tracking and GPS

    NASA Technical Reports Server (NTRS)

    Berry, Kevin; Carpenter, Russell; Moreau, Michael C.; Lee, Taesul; Holt, Gregg N.

    2009-01-01

    NASA s Constellation Program is planning a human return to the Moon late in the next decade. From a navigation perspective, one of the most critical phases of a lunar mission is the series of burns performed to leave lunar orbit, insert onto a trans-Earth trajectory, and target a precise re-entry corridor in the Earth s atmosphere. A study was conducted to examine sensitivity of the navigation performance during this phase of the mission to the type and availability of tracking data from Earth-based ground stations, and the sensitivity to key error sources. This study also investigated whether GPS measurements could be used to augment Earth-based tracking data, and how far from the Earth GPS measurements would be useful. The ability to track and utilize weak GPS signals transmitted across the limb of the Earth is highly dependent on the configuration and sensitivity of the GPS receiver being used. For this study three GPS configurations were considered: a "standard" GPS receiver with zero dB antenna gain, a "weak signal" GPS receiver with zero dB antenna gain, and a "weak signal" GPS receiver with an Earth-pointing direction antenna (providing 10 dB additional gain). The analysis indicates that with proper selection and configuration of the GPS receiver on the Orion spacecraft, GPS can potentially improve navigation performance during the critical final phases of flight prior to Earth atmospheric entry interface, and may reduce reliance on two-way range tracking from Earth-based ground stations.

  14. Ranging error overbounds for navigation integrity of local area augmented GPS

    NASA Astrophysics Data System (ADS)

    Sayim, Irfan

    The use of Differential GPS (DGPS) in aviation has been especially attractive in the past decade because of its potential to provide the means for satellite-based aircraft navigation spanning all aspects of flight, from takeoff to touchdown, with low cost and high availability. While this has been an inspiring goal, serious technical obstacles exist, the most difficult of which are related with navigation integrity for aircraft precision approach and landing. For example, for Category I precision approach, it is required that integrity risk (probability of hazardously misleading navigation information) never exceed 10-8. The Local Area Augmentation System (LAAS) is the DGPS architecture standard under development by the Federal Aviation Administration (FAA) to provide precision approach and landing navigation for civil aircraft. Navigation integrity risk for LAAS will be managed at the aircraft via the computation of Protection Levels, which are position error bounds within which navigation integrity is to be ensured. Existing standardized algorithms for the generation of the protection levels implicitly assume zero-mean, normally distributed ranging error distributions. Unfortunately, while the assumed error model is likely consistent with the effects of certain error sources (receiver thermal noise and diffuse multipath), it is widely understood that significant remaining errors, such as ground reflection multipath and systematic receiver/antenna errors, cannot be directly modeled by zero-mean normal distributions. In this dissertation, the critical issues concerning establishment and sufficiency of overbounding ranging error distributions are addressed in detail. These include: quantification of the sensitivity of integrity risk due to statistical uncertainty; derivation of theoretical bounding models for non-zero-mean error sources; derivation of new bounding distribution models for non-gaussian ground-reflection multipath error; quantification and compensation for the effects of seasonal variation of multipath error; development, implementation, and testing of a new, adaptive binning algorithm to conservatively accommodate non-stationary and time-correlated empirical satellite ranging error data.

  15. Cloud Absorption Radiometer Autonomous Navigation System - CANS

    NASA Technical Reports Server (NTRS)

    Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan

    2013-01-01

    CAR (cloud absorption radiometer) acquires spatial reference data from host aircraft navigation systems. This poses various problems during CAR data reduction, including navigation data format, accuracy of position data, accuracy of airframe inertial data, and navigation data rate. Incorporating its own navigation system, which included GPS (Global Positioning System), roll axis inertia and rates, and three axis acceleration, CANS expedites data reduction and increases the accuracy of the CAR end data product. CANS provides a self-contained navigation system for the CAR, using inertial reference and GPS positional information. The intent of the software application was to correct the sensor with respect to aircraft roll in real time based upon inputs from a precision navigation sensor. In addition, the navigation information (including GPS position), attitude data, and sensor position details are all streamed to a remote system for recording and later analysis. CANS comprises a commercially available inertial navigation system with integral GPS capability (Attitude Heading Reference System AHRS) integrated into the CAR support structure and data system. The unit is attached to the bottom of the tripod support structure. The related GPS antenna is located on the P-3 radome immediately above the CAR. The AHRS unit provides a RS-232 data stream containing global position and inertial attitude and velocity data to the CAR, which is recorded concurrently with the CAR data. This independence from aircraft navigation input provides for position and inertial state data that accounts for very small changes in aircraft attitude and position, sensed at the CAR location as opposed to aircraft state sensors typically installed close to the aircraft center of gravity. More accurate positional data enables quicker CAR data reduction with better resolution. The CANS software operates in two modes: initialization/calibration and operational. In the initialization/calibration mode, the software aligns the precision navigation sensors and initializes the communications interfaces with the sensor and the remote computing system. It also monitors the navigation data state for quality and ensures that the system maintains the required fidelity for attitude and positional information. In the operational mode, the software runs at 12.5 Hz and gathers the required navigation/attitude data, computes the required sensor correction values, and then commands the sensor to the required roll correction. In this manner, the sensor will stay very near to vertical at all times, greatly improving the resulting collected data and imagery. CANS greatly improves quality of resulting imagery and data collected. In addition, the software component of the system outputs a concisely formatted, high-speed data stream that can be used for further science data processing. This precision, time-stamped data also can benefit other instruments on the same aircraft platform by providing extra information from the mission flight.

  16. Navigator GPS Receiver for Fast Acquisition and Weak Signal Space Applications

    NASA Technical Reports Server (NTRS)

    Winternitz, Luke; Moreau, Michael; Boegner, Gregory J.; Sirotzky, Steve

    2004-01-01

    NASA Goddard Space Flight Center (GSFC) is developing a new space-borne GPS receiver that can operate effectively in the full range of Earth orbiting missions from Low Earth Orbit (LEO) to geostationary and beyond. Navigator is designed to be a fully space flight qualified GPS receiver optimized for fast signal acquisition and weak signal tracking. The fast acquisition capabilities provide exceptional time to first fix performance (TIFF) with no a priori receiver state or GPS almanac information, even in the presence of high Doppler shifts present in LEO (or near perigee in highly eccentric orbits). The fast acquisition capability also makes it feasible to implement extended correlation intervals and therefore significantly reduce Navigator s acquisition threshold. This greatly improves GPS observability when the receiver is above the GPS constellation (and satellites must be tracked from the opposite side of the Earth) by providing at least 10 dB of increased acquisition sensitivity. Fast acquisition and weak signal tracking algorithms have been implemented and validated on a hardware development board. A fully functional version of the receiver, employing most of the flight parts, with integrated navigation software is expected by mid 2005. An ultimate goal of this project is to license the Navigator design to an industry partner who will then market the receiver as a commercial product.

  17. NFC internal: an indoor navigation system.

    PubMed

    Ozdenizci, Busra; Coskun, Vedat; Ok, Kerem

    2015-01-01

    Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability. PMID:25825976

  18. NFC Internal: An Indoor Navigation System

    PubMed Central

    Ozdenizci, Busra; Coskun, Vedat; Ok, Kerem

    2015-01-01

    Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability. PMID:25825976

  19. Pulsar Navigation in the Solar System

    E-print Network

    Jiang Dong

    2011-02-04

    The X-ray Navigation and Autonomous position Verification (XNAV) is tested which use the Crab pulsar under the Space Test Program that use starlight refraction. It provide the way that the spacecraft could autonomously determine its position with respect to an inertial origin. Now we analysis the sensitivity of the exist instrument and the signal process that use radio pulsar navigation and discuss the integrated navigation which use radio pulsar, then give the different navigation mission analysis and design process basically which include the space, the airborne, the ship and the land of the planet or the lunar. Our analysis show that we will have the stability profile (signal-to-noise is 5) that use a 2 meters antenna observe some strong sources of radio pulsar in 36 minutes which based on the today's technology. So the pulsar navigation can give the continuous position in deep space, hat means we can freedom fly successfully in the solar system use celestial navigation that include pulsar and traditional star sensor. It also can less or abolish the dependence to Global Navigation Satellite System (GNSS) which include GPS, GRONSS, Galileo and BeiDou et al.

  20. Pulsar Navigation in the Solar System

    E-print Network

    Dong, Jiang

    2008-01-01

    The X-ray Pulsar-based Autonomous Navigation(XNAV) were recently tested which use the Crab pulsar (PSR B0531+21) in the USA Experiment on flown by the Navy on the Air Force Advanced Research and Global Observation Satellite (ARGOS) under the Space Test Program. It provide the way that the spacecraft could autonomously determine its position with respect to an inertial origin. Now I analysis the sensitivity of the exist instrument and the signal process to use radio pulsar navigation and discuss the integrated navigation use pulsar,then give the different navigation mission analysis and design process basically which include the space, the airborne, the ship and the land of the planet or the lunar.So the pulsar navigation can give the continuous position in deep spaces, that means we can freedom fly successfully in the solar system use celestial navigation that include pulsar and traditional star sensor.It also can less or abolish the depend of Global Navigation Satellite System which include GPS, GRONSS, Gali...

  1. Design and Performance Analysis of GPS Based Precise Relative Navigation for Rendezvous and Formation Flying Missions in Low Earth Orbit

    NASA Astrophysics Data System (ADS)

    Yamamoto, Toru

    Precise relative GPS navigation is essential technology for rendezvous and formation flying of spacecraft in Low Earth Orbit. Key design issues of precise relative GPS navigation software are studied and a novel formulation is proposed for the mission which requires high accuracy when the separation distance is up to several km. The navigation filter estimates float navigation solutions by extended Kalman filter with elaborate dynamics models, and resolves ambiguities of integer carrier phase biases to achieve high accuracy fix navigation solutions. A relative navigation software with the proposed formulation is implemented and evaluated in two different ways. One is a test using spacebourne GPS receivers and a GPS signal simulator to evaluate the performance and sensitivity of the software against variation of parameters. The other is a test using actual telemetry data from Gravity Recovery and Climate Experiment (GRACE) to demonstrate the software performance. The design, implementation, and results of the evaluation are presented and discussed on this paper.

  2. Delay/Doppler-Mapping GPS-Reflection Remote-Sensing System

    NASA Technical Reports Server (NTRS)

    Lowe, Stephen; Kroger, Peter; Franklin, Garth; LeBrecque, John; Lerma, Jesse; Lough, Michael; Marcin, Martin; Muellerschoen, Ronald; Spitzmesser, Donovan; Young, Lawrence

    2003-01-01

    A radio receiver system that features enhanced capabilities for remote sensing by use of reflected Global Positioning System (GPS) signals has been developed. This system was designed primarily for ocean altimetry, but can also be used for scatterometry and bistatic synthetic-aperture radar imaging. Moreover, it could readily be adapted to utilize navigation-satellite systems other than the GPS, including the Russian Global Navigation Satellite System GLONASS) and the proposed European Galileo system. This remote-sensing system offers both advantages and disadvantages over traditional radar altimeters: One advantage of GPS-reflection systems is that they cost less because there is no need to transmit signals. Another advantage is that there are more simultaneous measurement opportunities - one for each GPS satellite in view. The primary disadvantage is that in comparison with radar signals, GPS signals are weaker, necessitating larger antennas and/or longer observations. This GPS-reflection remote-sensing system was tested in aircraft and made to record and process both (1) signals coming directly from GPS satellites by means of an upward-looking antenna and (2) GPS signals reflected from the ground by means of a downward-looking antenna. In addition to performing conventional GPS processing, the system records raw signals for postprocessing as required.

  3. Space-qualified GPS receiver and MIMU for an autonomous on-board guidance and navigation package

    NASA Astrophysics Data System (ADS)

    Garavelli, B.; Marradi, L.; Morgan, A.

    1995-12-01

    The interest for an integrated autonomous guidance and navigation control package, satisfying to different mission requirements with a common architecture, is becoming very attractive in the perspective to reduce cost mission and to provide significant benefits when measurements noise conditions may change during the mission and safety critical spacecraft operations are involved. In this paper Laben and Honeywell present an interesting approach to integrate an attitude GPS space receiver and a miniaturized inertial measurement unit (MIMU), to enhance the performances of both sensor systems. In traditional G&NC systems, based on Inertial Navigation Sensor (INS) Measurements, long term drift, affecting zero point stability of gyroscope and accelerometer, are integrated over time during the measurement process, resulting in an increasing attitude and navigation error. These errors can be reduced by periodic reset, shifting the problem to the need of on board accurate and precise absolute position and attitude references. A convenient way to overcome such limitation is here discussed making profit of Laben experience, matured as a company leader in on board data handling and space qualified GPS receiver systems, and by Honeywell as a world leader manufacturer of guidance and navigation packages. The approach would be a guideline for a novel scheme of G&NC architecture where a GPS receiver, performing both attitude and orbit determination, and a MIMU that includes three ring laser gyro and three accelerometers, are integrated in a common unit. In such a system, the measurements performed by the sensors are numerically filtered, removing high side frequency bandwidth noise components, to provide accurate and reliable input data for the attitude and navigation algorithms that will be executed by the embedded guidance computer. The results of such elaboration will be directly the actuation values to drive the space vehicle under both operative and non operative conditions, according to control laws established for the specific mission. With respect to other papers on the subject, the present introduces the characterization of the noise performances of the GPS tensor receiver, the first space qualified GPS receiver performing attitude and orbit determination -- designed and manufactured by Laben, and the analysis of the error model of the MIMU designed and manufactured by Honeywell. From the discussion of such error models a scheme for the sensors data fusion based on an extended Kalman filter is then proposed.

  4. Doppler lidar sensor for precision navigation in GPS-deprived environment

    NASA Astrophysics Data System (ADS)

    Amzajerdian, F.; Pierrottet, D. F.; Hines, G. D.; Petway, L. B.; Barnes, B. W.

    2013-05-01

    Landing mission concepts that are being developed for exploration of solar system bodies are increasingly ambitious in their implementations and objectives. Most of these missions require accurate position and velocity data during their descent phase in order to ensure safe, soft landing at the pre-designated sites. Data from the vehicle's Inertial Measurement Unit will not be sufficient due to significant drift error after extended travel time in space. Therefore, an onboard sensor is required to provide the necessary data for landing in the GPS-deprived environment of space. For this reason, NASA Langley Research Center has been developing an advanced Doppler lidar sensor capable of providing accurate and reliable data suitable for operation in the highly constrained environment of space. The Doppler lidar transmits three laser beams in different directions toward the ground. The signal from each beam provides the platform velocity and range to the ground along the laser line-of-sight (LOS). The six LOS measurements are then combined in order to determine the three components of the vehicle velocity vector, and to accurately measure altitude and attitude angles relative to the local ground. These measurements are used by an autonomous Guidance, Navigation, and Control system to accurately navigate the vehicle from a few kilometers above the ground to the designated location and to execute a gentle touchdown. A prototype version of our lidar sensor has been completed for a closed-loop demonstration onboard a rocket-powered terrestrial free-flyer vehicle.

  5. Doppler Lidar Sensor for Precision Navigation in GPS-Deprived Environment

    NASA Technical Reports Server (NTRS)

    Amzajerdian, F.; Pierrottet, D. F.; Hines, G. D.; Hines, G. D.; Petway, L. B.; Barnes, B. W.

    2013-01-01

    Landing mission concepts that are being developed for exploration of solar system bodies are increasingly ambitious in their implementations and objectives. Most of these missions require accurate position and velocity data during their descent phase in order to ensure safe, soft landing at the pre-designated sites. Data from the vehicle's Inertial Measurement Unit will not be sufficient due to significant drift error after extended travel time in space. Therefore, an onboard sensor is required to provide the necessary data for landing in the GPS-deprived environment of space. For this reason, NASA Langley Research Center has been developing an advanced Doppler lidar sensor capable of providing accurate and reliable data suitable for operation in the highly constrained environment of space. The Doppler lidar transmits three laser beams in different directions toward the ground. The signal from each beam provides the platform velocity and range to the ground along the laser line-of-sight (LOS). The six LOS measurements are then combined in order to determine the three components of the vehicle velocity vector, and to accurately measure altitude and attitude angles relative to the local ground. These measurements are used by an autonomous Guidance, Navigation, and Control system to accurately navigate the vehicle from a few kilometers above the ground to the designated location and to execute a gentle touchdown. A prototype version of our lidar sensor has been completed for a closed-loop demonstration onboard a rocket-powered terrestrial free-flyer vehicle.

  6. GPS/Magnetometer Based Satellite Navigation and Attitude Determination

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Bar-Itzhack, Itzhack; Harman, Rick; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    In recent years algorithms were developed for orbit, attitude and angular-rate determination of Low Earth Orbiting (LEO) satellites. Those algorithms rely on measurements of magnetometers, which are standard, relatively inexpensive, sensors that are normally installed on every LEO satellite. Although magnetometers alone are sufficient for obtaining the desired information, the convergence of the algorithms to the correct values of the satellite orbital parameters, position, attitude and angular velocity is very slow. The addition of sun sensors reduces the convergence time considerably. However, for many LEO satellites the sun data is not available during portions of the orbit when the spacecraft (SC) is in the earth shadow. It is here where the GPS space vehicles (SV) can provide valuable support. This is clearly demonstrated in the present paper. Although GPS measurements alone can be used to obtain SC position, velocity, attitude and angular-rate, the use of magnetometers improve the results due to the synergistic effect of sensor fusion. Moreover, it is possible to obtain these results with less than three SVs. In this paper we introduce an estimation algorithm, which is a combination of an Extended Kalman Filter (EKF) and a Pseudo Linear Kalman Filter (PSELIKA).

  7. Shuttle Global Positioning System (GPS) system design study

    NASA Technical Reports Server (NTRS)

    Nilsen, P. W.

    1979-01-01

    The various integration problems in the Shuttle GPS system were investigated. The analysis of the Shuttle GPS link was studied. A preamplifier was designed since the Shuttle GPS antennas must be located remotely from the receiver. Several GPS receiver architecture trade-offs were discussed. The Shuttle RF harmonics and intermode that fall within the GPS receiver bandwidth were analyzed. The GPS PN code acquisition was examined. Since the receiver clock strongly affects both GPS carrier and code acquisition performance, a clock model was developed.

  8. Vision enhanced navigation for unmanned systems

    NASA Astrophysics Data System (ADS)

    Wampler, Brandon Loy

    A vision based simultaneous localization and mapping (SLAM) algorithm is evaluated for use on unmanned systems. SLAM is a technique used by a vehicle to build a map of an environment while concurrently keeping track of its location within the map, without a priori knowledge. The work in this thesis is focused on using SLAM as a navigation solution when global positioning system (GPS) service is degraded or temporarily unavailable. Previous work on unmanned systems that lead up to the determination that a better navigation solution than GPS alone is first presented. This previous work includes control of unmanned systems, simulation, and unmanned vehicle hardware testing. The proposed SLAM algorithm follows the work originally developed by Davidson et al. in which they dub their algorithm MonoSLAM [1--4]. A new approach using the Pyramidal Lucas-Kanade feature tracking algorithm from Intel's OpenCV (open computer vision) library is presented as a means of keeping correct landmark correspondences as the vehicle moves through the scene. Though this landmark tracking method is unusable for long term SLAM due to its inability to recognize revisited landmarks, as opposed to the Scale Invariant Feature Transform (SIFT) and Speeded Up Robust Features (SURF), its computational efficiency makes it a good candidate for short term navigation between GPS position updates. Additional sensor information is then considered by fusing INS and GPS information into the SLAM filter. The SLAM system, in its vision only and vision/IMU form, is tested on a table top, in an open room, and finally in an outdoor environment. For the outdoor environment, a form of the slam algorithm that fuses vision, IMU, and GPS information is tested. The proposed SLAM algorithm, and its several forms, are implemented in C++ using an Extended Kalman Filter (EKF). Experiments utilizing a live video feed from a webcam are performed. The different forms of the filter are compared and conclusions are made on the effectiveness of the SLAM algorithm for use on the current unmanned vehicles in Purdue's Hybrid Systems Lab. Recommendations for future improvements in applying computer vision to unmanned systems are also presented in the final chapter.

  9. GPS

    NASA Technical Reports Server (NTRS)

    Webb, Frank H.

    2006-01-01

    Geodetic networks support the TRF requirements of NASA ESE missions. Each of SLR, VLBI, GPS substantially and uniquely contributes to TRF determination. NASA's SLR, VLBI, and GPS groups collaborate toward wide-ranging improvements in the next 5 years. NASA leverages considerable resources through its significant activity in international services. NASA faces certain challenges in continuing and advancing these activities. The Terrestrial Reference Frame (TRF) is an accurate, stable set of positions and velocities. The TRF provides the stable coordinate system that allows us to link measurements over space and time. The geodetic networks provide data for determination of the TRF as well as direct science observations.

  10. Integrated Navigation System for the Second Generation Reusable Launch Vehicle

    NASA Technical Reports Server (NTRS)

    2002-01-01

    An array of components in a laboratory at NASA's Marshall Space Flight Center (MSFC) is being tested by the Flight Mechanics Office to develop an integrated navigation system for the second generation reusable launch vehicle. The laboratory is testing Global Positioning System (GPS) components, a satellite-based location and navigation system, and Inertial Navigation System (INS) components, sensors on a vehicle that determine angular velocity and linear acceleration at various points. The GPS and INS components work together to provide a space vehicle with guidance and navigation, like the push of the OnStar button in your car assists you with directions to a specific address. The integration will enable the vehicle operating system to track where the vehicle is in space and define its trajectory. The use of INS components for navigation is not new to space technology. The Space Shuttle currently uses them. However, the Space Launch Initiative is expanding the technology to integrate GPS and INS components to allow the vehicle to better define its position and more accurately determine vehicle acceleration and velocity. This advanced technology will lower operational costs and enhance the safety of reusable launch vehicles by providing a more comprehensive navigation system with greater capabilities. In this photograph, Dr. Jason Chuang of MSFC inspects an INS component in the laboratory.

  11. GPS-Based Navigation and Orbit Determination for the AMSAT Phase 3D Satellite

    NASA Technical Reports Server (NTRS)

    Davis, George; Carpenter, Russell; Moreau, Michael; Bauer, Frank H.; Long, Anne; Kelbel, David; Martin, Thomas

    2002-01-01

    This paper summarizes the results of processing GPS data from the AMSAT Phase 3D (AP3) satellite for real-time navigation and post-processed orbit determination experiments. AP3 was launched into a geostationary transfer orbit (GTO) on November 16, 2000 from Kourou, French Guiana, and then was maneuvered into its HEO over the next several months. It carries two Trimble TANS Vector GPS receivers for signal reception at apogee and at perigee. Its spin stabilization mode currently makes it favorable to track GPS satellites from the backside of the constellation while at perigee, and to track GPS satellites from below while at perigee. To date, the experiment has demonstrated that it is feasible to use GPS for navigation and orbit determination in HEO, which will be of great benefit to planned and proposed missions that will utilize such orbits for science observations. It has also shown that there are many important operational considerations to take into account. For example, GPS signals can be tracked above the constellation at altitudes as high as 58000 km, but sufficient amplification of those weak signals is needed. Moreover, GPS receivers can track up to 4 GPS satellites at perigee while moving as fast as 9.8 km/sec, but unless the receiver can maintain lock on the signals long enough, point solutions will be difficult to generate. The spin stabilization of AP3, for example, appears to cause signal levels to fluctuate as other antennas on the satellite block the signals. As a result, its TANS Vectors have been unable to lock on to the GPS signals long enough to down load the broadcast ephemeris and then generate position and velocity solutions. AP3 is currently in its eclipse season, and thus most of the spacecraft subsystems have been powered off. In Spring 2002, they will again be powered up and AP3 will be placed into a three-axis stabilization mode. This will significantly enhance the likelihood that point solutions can be generated, and perhaps more important, that the receiver clock can be synchronized to GPS time. This is extremely important for real-time and post-processed orbit determination, where removal of receiver clock bias from the data time tags is needed, for time-tagging of science observations. Current analysis suggests that the inability to generate point solutions has allowed the TANS Vector clock bias to drift freely, being perhaps as large as 5-7 seconds by October, 2001, thus causing up to 50 km of along-track orbit error. The data collected in May, 2002 while in three-axis stabilized mode should provide a significant improvement in the orbit determination results.

  12. An alternative ionospheric correction model for global navigation satellite systems

    NASA Astrophysics Data System (ADS)

    Hoque, M. M.; Jakowski, N.

    2015-04-01

    The ionosphere is recognized as a major error source for single-frequency operations of global navigation satellite systems (GNSS). To enhance single-frequency operations the global positioning system (GPS) uses an ionospheric correction algorithm (ICA) driven by 8 coefficients broadcasted in the navigation message every 24 h. Similarly, the global navigation satellite system Galileo uses the electron density NeQuick model for ionospheric correction. The Galileo satellite vehicles (SVs) transmit 3 ionospheric correction coefficients as driver parameters of the NeQuick model. In the present work, we propose an alternative ionospheric correction algorithm called Neustrelitz TEC broadcast model NTCM-BC that is also applicable for global satellite navigation systems. Like the GPS ICA or Galileo NeQuick, the NTCM-BC can be optimized on a daily basis by utilizing GNSS data obtained at the previous day at monitor stations. To drive the NTCM-BC, 9 ionospheric correction coefficients need to be uploaded to the SVs for broadcasting in the navigation message. Our investigation using GPS data of about 200 worldwide ground stations shows that the 24-h-ahead prediction performance of the NTCM-BC is better than the GPS ICA and comparable to the Galileo NeQuick model. We have found that the 95 percentiles of the prediction error are about 16.1, 16.1 and 13.4 TECU for the GPS ICA, Galileo NeQuick and NTCM-BC, respectively, during a selected quiet ionospheric period, whereas the corresponding numbers are found about 40.5, 28.2 and 26.5 TECU during a selected geomagnetic perturbed period. However, in terms of complexity the NTCM-BC is easier to handle than the Galileo NeQuick and in this respect comparable to the GPS ICA.

  13. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION AND INITIALIZATION OF THE MAGELLAN GPS SATELLITE NAVIGATOR (UA-F-22.1)

    EPA Science Inventory

    The purpose of this SOP is to describe the general procedures for the operation and initialization of the Magellan Global Positioning System (GPS) Satellite Navigator. This procedure was followed to ensure consistent data retrieval during the Arizona NHEXAS project and the "Bord...

  14. Autonomous satellite navigation methods using the Global Positioning Satellite System

    NASA Technical Reports Server (NTRS)

    Murata, M.; Tapley, B. D.; Schutz, B. E.

    1982-01-01

    This investigation considers the problem of autonomous satellite navigation using the NAVSTAR Global Positioning System (GPS). The major topics covered include the design, implementation, and validation of onboard navigation filter algorithms by means of computer simulations. The primary errors that the navigation filter design must minimize are computational effects and modeling inaccuracies due to limited capability of the onboard computer. The minimization of the effect of these errors is attained by applying the sequential extended Kalman filter using a factored covariance implementation with Q-matrix or dynamical model compensations. Peformance evaluation of the navigation filter design is carried out using both the CDC Cyber 170/750 computer and the PDP-11/60 computer. The results are obtained assuming the Phase I GPS constellation, consisting of six satellites, and a Landsat-D type spacecraft as the model for the user satellite orbit.

  15. Wellborne inertial navigation system

    SciTech Connect

    Kelsey, J.R.

    1983-01-01

    A phototype wireline tool which includes a downhole inertial platform and a surface computer to spatially map a well is described. The hardware consists of a single-gimbaled inertial platform with accelerometers and gyros to obtain three-axis motion information. The gyroscope and accelerometer outputs are transmitted to a computer at the surface which calculates probe attitude relative to north, east, and vertical. Double integration of the accelerometer data provides the position information. A conventional 7-conductor wireline is used for the system data transmission. System accuracy is enhanced by advances made in the computer software which processes the data received from the tool. The software uses statistical sampling estimation to obtain optimal estimates of the system errors. Measurement errors are determined by periodically stopping the tool during the logging procedure and observing the indicated velocity measurements. This procedure, known as Kalman filtering, results in increased accuracy of the data. Present mapping systems have an X-Y-Z location accuracy of +- 100 to +- 200 feet for a typical well depth of 10,000 feet. Test results show that the new system is accurate to about +- 1 foot per 1000 feet of well depth. Unlike conventional systems, the inertial navigator does not require any sort of projection of the cable length (which may not be accurately known). Also this system provides continuous data throughout the wellbore and logging speeds on the order of 10 ft/sec appear possible. The hardware and software associated with this mapping system are described and the recent field test results are reported.

  16. Using APEX to Model Anticipated Human Error: Analysis of a GPS Navigational Aid

    NASA Technical Reports Server (NTRS)

    VanSelst, Mark; Freed, Michael; Shefto, Michael (Technical Monitor)

    1997-01-01

    The interface development process can be dramatically improved by predicting design facilitated human error at an early stage in the design process. The approach we advocate is to SIMULATE the behavior of a human agent carrying out tasks with a well-specified user interface, ANALYZE the simulation for instances of human error, and then REFINE the interface or protocol to minimize predicted error. This approach, incorporated into the APEX modeling architecture, differs from past approaches to human simulation in Its emphasis on error rather than e.g. learning rate or speed of response. The APEX model consists of two major components: (1) a powerful action selection component capable of simulating behavior in complex, multiple-task environments; and (2) a resource architecture which constrains cognitive, perceptual, and motor capabilities to within empirically demonstrated limits. The model mimics human errors arising from interactions between limited human resources and elements of the computer interface whose design falls to anticipate those limits. We analyze the design of a hand-held Global Positioning System (GPS) device used for radical and navigational decisions in small yacht recalls. The analysis demonstrates how human system modeling can be an effective design aid, helping to accelerate the process of refining a product (or procedure).

  17. Performance of Hybrid Positioning System Combining GPS and Television Signals

    E-print Network

    Stanford University

    Performance of Hybrid Positioning System Combining GPS and Television Signals Ju-Yong Do Electrical system), GPS receivers have not been able to overcome the critical weakness of a GPS signal in indoor the benefits of a hybrid positioning system combining GPS and television signals, a prototype of TV signal

  18. Miniaturized GPS/MEMS IMU integrated board

    NASA Technical Reports Server (NTRS)

    Lin, Ching-Fang (Inventor)

    2012-01-01

    This invention documents the efforts on the research and development of a miniaturized GPS/MEMS IMU integrated navigation system. A miniaturized GPS/MEMS IMU integrated navigation system is presented; Laser Dynamic Range Imager (LDRI) based alignment algorithm for space applications is discussed. Two navigation cameras are also included to measure the range and range rate which can be integrated into the GPS/MEMS IMU system to enhance the navigation solution.

  19. NASA tracking ship navigation systems

    NASA Technical Reports Server (NTRS)

    Mckenna, J. J.

    1976-01-01

    The ship position and attitude measurement system that was installed aboard the tracking ship Vanguard is described. An overview of the entire system is given along with a description of how precise time and frequency is utilized. The instrumentation is broken down into its basic components. Particular emphasis is given to the inertial navigation system. Each navigation system used, a mariner star tracker, navigation satellite system, Loran C and OMEGA in conjunction with the inertial system is described. The accuracy of each system is compared along with their limitations.

  20. Individual Global Navigation Satellite Systems in the Space Service Volume

    NASA Technical Reports Server (NTRS)

    Force, Dale A.

    2015-01-01

    Besides providing position, navigation, and timing (PNT) to terrestrial users, GPS is currently used to provide for precision orbit determination, precise time synchronization, real-time spacecraft navigation, and three-axis control of Earth orbiting satellites. With additional Global Navigation Satellite Systems (GNSS) coming into service (GLONASS, Beidou, and Galileo), it will be possible to provide these services by using other GNSS constellations. The paper, "GPS in the Space Service Volume," presented at the ION GNSS 19th International Technical Meeting in 2006 (Ref. 1), defined the Space Service Volume, and analyzed the performance of GPS out to 70,000 km. This paper will report a similar analysis of the performance of each of the additional GNSS and compare them with GPS alone. The Space Service Volume, defined as the volume between 3,000 km altitude and geosynchronous altitude, as compared with the Terrestrial Service Volume between the surface and 3,000 km. In the Terrestrial Service Volume, GNSS performance will be similar to performance on the Earth's surface. The GPS system has established signal requirements for the Space Service Volume. A separate paper presented at the conference covers the use of multiple GNSS in the Space Service Volume.

  1. Combined Global Navigation Satellite Systems in the Space Service Volume

    NASA Technical Reports Server (NTRS)

    Force, Dale A.; Miller, James J.

    2015-01-01

    Besides providing position, navigation, and timing (PNT) services to traditional terrestrial and airborne users, GPS is also being increasingly used as a tool to enable precision orbit determination, precise time synchronization, real-time spacecraft navigation, and three-axis attitude control of Earth orbiting satellites. With additional Global Navigation Satellite System (GNSS) constellations being replenished and coming into service (GLONASS, Beidou, and Galileo), it will become possible to benefit from greater signal availability and robustness by using evolving multi-constellation receivers. The paper, "GPS in the Space Service Volume," presented at the ION GNSS 19th International Technical Meeting in 2006 (Ref. 1), defined the Space Service Volume, and analyzed the performance of GPS out to seventy thousand kilometers. This paper will report a similar analysis of the signal coverage of GPS in the space domain; however, the analyses will also consider signal coverage from each of the additional GNSS constellations noted earlier to specifically demonstrate the expected benefits to be derived from using GPS in conjunction with other foreign systems. The Space Service Volume is formally defined as the volume of space between three thousand kilometers altitude and geosynchronous altitude circa 36,000 km, as compared with the Terrestrial Service Volume between 3,000 km and the surface of the Earth. In the Terrestrial Service Volume, GNSS performance is the same as on or near the Earth's surface due to satellite vehicle availability and geometry similarities. The core GPS system has thereby established signal requirements for the Space Service Volume as part of technical Capability Development Documentation (CDD) that specifies system performance. Besides the technical discussion, we also present diplomatic efforts to extend the GPS Space Service Volume concept to other PNT service providers in an effort to assure that all space users will benefit from the enhanced interoperability of GNSS services in the space domain. A separate paper presented at the conference covers the individual GNSS performance parameters for respective Space Service Volumes.

  2. Space shuttle navigation analysis. Volume 2: Baseline system navigation

    NASA Technical Reports Server (NTRS)

    Jones, H. L.; Luders, G.; Matchett, G. A.; Rains, R. G.

    1980-01-01

    Studies related to the baseline navigation system for the orbiter are presented. The baseline navigation system studies include a covariance analysis of the Inertial Measurement Unit calibration and alignment procedures, postflight IMU error recovery for the approach and landing phases, on-orbit calibration of IMU instrument biases, and a covariance analysis of entry and prelaunch navigation system performance.

  3. Road to Seamless Positioning: Hybrid Positioning System Combining GPS

    E-print Network

    Stanford University

    Road to Seamless Positioning: Hybrid Positioning System Combining GPS and Television Signals Ju-Yong Do jdo@stanford.edu GPS Lab Stanford University April 18, 2007 #12;Ju-Yong Do 2007/4/18 GPS: Time and Position Reference Time & Position (4D) Time (1D) Position (3D) + = (GPS: Global Positioning System) Hybrid

  4. Software for a GPS-Reflection Remote-Sensing System

    NASA Technical Reports Server (NTRS)

    Lowe, Stephen

    2003-01-01

    A special-purpose software Global Positioning System (GPS) receiver designed for remote sensing with reflected GPS signals is described in Delay/Doppler-Mapping GPS-Reflection Remote-Sensing System (NPO-30385), which appears elsewhere in this issue of NASA Tech Briefs. The input accepted by this program comprises raw (open-loop) digitized GPS signals sampled at a rate of about 20 MHz. The program processes the data samples to perform the following functions: detection of signals; tracking of phases and delays; mapping of delay, Doppler, and delay/Doppler waveforms; dual-frequency processing; coherent integrations as short as 125 s; decoding of navigation messages; and precise time tagging of observable quantities. The software can perform these functions on all detectable satellite signals without dead time. Open-loop data collected over water, land, or ice and processed by this software can be further processed to extract geophysical information. Possible examples include mean sea height, wind speed and direction, and significant wave height (for observations over the ocean); bistatic-radar terrain images and measures of soil moisture and biomass (for observations over land); and estimates of ice age, thickness, and surface density (for observations over ice).

  5. Using GPS and GPS/INS Systems to Assess Relative Antenna Motion Onboard an Aircraft

    E-print Network

    Calgary, University of

    Using GPS and GPS/INS Systems to Assess Relative Antenna Motion Onboard an Aircraft Carrier at reducing GPS errors which are likely be more prevalent onboard an aircraft carrier under operational onboard an actual aircraft carrier is processed herein. Deviation in the estimated baseline length between

  6. GPS 375 (10033807,

    E-print Network

    Cho, Sung-Bae

    GPS 375 (10033807, ) 38 ` GPS ' : : : : sclab , . , . , , , . : 39 5(2012.5) GPS (An Energy Saving System for Smartphone GPS Sensors Using Bayesian Networks Modeling) (Si-Hyuk Yi) (Sung-Bae Cho) GPS . GPS . GPS , GPS

  7. Integrated communications and optical navigation system

    NASA Astrophysics Data System (ADS)

    Mueller, J.; Pajer, G.; Paluszek, M.

    2013-12-01

    The Integrated Communications and Optical Navigation System (ICONS) is a flexible navigation system for spacecraft that does not require global positioning system (GPS) measurements. The navigation solution is computed using an Unscented Kalman Filter (UKF) that can accept any combination of range, range-rate, planet chord width, landmark, and angle measurements using any celestial object. Both absolute and relative orbit determination is supported. The UKF employs a full nonlinear dynamical model of the orbit including gravity models and disturbance models. The ICONS package also includes attitude determination algorithms using the UKF algorithm with the Inertial Measurement Unit (IMU). The IMU is used as the dynamical base for the attitude determination algorithms. This makes the sensor a more capable plug-in replacement for a star tracker, thus reducing the integration and test cost of adding this sensor to a spacecraft. Recent additions include an integrated optical communications system which adds communications, and integrated range and range rate measurement and timing. The paper includes test results from trajectories based on the NASA New Horizons spacecraft.

  8. Relative navigation requirements for automatic rendezvous and capture systems

    NASA Technical Reports Server (NTRS)

    Kachmar, Peter M.; Polutchko, Robert J.; Chu, William; Montez, Moises

    1991-01-01

    This paper will discuss in detail the relative navigation system requirements and sensor trade-offs for Automatic Rendezvous and Capture. Rendezvous navigation filter development will be discussed in the context of navigation performance requirements for a 'Phase One' AR&C system capability. Navigation system architectures and the resulting relative navigation performance for both cooperative and uncooperative target vehicles will be assessed. Relative navigation performance using rendezvous radar, star tracker, radiometric, laser and GPS navigation sensors during appropriate phases of the trajectory will be presented. The effect of relative navigation performance on the Integrated AR&C system performance will be addressed. Linear covariance and deterministic simulation results will be used. Evaluation of relative navigation and IGN&C system performance for several representative relative approach profiles will be presented in order to demonstrate the full range of system capabilities. A summary of the sensor requirements and recommendations for AR&C system capabilities for several programs requiring AR&C will be presented.

  9. Precise near-earth navigation with GPS: A survey of techniques

    NASA Technical Reports Server (NTRS)

    Yunck, T. P.; Wu, S. C.; Wu, J.

    1987-01-01

    The tracking accuracy of the low earth orbiters (below about 3000 km altitude) can be brought below 10 cm with a variety of differential techniques that exploit the Global Positioning System (GPS). All of these techniques require a precisely known global network of GPS ground receivers and a receiver aboard the user satellite, and all simultaneously estimate the user and GPS satellite orbits. Three basic approaches are the geometric, dynamic, and nondynamic strategies. The last combines dynamic GPS solutions with a geometric user solution. Two powerful extensions of the nondynamic strategy show considerable promise. The first uses an optimized synthesis of dynamics and geometry in the user solution, while the second uses a novel gravity-adjustment method to exploit data from repeat ground tracks. These techniques will offer sub-decimeter accuracy for dynamically unpredictable satellites down to the lowesst possible altitudes.

  10. Non-GPS Navigation for Emergency Responders Lauro Ojeda and Johann Borenstein*

    E-print Network

    Borenstein, Johann

    . We refer to our system as "Personal Odometry System" (POS). The POS measures the position. There are some approaches to personal position estimation without GPS. Typically, these systems require external retroreflectors. Common to all fiducial-based position estimation systems is that the fiducials must be installed

  11. Proceedings of GPS/GNSS 2003 Conference (Session C3), Portland, OR, September 9-12, 2003, The Institute of Navigation. 1/7 INDOOR POSITIONING SYSTEM USING ACCELEROMETRY

    E-print Network

    Calgary, University of

    , The Institute of Navigation. 1/7 INDOOR POSITIONING SYSTEM USING ACCELEROMETRY AND HIGH ACCURACY HEADING SENSORS of Digital and Computer Systems doing research in the area of personal positioning. Oleg Mezentsev is a Ph developments in high sensitivity receiver technology are promising for indoor positioning inside light

  12. Global Positioning System Time Transfer Receiver (GPS/TTR) prototype design and initial test evaluation

    NASA Technical Reports Server (NTRS)

    Oaks, J.; Frank, A.; Falvey, S.; Lister, M.; Buisson, J.; Wardrip, C.; Warren, H.

    1982-01-01

    Time transfer equipment and techniques used with the Navigation Technology Satellites were modified and extended for use with the Global Positioning System (GPS) satellites. A prototype receiver was built and field tested. The receiver uses the GPS L1 link at 1575 MHz with C/A code only to resolve a measured range to the satellite. A theoretical range is computed from the satellite ephemeris transmitted in the data message and the user's coordinates. Results of user offset from GPS time are obtained by differencing the measured and theoretical ranges and applying calibration corrections. Results of the first field test evaluation of the receiver are presented.

  13. Combined Global Navigation Satellite Systems in the Space Service Volume

    NASA Technical Reports Server (NTRS)

    Force, Dale A.; Miller, James J.

    2013-01-01

    Besides providing position, velocity, and timing (PVT) for terrestrial users, the Global Positioning System (GPS) is also being used to provide PVT information for earth orbiting satellites. In 2006, F. H. Bauer, et. al., defined the Space Service Volume in the paper GPS in the Space Service Volume , presented at ION s 19th international Technical Meeting of the Satellite Division, and looked at GPS coverage for orbiting satellites. With GLONASS already operational, and the first satellites of the Galileo and Beidou/COMPASS constellations already in orbit, it is time to look at the use of the new Global Navigation Satellite Systems (GNSS) coming into service to provide PVT information for earth orbiting satellites. This presentation extends GPS in the Space Service Volume by examining the coverage capability of combinations of the new constellations with GPS GPS was first explored as a system for refining the position, velocity, and timing of other spacecraft equipped with GPS receivers in the early eighties. Because of this, a new GPS utility developed beyond the original purpose of providing position, velocity, and timing services for land, maritime, and aerial applications. GPS signals are now received and processed by spacecraft both above and below the GPS constellation, including signals that spill over the limb of the earth. Support of GPS space applications is now part of the system plan for GPS, and support of the Space Service Volume by other GNSS providers has been proposed to the UN International Committee on GNSS (ICG). GPS has been demonstrated to provide decimeter level position accuracy in real-time for satellites in low Earth orbit (centimeter level in non-real-time applications). GPS has been proven useful for satellites in geosynchronous orbit, and also for satellites in highly elliptical orbits. Depending on how many satellites are in view, one can keep time locked to the GNSS standard, and through that to Universal Time as long as at least one satellite is in view (the longest duration with no satellites in view is important in determining the maximum clock drift from GNSS time). Instantaneous position requires four satellites in view, but because orbital motion is predictable, it is possible to build up knowledge of the orbital position gradually through time without a need for constant four satellite coverage. However, it is desirable to have four satellite coverage when performing satellite maneuvers, since there can be significant changes in velocity, leading to large changes in orbit parameter, causing substantial divergence in position over time. The Space Service Volume has been defined as the volume between three thousand km altitude and geosynchronous altitude, and can be divided into medium orbit services between three thousand km altitude and eight thousand km altitude, and high orbit services above eight thousand km. The Terrestrial Service Volume includes the Earth s surface, the atmosphere, and space below the altitude of three thousand km. The Terrestrial Service Volume is the volume within which the GNSS systems will have very similar performance to the Earth surface, and satellites need only use the signals specified to provide terrestrial performance. Above three thousand km the use of signals passing by the Earth s limb becomes important, so it is desirable to have additional information on signal strength, phase delay, and group delay covering wider beam angles than are needed for terrestrial service (and which can be obtained by monitoring GNSS signals from the Earth s surface). This presentation will look at each of the new GNSS constellations in combination with GPS (GLONASS with GPS, Galileo with GPS, Beidou/COMPASS with GPS), and also at the combination of all four GNSS systems. The presentation will largely follow the format of GPS in the Space Service Volume , presenting data on the availability of one, two, three, or four of the various combinations of GNSS constellation satelles at approximately two thousand grid points evenly spaced and fixed in longitude and latitude, t

  14. Improving CAR Navigation with a Vision-Based System

    NASA Astrophysics Data System (ADS)

    Kim, H.; Choi, K.; Lee, I.

    2015-08-01

    The real-time acquisition of the accurate positions is very important for the proper operations of driver assistance systems or autonomous vehicles. Since the current systems mostly depend on a GPS and map-matching technique, they show poor and unreliable performance in blockage and weak areas of GPS signals. In this study, we propose a vision oriented car navigation method based on sensor fusion with a GPS and in-vehicle sensors. We employed a single photo resection process to derive the position and attitude of the camera and thus those of the car. This image georeferencing results are combined with other sensory data under the sensor fusion framework for more accurate estimation of the positions using an extended Kalman filter. The proposed system estimated the positions with an accuracy of 15 m although GPS signals are not available at all during the entire test drive of 15 minutes. The proposed vision based system can be effectively utilized for the low-cost but high-accurate and reliable navigation systems required for intelligent or autonomous vehicles.

  15. Decentralised approach to UAV navigation: without the use of GPS and preloaded maps

    E-print Network

    Kim, Jonghyuk "Jon"

    blocked or jammed by intentional interferences. As a result, research into Terrain Aided Navigation (TERCOM) system has been successfully applied in cruise missile systems [5]. It combines onboard radar

  16. A magnetic pulse does not affect homing pigeon navigation: a GPS tracking experiment.

    PubMed

    Holland, Richard; Filannino, Caterina; Gagliardo, Anna

    2013-06-15

    The cues by which homing pigeons are able to return to a home loft after displacement to unfamiliar release sites remain debated. A number of experiments in which migratory birds have been treated with a magnetic pulse have produced a disruption in their orientation, which argues that a ferrimagnetic sense is used for navigation in birds. One previous experiment has also indicated an effect of magnetic pulses on homing pigeon navigation, although with inconsistent results. Previous studies have shown that some magnetic-related information is transmitted by the trigeminal nerve to the brain in some bird species, including the homing pigeon. The function of this information is still unclear. It has been suggested that this information is important for navigation. Previous studies with trigeminal nerve lesioned homing pigeons have clearly shown that the lack of trigeminally mediated information, even if magnetic, is not crucial for homing performance. However, this result does not completely exclude the possibility that other ferrimagnetic receptors in the homing pigeon play a role in navigation. Additionally, recent studies on homing pigeons suggested the existence of a ferrimagnetic sense in a novel location presumably located in the inner ear (lagena). In the present study, we tested whether any ferrimagnetic magnetoreceptors, irrespective of their location in the bird's head, are involved in pigeons' homing. To do this, we treated homing pigeons with a strong magnetic pulse before release, tracked birds with GPS loggers and analyzed whether this treatment affected homing performance. In the single previous magnetic pulse experiment on homing pigeons, only initial orientation at a release site was considered and the results were inconsistent. We observed no effect of the magnetic pulse at any of the sites used on initial orientation, homing performance, tortuosity or track efficiency, which does not support a role for the ferrimagnetic sense in homing pigeon navigation, at least not in this geographic area, where magnetic field variations are in the region of 200 nT intensity and 0.8 deg inclination. PMID:23470658

  17. Environmental applications of GPS

    SciTech Connect

    Vigil, S.A.; Zueck, D.

    1999-07-01

    The use of the Global Positioning System (GPS) has revolutionized air travel, ocean navigation, land navigation, and the collection of environmental data. Although a basic civilian GPS receiver can be purchased for as little as $100, the receiver is only the tip of a 12 billion dollar iceberg. This paper will discuss the history and basic operation of the Global Positioning System, a satellite-based precision positioning and timing service developed and operated by the Department of Defense. It will also describe the accuracy limitations of the civil GPS service and how accuracy can be enhanced by the use of differential GPS (DGPS), using either the free National Differential GPS system, or commercial differential monitor stations. Finally, the paper will discuss the future accuracy upgrades of civil GPS as a result of recent federal policy decisions.

  18. The Open Service Signal in Space Navigation Data Comparison of the Global Positioning System and the BeiDou Navigation Satellite System

    PubMed Central

    Jan, Shau-Shiun; Tao, An-Lin

    2014-01-01

    More and more Global Navigation Satellite Systems (GNSSs) have been developed and are in operation. Before integrating information on various GNSSs, the differences between the various systems must be studied first. This research focuses on analyzing the navigation data differences between the Chinese BeiDou Navigation Satellite System (BDS) and the United States' Global Positioning System (GPS). In addition to explaining the impact caused by these two different coordinate and time systems, this research uses an actual open service signal in space (SIS) for both GPS and BDS to analyze their current system performance. Five data quality analysis (DQA) mechanisms are proposed in this research to validate both systems' SIS navigation data. These five DQAs evaluate the differences in ephemeris and almanac messages from both systems for stability and accuracy. After all of the DQAs, the different issues related to GPS and BDS satellite information are presented. Finally, based on these DQA results, this research provides suggested resolutions for the combined use of GPS and BDS for navigation and guidance. PMID:25195848

  19. The open service signal in space navigation data comparison of the Global Positioning System and the BeiDou Navigation Satellite System.

    PubMed

    Jan, Shau-Shiun; Tao, An-Lin

    2014-01-01

    More and more Global Navigation Satellite Systems (GNSSs) have been developed and are in operation. Before integrating information on various GNSSs, the differences between the various systems must be studied first. This research focuses on analyzing the navigation data differences between the Chinese BeiDou Navigation Satellite System (BDS) and the United States' Global Positioning System (GPS). In addition to explaining the impact caused by these two different coordinate and time systems, this research uses an actual open service signal in space (SIS) for both GPS and BDS to analyze their current system performance. Five data quality analysis (DQA) mechanisms are proposed in this research to validate both systems' SIS navigation data. These five DQAs evaluate the differences in ephemeris and almanac messages from both systems for stability and accuracy. After all of the DQAs, the different issues related to GPS and BDS satellite information are presented. Finally, based on these DQA results, this research provides suggested resolutions for the combined use of GPS and BDS for navigation and guidance. PMID:25195848

  20. Airborne Antenna System for Minimum-Cycle-Slip GPS Reception

    NASA Technical Reports Server (NTRS)

    Wright, C. Wayne

    2009-01-01

    A system that includes a Global Positioning System (GPS) antenna and associated apparatus for keeping the antenna aimed upward has been developed for use aboard a remote-sensing-survey airplane. The purpose served by the system is to enable minimum- cycle-slip reception of GPS signals used in precise computation of the trajectory of the airplane, without having to restrict the airplane to maneuvers that increase the flight time needed to perform a survey. Cycle slip signifies loss of continuous track of the phase of a signal. Minimum-cycle-slip reception is desirable because maintaining constant track of the phase of the carrier signal from each available GPS satellite is necessary for surveying to centimeter or subcentimeter precision. Even a loss of signal for as short a time as a nanosecond can cause cycle slip. Cycle slips degrade the quality and precision of survey data acquired during a flight. The two principal causes of cycle slip are weakness of signals and multipath propagation. Heretofore, it has been standard practice to mount a GPS antenna rigidly on top of an airplane, and the radiation pattern of the antenna is typically hemispherical, so that all GPS satellites above the horizon are viewed by the antenna during level flight. When the airplane must be banked for a turn or other maneuver, the reception hemisphere becomes correspondingly tilted; hence, the antenna no longer views satellites that may still be above the Earth horizon but are now below the equatorial plane of the tilted reception hemisphere. Moreover, part of the reception hemisphere (typically, on the inside of a turn) becomes pointed toward ground, with a consequent increase in received noise and, therefore, degradation of GPS measurements. To minimize the likelihood of loss of signal and cycle slip, bank angles of remote-sensing survey airplanes have generally been limited to 10 or less, resulting in skidding or slipping uncoordinated turns. An airplane must be banked in order to make a coordinated turn. For small-radius, short-time coordinated turns, it is necessary to employ banks as steep as 45 , and turns involving such banks are times and for confining airplanes as closely as possible to areas to be surveyed. The idea underlying the design is that if the antenna can be kept properly aimed, then the incidence of cycle slips caused by loss or weakness of signals can be minimized. The system includes an articulating GPS antenna and associated electronic circuitry mounted under a radome atop an airplane. The electronic circuitry includes a microprocessor-based interface-circuit-and-data-translation module. The system receives data on the current attitude of the airplane from the inertial navigation system of the airplane. The microprocessor decodes the attitude data and uses them to compute commands for the GPS-antenna-articulating mechanism to tilt the antenna, relative to the airplane, in opposition to the roll or bank of the airplane to keep the antenna pointed toward the zenith. The system was tested aboard the hurricane- hunting airplane of the National Oceanic and Atmospheric Administration (NOAA) [see figure] during an 11-hour flight to observe the landfall of Hurricane Bret in late summer of 1999. No bank-angle restrictions were imposed during the flight. Post-flight analysis of the GPS trajectory data revealed that no cycle slip had occurred.considered normal maneuvers. These steep banks are highly desirable for minimizing flight

  1. Orion Absolute Navigation System Progress and Challenges

    NASA Technical Reports Server (NTRS)

    Holt, Greg N.; D'Souza, Christopher

    2011-01-01

    The Orion spacecraft is being designed as NASA's next-generation exploration vehicle for crewed missions beyond Low-Earth Orbit. The navigation system for the Orion spacecraft is being designed in a Multi-Organizational Design Environment (MODE) team including contractor and NASA personnel. The system uses an Extended Kalman Filter to process measurements and determine the state. The design of the navigation system has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudorange and deltarange, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, pad alignment, cold start are discussed as are strategies for whole and partial state updates as well as covariance considerations. Strategies are given for dealing with latent measurements and high-rate propagation using multi-rate architecture. The details of the rate groups and the data ow between the elements is discussed and evaluated.

  2. The Evolution of Global Positioning System (GPS) Technology.

    ERIC Educational Resources Information Center

    Kumar, Sameer; Moore, Kevin B.

    2002-01-01

    Describes technological advances in the Global Positioning System (GPS), which is also known as the NAVSTAR GPS satellite constellation program developed in 1937, and changes in the nature of our world by GPS in the areas of agriculture, health, military, transportation, environment, wildlife biology, surveying and mapping, space applications, and…

  3. Le GPS (Global positioning system) pleinement oprationnel depuis 1995

    E-print Network

    Rousseau, Christiane

    Le GPS (Global positioning system) pleinement opérationnel depuis 1995 · Réseau de satellites en précision de 20 mètres. #12;Applications du GPS · Trouver son chemin dans la nature · Tracer une carte-voyants · Trouver son chemin sur la route · Atterrir dans le brouillard #12;Les GPS sont une référence de temps

  4. Tightly Coupled Inertial Navigation System/Global Positioning System (TCMIG)

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.; Jackson, Kurt (Technical Monitor)

    2002-01-01

    Many NASA applications planned for execution later this decade are seeking high performance, miniaturized, low power Inertial Management Units (IMU). Much research has gone into Micro-Electro-Mechanical System (MEMS) over the past decade as a solution to these needs. While MEMS devices have proven to provide high accuracy acceleration measurements, they have not yet proven to have the accuracy required by many NASA missions in rotational measurements. Therefore, a new solution has been formulated integrating the best of all IMU technologies to address these mid-term needs in the form of a Tightly Coupled Micro Inertial Navigation System (INS)/Global Positioning System (GPS) (TCMIG). The TCMIG consists of an INS and a GPS tightly coupled by a Kalman filter executing on an embedded Field Programmable Gate Array (FPGA) processor. The INS consists of a highly integrated Interferometric Fiber Optic Gyroscope (IFOG) and a MEMS accelerometer. The IFOG utilizes a tightly wound fiber coil to reduce volume and the high level of integration and advanced optical components to reduce power. The MEMS accelerometer utilizes a newly developed deep etch process to increase the proof mass and yield a highly accurate accelerometer. The GPS receiver consists of a low power miniaturized version of the Blackjack receiver. Such an IMU configuration is ideal to meet the mid-term needs of the NASA Science Enterprises and the new launch vehicles being developed for the Space Launch Initiative (SLI).

  5. Intelligent personal navigator supported by knowledge-based systems for estimating dead reckoning navigation parameters

    NASA Astrophysics Data System (ADS)

    Moafipoor, Shahram

    Personal navigators (PN) have been studied for about a decade in different fields and applications, such as safety and rescue operations, security and emergency services, and police and military applications. The common goal of all these applications is to provide precise and reliable position, velocity, and heading information of each individual in various environments. In the PN system developed in this dissertation, the underlying assumption is that the system does not require pre-existing infrastructure to enable pedestrian navigation. To facilitate this capability, a multisensor system concept, based on the Global Positioning System (GPS), inertial navigation, barometer, magnetometer, and a human pedometry model has been developed. An important aspect of this design is to use the human body as navigation sensor to facilitate Dead Reckoning (DR) navigation in GPS-challenged environments. The system is designed predominantly for outdoor environments, where occasional loss of GPS lock may happen; however, testing and performance demonstration have been extended to indoor environments. DR navigation is based on a relative-measurement approach, with the key idea of integrating the incremental motion information in the form of step direction (SD) and step length (SL) over time. The foundation of the intelligent navigation system concept proposed here rests in exploiting the human locomotion pattern, as well as change of locomotion in varying environments. In this context, the term intelligent navigation represents the transition from the conventional point-to-point DR to dynamic navigation using the knowledge about the mechanism of the moving person. This approach increasingly relies on integrating knowledge-based systems (KBS) and artificial intelligence (AI) methodologies, including artificial neural networks (ANN) and fuzzy logic (FL). In addition, a general framework of the quality control for the real-time validation of the DR processing is proposed, based on a two-stage Kalman Filter approach. The performance comparison of the algorithm based on different field and simulated datasets, with varying levels of sensor errors, showed that 90 per cent success rate was achieved in detection of outliers for SL and 80 per cent for SD. The SL is predicted for both KBS-based ANN and FL approaches with an average accumulated error of 2 per cent, observed for the total distance traveled, which is generally an improvement over most of the existing pedometry systems. The target accuracy of the system is +/-(3-5)m CEP50 (circular error, probable 50%). This dissertation provides a performance analysis in the outdoor and indoor environments for different operators. Another objective of this dissertation is to test the system's navigation limitation in DR mode in terms of time and trajectory length in order to determine the upper limit of indoor operations. It was determined that for more than four indoor loops, where the user walked 261m in about 6.5 minutes, the DR performance met the required accuracy specifications. However, these results are only relevant to the existing data. Future studies should consider more comprehensive performance analysis for longer trajectories in challenging environments and possible extension to image-based navigation to expand the indoor capability of the system.

  6. Navigating the System

    MedlinePLUS

    ... Video Games Video Sharing Sites Webcasts/ Webinars Widgets Wikis Follow Us on New Media Virtual Office Hours ... in mind when you are moving through the medical and service system. IT IS IMPORTANT TO REMEMBER: ...

  7. General GPS Antenna Information APPLICATION NOTE

    E-print Network

    Berns, Hans-Gerd

    General GPS Antenna Information APPLICATION NOTE #12;Global Positioning System and Precise Time & Frequency The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites that continuously orbit the earth. Each GPS satellite has on board several atomic

  8. 75 FR 8928 - Announcement of IS-GPS-200, IS-GPS-705, IS-GPS-800 Interface Control Working Group (ICWG...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ...This notice informs the public that the Global Positioning Systems Wing will be hosting an Interface Control Working Group (ICWG) teleconference meeting for document/s IS-GPS-200E (NAVSTAR GPS Space Segment/Navigation User Interfaces), IS-GPS-705A (NAVSTAR GPS Space Segment/User Segment L5 Interfaces), and IS-GPS-800A (NAVSTAR GPS Space Segment/User Segment L1C Interfaces). The main focus of......

  9. Precision navigation for aerospace applications

    E-print Network

    Stimac, Andrew K. (Andrew Kenneth), 1977-

    2004-01-01

    Navigation is important in a variety of aerospace applications, and commonly uses a blend of GPS and inertial sensors. In this thesis, a navigation system is designed, developed, and tested. Several alternatives are ...

  10. 12.215 Modern Navigation, Fall 2002

    E-print Network

    Herring, T. (Thomas)

    Introduces the concepts and applications of navigation techniques using celestial bodies and satellite positioning systems such as the Global Positioning System (GPS). Topics include astronomical observations, radio ...

  11. Development of a GPS-aided motion measurement, pointing, and stabilization system for a Synthetic Aperture Radar. [Global Positioning System (GPS)

    SciTech Connect

    Fellerhoff, J.R.; Kohler, S.M.

    1991-01-01

    An advanced Synthetic Aperture Radar Motion Compensation System has been developed by Sandia National Laboratories (SNL). The system includes a miniaturized high accuracy ring laser gyro inertial measurement unit, a three axis gimbal pointing and stabilization assembly, a differential Global Positioning System (GPS) navigation aiding system, and a pilot guidance system. The system provides several improvements over previous SNL motion compensation systems and is capable of antenna stabilization to less than 0.01 degrees RMS and absolute position measurement to less than 5.0 meters RMS. These accuracies have been demonstrated in recent flight testing aboard a DHC-6-300 Twin Otter'' aircraft.

  12. Autonomous navigation system. [gyroscopic pendulum for air navigation

    NASA Technical Reports Server (NTRS)

    Merhav, S. J. (inventor)

    1981-01-01

    An inertial navigation system utilizing a servo-controlled two degree of freedom pendulum to obtain specific force components in the locally level coordinate system is described. The pendulum includes a leveling gyroscope and an azimuth gyroscope supported on a two gimbal system. The specific force components in the locally level coordinate system are converted to components in the geographical coordinate system by means of a single Euler transformation. The standard navigation equations are solved to determine longitudinal and lateral velocities. Finally, vehicle position is determined by a further integration.

  13. GPS aiding of ocean current determination. [Global Positioning System

    NASA Technical Reports Server (NTRS)

    Mohan, S. N.

    1981-01-01

    The navigational accuracy of an oceangoing vessel using conventional GPS p-code data is examined. The GPS signal is transmitted over two carrier frequencies in the L-band at 1575.42 and 1227.6 MHz. Achievable navigational uncertainties of differenced positional estimates are presented as a function of the parameters of the problem, with particular attention given to the effect of sea-state, user equivalent range error, uncompensated antenna motion, varying delay intervals, and reduced data rate examined in the unaided mode. The unmodeled errors resulting from satellite ephemeris uncertainties are shown to be negligible for the GPS-NDS (Navigation Development) satellites. Requirements are met in relatively calm seas, but accuracy degradation by a factor of at least 2 must be anticipated in heavier sea states. The aided mode of operation is examined, and it is shown that requirements can be met by using an inertial measurement unit (IMU) to aid the GPS receiver operation. Since the use of an IMU would mean higher costs, direct Doppler from the GPS satellites is presented as a viable alternative.

  14. Simulation and analysis of differential GPS

    NASA Technical Reports Server (NTRS)

    Denaro, R. P.

    1984-01-01

    NASA is conducting a research program to evaluate differential Global Positioning System (GPS) concepts for civil helicopter navigation. It is pointed out that the civil helicopter community will probably be an early user of GPS because of the unique mission operations in areas where precise navigation aids are not available. However, many of these applications involve accuracy requirements which cannot be satisfied by conventional GPS. Such applications include remote area search and rescue, offshore oil platform approach, remote area precision landing, and other precise navigation operations. Differential GPS provides a promising approach for meeting very demanding accuracy requirements. The considered procedure eliminates some of the common bias errors experienced by conventional GPS. This is done by making use of a second GPS receiver. A simulation process is developed as a tool for analyzing various scenarios of GPS-referenced civil aircraft navigation.

  15. Lunar roving vehicle navigation system performance review

    NASA Technical Reports Server (NTRS)

    Smith, E. C.; Mastin, W. C.

    1973-01-01

    The design and operation of the lunar roving vehicle (LRV) navigation system are briefly described. The basis for the premission LRV navigation error analysis is explained and an example included. The real time mission support operations philosophy is presented. The LRV navigation system operation and accuracy during the lunar missions are evaluated.

  16. GPS-based system for satellite tracking and geodesy

    NASA Technical Reports Server (NTRS)

    Bertiger, Willy I.; Thornton, Catherine L.

    1989-01-01

    High-performance receivers and data processing systems developed for GPS are reviewed. The GPS Inferred Positioning System (GIPSY) and the Orbiter Analysis and Simulation Software (OASIS) are described. The OASIS software is used to assess GPS system performance using GIPSY for data processing. Consideration is given to parameter estimation for multiday arcs, orbit repeatability, orbit prediction, daily baseline repeatability, agreement with VLBI, and ambiguity resolution. Also, the dual-frequency Rogue receiver, which can track up to eight GPS satellites simultaneously, is discussed.

  17. U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION AND INITIALIZATION OF THE MAGELLAN GPS SATELLITE NAVIGATOR (UA-F-22.1)

    EPA Science Inventory

    The purpose of this SOP is to describe the general procedures for the operation and initialization of the Magellan Global Positioning System (GPS) Satellite Navigator. This procedure was followed to ensure consistent data retrieval during the Arizona NHEXAS project and the Borde...

  18. Integrated Global Positioning Systems (GPS) Laboratory

    NASA Technical Reports Server (NTRS)

    Brown, Dewayne Randolph

    2002-01-01

    The purpose of this research is to develop a user-friendly Integrated GPS lab manual. This manual will help range engineers at NASA to integrate the use of GPS Simulators, GPS receivers, computers, MATLAB software, FUGAWI software and SATELLITE TOOL KIT software. The lab manual will be used in an effort to help NASA engineers predict GPS Coverage of planned operations and analyze GPS coverage of operation post mission. The Integrated GPS Laboratory was used to do GPS Coverage for two extensive case studies. The first scenario was an airplane trajectory in which an aircraft flew from Cape Canaveral to Los Angeles, California. In the second scenario, a rocket trajectory was done whereas a rocket was launched from Cape Canaveral to one thousand kilometers due east in the Atlantic Ocean.

  19. Regional Navigation System Using Geosynchronous Satellites and Stratospheric Airships

    E-print Network

    Won, Chang-Hee

    - 1 - Regional Navigation System Using Geosynchronous Satellites and Stratospheric Airships Chang navigation system using geosynchronous satellites and stratospheric airships. One important factor in designing a navigation system is dilution of precision. We design a regional navigation system based

  20. Precise Point Positioning with the BeiDou Navigation Satellite System

    PubMed Central

    Li, Min; Qu, Lizhong; Zhao, Qile; Guo, Jing; Su, Xing; Li, Xiaotao

    2014-01-01

    By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS) around the World. The Position and Navigation Data Analyst (PANDA) software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP). The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems. PMID:24406856

  1. GENESIS: GPS Environmental and Earth Science Information System

    NASA Technical Reports Server (NTRS)

    Hajj, George

    1999-01-01

    This presentation reviews the GPS ENvironmental and Earth Science Information System (GENESIS). The objectives of GENESIS are outlined (1) Data Archiving, searching and distribution for science data products derived from Space borne TurboRogue Space Receivers for GPS science and other ground based GPS receivers, (2) Data browsing using integrated visualization tools, (3) Interactive web/java-based data search and retrieval, (4) Data subscription service, (5) Data migration from existing GPS archived data, (6) On-line help and documentation, and (7) participation in the WP-ESIP federation. The presentation reviews the products and services of Genesis, and the technology behind the system.

  2. 76 FR 67019 - Eighty-Seventh: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ...Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration...159 meeting: Global Positioning System (GPS...Committee 159: Global Positioning System (GPS) 87th meeting. DATES: The meeting...

  3. 75 FR 28318 - Eighty-Second Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ...Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration...159 meeting: Global Positioning System (GPS...Committee 159: Global Positioning System (GPS). DATES: The meeting will be held...

  4. 78 FR 13396 - 90th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-27

    ...Committee 159, Global Positioning Systems (GPS) AGENCY: Federal Aviation Administration...Committee 159, Global Positioning Systems (GPS...Committee 159, Global Positioning Systems (GPS). DATES: The meeting will be held...

  5. 76 FR 33022 - Eighty-Sixth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-07

    ...Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration...159 meeting: Global Positioning System (GPS...Committee 159: Global Positioning System (GPS). DATES: The meeting will be held...

  6. 77 FR 56254 - 89th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-12

    ...Committee 159, Global Positioning Systems (GPS) AGENCY: Federal Aviation Administration...Committee 159, Global Positioning Systems (GPS...Committee 159, Global Positioning Systems (GPS). DATES: The meeting will be held...

  7. 75 FR 2581 - Eighty-First Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-15

    ...Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration...159 meeting: Global Positioning System (GPS...Committee 159: Global Positioning System (GPS). DATES: The meeting will be held...

  8. 76 FR 27744 - Eighty-Fifth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-12

    ...Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration...159 meeting: Global Positioning System (GPS...Committee 159: Global Positioning System (GPS). DATES: The meeting will be held...

  9. 75 FR 61818 - Eighty-Third Meeting: RTCA Special Committee 159: Global Positioning System (GPS).

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ...Committee 159: Global Positioning System (GPS). AGENCY: Federal Aviation Administration...159 meeting: Global Positioning System (GPS...Committee 159: Global Positioning System (GPS). DATES: The meeting will be held...

  10. 78 FR 57672 - 91st Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ...Committee 159, Global Positioning Systems (GPS) AGENCY: Federal Aviation Administration...Committee 159, Global Positioning Systems (GPS...Committee 159, Global Positioning Systems (GPS) DATES: The meeting will be held...

  11. 77 FR 12106 - 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    ...Committee 159, Global Positioning System (GPS) AGENCY: Federal Aviation Administration...Committee 159, Global Positioning System (GPS...Committee 159, Global Positioning System (GPS). DATES: The meeting will be held...

  12. Hydrographic surveying of reservoirs using differential GPS navigation and GIS data analysis

    SciTech Connect

    White, C.O.

    1995-12-31

    In 1993 and 1994, the Pacific Gas and Electric Company (PG&E) conducted hydrographic surveys on their Rock Creek and Cresta reservoirs. PG&E`s Rock Creek and Cresta reservoirs are located on the North Fork of the Feather River in northern California. Hydrographic surveys were conducted to determine sedimentation levels in the two reservoirs. This paper outlines PG&E`s efforts to monitor sedimentation levels from year-to-year. A survey-grade recording fathometer was used to record the reservoir depths. Survey vessel location was monitored using a Global Positioning System (GPS). Bathymetric contours and reservoir volumes were calculated using a Geographic Information System (GIS). This paper presents the methodology, results, and limitations of this technique for conducting hydrographic surveys. The results of the 1993 and 1994 hydrographic surveys and comparisons to a 1986 photogrammetric survey when the reservoirs were completely drawn down are presented. It is concluded that the GPS hydrographic survey methodology is an accurate and cost effective technique to monitor and address the long-term sediment balance in the reservoirs.

  13. The GPS Space Service Volume

    NASA Technical Reports Server (NTRS)

    Bauer, F. H.; Moreau, M. C.; Dahle-Melsaether, M. E.; Petrofski, W. P.; Stanton, B. J.; Thomason, S.; Harris, G. A.; Sena, R. P.; Temple, L. Parker, III

    2006-01-01

    Prior to the advent of artificial satellites, the concept of navigating in space and the desire to understand and validate the laws of planetary and satellite motion dates back centuries. At the initiation of orbital flight in 1957, space navigation was dominated by inertial and groundbased tracking methods, underpinned by the laws of planetary motion. It was early in the 1980s that GPS was first explored as a system useful for refining the position, velocity, and timing (PVT) of other spacecraft equipped with GPS receivers. As a result, an entirely new GPS utility was developed beyond its original purpose of providing PVT services for land, maritime, and air applications. Spacecraft both above and below the GPS constellation now receive the GPS signals, including the signals that spill over the limb of the Earth. The use of radionavigation satellite services for space navigation in High Earth Orbits is in fact a capability unique to GPS. Support to GPS space applications is being studied and planned as an important improvement to GPS. This paper discusses the formalization of PVT services in space as part of an overall GPS improvement effort. It describes the GPS Space Service Volume (SSV) and compares it to the Terrestrial Service Volume (TSV). It also discusses SSV coverage with the current GPS constellation, coverage characteristics as a function of altitude, expected power levels, and coverage figures of merit.

  14. Navigation system for flexible endoscopes

    NASA Astrophysics Data System (ADS)

    Hummel, Johann; Figl, Michael; Birkfellner, Wolfgang; Häfner, Michael; Kollmann, Christian; Bergmann, Helmar

    2003-05-01

    Endoscopic Ultrasound (EUS) features flexible endoscopes equipped with a radial or linear array scanhead allowing high resolution examination of organs adjacent to the upper gastrointestinal tract. An optical system based on fibre-glass or a CCD-chip allows additional orientation. However, 3-dimensional orientation and correct identification of the various anatomical structures may be difficult. It therefore seems desirable to merge real-time US images with high resolution CT or MR images acquired prior to EUS to simplify navigation during the intervention. The additional information provided by CT or MR images might facilitate diagnosis of tumors and, ultimately, guided puncture of suspicious lesions. We built a grid with 15 plastic spheres and measured their positions relatively to five fiducial markers placed on the top of the grid. For this measurement we used an optical tracking system (OTS) (Polaris, NDI, Can). Two sensors of an electromagnetic tracking system (EMTS) (Aurora, NDI, Can) were mounted on a flexible endoscope (Pentax GG 38 UX, USA) to enable a free hand ultrasound calibration. To determine the position of the plastic spheres in the emitter coordinate system of the EMTS we applied a point-to-point registration (Horn) using the coordinates of the fiducial markers in both coordinate systems (OTS and EMTS). For the transformation between EMTS to the CT space the Horn algorithm was adopted again using the fiducial markers. Visualization was enabled by the use of the AVW-4.0 library (Biomedical Imaging Resource, Mayo Clinic, Rochester/MN, USA). To evaluate the suitability of our new navigation system we measured the Fiducial Registration Error (FRE) of the diverse registrations and the Target Registration Error (TRE) for the complete transformation from the US space to the CT space. The FRE for the ultrasound calibration amounted to 4.3 mm +/- 4.2 mm, resulting from 10 calibration procedures. For the transformation from the OTS reference system to the EMTS emitter space we found an average FRE of 0.8 mm +/- 0.2 mm. The FRE for the CT registration was 1.0 mm +/- 0.3 mm. The TRE was found to be 3.8 mm +/- 1.3 mm if we target the same spheres which where used for the calibration procedure. A movement of the phantom results in higher TREs because of the orientation sensitivity of the sensor. In that case the TRE in the area where the biopsy is supposed to be taken place was found to be 7.9 mm +/- 3.2 mm. Our system provides the interventionist with additional information about position and orientation of the used flexible instrument. Additionally, it improves the marksmanship of biopsies. The use of the miniaturized EMTS enables for the first time the navigation of flexible instruments in this way. For the successful application of navigation systems in interventional radiology, an accuracy in the range of 5 mm is desirable. The accuracy of the localization of a point in CT space are just 3 mm too high as required. One of the possibilities to overcome this difference is to mount the two sensors in such a way that the interference of their electromagnetic fields is minimized. A considerable restraint constitutes the small characteristic volume (360mm x 600mm x 600mm), which requires for most application an additional optical system.

  15. Rip current monitoring using GPS buoy system

    NASA Astrophysics Data System (ADS)

    Song, DongSeob; Kim, InHo; Kang, DongSoo

    2014-05-01

    The occurrence of rip current in the Haeundae beach, which is one of the most famous beaches in South Korea, has been threatening beach-goers security in summer season annually. Many coastal scientists have been investigating rip currents by using field observations and measurements, laboratory measurements and wave tank experiments, and computer and numerical modeling. Rip current velocity is intermittent and may rapidly increase within minutes due to larger incoming wave groups or nearshore circulation instabilities. It is important to understand that changes in rip current velocity occur in response to changes in incoming wave height and period as well as changes in water level. GPS buoys have been used to acquire sea level change data, atmospheric parameters and other oceanic variables in sea for the purposes of vertical datum determination, tide correction, radar altimeter calibration, ocean environment and marine pollution monitoring. Therefore, we adopted GPS buoy system for an experiment which is to investigate rip current velocity; it is sporadic and may quickly upsurge within minutes due to larger arriving wave groups or nearshore flow uncertainties. In this study, for high accurate positioning of buy equipment, a Satellite Based Argumentation System DGPS data logger was deployed to investigate within floating object, and it can be acquired three-dimensional coordinate or geodetic position of buoy with continuous NMEA-0183 protocol during 24 hours. The wave height measured by in-situ hydrometer in a cross-shore array clearly increased before and after occurrence of rip current, and wave period also was lengthened around an event. These results show that wave height and period correlate reasonably well with long-shore current interaction in the Haeundae beach. Additionally, current meter data and GPS buoy data showed that rip current velocities, about 0.2 m/s, may become dangerously strong under specific conditions. Acknowledgement This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology(2010-0024670)

  16. Study of the global positioning system for maritime concepts/applications: Study of the feasibility of replacing maritime shipborne navigation systems with NAVSTAR

    NASA Technical Reports Server (NTRS)

    Winn, C. B.; Huston, W.

    1981-01-01

    A geostationary reference satellite (REFSAT) that broadcasts every four seconds updated GPS satellite coordinates was developed. This procedure reduces the complexity of the GPS receiver. The economic and performance payoffs associated with replacing maritime stripborne navigation systems with NAVSTAR was quantified and the use of NAVSTAR for measurements of ocean currents in the broad ocean areas of the world was evaluated.

  17. Validation on flight data of a closed-loop approach for GPS-based relative navigation of LEO satellites

    NASA Astrophysics Data System (ADS)

    Tancredi, U.; Renga, A.; Grassi, M.

    2013-05-01

    This paper describes a carrier-phase differential GPS approach for real-time relative navigation of LEO satellites flying in formation with large separations. These applications are characterized indeed by a highly varying number of GPS satellites in common view and large ionospheric differential errors, which significantly impact relative navigation performance and robustness. To achieve high relative positioning accuracy a navigation algorithm is proposed which processes double-difference code and carrier measurements on two frequencies, to fully exploit the integer nature of the related ambiguities. Specifically, a closed-loop scheme is proposed in which fixed estimates of the baseline and integer ambiguities produced by means of a partial integer fixing step are fed back to an Extended Kalman Filter for improving the float estimate at successive time instants. The approach also benefits from the inclusion in the filter state of the differential ionospheric delay in terms of the Vertical Total Electron Content of each satellite. The navigation algorithm performance is tested on actual flight data from GRACE mission. Results demonstrate the effectiveness of the proposed approach in managing integer unknowns in conjunction with Extended Kalman Filtering, and that centimeter-level accuracy can be achieved in real-time also with large separations.

  18. Two Systems of Spatial Representation Underlying Navigation

    PubMed Central

    Lee, Sang Ah; Spelke, Elizabeth S.

    2011-01-01

    We review evidence for two distinct cognitive processes by which humans and animals represent the navigable environment. One process uses the shape of the extended 3D surface layout to specify the navigator’s position and orientation. A second process uses objects and patterns as beacons to specify the locations of significant objects. Although much of the evidence for these processes comes from neurophysiological studies of navigating animals and neuroimaging studies of human adults, behavioral studies of navigating children shed light both on the nature of these systems and on their interactions. PMID:20614214

  19. Novel closed-loop approaches for precise relative navigation of widely separated GPS receivers in LEO

    NASA Astrophysics Data System (ADS)

    Tancredi, U.; Renga, A.; Grassi, M.

    2014-01-01

    This paper deals with the relative navigation of a formation of two spacecrafts separated by hundreds of kilometers based on processing dual-frequency differential carrier-phase GPS measurements. Specific requirements of the considered application are high relative positioning accuracy and real-time on board implementation. These can be conflicting requirements. Indeed, if on one hand high accuracy can be achieved by exploiting the integer nature of double-difference carrier-phase ambiguities, on the other hand the presence of large ephemeris errors and differential ionospheric delays makes the integer ambiguities determination challenging. Closed-loop schemes, which update the relative position estimates of a dynamic filter with feedback from integer ambiguities fixing algorithms, are customarily employed in these cases. This paper further elaborates such approaches, proposing novel closed loop techniques aimed at overcoming some of the limitations of traditional algorithms. They extend techniques developed for spaceborne long baseline relative positioning by making use of an on-the-fly ambiguity resolution technique especially developed for the applications of interest. Such techniques blend together ionospheric delay compensation techniques, nonlinear models of relative spacecraft dynamics, and partial integer validation techniques. The approaches are validated using flight data from the Gravity Recovery and Climate Experiment (GRACE) mission. Performance is compared to that of the traditional closed-loop scheme analyzing the capability of each scheme to maximize the percentage of correctly fixed integer ambiguities as well as the relative positioning accuracy. Results show that the proposed approach substantially improves performance of the traditional approaches. More specifically, centimeter-level root-mean square relative positioning is feasible for spacecraft separations of more than 260 km, and an integer ambiguity fixing performance as high as 98% is achieved in a 1-day long dataset. Results also show that approaches exploiting ionospheric delay models are more robust and precise of approaches relying on ionospheric-delay removal techniques.

  20. SIG Technology Review Summer 1994 57 Real-Time Navigation Using the Global Positioning System

    E-print Network

    Simon, Dan

    - grated missile navigation. We present quantifiable measures of navigation accuracy as a function of GPS of air and spacecraft since the introduction of radio navigation 50 years ago" [1]. The successful for this satellite-based navigation tool. Civilian applications of GPS are found in such areas as ship and aircraft

  1. Autonomous navigation system and method

    SciTech Connect

    Bruemmer, David J.; Few, Douglas A.

    2009-09-08

    A robot platform includes perceptors, locomotors, and a system controller, which executes instructions for autonomously navigating a robot. The instructions repeat, on each iteration through an event timing loop, the acts of defining an event horizon based on the robot's current velocity, detecting a range to obstacles around the robot, testing for an event horizon intrusion by determining if any range to the obstacles is within the event horizon, and adjusting rotational and translational velocity of the robot accordingly. If the event horizon intrusion occurs, rotational velocity is modified by a proportion of the current rotational velocity reduced by a proportion of the range to the nearest obstacle and translational velocity is modified by a proportion of the range to the nearest obstacle. If no event horizon intrusion occurs, translational velocity is set as a ratio of a speed factor relative to a maximum speed.

  2. GPS 2002 Conference (Session C3a), Portland, OR, 24-27 September, U.S. Institute of Navigation 1/9 MEMS-IMU for Personal Positioning in a Vehicle

    E-print Network

    Calgary, University of

    GPS 2002 Conference (Session C3a), Portland, OR, 24-27 September, U.S. Institute of Navigation 1 is discussed. 1 On leave from Tampere University of Technology, Finland #12;GPS 2002 Conference (Session C3a

  3. GPS-based certification for the microwave landing system

    NASA Technical Reports Server (NTRS)

    Thornton, C. L.; Young, L. E.; Wu, S. C.; Thomas, J. B.

    1984-01-01

    An MLS (microwave landing system) certification system based on the Global Positioning System (GPS) is described. To determine the position history of the flight inspection aircraft during runway approach, signals from the GPS satellites, together with on-board radar altimetry, are used. It is shown that the aircraft position relative to a fixed point on the runway at threshold can be determined to about 30 cm vertically and 1 m horizontally. A requirement of the system is that the GPS receivers be placed on each flight inspection aircraft and at selected ground sites. The effects of different error sources on the determination of aircraft instantaneous position and its dynamics are analyzed.

  4. A wellbore inertial navigation system

    SciTech Connect

    Kelsey, J.R.

    1983-02-01

    A prototype wireline tool which includes a downhole inertial platform and a surface computer to spatially map a well is described. The hardware consists of a single-gimballed inertial platform with accelerometers and gyros to obtain three-axis motion information. The gyroscope and accelerometer outputs are transmitted to a computer at the surface which calculates probe attitude relative to north, east, and vertical. Double integration of the accelerometer data provides the position information. A conventional 7-conductor wireline is used for the system data transmission. System accuracy is enhanced by advances made in the computer software which processes the data received from the tool. The software uses statistical sampling estimation to obtain optimal estimates of the system errors. Measurement errors are determined by periodically stopping the tool during the logging procedure and observing the indicated velocity measurements. This procedure, known as Kalman filtering, results in increased accuracy of the data. Present mapping systems have an X-Y-Z location accuracy of 100 to 200 feet for a typical well depth of 10,000 feet. Test results show that the new system is accurate to about 1 foot per 1000 feet of well depth. Unlike conventional systems, the inertial navigator does not require any sort of projection of the cable length (which may not be accurately known). Also, this system provides continuous data throughout the wellbore and logging speeds on the order of 10 ft/sec appear possible. The hardware and software associated with this mapping system are described and the recent field test results are reported.

  5. Autonomous Navigation System Using a Fuzzy Adaptive Nonlinear H? Filter

    PubMed Central

    Outamazirt, Fariz; Li, Fu; Yan, Lin; Nemra, Abdelkrim

    2014-01-01

    Although nonlinear H? (NH?) filters offer good performance without requiring assumptions concerning the characteristics of process and/or measurement noises, they still require additional tuning parameters that remain fixed and that need to be determined through trial and error. To address issues associated with NH? filters, a new SINS/GPS sensor fusion scheme known as the Fuzzy Adaptive Nonlinear H? (FANH?) filter is proposed for the Unmanned Aerial Vehicle (UAV) localization problem. Based on a real-time Fuzzy Inference System (FIS), the FANH? filter continually adjusts the higher order of the Taylor development thorough adaptive bounds (?i) and adaptive disturbance attenuation (?), which significantly increases the UAV localization performance. The results obtained using the FANH? navigation filter are compared to the NH? navigation filter results and are validated using a 3D UAV flight scenario. The comparison proves the efficiency and robustness of the UAV localization process using the FANH? filter. PMID:25244587

  6. Autonomous navigation system using a fuzzy adaptive nonlinear H? filter.

    PubMed

    Outamazirt, Fariz; Li, Fu; Yan, Lin; Nemra, Abdelkrim

    2014-01-01

    Although nonlinear H? (NH?) filters offer good performance without requiring assumptions concerning the characteristics of process and/or measurement noises, they still require additional tuning parameters that remain fixed and that need to be determined through trial and error. To address issues associated with NH? filters, a new SINS/GPS sensor fusion scheme known as the Fuzzy Adaptive Nonlinear H? (FANH?) filter is proposed for the Unmanned Aerial Vehicle (UAV) localization problem. Based on a real-time Fuzzy Inference System (FIS), the FANH? filter continually adjusts the higher order of the Taylor development thorough adaptive bounds  and adaptive disturbance attenuation , which significantly increases the UAV localization performance. The results obtained using the FANH? navigation filter are compared to the NH? navigation filter results and are validated using a 3D UAV flight scenario. The comparison proves the efficiency and robustness of the UAV localization process using the FANH? filter. PMID:25244587

  7. Individual Global Navigation Satellite Systems in the Space Service Volume

    NASA Technical Reports Server (NTRS)

    Force, Dale A.

    2013-01-01

    The use of individual Global Navigation Satellite Services (GPS, GLONASS, Galileo, and Beidou/COMPASS) for the position, navigation, and timing in the Space Service Volume at altitudes of 300 km, 3000 km, 8000 km, 15000 km, 25000 km, 36500km and 70000 km is examined and the percent availability of at least one and at least four satellites is presented.

  8. New vision system and navigation algorithm for an autonomous ground vehicle

    NASA Astrophysics Data System (ADS)

    Tann, Hokchhay; Shakya, Bicky; Merchen, Alex C.; Williams, Benjamin C.; Khanal, Abhishek; Zhao, Jiajia; Ahlgren, David J.

    2013-12-01

    Improvements were made to the intelligence algorithms of an autonomously operating ground vehicle, Q, which competed in the 2013 Intelligent Ground Vehicle Competition (IGVC). The IGVC required the vehicle to first navigate between two white lines on a grassy obstacle course, then pass through eight GPS waypoints, and pass through a final obstacle field. Modifications to Q included a new vision system with a more effective image processing algorithm for white line extraction. The path-planning algorithm adopted the vision system, creating smoother, more reliable navigation. With these improvements, Q successfully completed the basic autonomous navigation challenge, finishing tenth out of over 50 teams.

  9. Basic Mars Navigation System For Local Areas

    NASA Astrophysics Data System (ADS)

    Petitfils, E.-A.; Boche-Sauvan, L.; Foing, B. H.; Monaghan, E.; Crews, Eurogeomars

    2009-04-01

    Introduction: This project has been first set up as a basic solution in navigation during EVA (extra-vehicular activities) in the Mars Society Desert Research Station in the desert of Utah. The main idea is to keep the system as simple as possible so that it can be easily adaptable and portable. The purpose of such a device is to tell the astronauts in EVA where they roughly are and then letting them reaching different points in avoiding any risky way. Thus the precision needed has not to be really high: even if it is about 50m, every astronaut can then look on a map and be able to design a way to another point. This navigation system will improve the safety of the EVA as it is an added reliable orientating tool. Concept: To look at a simple way to localize oneself, one should have a look at what has been done by mankind on Earth. Today, everyone can think of the GPS because it's simple and very reliable. However the infrastructure for such a system is huge and will not be for sure available during the first missions. We can think of course of a basic GPS using the satellites being in orbit but this approach is not yet as simple as we would like. If we want to keep the sky in sight, we can use the stars and the moons of Mars. Yet this would be a good solution and we can even have a star tracker that would give a good position according to the time of the picture. This solution has to be kept in mind but a star tracker is quite big for an astronaut without any rover nearby and using the sky may not be as precise as one should expect. Another useful tool is the compass. It has been used for centuries by sailors but on Mars, without a good magnetic field for this purpose. But sailors also use lighthouses and some placemarks on the land to localize themselves. This is done with a compass, measuring the angle between a placemark and the magnetic North. With two angles, we can then have the position of the boat. The idea here is the same: measuring the angles between different placemarks so that we can compute the position. But which placemarks? We have to think about something that can be installed on Mars and is light enough to be brought there. Balloons are really light, and in order to place them, we need a gas as helium (or hydrogen) and also some rope. Hydrogen is likely to be produced in situ and rope will be useful for astronauts. So we started on a concept with some balloons around the base, with different colors or patterns. The crew in EVA can thus know where the base is every time they are in sight of a balloon and with at least three balloons; they can compute their position according to the base. Procedure of the test: During EVA, the astronauts will measure the angle between the different balloons. The balloons are high in the sky so they can be seen far from their location. This is particularly important on Mars where the horizon is nearer than on Earth. The balloons have different colors so they can be identified and we can even think of adding an autonomous colored light under so they can be observed during the night. With good quality balloons, we can keep them in the sky for a few days without maintenance. Angle measurement is done thanks to a camera. A numeric camera can have a precision of less than 0.01°/pixel, which is enough for our application. The distance between the different balloons can easily be seen in a free picture management software and a Matlab tool is under development for this. An algorithm is then run and it gives the positions that fit with the observations on a map. Simulation gave areas 20m width, which is enough for the astronaut who has a map. The exact precision will be investigated in situ, at the MDRS. For this first test bench, computations will be manually done on a computer in order to validate the concept without huge development. Afterwards, one can imagine an implementation on a PDA brought by the astronauts. This PDA would have its own camera so the process can be fully automatic. Such a system can also implement other navigation system as a Martian GPS or a radio locali

  10. Fundamentals of satellite navigation

    NASA Astrophysics Data System (ADS)

    Stiller, A. H.

    The basic operating principles and capabilities of conventional and satellite-based navigation systems for air, sea, and land vehicles are reviewed and illustrated with diagrams. Consideration is given to autonomous onboard systems; systems based on visible or radio beacons; the Transit, Cicada, Navstar-GPS, and Glonass satellite systems; the physical laws and parameters of satellite motion; the definition of time in satellite systems; and the content of the demodulated GPS data signal. The GPS and Glonass data format frames are presented graphically, and tables listing the GPS and Glonass satellites, their technical characteristics, and the (past or scheduled) launch dates are provided.

  11. Ultra-Wideband Tracking System Design for Relative Navigation

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun David; Arndt, Dickey; Bgo, Phong; Dekome, Kent; Dusl, John

    2011-01-01

    This presentation briefly discusses a design effort for a prototype ultra-wideband (UWB) time-difference-of-arrival (TDOA) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being designed for use in localization and navigation of a rover in a GPS deprived environment for surface missions. In one application enabled by the UWB tracking, a robotic vehicle carrying equipments can autonomously follow a crewed rover from work site to work site such that resources can be carried from one landing mission to the next thereby saving up-mass. The UWB Systems Group at JSC has developed a UWB TDOA High Resolution Proximity Tracking System which can achieve sub-inch tracking accuracy of a target within the radius of the tracking baseline [1]. By extending the tracking capability beyond the radius of the tracking baseline, a tracking system is being designed to enable relative navigation between two vehicles for surface missions. A prototype UWB TDOA tracking system has been designed, implemented, tested, and proven feasible for relative navigation of robotic vehicles. Future work includes testing the system with the application code to increase the tracking update rate and evaluating the linear tracking baseline to improve the flexibility of antenna mounting on the following vehicle.

  12. A weighted combination filter with nonholonomic constrains for integrated navigation systems

    NASA Astrophysics Data System (ADS)

    Guo, Hang; Guo, Junge; Yu, Min; Hong, Haibin; Xiong, Jian; Tian, Baolian

    2015-03-01

    To meet the requirements of higher accuracy and stability of integrated navigation system, this paper applied Sage-Husa adaptive Kalman filter with nonholonomic constraints and forward/backward filtering to IMU/GPS integrated system, and the results of the forward and backward filtering are weighted and combined. A weighted combination filter is proposed in this paper, and which has been used in post-processing to improve MEMS IMU/GPS accuracy. Through the car navigation experiment, data set has been processed by four filtering algorithms. By means of comparing the four results, the method proposed for the vehicle integrated navigation system achieved the best accuracy with standard deviations of latitude = 1.03 m, longitude = 1.31 m, and heading angle = 0.84 deg°, which demonstrated the advantages of the new method.

  13. Post-disposal orbital evolution of satellites and upper stages used by the GPS and GLONASS navigation constellations: The long-term impact on the Medium Earth Orbit environment

    NASA Astrophysics Data System (ADS)

    Pardini, Carmen; Anselmo, Luciano

    2012-08-01

    The long-term evolution and environmental impact in MEO of all the abandoned spacecraft and upper stages associated with the GPS and GLONASS navigation constellations were analyzed. The orbits of the disposed objects, as of 1 May 2011, were propagated for 200 years and snapshots of their evolving distribution were obtained, together with an estimation of the changing collision probability with the spacecraft of the operational navigation systems existing or planned in MEO, i.e., GLONASS, GPS, Beidou and Galileo. The probability that the abandoned objects considered will collide with the operational spacecraft of the navigation constellations is very low, even taking into account the intrinsic eccentricity instability of the disposal orbits. Assuming the present or envisaged configuration of the constellations in MEO, the probability of collision, integrated over 200 years, would be <1/300 with a GLONASS spacecraft, <1/15,000 with a GPS or Beidou spacecraft, and <1/250,000 with a Galileo spacecraft. The worst disposal strategy consists in abandoning satellites and upper stages close to the altitude of the operational constellation (GLONASS), while a re-orbiting a few hundred km away (GPS) is able to guarantee an effective long-term dilution of the collision risk, irrespective of the eccentricity instability due to geopotential and luni-solar perturbations. The disposal strategies applied so far to the GPS satellites should be able to guarantee for at least a few centuries a sustainable MEO environment free of collisions among intact objects. Consequently, there would be no need to adopt disposal schemes targeting also the optimal value of the eccentricity vector. However, it should be pointed out that the GPS disposal strategy was devised well in advance of the Beidou constellation announcement, so most of the abandoned satellites were re-orbited fairly close to the altitude of the new Chinese system. A new re-orbiting approach will be therefore needed in the future.

  14. Positional Accuracy of Airborne Integrated Global Positioning and Inertial Navigation Systems for Mapping in Glen Canyon, Arizona

    USGS Publications Warehouse

    Sanchez, Richard D.; Hothem, Larry D.

    2002-01-01

    High-resolution airborne and satellite image sensor systems integrated with onboard data collection based on the Global Positioning System (GPS) and inertial navigation systems (INS) may offer a quick and cost-effective way to gather accurate topographic map information without ground control or aerial triangulation. The Applanix Corporation?s Position and Orientation Solutions for Direct Georeferencing of aerial photography was used in this project to examine the positional accuracy of integrated GPS/INS for terrain mapping in Glen Canyon, Arizona. The research application in this study yielded important information on the usefulness and limits of airborne integrated GPS/INS data-capture systems for mapping.

  15. System using leo satellites for centimeter-level navigation

    NASA Technical Reports Server (NTRS)

    Rabinowitz, Matthew (Inventor); Parkinson, Bradford W. (Inventor); Cohen, Clark E. (Inventor); Lawrence, David G. (Inventor)

    2002-01-01

    Disclosed herein is a system for rapidly resolving position with centimeter-level accuracy for a mobile or stationary receiver [4]. This is achieved by estimating a set of parameters that are related to the integer cycle ambiguities which arise in tracking the carrier phase of satellite downlinks [5,6]. In the preferred embodiment, the technique involves a navigation receiver [4] simultaneously tracking transmissions [6] from Low Earth Orbit Satellites (LEOS) [2] together with transmissions [5] from GPS navigation satellites [1]. The rapid change in the line-of-sight vectors from the receiver [4] to the LEO signal sources [2], due to the orbital motion of the LEOS, enables the resolution with integrity of the integer cycle ambiguities of the GPS signals [5] as well as parameters related to the integer cycle ambiguity on the LEOS signals [6]. These parameters, once identified, enable real-time centimeter-level positioning of the receiver [4]. In order to achieve high-precision position estimates without the use of specialized electronics such as atomic clocks, the technique accounts for instabilities in the crystal oscillators driving the satellite transmitters, as well as those in the reference [3] and user [4] receivers. In addition, the algorithm accommodates as well as to LEOS that receive signals from ground-based transmitters, then re-transmit frequency-converted signals to the ground.

  16. The Navy Navigation Satellite System (TRANSIT)

    NASA Astrophysics Data System (ADS)

    Danchik, R. J.

    1984-12-01

    The present article provides an update on the status of the Navy Navigation Satellite System (Transit). It is pointed out, that, in 1958, research scientists at the Applied Physics Laboratory (APL) solved the orbit of the first Russian satellite, Sputnik-1, by analysis of the observed Doppler shift of its transmitted signal. This result led immediately to the concept of satellite navigation and the development of the U.S. Navy Navigation Satellite System (Transit) by APL, to provide position fixes for the Fleet Ballistic Missile Weapon System submarines. At the present time, 26 years after its conception, the system is mature. Beginning with the release of the system to industry in July 1967, it has been used by military and civilian navigators for position fixing and for surveying. Attention is given to system reliability, developments regarding the constellation of satellites, satellite configurations, the users of the Transit system, and plans to continue operation of Transit until 1994.

  17. Hardware-in-the-loop simulations of GPS-based navigation and control for satellite formation flying

    NASA Astrophysics Data System (ADS)

    Park, Jae-Ik; Park, Han-Earl; Park, Sang-Young; Choi, Kyu-Hong

    2010-12-01

    A relative navigation and formation control algorithm for satellite formation flying was developed, and a hardware-in-the-loop (HIL) simulation testbed was established and configured to evaluate this algorithm. The algorithm presented is a relative navigation estimation algorithm using double-difference carrier-phase and single-difference code measurements based on the extended Kalman filter (EKF). In addition, a state-dependent Riccati equation (SDRE) technique is utilized as a nonlinear controller for the formation control problem. The state-dependent coefficient (SDC) form is formulated to include nonlinearities in the relative dynamics. To evaluate the relative navigation and control algorithms developed, a closed-loop HIL testbed is configured. To demonstrate the performance of the testbed, a test formation flying scenario comprising formation acquisition and keeping in a low earth orbit (LEO) has been established. The relative navigation results from the closed-loop simulations show that a 3D RMS of 0.07 m can be achieved for position accuracy. The targeted leader-follower formation flying in the along-track separation of 100 m was maintained with a mean position error of approximately 0.2 m and a standard deviation of 0.9 m. The simulation results show that the HIL testbed is capable of successful demonstration of the GPS-based satellite autonomous formation flying mission.

  18. Bluetooth Navigation System using Wi-Fi Access Points

    E-print Network

    Agrawal, Rohit

    2012-01-01

    There have been various navigation and tracking systems being developed with the help of technologies like GPS, GSM, Bluetooth, IR, Wi-Fi and Radar. Outdoor positioning systems have been deployed quite successfully using GPS but positioning systems for indoor environments still do not have widespread deployment due to various reasons. Most of these use only a single technology for positioning but using more than one in cooperation with each other is always advantageous for obtaining greater accuracy. Particularly, the ones which use Bluetooth are better since they would enhance the scalability of such a system because of the fact that this technology is in use by the common people so it would always be easy to track them. Moreover it would also reduce the hardware installation cost to some extent. The system that has been introduced here uses Bluetooth primarily for positioning and tracking in combination with Wi-Fi access points. The reason that makes the commercial application of such a system easier and ch...

  19. 75 FR 998 - Terminate Long Range Aids to Navigation (Loran-C) Signal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-07

    ...infrastructure is not needed as a backup to the GPS system or to meet any other Federal navigation...the U.S. Global Positioning System (GPS), Loran-C is no longer required by the...intended to be, a viable systemic backup for GPS. Backups to GPS for...

  20. Navigation System for Ground Vehicles using Temporally Interconnected Observers

    E-print Network

    Navigation System for Ground Vehicles using Temporally Interconnected Observers Pierre navigation technique for an automotive vehicle. This method involves several observers, each designed observability properties, are used to guarantee convergence of the constituted navigation system. I

  1. A Comparison between Different Error Modeling of MEMS Applied to GPS/INS Integrated Systems

    PubMed Central

    Quinchia, Alex G.; Falco, Gianluca; Falletti, Emanuela; Dovis, Fabio; Ferrer, Carles

    2013-01-01

    Advances in the development of micro-electromechanical systems (MEMS) have made possible the fabrication of cheap and small dimension accelerometers and gyroscopes, which are being used in many applications where the global positioning system (GPS) and the inertial navigation system (INS) integration is carried out, i.e., identifying track defects, terrestrial and pedestrian navigation, unmanned aerial vehicles (UAVs), stabilization of many platforms, etc. Although these MEMS sensors are low-cost, they present different errors, which degrade the accuracy of the navigation systems in a short period of time. Therefore, a suitable modeling of these errors is necessary in order to minimize them and, consequently, improve the system performance. In this work, the most used techniques currently to analyze the stochastic errors that affect these sensors are shown and compared: we examine in detail the autocorrelation, the Allan variance (AV) and the power spectral density (PSD) techniques. Subsequently, an analysis and modeling of the inertial sensors, which combines autoregressive (AR) filters and wavelet de-noising, is also achieved. Since a low-cost INS (MEMS grade) presents error sources with short-term (high-frequency) and long-term (low-frequency) components, we introduce a method that compensates for these error terms by doing a complete analysis of Allan variance, wavelet de-nosing and the selection of the level of decomposition for a suitable combination between these techniques. Eventually, in order to assess the stochastic models obtained with these techniques, the Extended Kalman Filter (EKF) of a loosely-coupled GPS/INS integration strategy is augmented with different states. Results show a comparison between the proposed method and the traditional sensor error models under GPS signal blockages using real data collected in urban roadways. PMID:23887084

  2. A comparison between different error modeling of MEMS applied to GPS/INS integrated systems.

    PubMed

    Quinchia, Alex G; Falco, Gianluca; Falletti, Emanuela; Dovis, Fabio; Ferrer, Carles

    2013-01-01

    Advances in the development of micro-electromechanical systems (MEMS) have made possible the fabrication of cheap and small dimension accelerometers and gyroscopes, which are being used in many applications where the global positioning system (GPS) and the inertial navigation system (INS) integration is carried out, i.e., identifying track defects, terrestrial and pedestrian navigation, unmanned aerial vehicles (UAVs), stabilization of many platforms, etc. Although these MEMS sensors are low-cost, they present different errors, which degrade the accuracy of the navigation systems in a short period of time. Therefore, a suitable modeling of these errors is necessary in order to minimize them and, consequently, improve the system performance. In this work, the most used techniques currently to analyze the stochastic errors that affect these sensors are shown and compared: we examine in detail the autocorrelation, the Allan variance (AV) and the power spectral density (PSD) techniques. Subsequently, an analysis and modeling of the inertial sensors, which combines autoregressive (AR) filters and wavelet de-noising, is also achieved. Since a low-cost INS (MEMS grade) presents error sources with short-term (high-frequency) and long-term (low-frequency) components, we introduce a method that compensates for these error terms by doing a complete analysis of Allan variance, wavelet de-nosing and the selection of the level of decomposition for a suitable combination between these techniques. Eventually, in order to assess the stochastic models obtained with these techniques, the Extended Kalman Filter (EKF) of a loosely-coupled GPS/INS integration strategy is augmented with different states. Results show a comparison between the proposed method and the traditional sensor error models under GPS signal blockages using real data collected in urban roadways. PMID:23887084

  3. Design study of a low cost civil aviation GPS receiver system

    NASA Technical Reports Server (NTRS)

    Cnossen, R.; Gilbert, G. A.

    1979-01-01

    A low cost Navstar receiver system for civil aviation applications was defined. User objectives and constraints were established. Alternative navigation processing design trades were evaluated. Receiver hardware was synthesized by comparing technology projections with various candidate system designs. A control display unit design was recommended as the result of field test experience with Phase I GPS sets and a review of special human factors for general aviation users. Areas requiring technology development to ensure a low cost Navstar Set in the 1985 timeframe were identified.

  4. High Sensitivity GPS Velocity Updates For Personal Indoor Navigation Using Inertial

    E-print Network

    Calgary, University of

    - reckoning sensors. Unfortunately, these pseudorange measurements are noisy under degraded signal as a function of received signal power. This assessment is performed using data collected on a hardware by approximately 25 dB relative to nominal GPS environments. Unfortunately, the Doppler measurements are also shown

  5. Spacecraft Navigation Using the Modernized Global Positioning System Signal

    NASA Astrophysics Data System (ADS)

    Lightsey, E. G.; Harris, R. B.

    2009-01-01

    Navigation is examined using information that is presently known about the modernized GPS signal. Although the full signal has not yet been fielded, its technical description can be used to predict its performance. The ranging accuracy of the new signal is compared to the classic signal. First, the signals are described. The correlation processes and consequent tracking accuracies are then determined. Finally the effect of multipath on the M-code is examined as a method to assess the future performance of the broadcast ephemeris. In most cases the performance of the modernized GPS signal is improved over the classic GPS signal, implying that it would be advantageous for receivers to employ it.

  6. Orion Absolute Navigation System Progress and Challenge

    NASA Technical Reports Server (NTRS)

    Holt, Greg N.; D'Souza, Christopher

    2012-01-01

    The absolute navigation design of NASA's Orion vehicle is described. It has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary onboard measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudo-range and delta-range, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, and cold start are discussed as are strategies for whole and partial state updates as well as covariance considerations. Strategies are given for dealing with latent measurements and high-rate propagation using multi-rate architecture. The details of the rate groups and the data ow between the elements is discussed and evaluated.

  7. System architecture study of an orbital GPS user terminal

    NASA Technical Reports Server (NTRS)

    Martin, D. P.; Neily, C. M., Jr.

    1980-01-01

    The generic RF and applications processing requirements for a GPS orbital navigator are considered. A line of demarcation between dedicated analog hardware, and software/processor implementation, maximizing the latter is discussed. A modular approach to R/PA design which permits several varieties of receiver to be constructed from basic components is described. It is a basic conclusion that software signal processing of the output of the baseband correlator is the best choice of transition from analog to digital signal processing. High performance sets requiring multiple channels are developed from a generic design by replicating the RF processing segment, and modifying the applications software to provide enhanced state propagation and estimation.

  8. Pre-Flight Testing of Spaceborne GPS Receivers Using a GPS Constellation Simulator

    NASA Technical Reports Server (NTRS)

    Kizhner, Semion; Davis, Edward; Alonso, Roberto

    1999-01-01

    The NASA Goddard Space Flight Center (GSFC) Global Positioning System (GPS) applications test facility has been established within the GSFC Guidance Navigation and Control Center. The GPS test facility is currently housing the Global Simulation Systems Inc. (GSSI) STR2760 GPS satellite 40-channel attitude simulator and a STR4760 12-channel navigation simulator. The facility also contains a few other resources such as an atomic time standard test bed, a rooftop antenna platform and a radome. It provides a new capability for high dynamics GPS simulations of space flight that is unique within the aerospace community. The GPS facility provides a critical element for the development and testing of GPS based technologies i.e. position, attitude and precise time determination used on-board a spacecraft, suborbital rocket or balloon. The GPS simulator system is configured in a transportable rack and is available for GPS component development as well as for component, spacecraft subsystem and system level testing at spacecraft integration and test sites. The GPS facility has been operational since early 1996 and has been utilized by space flight projects carrying GPS experiments, such as the OrbView-2 and the Argentine SAC-A spacecrafts. The SAC-A pre-flight test data obtained by using the STR2760 simulator and the comparison with preliminary analysis of the GPS data from SAC-A telemetry are summarized. This paper describes pre-flight tests and simulations used to support a unique spaceborne GPS experiment. The GPS experiment mission objectives and the test program are described, as well as the GPS test facility configuration needed to verify experiment feasibility. Some operational and critical issues inherent in GPS receiver pre-flight tests and simulations using this GPS simulator, and test methodology are described. Simulation and flight data are presented. A complete program of pre-flight testing of spaceborne GPS receivers using a GPS constellation simulator is detailed.

  9. Pre-Flight Testing of Spaceborne GPS Receivers using a GPS Constellation Simulator

    NASA Technical Reports Server (NTRS)

    Kizhner, Semion; Davis, Edward; Alonso, R.

    1999-01-01

    The NASA Goddard Space Flight Center (GSFC) Global Positioning System (GPS) applications test facility has been established within the GSFC Guidance Navigation and Control Center. The GPS test facility is currently housing the Global Simulation Systems Inc. (GSSI) STR2760 GPS satellite 40-channel attitude simulator and a STR4760 12-channel navigation simulator. The facility also contains a few other resources such as an atomic time standard test bed, a rooftop antenna platform and a radome. It provides a new capability for high dynamics GPS simulations of space flight that is unique within the aerospace community. The GPS facility provides a critical element for the development and testing of GPS based technologies i.e. position, attitude and precise time determination used on-board a spacecraft, suborbital rocket balloon. The GPS simulation system is configured in a transportable rack and is available for GPS component development as well as for component, spacecraft subsystem and system level testing at spacecraft integration and tests sites. The GPS facility has been operational since early 1996 and has utilized by space flight projects carrying GPS experiments, such as the OrbView-2 and the Argentine SAC-A spacecrafts. The SAC-A pre-flight test data obtained by using the STR2760 simulator and the comparison with preliminary analysis of the GPS data from SAC-A telemetry are summarized. This paper describes pre-flight tests and simulations used to support a unique spaceborne GPS experiment. The GPS experiment mission objectives and the test program are described, as well as the GPS test facility configuration needed to verify experiment feasibility. Some operational and critical issues inherent in GPS receiver pre-flight tests and simulations using this GPS simulation, and test methodology are described. Simulation and flight data are presented. A complete program of pre-flight testing of spaceborne GPS receivers using a GPS constellation simulator is detailed.

  10. GPS-Like Phasing Control of the Space Solar Power System Transmission Array

    NASA Technical Reports Server (NTRS)

    Psiaki, Mark L.

    2003-01-01

    The problem of phasing of the Space Solar Power System's transmission array has been addressed by developing a GPS-like radio navigation system. The goal of this system is to provide power transmission phasing control for each node of the array that causes the power signals to add constructively at the ground reception station. The phasing control system operates in a distributed manner, which makes it practical to implement. A leader node and two radio navigation beacons are used to control the power transmission phasing of multiple follower nodes. The necessary one-way communications to the follower nodes are implemented using the RF beacon signals. The phasing control system uses differential carrier phase relative navigation/timing techniques. A special feature of the system is an integer ambiguity resolution procedure that periodically resolves carrier phase cycle count ambiguities via encoding of pseudo-random number codes on the power transmission signals. The system is capable of achieving phasing accuracies on the order of 3 mm down to 0.4 mm depending on whether the radio navigation beacons operate in the L or C bands.

  11. GPS water level measurements for Indonesia's Tsunami Early Warning System

    NASA Astrophysics Data System (ADS)

    Schöne, T.; Pandoe, W.; Mudita, I.; Roemer, S.; Illigner, J.; Zech, C.; Galas, R.

    2011-03-01

    On Boxing Day 2004, a severe tsunami was generated by a strong earthquake in Northern Sumatra causing a large number of casualties. At this time, neither an offshore buoy network was in place to measure tsunami waves, nor a system to disseminate tsunami warnings to local governmental entities. Since then, buoys have been developed by Indonesia and Germany, complemented by NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys, and have been moored offshore Sumatra and Java. The suite of sensors for offshore tsunami detection in Indonesia has been advanced by adding GPS technology for water level measurements. The usage of GPS buoys in tsunami warning systems is a relatively new approach. The concept of the German Indonesian Tsunami Early Warning System (GITEWS) (Rudloff et al., 2009) combines GPS technology and ocean bottom pressure (OBP) measurements. Especially for near-field installations where the seismic noise may deteriorate the OBP data, GPS-derived sea level heights provide additional information. The GPS buoy technology is precise enough to detect medium to large tsunamis of amplitudes larger than 10 cm. The analysis presented here suggests that for about 68% of the time, tsunamis larger than 5 cm may be detectable.

  12. Investigation of GPS/IMU Positioning System for Mining Equipment

    SciTech Connect

    Ken L. Stratton

    2006-09-13

    The objective of this project is to investigate the applicability of a combined Global Positioning System and Inertial Measurement Unit (GPS/IMU) for information based displays on earthmoving machines and for automated earthmoving machines in the future. This technology has the potential of allowing an information-based product like Caterpillar's Computer Aided Earthmoving System (CAES) to operate in areas with satellite shading. Satellite shading is an issue in open pit mining because machines are routinely required to operate close to high walls, which reduces significantly the amount of the visible sky to the GPS antenna mounted on the machine. An inertial measurement unit is a product, which provides data for the calculation of position based on sensing accelerations and rotation rates of the machine's rigid body. When this information is coupled with GPS it results in a positioning system that can maintain positioning capability during time periods of shading.

  13. A Navigation System for Robots Operating in Crowded Urban Environments

    E-print Network

    Teschner, Matthias

    to that dynamic. In this paper, we present a navigation system for pedestrian-like autonomous navigation Obelix managed to autonomously navigate from our university campus over a 3.3 km long route to the city progress has been made in the area of autonomous navigation over the past years. The majority of navigation

  14. Fault tolerant integrated inertial navigation/global positioning systems for next generation spacecraft

    NASA Astrophysics Data System (ADS)

    Miller, Hugh; Hilts, David A.

    The authors address the requirements, benefits, and mitigation of risks to adapt a commercial Hexad fault-tolerant inertial navigation/global positioning system (FT IN/GPS) for use in next-generation spacecraft. Next-generation requirements are examined to determine whether a high production base system can meet autonomous, reliable, and low-cost requirements for future spacecraft. The major benefits are the combining and replacement of functions, the reduction of unscheduled maintenance and operations costs, and a higher probability of mission success. The design, development, and production risks are mitigated by the long-term commercial production schedule for the Boeing 777 air data inertial reference unit (ADIRU) which begins in the mid-1990s. The conclusion is that a strapdown ring laser gyro (RLG) Hexad FT IN/GPS is the preferred integrated navigation and control system for next-generation vehicles.

  15. The Utility and Validity of Kinematic GPS Positioning for the Geosar Airborne Terrain Mapping Radar System

    NASA Technical Reports Server (NTRS)

    Freedman, Adam; Hensley, Scott; Chapin, Elaine; Kroger, Peter; Hussain, Mushtaq; Allred, Bruce

    1999-01-01

    GeoSAR is an airborne, interferometric Synthetic Aperture Radar (IFSAR) system for terrain mapping, currently under development by a consortium including NASA's Jet Propulsion Laboratory (JPL), Calgis, Inc., a California mapping sciences company, and the California Department of Conservation (CaIDOC), with funding provided by the U.S. Army Corps of Engineers Topographic Engineering Center (TEC) and the U.S. Defense Advanced Research Projects Agency (DARPA). IFSAR data processing requires high-accuracy platform position and attitude knowledge. On 9 GeoSAR, these are provided by one or two Honeywell Embedded GPS Inertial Navigation Units (EGI) and an Ashtech Z12 GPS receiver. The EGIs provide real-time high-accuracy attitude and moderate-accuracy position data, while the Ashtech data, post-processed differentially with data from a nearby ground station using Ashtech PNAV software, provide high-accuracy differential GPS positions. These data are optimally combined using a Kalman filter within the GeoSAR motion measurement software, and the resultant position and orientation information are used to process the dual frequency (X-band and P-band) radar data to generate high-accuracy, high -resolution terrain imagery and digital elevation models (DEMs). GeoSAR requirements specify sub-meter level planimetric and vertical accuracies for the resultant DEMS. To achieve this, platform positioning errors well below one meter are needed. The goal of GeoSAR is to obtain 25 cm or better 3-D positions from the GPS systems on board the aircraft. By imaging a set of known point target corner-cube reflectors, the GeoSAR system can be calibrated. This calibration process yields the true position of the aircraft with an uncertainty of 20- 50 cm. This process thus allows an independent assessment of the accuracy of our GPS-based positioning systems. We will present an overview of the GeoSAR motion measurement system, focusing on the use of GPS and the blending of position data from the various systems. We will present the results of our calibration studies that relate to the accuracy the GPS positioning. We will discuss the effects these positioning, errors have on the resultant DEM products and imagery.

  16. The Mathematics of Navigating the Solar System

    NASA Technical Reports Server (NTRS)

    Hintz, Gerald

    2000-01-01

    In navigating spacecraft throughout the solar system, the space navigator relies on three academic disciplines - optimization, estimation, and control - that work on mathematical models of the real world. Thus, the navigator determines the flight path that will consume propellant and other resources in an efficient manner, determines where the craft is and predicts where it will go, and transfers it onto the optimal trajectory that meets operational and mission constraints. Mission requirements, for example, demand that observational measurements be made with sufficient precision that relativity must be modeled in collecting and fitting (the estimation process) the data, and propagating the trajectory. Thousands of parameters are now determined in near real-time to model the gravitational forces acting on a spacecraft in the vicinity of an irregularly shaped body. Completing these tasks requires mathematical models, analyses, and processing techniques. Newton, Gauss, Lambert, Legendre, and others are justly famous for their contributions to the mathematics of these tasks. More recently, graduate students participated in research to update the gravity model of the Saturnian system, including higher order gravity harmonics, tidal effects, and the influence of the rings. This investigation was conducted for the Cassini project to incorporate new trajectory modeling features in the navigation software. The resulting trajectory model will be used in navigating the 4-year tour of the Saturnian satellites. Also, undergraduate students are determining the ephemerides (locations versus time) of asteroids that will be used as reference objects in navigating the New Millennium's Deep Space 1 spacecraft autonomously.

  17. INTERACTION DESIGN ISSUES FOR CAR NAVIGATION SYSTEMS Paul Curzon

    E-print Network

    Curzon, Paul

    INTERACTION DESIGN ISSUES FOR CAR NAVIGATION SYSTEMS Paul Curzon Middlesex University Interaction the interaction design of car navigation systems. Keywords In-car navigation systems, cognitive walkthrough. 1 car navigation systems are a solved problem and, if not, suggest general lessons for their design

  18. US Coast Guard differential GPS network

    SciTech Connect

    Alsip, D.H.; Butler, J.M.; Radice, J.T.

    1993-03-01

    In order to aid navigation and to prevent disasters such as oil spills, collisions, and wrecks of vessels and aircraft, the US Coast Guard is charged with establishing, maintaining, and operating electronic aids to navigation. In a technological advance developed and operated by the Department of Defense, the global positioning system (GPS) provides all-weather global coverage, 24 hours/day at unprecedented accuracies. GPS provides standard positioning service (SPS) and precise positioning service (PPS). By applying differential techniques to GPS, navigational accuracies of better than 10 meters can be achieved. For the first time, an all-weather system is possible to meet all the marine navigator's needs including harbor and harbor approach navigation. This should revolutionize navigation safety and efficiency, surveying operations, search and rescue operations, and underwater mine disposal efficiency and safety.

  19. International GPS (Global Positioning System) Service for Geodynamics

    NASA Technical Reports Server (NTRS)

    Zumberge, J. F. (Editor); Liu, R. (Editor); Neilan, R. E. (Editor)

    1995-01-01

    The International GPS (Global Positioning System) Service for Geodynamics (IGS) began formal operation on January 1, 1994. This first annual report is divided into sections, which mirror different aspects of the service. Section (1) contains general information, including the history of the IGS, its organization, and the global network of GPS tracking sites; (2) contains information on the Central Bureau Information System; (3) describes the International Earth Rotation Service (IERS); (4) details collecting and distributing IGS data in Data Center reports; (6) describes how the IGS Analysis Centers generate their products; (7) contains miscellaneous contributions from other organizations that share common interests with the IGS.

  20. An Interdisciplinary Approach at Studying the Earth-Sun System with GPS/GNSS and GPS-like Signals

    NASA Technical Reports Server (NTRS)

    Zuffada, Cinzia; Hajj, George; Mannucci, Anthony J.; Chao, Yi; Ao, Chi; Zumberge, James

    2005-01-01

    The value of Global Positioning Satellites (GPS) measurements to atmospheric science, space physics, and ocean science, is now emerging or showing a potential to play a major role in the evolving programs of NASA, NSF and NOAA. The objective of this communication is to identify and articulate the key scientific questions that are optimally, or perhaps uniquely, addressed by GPS or GPS-like observations, and discuss their relevance to existing or planned national Earth-science research programs. The GPS-based ocean reflection experiments performed to date have demonstrated the precision and spatial resolution suitable to altimetric applications that require higher spatial resolution and more frequent repeat than the current radar altimeter satellites. GPS radio occultation is promising as a climate monitoring tool because of its benchmark properties: its raw observable is based on extremely accurate timing measurements. GPS-derived temperature profiles can provide meaningful climate trend information over decadal time scales without the need for overlapping missions or mission-to-mission calibrations. By acquiring data as GPS satellites occult behind the Earth's limb, GPS also provides high vertical resolution information on the vertical structure of electron density with global coverage. New experimental techniques will create more comprehensive TEC maps by using signals reflected from the oceans and received in orbit. This communication will discuss a potential future GNSS Earth Observing System project which would deploy a constellation of satellites using GPS and GPS-like measurements, to obtain a) topography measurements based on GPS reflections with an accuracy and horizontal resolution suitable for eddy monitoring, and h) climate-records quality atmospheric temperature profiles. The constellation would also provide for measurements of ionospheric elec tron density. This is a good example of an interdisciplinary mission concept, with broad science objectives of high societal relevance, al l resting on common cost-effective technology.

  1. A computer system for geosynchronous satellite navigation

    NASA Technical Reports Server (NTRS)

    Koch, D. W.

    1980-01-01

    A computer system specifically designed to estimate and predict Geostationary Operational Environmental Satellite (GOES-4) navigation parameters using Earth imagery is described. The estimates are needed for spacecraft maneuvers while prediction provide the capability for near real-time image registration. System software is composed of four functional subsystems: (1) data base management; (2) image processing; (3) navigation; and (4) output. Hardware consists of a host minicomputer, a cathode ray tube terminal, a graphics/video display unit, and associated input/output peripherals. System validity is established through the processing of actual imagery obtained by sensors on board the Synchronous Meteorological Satellite (SMS-2). Results indicate the system is capable of operationally providing both accurate GOES-4 navigation estimates and images with a potential registration accuracy of several picture elements (pixels).

  2. Ionospheric effects upon a satellite navigation system at Mars

    NASA Astrophysics Data System (ADS)

    Mendillo, Michael; Pi, Xiaoqing; Smith, Steven; Martinis, Carlos; Wilson, Jody; Hinson, David

    2004-04-01

    Trans-ionospheric radio propagation effects resulting in ranging errors are examined for a potential orbital network of communications and navigational satellites at Mars. Using recent results from the radio science experiment on board the Mars Global Surveyor (MGS) spacecraft and a photochemical model of Mars' ionosphere, we study the total electron content (TEC) at Mars to investigate how its latitude, local time, and solar cycle patterns would contribute to errors in positioning on the planet. In addition, we examine the relationship between TEC and peak density (Nmax) and find that their ratio, called the equivalent slab thickness, shows that integral preserving distortions of the Ne(h) profile can be rather substantial, implying that neutral atmosphere dynamics can have strong effects upon Mars' photochemical ionosphere. We use MGS observations to validate modeling results and determine the extreme cases for TEC at Mars (i.e., when the planet is at perihelion during solar maximum years and at aphelion during solar minimum years). If a proposed Mars Communication and Navigation (MC&N) System used UHF/L-band (1-2 GHz) transmission frequencies similar to those used for the terrestrial Global Positioning System (GPS) satellites, upper limits to the magnitude and variability of the martian ionosphere (TEC < ~few × 1016 el m-2, with ? ~ 10%) would not be of concern unless extremely precise positional information were required (<1 m). The impact of the ionosphere would be greater along slanted ray paths, and especially if lower frequency UHF beacon frequencies (e.g., 400 MHz) were selected for use. Indeed, such effects could be used as a diagnostic for the global structure of Mars' ionosphere, much in the same way as GPS measurements are used in terrestrial ionospheric physics.

  3. Flight-control/navigation inertial reference system

    NASA Technical Reports Server (NTRS)

    Ebner, R. E.

    1977-01-01

    The preliminary design of a redundant strapdown navigation system for integrated flight-control/navigation use has been completed. Based on application of tuned-gimbal gyros, a compact configuration (13 in x 13 in x 14 in) has been achieved for fail-operational/fail-operational redundancy. Test data are presented for strapdown system test programs including flight testing of the LN-50 tuned-gimbal gyro system. Testing of a redundant sensor configuration is currently in process. Strapdown gyro development also includes ring laser and nuclear magnetic resonance techniques.

  4. A Short Tutorial on Inertial Navigation System and Global Positioning System Integration

    NASA Technical Reports Server (NTRS)

    Smalling, Kyle M.; Eure, Kenneth W.

    2015-01-01

    The purpose of this document is to describe a simple method of integrating Inertial Navigation System (INS) information with Global Positioning System (GPS) information for an improved estimate of vehicle attitude and position. A simple two dimensional (2D) case is considered. The attitude estimates are derived from sensor data and used in the estimation of vehicle position and velocity through dead reckoning within the INS. The INS estimates are updated with GPS estimates using a Kalman filter. This tutorial is intended for the novice user with a focus on bringing the reader from raw sensor measurements to an integrated position and attitude estimate. An application is given using a remotely controlled ground vehicle operating in assumed 2D environment. The theory is developed first followed by an illustrative example.

  5. Exploitation of Semantic Building Model in Indoor Navigation Systems

    NASA Astrophysics Data System (ADS)

    Anjomshoaa, A.; Shayeganfar, F.; Tjoa, A. Min

    2009-04-01

    There are many types of indoor and outdoor navigation tools and methodologies available. A majority of these solutions are based on Global Positioning Systems (GPS) and instant video and image processing. These approaches are ideal for open world environments where very few information about the target location is available, but for large scale building environments such as hospitals, governmental offices, etc the end-user will need more detailed information about the surrounding context which is especially important in case of people with special needs. This paper presents a smart indoor navigation solution that is based on Semantic Web technologies and Building Information Model (BIM). The proposed solution is also aligned with Google Android's concepts to enlighten the realization of results. Keywords: IAI IFCXML, Building Information Model, Indoor Navigation, Semantic Web, Google Android, People with Special Needs 1 Introduction Built environment is a central factor in our daily life and a big portion of human life is spent inside buildings. Traditionally the buildings are documented using building maps and plans by utilization of IT tools such as computer-aided design (CAD) applications. Documenting the maps in an electronic way is already pervasive but CAD drawings do not suffice the requirements regarding effective building models that can be shared with other building-related applications such as indoor navigation systems. The navigation in built environment is not a new issue, however with the advances in emerging technologies like GPS, mobile and networked environments, and Semantic Web new solutions have been suggested to enrich the traditional building maps and convert them to smart information resources that can be reused in other applications and improve the interpretability with building inhabitants and building visitors. Other important issues that should be addressed in building navigation scenarios are location tagging and end-user communication. The available solutions for location tagging are mostly based on proximity sensors and the information are bound to sensor references. In the proposed solution of this paper, the sensors simply play a role similar to annotations in Semantic Web world. Hence the sensors data in ontology sense bridges the gap between sensed information and building model. Combining these two and applying the proper inference rules, the building visitors will be able to reach their destinations with instant support of their communication devices such as hand helds, wearable computers, mobiles, etc. In a typical scenario of this kind, user's profile will be delivered to the smart building (via building ad-hoc services) and the appropriate route for user will be calculated and delivered to user's end-device. The calculated route is calculated by considering all constraints and requirements of the end user. So for example if the user is using a wheelchair, the calculated route should not contain stairs or narrow corridors that the wheelchair does not pass through. Then user starts to navigate through building by following the instructions of the end-device which are in turn generated from the calculated route. During the navigation process, the end-device should also interact with the smart building to sense the locations by reading the surrounding tags. So for example when a visually impaired person arrives at an unknown space, the tags will be sensed and the relevant information will be delivered to user in the proper way of communication. For example the building model can be used to generate a voice message for a blind person about a space and tell him/her that "the space has 3 doors, and the door on the left should be chosen which needs to be pushed to open". In this paper we will mainly focus on automatic generation of semantic building information models (Semantic BIM) and delivery of results to the end user. Combining the building information model with the environment and user constraints using Semantic Web technologies will make many scenarios conceivable. The gen

  6. Satellite emission radio interferometric earth surveying series - GPS geodetic system

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.

    1979-01-01

    A concept called SERIES (satellite emissions radio interferometric earth surveying) which makes use of GPS (global positioning system) radio transmissions without any satellite modifications, is described. Through the use of very long baseline interferometry (VLBI) and its calibration methods, 0.5 to 3 cm three dimensional baseline accuracy can be achieved over distances of 2 to 200 km respectively, with only 2 hours of on-site data acquisition. Attention is given to such areas as: the radio flux equivalent of GPS transmissions, synthesized delay precision, transmission and frequency subsystem requirements, tropospheric and ionospheric errors. Applications covered include geodesy and seismic tectonics.

  7. An Inexpensive and Robust GPS/INS Attitude System for Automobiles

    E-print Network

    Stanford University

    An Inexpensive and Robust GPS/INS Attitude System for Automobiles Santiago Alban, Stanford-cost and robust GPS/INS attitude system for automobiles, and deep integration of INS systems with GPS tracking loops. ABSTRACT Many of the sophisticated control systems of modern automobiles require measurements

  8. GPS/INS Sensor Fusion Using GPS Wind up Model

    NASA Technical Reports Server (NTRS)

    Williamson, Walton R. (Inventor)

    2013-01-01

    A method of stabilizing an inertial navigation system (INS), includes the steps of: receiving data from an inertial navigation system; and receiving a finite number of carrier phase observables using at least one GPS receiver from a plurality of GPS satellites; calculating a phase wind up correction; correcting at least one of the finite number of carrier phase observables using the phase wind up correction; and calculating a corrected IMU attitude or velocity or position using the corrected at least one of the finite number of carrier phase observables; and performing a step selected from the steps consisting of recording, reporting, or providing the corrected IMU attitude or velocity or position to another process that uses the corrected IMU attitude or velocity or position. A GPS stabilized inertial navigation system apparatus is also described.

  9. Global Positioning System (GPS) Bias Correction and Habitat Analysis of

    E-print Network

    Wallin, David O.

    Global Positioning System (GPS) Bias Correction and Habitat Analysis of Mountain Goats Oreamnos) Bias Correction and Habitat Analysis of Mountain Goats Oreamnos americanus in the Cascades Seasonal variation in habitat selection by the mountain goat Oreamnos americanus is not well understood due

  10. Evolving a Multiagent System for Landmark-Based Robot Navigation

    E-print Network

    Mántaras, Ramon López de

    Evolving a Multiagent System for Landmark-Based Robot Navigation Madhur Ambastha,1,* Dídac Busquets: the Pilot system, the Vision system, and the Navigation system. Each system competes for the two avail- able to carry out commands from the Navigation system and, independently, to avoid obstacles. The Vision system

  11. Autonomous system for cross-country navigation

    NASA Astrophysics Data System (ADS)

    Stentz, Anthony; Brumitt, Barry L.; Coulter, R. C.; Kelly, Alonzo

    1993-05-01

    Autonomous cross-country navigation is essential for outdoor robots moving about in unstructured environments. Most existing systems use range sensors to determine the shape of the terrain, plan a trajectory that avoids obstacles, and then drive the trajectory. Performance has been limited by the range and accuracy of sensors, insufficient vehicle-terrain interaction models, and the availability of high-speed computers. As these elements improve, higher- speed navigation on rougher terrain becomes possible. We have developed a software system for autonomous navigation that provides for greater capability. The perception system supports a large braking distance by fusing multiple range images to build a map of the terrain in front of the vehicle. The system identifies range shadows and interpolates undersamples regions to account for rough terrain effects. The motion planner reduces computational complexity by investigating a minimum number of trajectories. Speeds along the trajectory are set to provide for dynamic stability. The entire system was tested in simulation, and a subset of the capability was demonstrated on a real vehicle. Results to date include a continuous 5.1 kilometer run across moderate terrain with obstacles. This paper begins with the applications, prior work, limitations, and current paradigms for autonomous cross-country navigation, and then describes our contribution to the area.

  12. 78 FR 13396 - 90th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-27

    ... Federal Aviation Administration 90th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS... Notice of RTCA Special Committee 159, RTCA Special Committee 159, Global Positioning Systems (GPS... Special Committee 159, Global Positioning Systems (GPS). DATES: The meeting will be held March 12-15,...

  13. 75 FR 28318 - Eighty-Second Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 159: Global Positioning System (GPS). DATES: The...

  14. 75 FR 2581 - Eighty-First Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-15

    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 159: Global Positioning System (GPS). DATES: The...

  15. 77 FR 56254 - 89th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-12

    ... Federal Aviation Administration 89th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS... Notice of RTCA Special Committee 159, RTCA Special Committee 159, Global Positioning Systems (GPS... Special Committee 159, Global Positioning Systems (GPS). DATES: The meeting will be held October 5,...

  16. 76 FR 33022 - Eighty-Sixth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-07

    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 159: Global Positioning System (GPS). DATES: The...

  17. 78 FR 57672 - 91st Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... Federal Aviation Administration 91st Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS... Notice of RTCA Special Committee 159, RTCA Special Committee 159, Global Positioning Systems (GPS... Special Committee 159, Global Positioning Systems (GPS) DATES: The meeting will be held October 7-11,...

  18. 76 FR 27744 - Eighty-Fifth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-12

    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 159: Global Positioning System (GPS). DATES: The...

  19. 75 FR 61818 - Eighty-Third Meeting: RTCA Special Committee 159: Global Positioning System (GPS).

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ... System (GPS). AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 159: Global Positioning System (GPS). DATES:...

  20. Implementation of a Dual-Frequency GLONASS and GPS L1 C/A

    E-print Network

    Calgary, University of

    . Although the Global Positioning System (GPS) has become nearly ubiquitous in positioning and navigation Navigation Satellite System (GNSS) technology plays a critical role in positioning and navigation-of-life purposes. With the recent revitalization of Russian Global Navigation Satellite System (GLONASS

  1. Autonomous integrated navigation method based on the strapdown inertial navigation system and Lidar

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyue; Lin, Zhili; Zhang, Chunxi

    2014-07-01

    An integrated navigation method based on the strapdown inertial navigation system (SINS) and Doppler Lidar was presented and its validity is demonstrated by practical experiments. A very effective and independent integrated navigation mode is realized that both an inertial navigation system (INS) and Lidar are not interfered with or screened by electromagnetic waves. In our work, the SINS error model was first introduced, and the velocity error model was transformed into body reference coordinates. Then the expression for measurement model of SINS/Lidar integrated navigation was deduced under Lidar reference coordinates. For application of land or vehicle navigation, the expression for the measurement model was simplified, and observation analysis was carried out. Finally, numerical simulation and vehicle test results were carried out to validate the availability and utility of the proposed SINS/Lidar integrated navigation method for land navigation.

  2. Precise GPS orbits for geodesy

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L.

    1994-01-01

    The Global Positioning System (GPS) has become, in recent years, the main space-based system for surveying and navigation in many military, commercial, cadastral, mapping, and scientific applications. Better receivers, interferometric techniques (DGPS), and advances in post-processing methods have made possible to position fixed or moving receivers with sub-decimeter accuracies in a global reference frame. Improved methods for obtaining the orbits of the GPS satellites have played a major role in these achievements; this paper gives a personal view of the main developments in GPS orbit determination.

  3. Differential GPS and system integration of the Low Visibility Landing and Surface Operations (LVLASO) demonstration

    NASA Technical Reports Server (NTRS)

    Rankin, James M.

    1994-01-01

    The LVLASO Flight Demonstration of ASTA concepts (FDAC) integrates NASA-Langley's electronic moving map display and Transport Systems Research Vehicle (TSRV) (a modified Boeing 737 aircraft); ARINC's VHF data link, GPS ground station, and automated controller workstation; and Norden's surface radar/airport movement safety system. Aircraft location is shown on the electronic map display in the cockpit. An approved taxi route as well as other aircraft and surface traffic are also displayed. An Ashtech Z12 Global Positioning System (GPS) receiver on the TSRV estimates the aircraft's position. In Differential mode (DSPS), the Ashtech receiver accepts differential C/A code pseudorange corrections from a GPS ground station. The GPS ground station provides corrections up to ten satellites. The corrections are transmitted on a VHF data link at a 1 Hz. rate using the RTCM-104 format. DGPS position estimates will be within 5 meters of actual aircraft position. DGPS position estimates are blended with position, velocity, acceleration, and heading data from the TSRV Air Data/Inertial Reference System (ADIRS). The ADIRS data is accurate in the short-term, but drifts over time. The DGPS data is used to keep the ADIRS position accurate. Ownship position, velocity, heading, and turn rate are sent at a 20 Hz. rate to the electronic map display. Airport traffic is detected by the airport surface radar system. Aircraft and vehicles such as fuel trucks and baggage carts are detected. The traffic's location, velocity, and heading are sent to the TSRV. To prevent traffic symbology from jumping each second when a location update arrives, velocity and heading are used to predict a new traffic location for each display update. Possible runway incursions and collisions can be shown on the electronic map. Integrating the different systems used in the FDAC requires attention to the underlying coordinate systems. The airport diagram displayed on the electronic map is obtained from published navigational charts. The charts reference the North American Datum of 1927 (NAD27) or a local state-plane coordinate system. GPS uses the World Geodetic Standard of 1984 (WGS84). Both NAD27 and WGS84 model the Earth as an ellipsoid, however, they use a different origin and different size ellipsoids. Latitudes and longitudes given in these systems can be converted to a Cartesian system with the origin at the Earth's center. The surface radar detects traffic in a locally-level, rho-theta coordiante system. The electronic airport diagram is stored using a flat XY coordinate system. The map origin is at the tower and is referenced as True North up. All ownship and other traffic positions must be converted to the electronic map's frame of reference for display.

  4. GPS Time Synchronization System for K2K1 H. G. Berns and R. J. Wilkes

    E-print Network

    Berns, Hans-Gerd

    GPS Time Synchronization System for K2K1 H. G. Berns and R. J. Wilkes Department of Physics System (GPS) provides a means for satisfying this requirement at very low cost. In addition to low- resolution time data (day of year, hour, minute, second), commercial GPS receivers output a 1 pulse per sec

  5. Reliable GPS-Based Timing for Power Systems: A Multi-Layered Multi-Receiver Architecture

    E-print Network

    Gao, Grace Xingxin

    Reliable GPS-Based Timing for Power Systems: A Multi-Layered Multi-Receiver Architecture Liang Heng, and protection functions. PMUs use the Global Positioning System (GPS) to synchronize measurements across a wide geographical area. Unfortunately, low-received-power, unencrypted civil GPS signals are vulnerable to jamming

  6. GPS Time Synchronization System for K2K 1 H. G. Berns and R. J. Wilkes

    E-print Network

    Berns, Hans-Gerd

    GPS Time Synchronization System for K2K 1 H. G. Berns and R. J. Wilkes Department of Physics System (GPS) provides a means for satisfying this requirement at very low cost. In addition to low­resolution time data (day of year, hour, minute, second), commercial GPS receivers output a 1 pulse per sec (1PPS

  7. Visual navigation system for autonomous indoor blimps

    NASA Astrophysics Data System (ADS)

    Campos, Mario F.; de Souza Coelho, Lucio

    1999-07-01

    Autonomous dirigibles - aerial robots that are a blimp controlled by computer based on information gathered by sensors - are a new and promising research field in Robotics, offering several original work opportunities. One of them is the study of visual navigation of UAVs. In the work described in this paper, a Computer Vision and Control system was developed to perform automatically very simple navigation task for a small indoor blimp. The vision system is able to track artificial visual beacons - objects with known geometrical properties - and from them a geometrical methodology can extract information about orientation of the blimp. The tracking of natural landmarks is also a possibility for the vision technique developed. The control system uses that data to keep the dirigible on a programmed orientation. Experimental results showing the correct and efficient functioning of the system are shown and have your implications and future possibilities discussed.

  8. Civil Application of Differential GPS Using a Single Channel Sequential Receiver

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The Global Positioning System (GPS) and its potential for area navigation, landing, and takeoff under minimum ceilings and advanced air traffic control operation is discussed. The following topics are reported: status of the GPS system; GPS signal availability for the civil community; alternative differential GPS concepts; predicted performance enhancement achievable with differential GPS and the operational improvements which will result; and a development program to test and evaluate differential GPS concepts, performance and operational procedures applicable to helicopters. Potential benefits which will be derived from helicopter use of GPS in the differential mode are identified.

  9. ORIGINAL ARTICLE NAVIG: augmented reality guidance system for the visually

    E-print Network

    ORIGINAL ARTICLE NAVIG: augmented reality guidance system for the visually impaired Combining Springer-Verlag London Limited 2012 Abstract Navigating complex routes and finding objects of interest are challenging tasks for the visually impaired. The project NAVIG (Navigation Assisted by artificial VIsion

  10. A Navigation System for Robots Operating in Crowded Urban Environments

    E-print Network

    Stachniss, Cyrill

    to that dynamic. In this paper, we present a navigation system for pedestrian-like autonomous navigation the robot Obelix managed to autonomously navigate from our University Campus over a 3.3 km long route and substantial progress has been made in the area of autonomous navigation over the past years. The majority

  11. Pre-Flight Testing of Spaceborne GPS Receivers Using a GPS Constellation Simulator

    NASA Technical Reports Server (NTRS)

    Kizhner, Semion; Alonso, Roberto

    1999-01-01

    The NASA Goddard Space Flight Center (GSFC) Global Positioning System (GPS) test facility has been established within the GSFC Guidance Navigation and Control Center. The GPS test facility is currently housing the STR2760 GPS satellite 40-channel attitude simulator and an STR4760 12-channel navigation simulator. The facility also contains a few other Goddard resources such as an atomic time standard test bed, a rooftop antenna platform and a radome. It provides a new capability of high dynamics GPS simulations for space flight that is unique within the aerospace community. The GPS facility gives a significant advantage in the development and support of GPS based technologies for position, attitude and precise time determination on-board a spacecraft, sounding rocket or balloon. The GPS simulator system is configured in a transportable rack and is available for GPS applications' component development as well as for spacecraft subsystem and system level testing at spacecraft integration and test sites. The GPS facility has been operational since early 1996 and has been already utilized by a few successful flight projects carrying GPS experiments, such as USA Seastar satellite and the first Argentine satellite SAC-A. The experience in the SAC-A pre-flight testing using the STR2760 simulator is summarized as well as the comparison with preliminary analysis of the GPS data from SAC-A telemetry.

  12. GOES image navigation and registration system

    NASA Astrophysics Data System (ADS)

    Kamel, Ahmed

    1996-10-01

    The GOES I-M image navigation and registration (INR) system was developed and patented by Space Systems/Loral in response to NASA/NOAA pointing requirements of Imager and Sounder payloads. This INR system is divided into space segment and ground segment. The space segment consist of image motion compensation (IMC) system that compensates for deterministic errors caused by orbit and attitude motions and mirror motion compensations system that compensates for spacecraft attitude motion caused by Imager and Sounder scanner mirror motion. The ground segment consists mainly of Orbit and Attitude Tracking System (OATS) that determines the IMC orbit and attitude coefficients from star, landmark, and range measurements.

  13. Airborne Digital Sensor System and GPS-aided inertial technology for direct geopositioning in rough terrain

    USGS Publications Warehouse

    Sanchez, Richard D.

    2004-01-01

    High-resolution airborne digital cameras with onboard data collection based on the Global Positioning System (GPS) and inertial navigation systems (INS) technology may offer a real-time means to gather accurate topographic map information by reducing ground control and eliminating aerial triangulation. Past evaluations of this integrated system over relatively flat terrain have proven successful. The author uses Emerge Digital Sensor System (DSS) combined with Applanix Corporation?s Position and Orientation Solutions for Direct Georeferencing to examine the positional mapping accuracy in rough terrain. The positional accuracy documented in this study did not meet large-scale mapping requirements owing to an apparent system mechanical failure. Nonetheless, the findings yield important information on a new approach for mapping in Antarctica and other remote or inaccessible areas of the world.

  14. Memetic Simulated Annealing for the GPS Surveying Problem

    E-print Network

    Fidanova, Stefka

    ~na {eat,guillermo}@lcc.uma.es Abstract. In designing Global Positioning System (GPS) surveying net- work for large networks with bounded computational effort. 1 Introduction A Global Positioning System (GPS positioning system, the Russian GLObal Navigation Satellite System (GLONASS), and the forthcoming Euro- pean

  15. GPS-based outdoor activity pattern recording and analysis system.

    PubMed

    Chen, Yan-Ming; Cheng, Kuo-Sheng

    2013-01-01

    In this paper, a recording and analysis system is designed and developed for outdoor activity patterns characterization. Some mental problems of aging, especially the occurrence of dementia, are not easily noticed in early stage. In this study, the proposed system is employed for outdoor activity patterns analysis. From the pattern analysis, the abnormal activity which is different from the usual patterns may be differentiated and warned. The proposed system integrates the tablet PC and GPS to track and to detect the occurrence of abnormal condition off-line. In the beginning, the sequence of GPS data is segmented in time frame, and represented in vector form for data reduction. Some filtering technique is also applied for noise reduction. PMID:24109899

  16. Simulation of Guidance, Navigation, and Control Systems for Formation Flying Missions

    NASA Technical Reports Server (NTRS)

    Burns, Rich; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    Concepts for missions of distributed spacecraft flying in formation abound. From high resolution interferometry to spatially distributed in-situ measurements, these mission concepts levy a myriad of guidance, navigation, and control (GNC) requirements on the spacecraft/formation as a single system. A critical step toward assessing and meeting these challenges lies in realistically simulating distributed spacecraft systems. The Formation Flying TestBed (FFTB) at NASA Goddard Space Flight Center's (GSFC) Guidance, Navigation, and Control Center is a hardware-in-the-loop simulation and development facility focused on GNC issues relevant to formation flying systems. The FFTB provides a realistic simulation of the vehicle dynamics and control for formation flying missions in order to: (1) conduct feasibility analyses of mission requirements, (2) conduct and answer mission and spacecraft design trades, and (3) serve as a host for GNC software and hardware development and testing. The initial capabilities of the FFTB are based upon an integration of high fidelity hardware and software simulation, emulation, and test platforms developed or employed at GSFC in recent years, including a high-fidelity Global Positioning System (GPS) simulator which has been a fundamental component of the GNC Center's GPS Test Facility. The FFTB will be continuously evolving over the next several years from a tool with capabilities in GPS navigation hardware/software-in-the-loop analysis and closed loop GPS-based orbit control algorithm assessment. Eventually, it will include full capability to support all aspects of multi-sensor, absolute and relative state determination and control, in all (attitude and orbit) degrees of freedom, as well as information management for satellite clusters and constellations. A detailed description of the FFTB architecture is presented in the paper.

  17. Obstacle-avoiding navigation system

    DOEpatents

    Borenstein, Johann (Ann Arbor, MI); Koren, Yoram (Ann Arbor, MI); Levine, Simon P. (Ann Arbor, MI)

    1991-01-01

    A system for guiding an autonomous or semi-autonomous vehicle through a field of operation having obstacles thereon to be avoided employs a memory for containing data which defines an array of grid cells which correspond to respective subfields in the field of operation of the vehicle. Each grid cell in the memory contains a value which is indicative of the likelihood, or probability, that an obstacle is present in the respectively associated subfield. The values in the grid cells are incremented individually in response to each scan of the subfields, and precomputation and use of a look-up table avoids complex trigonometric functions. A further array of grid cells is fixed with respect to the vehicle form a conceptual active window which overlies the incremented grid cells. Thus, when the cells in the active window overly grid cell having values which are indicative of the presence of obstacles, the value therein is used as a multiplier of the precomputed vectorial values. The resulting plurality of vectorial values are summed vectorially in one embodiment of the invention to produce a virtual composite repulsive vector which is then summed vectorially with a target-directed vector for producing a resultant vector for guiding the vehicle. In an alternative embodiment, a plurality of vectors surrounding the vehicle are computed, each having a value corresponding to obstacle density. In such an embodiment, target location information is used to select between alternative directions of travel having low associated obstacle densities.

  18. Lunar Navigation Determination System - LaNDS

    NASA Technical Reports Server (NTRS)

    Quinn, David; Talabac, Stephen

    2012-01-01

    A portable comprehensive navigational system has been developed that both robotic and human explorers can use to determine their location, attitude, and heading anywhere on the lunar surface independent of external infrastructure (needs no Lunar satellite network, line of sight to the Sun or Earth, etc.). The system combines robust processing power with an extensive topographical database to create a real-time atlas (GIS Geospatial Information System) that is able to autonomously control and monitor both single unmanned rovers and fleets of rovers, as well as science payload stations. The system includes provisions for teleoperation and tele-presence. The system accepts (but does not require) inputs from a wide range of sensors. A means was needed to establish a location when the search is taken deep in a crater (looking for water ice) and out of view of Earth or any other references. A star camera can be employed to determine the user's attitude in menial space and stellar map in body space. A local nadir reference (e.g., an accelerometer that orients the nadir vector in body space) can be used in conjunction with a digital ephemeris and gravity model of the Moon to isolate the latitude, longitude, and azimuth of the user on the surface. That information can be used in conjunction with a Lunar GIS and advanced navigation planning algorithms to aid astronauts (or other assets) to navigate on the Lunar surface.

  19. Fusion of Redundant Autonomous Sensors for Navigation

    E-print Network

    Lenstra, Arjen K.

    Fusion of Redundant Autonomous Sensors for Navigation Geodetic Engineering Laboratory Web Research Objective: To develop a low-cost autonomous navigation system that can operate in GPS : topo.epfl.ch Contact: yannick.stebler@epfl.ch The goal of navigation is to estimate the position

  20. Compensating For GPS Ephemeris Error

    NASA Technical Reports Server (NTRS)

    Wu, Jiun-Tsong

    1992-01-01

    Method of computing position of user station receiving signals from Global Positioning System (GPS) of navigational satellites compensates for most of GPS ephemeris error. Present method enables user station to reduce error in its computed position substantially. User station must have access to two or more reference stations at precisely known positions several hundred kilometers apart and must be in neighborhood of reference stations. Based on fact that when GPS data used to compute baseline between reference station and user station, vector error in computed baseline is proportional ephemeris error and length of baseline.

  1. Observability Analysis of a MEMS INS/GPS Integration System with Gyroscope G-Sensitivity Errors

    PubMed Central

    Fan, Chen; Hu, Xiaoping; He, Xiaofeng; Tang, Kanghua; Luo, Bing

    2014-01-01

    Gyroscopes based on micro-electromechanical system (MEMS) technology suffer in high-dynamic applications due to obvious g-sensitivity errors. These errors can induce large biases in the gyroscope, which can directly affect the accuracy of attitude estimation in the integration of the inertial navigation system (INS) and the Global Positioning System (GPS). The observability determines the existence of solutions for compensating them. In this paper, we investigate the observability of the INS/GPS system with consideration of the g-sensitivity errors. In terms of two types of g-sensitivity coefficients matrix, we add them as estimated states to the Kalman filter and analyze the observability of three or nine elements of the coefficient matrix respectively. A global observable condition of the system is presented and validated. Experimental results indicate that all the estimated states, which include position, velocity, attitude, gyro and accelerometer bias, and g-sensitivity coefficients, could be made observable by maneuvering based on the conditions. Compared with the integration system without compensation for the g-sensitivity errors, the attitude accuracy is raised obviously. PMID:25171122

  2. Observability analysis of a MEMS INS/GPS integration system with gyroscope G-sensitivity errors.

    PubMed

    Fan, Chen; Hu, Xiaoping; He, Xiaofeng; Tang, Kanghua; Luo, Bing

    2014-01-01

    Gyroscopes based on micro-electromechanical system (MEMS) technology suffer in high-dynamic applications due to obvious g-sensitivity errors. These errors can induce large biases in the gyroscope, which can directly affect the accuracy of attitude estimation in the integration of the inertial navigation system (INS) and the Global Positioning System (GPS). The observability determines the existence of solutions for compensating them. In this paper, we investigate the observability of the INS/GPS system with consideration of the g-sensitivity errors. In terms of two types of g-sensitivity coefficients matrix, we add them as estimated states to the Kalman filter and analyze the observability of three or nine elements of the coefficient matrix respectively. A global observable condition of the system is presented and validated. Experimental results indicate that all the estimated states, which include position, velocity, attitude, gyro and accelerometer bias, and g-sensitivity coefficients, could be made observable by maneuvering based on the conditions. Compared with the integration system without compensation for the g-sensitivity errors, the attitude accuracy is raised obviously. PMID:25171122

  3. Libration Point Navigation Concepts Supporting the Vision for Space Exploration

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Folta, David C.; Moreau, Michael C.; Quinn, David A.

    2004-01-01

    This work examines the autonomous navigation accuracy achievable for a lunar exploration trajectory from a translunar libration point lunar navigation relay satellite, augmented by signals from the Global Positioning System (GPS). We also provide a brief analysis comparing the libration point relay to lunar orbit relay architectures, and discuss some issues of GPS usage for cis-lunar trajectories.

  4. The investigation of a new monitoring system using leveling and GPS

    NASA Astrophysics Data System (ADS)

    Nojo, M.; Waki, F.; Akaishi, M.; Muramoto, Y.

    2015-11-01

    We installed GPS stations for monitoring of land subsidence of Kujukuri Plain in Chiba prefecture in 2003, and have been monitoring since then. In this paper, we discussed a data processing method capable of reducing noise in data collected by the GPS stations. Also, we compare the accuracy of leveling and GPS, and collected basic data for establishing a new monitoring system based on the combination of leveling and GPS.

  5. Tightly coupled integration of ionosphere-constrained precise point positioning and inertial navigation systems.

    PubMed

    Gao, Zhouzheng; Zhang, Hongping; Ge, Maorong; Niu, Xiaoji; Shen, Wenbin; Wickert, Jens; Schuh, Harald

    2015-01-01

    The continuity and reliability of precise GNSS positioning can be seriously limited by severe user observation environments. The Inertial Navigation System (INS) can overcome such drawbacks, but its performance is clearly restricted by INS sensor errors over time. Accordingly, the tightly coupled integration of GPS and INS can overcome the disadvantages of each individual system and together form a new navigation system with a higher accuracy, reliability and availability. Recently, ionosphere-constrained (IC) precise point positioning (PPP) utilizing raw GPS observations was proven able to improve both the convergence and positioning accuracy of the conventional PPP using ionosphere-free combined observations (LC-PPP). In this paper, a new mode of tightly coupled integration, in which the IC-PPP instead of LC-PPP is employed, is implemented to further improve the performance of the coupled system. We present the detailed mathematical model and the related algorithm of the new integration of IC-PPP and INS. To evaluate the performance of the new tightly coupled integration, data of both airborne and vehicle experiments with a geodetic GPS receiver and tactical grade inertial measurement unit are processed and the results are analyzed. The statistics show that the new approach can further improve the positioning accuracy compared with both IC-PPP and the tightly coupled integration of the conventional PPP and INS. PMID:25763647

  6. Tightly Coupled Integration of Ionosphere-Constrained Precise Point Positioning and Inertial Navigation Systems

    PubMed Central

    Gao, Zhouzheng; Zhang, Hongping; Ge, Maorong; Niu, Xiaoji; Shen, Wenbin; Wickert, Jens; Schuh, Harald

    2015-01-01

    The continuity and reliability of precise GNSS positioning can be seriously limited by severe user observation environments. The Inertial Navigation System (INS) can overcome such drawbacks, but its performance is clearly restricted by INS sensor errors over time. Accordingly, the tightly coupled integration of GPS and INS can overcome the disadvantages of each individual system and together form a new navigation system with a higher accuracy, reliability and availability. Recently, ionosphere-constrained (IC) precise point positioning (PPP) utilizing raw GPS observations was proven able to improve both the convergence and positioning accuracy of the conventional PPP using ionosphere-free combined observations (LC-PPP). In this paper, a new mode of tightly coupled integration, in which the IC-PPP instead of LC-PPP is employed, is implemented to further improve the performance of the coupled system. We present the detailed mathematical model and the related algorithm of the new integration of IC-PPP and INS. To evaluate the performance of the new tightly coupled integration, data of both airborne and vehicle experiments with a geodetic GPS receiver and tactical grade inertial measurement unit are processed and the results are analyzed. The statistics show that the new approach can further improve the positioning accuracy compared with both IC-PPP and the tightly coupled integration of the conventional PPP and INS. PMID:25763647

  7. Interference Effects on the GPS Signal Acquisition

    E-print Network

    Calgary, University of

    is a radio frequency (RF) based satellite navigation system which transmits signals containing information to compute a user position. GPS receivers rely on these external signals which make them vulnerable to RF interference. RF interference can cause degradation in the navigation accuracy or a complete loss

  8. A LAGRANGIAN DRIFTER WITH INEXPENSIVE WIDE AREA DIFFERENTIAL GPS POSITIONING

    E-print Network

    Kurapov, Alexander

    drifting buoys that acquire position data using Global Positioning System (GPS) navigation have proven. INTRODIJCTION Autonomous drifting buoys that acquire position data using Global Positioning System (GPS software and correction dzitil provided by the Canadian Active Control System (CACS). CACS is a global

  9. Optimization of the effective GPS data rate

    NASA Technical Reports Server (NTRS)

    Mcintyre, David S.

    1990-01-01

    Ohio University's Avionics Engineering Center is performing research directed towards the integration of the NAVSTAR Global Positioning System (GPS) and the Inertial Navigation System (INS) for attitude and heading determination. The integration of GPS/INS offers synergistic benefits. INS gyro drift error can be compensated by the long-term stability of GPS by means of an in-flight data monitoring algorithm. Using GPS data as a reference is more advantageous than implementing an additional INS since GPS offers a dissimilar redundancy to the attitude and heading determination configuration. In converse, the short-term stability of the INS can be used to correct or substitute for faulty GPS data due to tracking loop phase lag or data gaps because of satellite shielding. The optimization of the effective GPS data rate is essential for the proper execution of an integrated GPS/INS in-flight algorithm. GPS attitude and heading information must be consistently available during INS outages. Present research efforts involve the development of an in-flight algorithm that maximizes the potential of integrated GPS/INS. This algorithm determines the acceptable limits of phase lag that the GPS tracking loop introduces to the flight control system (FCS) during the transmission of information. Once these calculated limits are exceeded, INS data are used to insure the continuous availability of attitude and heading information to the flight control system.

  10. Application of new GPS aircraft control/display system to topographic mapping of the Greenland ice cap

    SciTech Connect

    Wright, C.W.; Swift, R.N.

    1996-10-01

    NASA has completed an accurate baseline map of the elevation of the Greenland ice sheet using a scanning airborne lidar in combination with differential kinematic Global Positioning System (GPS) techniques. The present plan is to reoccupy these survey lines which are spread over the major regions of the ice sheet beginning in 1997. The results are expected to provide a quantitative answer on how the ice sheet is responding to regional climatic changes. Navigation to within +-100 m of the desired track over lengths of up to 1,000 km are a requirement for the success of the program. To meet this navigational requirement, NASA developed the GPS Flight Management System (GFMS). GFMS is a PC based system that uses the real-time position update from a single GPS receiver located on the aircraft to calculate a cross-track error and generates aircraft steering commands which are converted into analog Instrument Landing System (OM) signals using an RF generator. TU GFMS also updates a cockpit display. 4 refs., 6 figs.

  11. Fiber optic gyroscopes for vehicle navigation systems

    NASA Astrophysics Data System (ADS)

    Kumagai, Tatsuya; Soekawa, Hirokazu; Yuhara, Toshiya; Kajioka, Hiroshi; Oho, Shigeru; Sonobe, Hisao

    1994-03-01

    Fiber optic gyroscopes (FOGs) have been developed for vehicle navigation systems and are used in Toyota Motor Corporation models Mark II, Chaser and Cresta in Japan. Use of FOGs in these systems requires high reliability under a wide range of conditions, especially in a temperature range between -40 and 85 degree(s)C. In addition, a high cost-performance ratio is needed. We have developed optical and electrical systems that are inexpensive and can perform well. They are ready to be mass-produced. FOGs have already been installed in luxury automobiles, and will soon be included in more basic vehicles. We have developed more inexpensive FOGs for this purpose.

  12. Inertial navigation system for directional surveying

    SciTech Connect

    Kohler, S.M.

    1982-09-01

    A Wellbore Inertial Navigation System (WINS) was developed and tested. Developed for directional surveying of geothermal, oil, and gas wells, the system uses gyros and accelerometers to obtain survey errors of less than 10 ft (approx. 3 m) in a 10,000-ft (approx. 300-m) well. The tool, which communicates with a computer at the surface, is 4 in. (approx. 10 cm) in diameter and 20 ft (approx. 6.1 m) long. The concept and hardware is based on a system developed by Sandia for flight vehicles.

  13. Institute of Navigation, Annual Meeting, 42nd, Seattle, WA, June 24-26, 1986, Proceedings

    SciTech Connect

    Not Available

    1986-01-01

    The conference presents papers on the analysis of range and position comparison methods as a means of providing GPS integrity in the user receiver, a software package for predicting the performance of VLF-navigation systems, and measurement errors in GPS observables. Other topics include the architecture and performance of a real time differential GPS ground station, optimal locations of pseudolites for differential GPS, and GPS receiver technologies. Consideration is also given to Australian trials of Phase II Navstar GPS user equipment and the sensitivity of an autonomous navigation landmark tracing system due to the variability of landmark availability and distribution.

  14. A persuasive GPS-controlled thermostat system

    E-print Network

    Gupta, Manu, S. M. Massachusetts Institute of Technology

    2008-01-01

    Using 10 weeks of data from a couple living in an instrumented home, we report on the potential of context-aware power management for energy saving. We identify an opportunity to save on heating and cooling using a system ...

  15. IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION, VOL. 19, NO. 1, FEBRUARY 2003 15 Autonomous Vehicle Positioning With GPS in

    E-print Network

    Ge, Shuzhi Sam

    --The Global Positioning System (GPS) has been widely used in land vehicle navigation applications. However problems successfully. Index Terms--Extended Kalman filtering, Global Positioning System (GPS), interacting multiple model, joint parameter and state estimation. I. INTRODUCTION THE GLOBAL Positioning System (GPS

  16. Performance Evaluation of Ultra-tight Integration of GPS/Vehicle Sensors for Land

    E-print Network

    Calgary, University of

    Performance Evaluation of Ultra-tight Integration of GPS/Vehicle Sensors for Land Vehicle research interest is ultra-tight integration of GPS /INS for land vehicle navigation. Dr. Mark Petovello. GPS/Vehicle Sensors integrated systems are typically capable of providing considerable accuracy

  17. Accurate Real-Time Relative Localization Using Single-Frequency GPS

    E-print Network

    Maróti, Miklós

    Accurate Real-Time Relative Localization Using Single-Frequency GPS Will Hedgecock, Miklos Maroti.volgyesi, rbanalagay}@vanderbilt.edu Abstract For outdoor navigation, GPS provides the most widely- used means of node configuration of the con- stituent nodes in a system. This paper presents a novel ap- proach that uses GPS

  18. A relativistic and autonomous navigation satellite system

    E-print Network

    Delva, Pacôme; Kosti?, Uros; Carloni, Sante

    2011-01-01

    A relativistic positioning system has been proposed by Bartolom\\'e Coll in 2002. Since then, several group developed this topic with different approaches. I will present a work done in collaboration with Ljubljana University and the ESA Advanced Concepts Team. We developed a concept, Autonomous Basis of Coordinates, in order to take advantage of the full autonomy of a satellite constellation for navigation and positioning, by means of satellite inter-links. I will present the advantages of this new paradigm and a number of potential application for reference systems, geophysics and relativistic gravitation.

  19. A relativistic and autonomous navigation satellite system

    E-print Network

    Pacôme Delva; Andrej Cadez; Uros Kostic; Sante Carloni

    2011-06-17

    A relativistic positioning system has been proposed by Bartolom\\'e Coll in 2002. Since then, several group developed this topic with different approaches. I will present a work done in collaboration with Ljubljana University and the ESA Advanced Concepts Team. We developed a concept, Autonomous Basis of Coordinates, in order to take advantage of the full autonomy of a satellite constellation for navigation and positioning, by means of satellite inter-links. I will present the advantages of this new paradigm and a number of potential application for reference systems, geophysics and relativistic gravitation.

  20. An Autonomous Vehicle Navigation System using Panoramic Machine Vision Techniques

    E-print Network

    Spacek, Libor

    An Autonomous Vehicle Navigation System using Panoramic Machine Vision Techniques Kevin Rushant@essex.ac.uk Keywords: Horizon, panoramic images, autonomous vehicle navigation. Abstract This paper describes a navigation system for an autonomous farm vehicle using machine vision techniques applied to panoramic images

  1. Can Planning and Reactive Systems Realize an Autonomous Navigation*

    E-print Network

    Zimmer, Uwe

    Can Planning and Reactive Systems Realize an Autonomous Navigation* Maki K. Habib GMD: The major challenges facing navigation of an autonomous mobile robot and need to be addressed are stem from). These issues are fundamental to autonomous systems that have to function effectively while navigating

  2. 76 FR 77939 - Proposed Provision of Navigation Services for the Next Generation Air Transportation System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-15

    ...largely by the Global Positioning System (GPS) and the Wide Area Augmentation System...recovery and dispatch of aircraft during GPS outages. This transition would be consistent...these operations are enabled primarily by GPS and WAAS. GPS provides a level of...

  3. 76 FR 12643 - Proposed Establishment of Helicopter Area Navigation (RNAV) Routes; Northeast United States

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ...having IFR- approved Global Positioning System (GPS)/Global Navigation Satellite...Washington, DC and New York City metropolitan areas...number along with a Global Navigation Satellite...between the New York City and Washington,...

  4. A Micromechanical INS/GPS System for Small Satellites

    NASA Technical Reports Server (NTRS)

    Barbour, N.; Brand, T.; Haley, R.; Socha, M.; Stoll, J.; Ward, P.; Weinberg, M.

    1995-01-01

    The cost and complexity of large satellite space missions continue to escalate. To reduce costs, more attention is being directed toward small lightweight satellites where future demand is expected to grow dramatically. Specifically, micromechanical inertial systems and microstrip global positioning system (GPS) antennas incorporating flip-chip bonding, application specific integrated circuits (ASIC) and MCM technologies will be required. Traditional microsatellite pointing systems do not employ active control. Many systems allow the satellite to point coarsely using gravity gradient, then attempt to maintain the image on the focal plane with fast-steering mirrors. Draper's approach is to actively control the line of sight pointing by utilizing on-board attitude determination with micromechanical inertial sensors and reaction wheel control actuators. Draper has developed commercial and tactical-grade micromechanical inertial sensors, The small size, low weight, and low cost of these gyroscopes and accelerometers enable systems previously impractical because of size and cost. Evolving micromechanical inertial sensors can be applied to closed-loop, active control of small satellites for micro-radian precision-pointing missions. An inertial reference feedback control loop can be used to determine attitude and line of sight jitter to provide error information to the controller for correction. At low frequencies, the error signal is provided by GPS. At higher frequencies, feedback is provided by the micromechanical gyros. This blending of sensors provides wide-band sensing from dc to operational frequencies. First order simulation has shown that the performance of existing micromechanical gyros, with integrated GPS, is feasible for a pointing mission of 10 micro-radians of jitter stability and approximately 1 milli-radian absolute error, for a satellite with 1 meter antenna separation. Improved performance micromechanical sensors currently under development will be suitable for a range of micro-nano-satellite applications.

  5. Autonomous underwater pipeline monitoring navigation system

    NASA Astrophysics Data System (ADS)

    Mitchell, Byrel; Mahmoudian, Nina; Meadows, Guy

    2014-06-01

    This paper details the development of an autonomous motion-control and navigation algorithm for an underwater autonomous vehicle, the Ocean Server IVER3, to track long linear features such as underwater pipelines. As part of this work, the Nonlinear and Autonomous Systems Laboratory (NAS Lab) developed an algorithm that utilizes inputs from the vehicles state of the art sensor package, which includes digital imaging, digital 3-D Sidescan Sonar, and Acoustic Doppler Current Profilers. The resulting algorithms should tolerate real-world waterway with episodic strong currents, low visibility, high sediment content, and a variety of small and large vessel traffic.

  6. Application of GPS attitude determination to gravity gradient stabilized spacecraft

    NASA Technical Reports Server (NTRS)

    Lightsey, E. G.; Cohen, Clark E.; Parkinson, Bradford W.

    1993-01-01

    Recent advances in the Global Positioning System (GPS) technology have initiated a new era in aerospace navigation and control. GPS receivers have become increasingly compact and affordable, and new developments have made attitude determination using subcentimeter positioning among two or more antennas feasible for real-time applications. GPS-based attitude control systems will become highly portable packages which provide time, navigation, and attitude information of sufficient accuracy for many aerospace needs. A typical spacecraft application of GPS attitude determination is a gravity gradient stabilized satellite in low Earth orbit that employs a GPS receiver and four body mounted patch antennas. The coupled, linearized equations of motion enable complete position and attitude information to be extracted from only two antennas. A discussion of the various error sources for spaceborne GPS attitude measurement systems is included. Attitude determination of better than 0.3 degrees is possible for 1 meter antenna separation. Suggestions are provided to improve the accuracy of the attitude solution.

  7. Time determination for spacecraft users of the Navstar Global Positioning System /GPS/

    NASA Technical Reports Server (NTRS)

    Grenchik, T. J.; Fang, B. T.

    1977-01-01

    Global Positioning System (GPS) navigation is performed by time measurements. A description is presented of a two body model of spacecraft motion. Orbit determination is the process of inferring the position, velocity, and clock offset of the user from measurements made of the user motion in the Newtonian coordinate system. To illustrate the effect of clock errors and the accuracy with which the user spacecraft time and orbit may be determined, a low-earth-orbit spacecraft (Seasat) as tracked by six Phase I GPS space vehicles is considered. The obtained results indicate that in the absence of unmodeled dynamic parameter errors clock biases may be determined to the nanosecond level. There is, however, a high correlation between the clock bias and the uncertainty in the gravitational parameter GM, i.e., the product of the universal gravitational constant and the total mass of the earth. It is, therefore, not possible to determine clock bias to better than 25 nanosecond accuracy in the presence of a gravitational error of one part per million.

  8. Tuning and Robustness Analysis for the Orion Absolute Navigation System

    NASA Technical Reports Server (NTRS)

    Holt, Greg N.; Zanetti, Renato; D'Souza, Christopher

    2013-01-01

    The Orion Multi-Purpose Crew Vehicle (MPCV) is currently under development as NASA's next-generation spacecraft for exploration missions beyond Low Earth Orbit. The MPCV is set to perform an orbital test flight, termed Exploration Flight Test 1 (EFT-1), some time in late 2014. The navigation system for the Orion spacecraft is being designed in a Multi-Organizational Design Environment (MODE) team including contractor and NASA personnel. The system uses an Extended Kalman Filter to process measurements and determine the state. The design of the navigation system has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to show the efforts made to-date in tuning the filter for the EFT-1 mission and instilling appropriate robustness into the system to meet the requirements of manned space ight. Filter performance is affected by many factors: data rates, sensor measurement errors, tuning, and others. This paper focuses mainly on the error characterization and tuning portion. Traditional efforts at tuning a navigation filter have centered around the observation/measurement noise and Gaussian process noise of the Extended Kalman Filter. While the Orion MODE team must certainly address those factors, the team is also looking at residual edit thresholds and measurement underweighting as tuning tools. Tuning analysis is presented with open loop Monte-Carlo simulation results showing statistical errors bounded by the 3-sigma filter uncertainty covariance. The Orion filter design uses 24 Exponentially Correlated Random Variable (ECRV) parameters to estimate the accel/gyro misalignment and nonorthogonality. By design, the time constant and noise terms of these ECRV parameters were set to manufacturer specifications and not used as tuning parameters. They are included in the filter as a more analytically correct method of modeling uncertainties than ad-hoc tuning of the process noise. Tuning is explored for the powered-flight ascent phase, where measurements are scarce and unmodelled vehicle accelerations dominate. On orbit, there are important trade-off cases between process and measurement noise. On entry, there are considerations about trading performance accuracy for robustness. Process Noise is divided into powered flight and coasting ight and can be adjusted for each phase and mode of the Orion EFT-1 mission. Measurement noise is used for the integrated velocity measurements during pad alignment. It is also used for Global Positioning System (GPS) pseudorange and delta- range measurements during the rest of the flight. The robustness effort has been focused on maintaining filter convergence and performance in the presence of unmodeled error sources. These include unmodeled forces on the vehicle and uncorrected errors on the sensor measurements. Orion uses a single-frequency, non-keyed GPS receiver, so the effects due to signal distortion in Earth's ionosphere and troposphere are present in the raw measurements. Results are presented showing the efforts to compensate for these errors as well as characterize the residual effect for measurement noise tuning. Another robustness tool in use is tuning the residual edit thresholds. The trade-off between noise tuning and edit thresholds is explored in the context of robustness to errors in dynamics models and sensor measurements. Measurement underweighting is also presented as a method of additional robustness when processing highly accurate measurements in the presence of large filter uncertainties.

  9. DEVELOPMENT AND EVALUATION OF A SYSTEM FOR WEARABLE AUDIO NAVIGATION

    E-print Network

    DEVELOPMENT AND EVALUATION OF A SYSTEM FOR WEARABLE AUDIO NAVIGATION Bruce N. Walker and Jeffrey If it is not possible to use vision when navigating through one's surroundings, moving safely and effectively becomes much harder. In such cases, non-speech audio cues can serve as navigation beacons, as well as denote

  10. Learning Adaptive Navigation Strategies for Resource-constrained Systems

    E-print Network

    Teschner, Matthias

    -constrained and possess only limited computational power. For truly autonomous navigation in initially unknown enviLearning Adaptive Navigation Strategies for Resource-constrained Systems Armin Hornung1 and Maren. The majority of navigation algorithms for mobile robots assume that the robots possess enough computational

  11. Robotics and Autonomous Systems 30 (2000) 133153 Biomimetic robot navigation

    E-print Network

    2000-01-01

    Robotics and Autonomous Systems 30 (2000) 133­153 Biomimetic robot navigation Matthias O. Franz Abstract In the past decade, a large number of robots has been built that explicitly implement biological applications, most notably in the field of indoor robot navigation. While simpler insect navigation behaviours

  12. A precise GPS-based time and frequency system

    NASA Technical Reports Server (NTRS)

    Mcnabb, Jack; Fossler, Earl

    1993-01-01

    An approach to implementing a compact, highly reliable and precise Master Time and Frequency subsystem usable in a variety of applications is described. These applications include, among others, Satellite Ground Terminals, Range Timing Stations, Communications Terminals, and Power Station Timing subsystems. All time and frequency output signals are locked to Universal Time via the GPS Satellite system. The system provides for continued output of precise signals in the event of GPS signal interruption from antenna or lead-in breakage or other causes. Cost/performance tradeoffs affecting system accuracy over the short, medium, and long term are discussed. A unique approach to redundant system design provides an architecture with the reliability advantage of triple-redundant majority voting and the cost advantages of dual-redundant elements. The system can be configured to output a variety of precise time and frequency signals and the design can be tailored to output as few, or as many, types and quantities of signals as are required by the application.

  13. Differential GPS for air transport: Status

    NASA Technical Reports Server (NTRS)

    Hueschen, Richard M.

    1993-01-01

    The presentation presents background on what the Global Navigation Satellite System (GNSS) is, desired target dates for initial GNSS capabilities for aircraft operations, and a description of differential GPS (Global Positioning System). The presentation also presents an overview of joint flight tests conducted by LaRC and Honeywell on an integrated differential GPS/inertial reference unit (IRU) navigation system. The overview describes the system tested and the results of the flight tests. The last item presented is an overview of a current grant with Ohio University from LaRC which has the goal of developing a precision DGPS navigation system based on interferometry techniques. The fundamentals of GPS interferometry are presented and its application to determine attitude and heading and precision positioning are shown. The presentation concludes with the current status of the grant.

  14. Proceedings of 2011 NSF Engineering Research and Innovation Conference, Atlanta, Georgia Grant #0927475 Integration of Global Positioning System and Inertial Navigation for

    E-print Network

    Kamat, Vineet R.

    #0927475 Integration of Global Positioning System and Inertial Navigation for Ubiquitous Context on the integration of Real Time Kinematic Global Positioning System (RTK-GPS) and Personal Dead Reckoning (PDR points, receivers, transmitters, etc.) at fixed positions indoors, the location of tagged users can

  15. First results from an airborne GPS radio occultation system for atmospheric profiling

    E-print Network

    Larson, Kristine

    First results from an airborne GPS radio occultation system for atmospheric profiling J. S. Haase1, Indiana, USA Abstract Global Positioning System (GPS) radio occultation (RO) from low Earth Satellite Systems Instrument System for Multistatic and Occultation Sensing (GISMOS), has been developed

  16. GPS PWV Information System of the Decision Making Support System Prototype for Typhoon-Flood Disaster

    NASA Astrophysics Data System (ADS)

    Sohn, D. H.; Shin, Y. H.; Cho, J. H.; Park, J. U.

    2009-04-01

    Under the frame of the Global Earth Observation System of Systems (GEOSS), we are developing a GPS Precipitable Water Vapor (PWV) Information System (IS) of the Decision Making Support System (DMSS) Prototype for Typhoon-Flood Disaster, funded by the Korea Research Council of Fundamental Science and Technology. The system is highly demanded because most, about 90%, of natural disasters happening in Korea have been caused by water, i.e. typhoon, flood, heavy rain and snow, etc. The DMSS prototype, developed mainly by the Korea Information Science and Technology Institute, consists of three sub-systems: observation, prediction, and assessment systems, which are based on the technology of data grid, computation grid, and access grid, respectively. With the augmented reality technology applied, the DMSS web portal that integrates the sub-systems will help the decision makers to access to the DMSS effectively. The GPS PWV IS is being developed as a component of the DMSS prototype for Typhoon-Flood Disaster. PWV estimated from GPS signal delay could be useful to enhance the reliability in numerical weather prediction, nowcasting, climate change monitoring, and so on. As a leading group on GPS Meteorology, the Korea Astronomy and Space Science Institute (KASI) is taking a charge of the GPS PWV IS development. The system will provide the near-real time PWV information based on the nine permanent GPS stations of KASI. Each GPS station of KASI equipped digital weather sensor and provided their own data to the center of KASI in real time. They are expected to be used for operational weather forecasting, researches, instrument validation, etc. Here we introduce the current and future status of our GPS PWV IS, presenting its detailed structures such as Meta Data and Data Base structure, data processing strategy and procedure, flow of information, and application of augmented reality technology.

  17. The satellite configuration of satellite-TV navigation system

    NASA Astrophysics Data System (ADS)

    Gao, Yu-Ping

    2001-02-01

    The positioning accuracy and availability of navigation system are affected directly by the quality of satellite configuration. The possible satellite configurations for satellite-TV navigation system are discussed and estimated in this paper. The results show that a well setted configuration or a resonable integration of satellite-TV navigation system and Chinese Loran-C will improve the positioning accuracy and availability of the system.

  18. USING DISTRIBUTED MAGNETOMETRY IN NAVIGATION OF HEAVY LAUNCHERS

    E-print Network

    such as Global Navigation Satellite Systems (GNSS) or Global Positioning System (GPS) are discarded becauseUSING DISTRIBUTED MAGNETOMETRY IN NAVIGATION OF HEAVY LAUNCHERS AND SPACE VEHICLES N. Praly1 , P-inertial navigation, MINAV) has emerged to address the general problem of reconstructing the inertial velocity

  19. A navigation system for shoulder arthroscopic surgery.

    PubMed

    Tyryshkin, K; Mousavi, P; Beek, M; Ellis, R E; Pichora, D R; Abolmaesumi, P

    2007-10-01

    The general framework and experimental validation of a novel navigation system designed for shoulder arthroscopy are presented. The system was designed to improve the surgeon's perception of the three-dimensional space within the human shoulder. Prior to surgery, a surface model of the shoulder was created from computed tomography images. Intraoperatively, optically tracked arthroscopic instruments were calibrated. The surface model was then registered to the patient using tracked freehand ultrasound images taken from predefined landmark regions on the scapula. Three-dimensional models of the surgical instruments were displayed, in real time, relative to the surface model in a user interface. Laboratory experiments revealed only small registration and calibration errors, with minimal time needed to complete the intraoperative tasks. PMID:18019466

  20. Where in the World?: GPS Projects for the Technology Class

    ERIC Educational Resources Information Center

    Guccione, Sam

    2005-01-01

    Global positioning system (GPS) has many uses. They include navigation, location finding, vehicle tracking, surveying, autonomous control of highway construction equipment, scientific activities, asset location and entertainment. The GPS is a constellation of 24 satellites located in a 10,000-mile radius orbit in a way that allows for at least six…

  1. Further Development of Galileo-GPS RAIM for Vertical Guidance

    E-print Network

    Stanford University

    Further Development of Galileo-GPS RAIM for Vertical Guidance Alexandru Ene, Stanford University of combined GPS/Galileo signals, positioning error threat space and integrity. He holds a Bachelors anticipated deployment of Galileo, a new partner will rise on the sky of Global Navigation Satellite Systems

  2. 77 FR 12106 - 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    ... Federal Aviation Administration 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS... RTCA Special Committee 159, Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of the 88th meeting of RTCA Special Committee 159, Global Positioning System...

  3. 76 FR 67019 - Eighty-Seventh: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... Federal Aviation Administration Eighty-Seventh: RTCA Special Committee 159: Global Positioning System (GPS... RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 159: Global Positioning System...

  4. Interplanetary GPS using pulsar signals

    NASA Astrophysics Data System (ADS)

    Becker, W.; Bernhardt, M. G.; Jessner, A.

    2015-11-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  5. Integrated navigation method of a marine strapdown inertial navigation system using a star sensor

    NASA Astrophysics Data System (ADS)

    Wang, Qiuying; Diao, Ming; Gao, Wei; Zhu, Minghong; Xiao, Shu

    2015-11-01

    This paper presents an integrated navigation method of the strapdown inertial navigation system (SINS) using a star sensor. According to the principle of SINS, its own navigation information contains an error that increases with time. Hence, the inertial attitude matrix from the star sensor is introduced as the reference information to correct the SINS increases error. For the integrated navigation method, the vehicle’s attitude can be obtained in two ways: one is calculated from SINS; the other, which we have called star sensor attitude, is obtained as the product between the SINS position and the inertial attitude matrix from the star sensor. Therefore, the SINS position error is introduced in the star sensor attitude error. Based on the characteristics of star sensor attitude error and the mathematical derivation, the SINS navigation errors can be obtained by the coupling calculation between the SINS attitude and the star sensor attitude. Unlike several current techniques, the navigation process of this method is non-radiating and invulnerable to jamming. The effectiveness of this approach was demonstrated by simulation and experimental study. The results show that this integrated navigation method can estimate the attitude error and the position error of SINS. Therefore, the SINS navigation accuracy is improved.

  6. A Real Time Differential GPS Tracking System for NASA Sounding Rockets

    NASA Technical Reports Server (NTRS)

    Bull, Barton; Bauer, Frank (Technical Monitor)

    2000-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads to several hundred miles in altitude. These missions return a variety of scientific data including: chemical makeup and physical processes taking place in the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices to be used on satellites and other spacecraft prior to their use in these more expensive missions. Typically around thirty of these rockets are launched each year, from established ranges at Wallops Island, Virginia; Poker Flat Research Range, Alaska; White Sands Missile Range, New Mexico and from a number of ranges outside the United States. Many times launches are conducted from temporary launch ranges in remote parts of the world requiring considerable expense to transport and operate tracking radars. In order to support these missions, an inverse differential GPS system has been developed. The flight system consists of a small, inexpensive receiver, a preamplifier and a wrap-around antenna. A rugged, compact, portable ground station extracts GPS data from the raw payload telemetry stream, performs a real time differential solution and graphically displays the rocket's path relative to a predicted trajectory plot. In addition to generating a real time navigation solution, the system has been used for payload recovery, timing, data timetagging, precise tracking of multiple payloads and slaving of optical tracking systems for over the horizon acquisition. This paper discusses, in detail, the flight and ground hardware, as well as data processing and operational aspects of the system, and provides evidence of the system accuracy.

  7. The Development of a Simulator System and Hardware Test Bed for Deep Space X-Ray Navigation

    NASA Astrophysics Data System (ADS)

    Doyle, Patrick T.

    2013-03-01

    Currently, there is a considerable interest in developing technologies that will allow using photon measurements from celestial x-ray sources for deep space navigation. The impetus for this is that many envisioned future space missions will require spacecraft to have autonomous navigation capabilities. For missions close to Earth, Global Navigation Satellite Systems (GNSS) such as GPS are readily available for use, but for missions far from Earth, other alternatives must be provided. While existing systems such as the Deep Space Network (DSN) can be used, latencies associated with servicing a fleet of vehicles may not be compatible with some autonomous operations requiring timely updates of their navigation solution. Because of their somewhat predictable emissions, pulsars are the ideal candidates for x-ray sources that can be used to provide key parameters for navigation. Algorithms and simulation tools that will enable designing and analyzing x-ray navigation concepts are presented. The development of a compact x-ray detector system is pivotal to the eventual deployment of such navigation systems. Therefore, results of a high altitude balloon test to evaluate the design of a compact x-ray detector system are described as well.

  8. prs (.Li2. LRV NAVIGATION AND GUIDANCE SYSTEM

    E-print Network

    Rathbun, Julie A.

    prs (£.Li2. u 1 f 8 1 760-42 LRV NAVIGATION AND GUIDANCE SYSTEM PHASE A STUDY REPORT October 15, 1969 O a ,, ^... ,«.,,-,,,V| LEV NAVIGATION ANH MTI -7-i. rr JGDIDANCE SYSTEM', PHASE A STUDY REPORT G A , C A L I F O R N I A mt SHr>,.;: W5T fflaw.^ JNAVIGATION AND GUIDANCE SYSTEM PHASE

  9. Indian Regional Navigation Satellites System (IRNSS) is the world's rst

    E-print Network

    Calgary, University of

    Indian Regional Navigation Satellites System (IRNSS) is the world's rst regional navigation system with its footprint primarily over the Indian subcontinent. The system is expected to have seven satellites satellite placing) available to the Indian Space Research Organization (ISRO), the agency responsible

  10. Overview of the Delay Doppler Mapping Instrument (DDMI) for the Cyclone Global Navigation Satellite Systems Mission (CYGNSS)

    E-print Network

    Ruf, Christopher

    -ReSI [12]). The instrument contains both a traditional GPS navigation receiver integratedOverview of the Delay Doppler Mapping Instrument (DDMI) for the Cyclone Global Navigation Satellite will be presented. The DDMI uses GPS forward scattered signals of opportunity to produce delay Doppler maps (DDMs

  11. Ubiquitous Positioning Technologies for Modern Intelligent Navigation Systems

    NASA Astrophysics Data System (ADS)

    Retscher, Guenther; Kealy, Allison

    2006-01-01

    Recently new location technologies have emerged that can be employed in modern advanced navigation systems. They can be employed to augment Global Navigation Satellite System (GNSS) positioning techniques and dead reckoning as they offer different levels of positioning accuracies and performance. An integration of other technologies is especially required in indoor and outdoor-to-indoor environments. The paper gives an overview of the newly developed ubiquitous positioning technologies and their integration in navigation systems. Furthermore two case studies are presented, i.e., the improvement of land vehicle safety using Augmented Reality (AR) technologies and pedestrian navigation services for the guidance of users to certain University offices. In the first case study the integration of map matching into a Kalman filter approach is performed (referred to as “Intelligent Vehicle Navigation”) and its principle is briefly described. This approach can also be adapted for the pedestrian navigation service described in the second case study.

  12. Enhancing Positioning Accuracy in Urban Terrain by Fusing Data from a GPS Receiver, Inertial Sensors, Stereo-Camera and Digital Maps for Pedestrian Navigation

    PubMed Central

    Przemyslaw, Baranski; Pawel, Strumillo

    2012-01-01

    The paper presents an algorithm for estimating a pedestrian location in an urban environment. The algorithm is based on the particle filter and uses different data sources: a GPS receiver, inertial sensors, probability maps and a stereo camera. Inertial sensors are used to estimate a relative displacement of a pedestrian. A gyroscope estimates a change in the heading direction. An accelerometer is used to count a pedestrian's steps and their lengths. The so-called probability maps help to limit GPS inaccuracy by imposing constraints on pedestrian kinematics, e.g., it is assumed that a pedestrian cannot cross buildings, fences etc. This limits position inaccuracy to ca. 10 m. Incorporation of depth estimates derived from a stereo camera that are compared to the 3D model of an environment has enabled further reduction of positioning errors. As a result, for 90% of the time, the algorithm is able to estimate a pedestrian location with an error smaller than 2 m, compared to an error of 6.5 m for a navigation based solely on GPS. PMID:22969321

  13. Enhancing positioning accuracy in urban terrain by fusing data from a GPS receiver, inertial sensors, stereo-camera and digital maps for pedestrian navigation.

    PubMed

    Przemyslaw, Baranski; Pawel, Strumillo

    2012-01-01

    The paper presents an algorithm for estimating a pedestrian location in an urban environment. The algorithm is based on the particle filter and uses different data sources: a GPS receiver, inertial sensors, probability maps and a stereo camera. Inertial sensors are used to estimate a relative displacement of a pedestrian. A gyroscope estimates a change in the heading direction. An accelerometer is used to count a pedestrian's steps and their lengths. The so-called probability maps help to limit GPS inaccuracy by imposing constraints on pedestrian kinematics, e.g., it is assumed that a pedestrian cannot cross buildings, fences etc. This limits position inaccuracy to ca. 10 m. Incorporation of depth estimates derived from a stereo camera that are compared to the 3D model of an environment has enabled further reduction of positioning errors. As a result, for 90% of the time, the algorithm is able to estimate a pedestrian location with an error smaller than 2 m, compared to an error of 6.5 m for a navigation based solely on GPS. PMID:22969321

  14. A GPS Receiver for Lunar Missions

    NASA Technical Reports Server (NTRS)

    Bamford, William A.; Heckler, Gregory W.; Holt, Greg N.; Moreau, Michael C.

    2008-01-01

    Beginning with the launch of the Lunar Reconnaissance Orbiter (LRO) in October of 2008, NASA will once again begin its quest to land humans on the Moon. This effort will require the development of new spacecraft which will safely transport people from the Earth to the Moon and back again, as well as robotic probes tagged with science, re-supply, and communication duties. In addition to the next-generation spacecraft currently under construction, including the Orion capsule, NASA is also investigating and developing cutting edge navigation sensors which will allow for autonomous state estimation in low Earth orbit (LEO) and cislunar space. Such instruments could provide an extra layer of redundancy in avionics systems and reduce the reliance on support and on the Deep Space Network (DSN). One such sensor is the weak-signal Global Positioning System (GPS) receiver "Navigator" being developed at NASA's Goddard Space Flight Center (GSFC). At the heart of the Navigator is a Field Programmable Gate Array (FPGA) based acquisition engine. This engine allows for the rapid acquisition/reacquisition of strong GPS signals, enabling the receiver to quickly recover from outages due to blocked satellites or atmospheric entry. Additionally, the acquisition algorithm provides significantly lower sensitivities than a conventional space-based GPS receiver, permitting it to acquire satellites well above the GPS constellation. This paper assesses the performance of the Navigator receiver based upon three of the major flight regimes of a manned lunar mission: Earth ascent, cislunar navigation, and entry. Representative trajectories for each of these segments were provided by NASA. The Navigator receiver was connected to a Spirent GPS signal generator, to allow for the collection of real-time, hardware-in-the-loop results for each phase of the flight. For each of the flight segments, the Navigator was tested on its ability to acquire and track GPS satellites under the dynamical environment unique to that trajectory.

  15. Lightweight Infrared Sensing for Relative Navigation of Quadrotors

    E-print Network

    Lightweight Infrared Sensing for Relative Navigation of Quadrotors Mark Cutler, Bernard Michini During the past decade significant advances have been made in the area of autonomous control and navigation of robotic systems, especially with regard to small, aerial vehicles navigating indoors where GPS

  16. Results from a GPS Shuttle Training Aircraft flight test

    NASA Technical Reports Server (NTRS)

    Saunders, Penny E.; Montez, Moises N.; Robel, Michael C.; Feuerstein, David N.; Aerni, Mike E.; Sangchat, S.; Rater, Lon M.; Cryan, Scott P.; Salazar, Lydia R.; Leach, Mark P.

    1991-01-01

    A series of Global Positioning System (GPS) flight tests were performed on a National Aeronautics and Space Administration's (NASA's) Shuttle Training Aircraft (STA). The objective of the tests was to evaluate the performance of GPS-based navigation during simulated Shuttle approach and landings for possible replacement of the current Shuttle landing navigation aid, the Microwave Scanning Beam Landing System (MSBLS). In particular, varying levels of sensor data integration would be evaluated to determine the minimum amount of integration required to meet the navigation accuracy requirements for a Shuttle landing. Four flight tests consisting of 8 to 9 simulation runs per flight test were performed at White Sands Space Harbor in April 1991. Three different GPS receivers were tested. The STA inertial navigation, tactical air navigation, and MSBLS sensor data were also recorded during each run. C-band radar aided laser trackers were utilized to provide the STA 'truth' trajectory.

  17. Estimating MEMS Gyroscope G-Sensitivity Errors in Foot Mounted Navigation

    E-print Network

    Calgary, University of

    Estimating MEMS Gyroscope G-Sensitivity Errors in Foot Mounted Navigation Jared B. Bancroft are often overlooked in foot mounted navigation systems. Accelerations of foot mounted IMUs can reach 5 g-g-sensitivity; linear acceleration effect on gyros; pedestrian navigation; foot mounted sensors; GPS denied navigation

  18. Re-entry plasma induced pseudorange and attenuation effects in a GPS simulator

    NASA Astrophysics Data System (ADS)

    Frankel, Donald S.; Nebolsine, Peter E.; Miller, Merlin G.; Glynn, James M.

    2004-09-01

    Physical Sciences Inc. (PSI) is developing, with Navy SBIR Phase II funding, a hardware in the loop Global Positioning System (GPS) receiver Testbed. A computer simulation will "fly" a re-entry body (RB) along its trajectory and compute plasma properties that produce GPS signal attenuation and pseudo-range changes for each GPS satellite in view for the specified day and time. (The specified day and time determine the locations of the GPS satellites relative to the RB.) The simulation will compose digital instructions that specify GPS signal attenuation and pseudo-range change. The instructions will be sent to a GPS signal simulator via Ethernet using UDP. The GPS signal simulator generates analog RF electronic signals that are fed into a real, physical GPS receiver, thus emulating what would occur on an RB in flight. The GPS receiver navigational output will be compared to the input trajectory to determine the accuracy of the GPS receiver. Because attenuation of the GPS satellite signals will be, in general, different for each satellite, the effect of sequential loss of signal from various GPS satellites and the degradation on GPS trajectory determination will be part of the capability. In addition, when the RB goes into and returns from plasma blackout, the simulation can be continued to determine the time required for the GPS receiver to acquire and establish navigational capability.

  19. Definition and Objectives Consider a pedestrian navigation system which

    E-print Network

    Dalang, Robert C.

    -Matching Techniques for Indoor Positioning 3D Link/Node model The map is represented by links passing through axes Navigation system Geometry Topology Position Recalibration Route Guidance Concept A dedicated motion modelDefinition and Objectives Consider a pedestrian navigation system which contains a set of inertial

  20. An IR Navigation System for Pleural PDT

    NASA Astrophysics Data System (ADS)

    Zhu, Timothy; Liang, Xing; Kim, Michele; Finlay, Jarod; Dimofte, Andreea; Rodriguez, Carmen; Simone, Charles; Friedberg, Joseph; Cengel, Keith

    2015-03-01

    Pleural photodynamic therapy (PDT) has been used as an adjuvant treatment with lung-sparing surgical treatment for malignant pleural mesothelioma (MPM). In the current pleural PDT protocol, a moving fiber-based point source is used to deliver the light. The light fluences at multiple locations are monitored by several isotropic detectors placed in the pleural cavity. To improve the delivery of light fluence uniformity, an infrared (IR) navigation system is used to track the motion of the light source in real-time at a rate of 20 - 60 Hz. A treatment planning system uses the laser source positions obtained from the IR camera to calculate light fluence distribution to monitor the light dose uniformity on the surface of the pleural cavity. A novel reconstruction algorithm is used to determine the pleural cavity surface contour. A dual-correction method is used to match the calculated fluences at detector locations to the detector readings. Preliminary data from a phantom shows superior light uniformity using this method. Light fluence uniformity from patient treatments is also shown with and without the correction method.

  1. A tactile communication system for navigation

    E-print Network

    Piateski, Erin M

    2005-01-01

    A vibrotactile display for use in navigation has been designed and evaluated. The arm and the torso, which offer relatively large and flat surface areas, were chosen as locations for the displays. The ability of subjects ...

  2. Measuring Highly Elliptical Orbits Using The GPS

    NASA Technical Reports Server (NTRS)

    Lichten, Stephen M.; Estefan, Jeffrey A.

    1993-01-01

    Report discusses precise determination of highly elliptical orbits of spacecraft around Earth, by use of one of following techniques: (1) conventional two-way Doppler tracking of spacecraft from ground stations, (2) conventional two-way Doppler tracking from ground stations augmented by tropospheric-delay calibrations obtained at ground stations by simultaneous tracking of navigation satellites of Global Positioning System (GPS), or (3) method of item 2 augmented further by GPS tracking from GPS flight instrument aboard spacecraft. Analysis applies especially to scientific satellites carrying radio telescopes.

  3. Comparative advantage between traditional and smart navigation systems

    NASA Astrophysics Data System (ADS)

    Shin, Jeongkyu; Kim, Pan-Jun; Kim, Seunghwan

    2013-03-01

    The smart navigation system that refers to real-time traffic data is believed to be superior to traditional navigation systems. To verify this belief, we created an agent-based traffic model and examined the effect of changing market share of the traditional shortest-travel-time algorithm based navigation and the smart navigation system. We tested our model on the grid and actual metropolitan road network structures. The result reveals that the traditional navigation system have better performance than the smart one as the market share of the smart navigation system exceeds a critical value, which is contrary to conventional expectation. We suggest that the superiority inversion between agent groups is strongly related to the traffic weight function form, and is general. We also found that the relationship of market share, traffic flow density and travel time is determined by the combination of congestion avoidance behavior of the smartly navigated agents and the inefficiency of shortest-travel-time based navigated agents. Our results can be interpreted with the minority game and extended to the diverse topics of opinion dynamics. This work was supported by the Original Technology Research Program for Brain Science through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology(No. 2010-0018847).

  4. Proceedings of the Institute of Navigation Satellite Division Technical Meeting, 1/12 GPS 02 (September 2002, Portland, USA)

    E-print Network

    Calgary, University of

    Astronomy Observatory and a lecturer at the department of Astronomy & Space Science of ChungNam National. Park, Korea Astronomy Observatory, Daejeon, South Korea BIOGRAPHY Paul Alves is a graduate student is a manager of GPS Research Group of Korea Astronomy Observatory. His area of expertise is the research

  5. GPS/GLONASS Attitude Determination with a Common Clock

    E-print Network

    Calgary, University of

    visibility conditions. Under reduced visibility, the combined GPS/GLONASS approach however yields superior pose significant difficulties in areas of reduced visibility, such as vehicular navigation in urban with INS (inertial navigation system) measurements to determine the attitude parameters. The cost of an INS

  6. Design of a twelve channel GPS receiver and a DGPS reference station - Data processing part 

    E-print Network

    Ren, Juxiang

    1995-01-01

    The global positioning system (GPS) is a satellite based navigation system which can give twenty-four hour three-dimensional worldwide coverage. The system consists of space, control, and user segments. The GPS receiver is part of the user segment...

  7. GPS BASED LAND VEHICLE POSITIONING USING GAUSSIAN SUM FILTERS A.Y. Kibangou and A. Monin

    E-print Network

    Monin, André

    Positioning System, Land vehicles, Non- linear filters, Jump processes 1. INTRODUCTION Nowadays, the Global Positioning System (GPS) is extensively used as a navigation system due to its world-wide coverage, low costGPS BASED LAND VEHICLE POSITIONING USING GAUSSIAN SUM FILTERS A.Y. Kibangou and A. Monin LAAS, CNRS

  8. MULTI-SENSOR NAVIGATION SYSTEM FOR AN AUTONOMOUS HELICOPTER

    E-print Network

    Johnson, Eric N.

    1 MULTI-SENSOR NAVIGATION SYSTEM FOR AN AUTONOMOUS HELICOPTER Joerg S. Dittrich, Eric N. Johnson, Georgia Institute of Technology, Atlanta, Georgia Abstract Autonomous Unmanned Aerial Vehicles (UAVs navigational and terrain information to the flight computer of a rotorcraft UAV. The process includes

  9. Regionalized Lunar South Pole Surface Navigation System Analysis

    NASA Technical Reports Server (NTRS)

    Welch, Bryan W.

    2008-01-01

    Apollo missions utilized Earth-based assets for navigation because the landings took place at lunar locations in constant view from the Earth. The new exploration campaign to the lunar south pole region will have limited Earth visibility, but the extent to which a navigation system comprised solely of Earth-based tracking stations will provide adequate navigation solutions in this region is unknown. This report presents a dilution-of-precision (DoP)-based, stationary surface navigation analysis of the performance of multiple lunar satellite constellations, Earth-based deep space network assets, and combinations thereof. Results show that kinematic and integrated solutions cannot be provided by the Earth-based deep space network stations. Also, the stationary surface navigation system needs to be operated either as a two-way navigation system or as a one-way navigation system with local terrain information, while the position solution is integrated over a short duration of time with navigation signals being provided by a lunar satellite constellation.

  10. Investigation on navigation patterns of inertial/celestial integrated systems

    NASA Astrophysics Data System (ADS)

    Luo, Dacheng; Liu, Yan; Liu, Zhiguo; Jiao, Wei; Wang, Qiuyan

    2014-11-01

    It is known that Strapdown Inertial Navigation System (SINS), Global Navigation Satellite System (GNSS) and Celestial Navigation System (CNS) can complement each other's advantages. The SINS/CNS integrated system, which has the characteristics of strong autonomy, high accuracy and good anti-jamming, is widely used in military and civilian applications. Similar to SINS/GNSS integrated system, the SINS/CNS integrated system can also be divided into three kinds according to the difference of integrating depth, i.e., loosely coupled pattern, tightly coupled pattern and deeply coupled pattern. In this paper, the principle and characteristics of each pattern of SINS/CNS system are analyzed. Based on the comparison of these patterns, a novel deeply coupled SINS/CNS integrated navigation scheme is proposed. The innovation of this scheme is that a new star pattern matching method aided by SINS information is put forward. Thus the complementary features of these two subsystems are reflected.

  11. Relative Navigation of Formation Flying Satellites

    NASA Technical Reports Server (NTRS)

    Long, Anne; Kelbel, David; Lee, Taesul; Leung, Dominic; Carpenter, Russell; Gramling, Cheryl; Bauer, Frank (Technical Monitor)

    2002-01-01

    The Guidance, Navigation, and Control Center (GNCC) at Goddard Space Flight Center (GSFC) has successfully developed high-accuracy autonomous satellite navigation systems using the National Aeronautics and Space Administration's (NASA's) space and ground communications systems and the Global Positioning System (GPS). In addition, an autonomous navigation system that uses celestial object sensor measurements is currently under development and has been successfully tested using real Sun and Earth horizon measurements.The GNCC has developed advanced spacecraft systems that provide autonomous navigation and control of formation flyers in near-Earth, high-Earth, and libration point orbits. To support this effort, the GNCC is assessing the relative navigation accuracy achievable for proposed formations using GPS, intersatellite crosslink, ground-to-satellite Doppler, and celestial object sensor measurements. This paper evaluates the performance of these relative navigation approaches for three proposed missions with two or more vehicles maintaining relatively tight formations. High-fidelity simulations were performed to quantify the absolute and relative navigation accuracy as a function of navigation algorithm and measurement type. Realistically-simulated measurements were processed using the extended Kalman filter implemented in the GPS Enhanced Inboard Navigation System (GEONS) flight software developed by GSFC GNCC. Solutions obtained by simultaneously estimating all satellites in the formation were compared with the results obtained using a simpler approach based on differencing independently estimated state vectors.

  12. Wireless GPS system for module fiber quality mapping: System improvement and field testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless GPS system for module-level fiber quality mapping has been developed at Texas A&M University. In its complete form, it includes subsystems for harvesters, boll buggies, and module builders. The system was field tested on a producer's farm near Plains, Texas, in 2006. The field test identi...

  13. Wireless GPS system for module-level fiber quality mapping: System improvement and field testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless GPS system for module-level fiber quality mapping has been developed at Texas A&M University. In its complete form, it includes subsystems for harvesters, boll buggies, and module builders. The system was field tested on a producer’s farm near Plains, Texas, in 2006. The field test identi...

  14. Monitoring mobility in older adults using global positioning system (GPS) watches and accelerometers: a feasibility study.

    PubMed

    Webber, Sandra C; Porter, Michelle M

    2009-10-01

    This exploratory study examined the feasibility of using Garmin global positioning system (GPS) watches and ActiGraph accelerometers to monitor walking and other aspects of community mobility in older adults. After accuracy at slow walking speeds was initially determined, 20 older adults (74.4 +/- 4.2 yr) wore the devices for 1 day. Steps, distances, and speeds (on foot and in vehicle) were determined. GPS data acquisition varied from 43 min to over 12 hr, with 55% of participants having more than 8 hr between initial and final data-collection points. When GPS data were acquired without interruptions, detailed mobility information was obtained regarding the timing, distances covered, and speeds reached during trips away from home. Although GPS and accelerometry technology offer promise for monitoring community mobility patterns, new GPS solutions are required that allow for data collection over an extended period of time between indoor and outdoor environments. PMID:19940324

  15. GPSZip : semantic representation and compression system for GPS using coresets

    E-print Network

    Wu, Cathy, M. Eng. Massachusetts Institute of Technology

    2013-01-01

    We present a semantic approach for compressing mobile sensor data and focus on GPS streams. Unlike popular text-compression methods, our approach takes advantage of the fact that agents (robotic, personal, or vehicular) ...

  16. Navigation Styles in Intro-urban Environment Using Map, Turn-by-turn Cue Sheet and Mobile GPS 

    E-print Network

    Wang, Kan

    2007-11-25

    Pedestrian navigation services enable people to retrieve instructions to reach a specific location. The high efficiency of wayfinding aids has created a demand for their use by pedestrians in recent years. A key prerequisite in helping to provide...

  17. An operational software system for geosynchronous satellite navigation

    NASA Technical Reports Server (NTRS)

    Koch, D. W.

    1980-01-01

    A software system has been designed to provide navigation parameters during the VAS experiment of the GOES-4 mission along with annotation data for near real time image registration. The four functional subsystems of the software system, Data Base Management, Image Processing, Navigation, and Output, and the principal hardware components are characterized. The ability of the system to fulfil its two principal objectives is verified by results obtained from processing actual SMS-2 satellite imagery.

  18. System and method for generating attitude determinations using GPS

    NASA Technical Reports Server (NTRS)

    Cohen, Clark E. (Inventor)

    1996-01-01

    A GPS attitude receiver for determining the attitude of a moving vehicle in conjunction with a first, a second, a third, and a fourth antenna mounted to the moving vehicle. Each of the antennas receives a plurality of GPS signals that each include a carrier component. For each of the carrier components of the received GPS signals there is an integer ambiguity associated with the first and fourth antennas, an integer ambiguity associated with second and fourth antennas, and an integer ambiguity associated with the third and fourth antennas. The GPS attitude receiver measures phase values for the carrier components of the GPS signals received from each of the antennas at a plurality of measurement epochs during an initialization period and at a measurement epoch after the initialization period. In response to the phase values measured at the measurement epochs during the initialization period, the GPS attitude receiver computes integer ambiguity resolution values representing resolution of the integer ambiguities. Then, in response to the computed integer ambiguity resolution values and the phase value measured at the measurement epoch after the initialization period, it computes values defining the attitude of the moving vehicle at the measurement epoch after the initialization period.

  19. Global positioning system (GPS) controlled triangulation of single flight lines

    NASA Astrophysics Data System (ADS)

    Novak, Kurt; Habib, Ayman; Toth, Charles K.

    1994-08-01

    Aerial triangulation controlled by GPS observations in the aircraft has been established as a precise method of photogrammetric point determination without the need of ground control. If the GPS observations are available for blocks of aerial photos, the aerial triangulation can be carried out without any ground control points. Unfortunately, this method cannot be applied for single flight lines, since the GPS observations do not recover the roll angle of the aircraft. Therefore, ground control is mandatory for GPS controlled strip triangulation. This paper investigates GPS controlled strip triangulation using known, linear features on the ground that are approximately parallel to the flight line. This described technique models the linear feature in the images by low order polynomials and forces the known line on the ground onto this function. Thus, the roll angle can be determined. We investigate the effects of different GPS measurement accuracies both in the air and on the ground on the results. Experiments using simulated and real data are presented. We also show that this new technique is useful for mapping railroads.

  20. Flight Test Result for the Ground-Based Radio Navigation System Sensor with an Unmanned Air Vehicle.

    PubMed

    Jang, Jaegyu; Ahn, Woo-Guen; Seo, Seungwoo; Lee, Jang Yong; Park, Jun-Pyo

    2015-01-01

    The Ground-based Radio Navigation System (GRNS) is an alternative/backup navigation system based on time synchronized pseudolites. It has been studied for some years due to the potential vulnerability issue of satellite navigation systems (e.g., GPS or Galileo). In the framework of our study, a periodic pulsed sequence was used instead of the randomized pulse sequence recommended as the RTCM (radio technical commission for maritime services) SC (special committee)-104 pseudolite signal, as a randomized pulse sequence with a long dwell time is not suitable for applications requiring high dynamics. This paper introduces a mathematical model of the post-correlation output in a navigation sensor, showing that the aliasing caused by the additional frequency term of a periodic pulsed signal leads to a false lock (i.e., Doppler frequency bias) during the signal acquisition process or in the carrier tracking loop of the navigation sensor. We suggest algorithms to resolve the frequency false lock issue in this paper, relying on the use of a multi-correlator. A flight test with an unmanned helicopter was conducted to verify the implemented navigation sensor. The results of this analysis show that there were no false locks during the flight test and that outliers stem from bad dilution of precision (DOP) or fluctuations in the received signal quality. PMID:26569251

  1. Proceedings of ION GNSS 2004 (Session B1), Long Beach, CA, September 21-24, 2004 Modulated Signal Interference in GPS

    E-print Network

    Calgary, University of

    Interference in GPS Acquisition S. Deshpande Position, Location and Navigation (PLAN) Group Department Engineering from Dharwar University, India. He has been involved in GPS research since 1999 in the area System (GPS) is poised to play a critical role offering commercial opportunities in wireless

  2. Wakeshield WSF-02 GPS Experiment

    NASA Technical Reports Server (NTRS)

    Schutz, B. E.; Abusali, P. A. M.; Schroeder, Christine; Tapley, Byron; Exner, Michael; Mccloskey, rick; Carpenter, Russell; Cooke, Michael; Mcdonald, samantha; Combs, Nick; Duncan, Courtney; Dunn, Charles; Meehan, Tom

    1995-01-01

    Shuttle mission STS-69 was launched on September 7, 1995, 10:09 CDT, carrying the Wake Shield Facility (WSF-02). The WSF-02 spacecraft included a set of payloads provided by the Texas Space Grant Consortium, known as TexasSat. One of the TexasSat payloads was a GPS TurboRogue receiver loaned by the University Corporation for Atmospheric Research. On September 11, the WSF-02 was unberthed from the Endeavour payload bay using the remote manipulator system. The GPS receiver was powered on prior to release and the WSF-02 remained in free-flight for three days before being retrieved on September 14. All WSF-02 GPS data, which includes dual frequency pseudorange and carrier phase, were stored in an on-board recorder for post-flight analysis, but "snap- shots" of data were transmitted for 2-3 minutes at intervals of several hours, when permitted by the telemetry band- widdl The GPS experiment goals were: (1) an evaluation of precision orbit determination in a low altitude environment (400 km) where perturbations due to atmospheric drag and the Earth's gravity field are more pronounced than for higher altitude satellites with high precision orbit requirements, such as TOPEX/POSEIDON; (2) an assessment of relative positioning using the WSF GPS receiver and the Endeavour Collins receiver; and (3) determination of atmospheric temperature profiles using GPS signals passing through the atmosphere. Analysis of snap-shot telemetry data indicate that 24 hours of continuous data were stored on board, which includes high rate (50 Hz) data for atmosphere temperature profiles. Examination of the limited number of real-time navigation solutions show that at least 7 GPS satellites were tracked simultaneously and the on-board clock corrections were at the microsec level, as expected. Furthermore, a dynamical consistency test provided a further validation of the on-board navigation solutions. Complete analysis will be conducted in post-flight using the data recorded on-board.

  3. Synthetic Aperture Digital Beamsteering Array for Global Positioning System Interference Mitigation: A Study on Array Topology 

    E-print Network

    Harms, Joel K

    2014-05-20

    The Global Positioning System (GPS) satellite navigation system is deeply intertwined with civilian everyday life. Unfortunately for the civilians that use the system, the GPS system is vulnerable to external interference. Antenna arrays...

  4. Developing a Fundamental Model for an Integrated GPS/INS State Estimation System with Kalman Filtering

    NASA Technical Reports Server (NTRS)

    Canfield, Stephen

    1999-01-01

    This work will demonstrate the integration of sensor and system dynamic data and their appropriate models using an optimal filter to create a robust, adaptable, easily reconfigurable state (motion) estimation system. This state estimation system will clearly show the application of fundamental modeling and filtering techniques. These techniques are presented at a general, first principles level, that can easily be adapted to specific applications. An example of such an application is demonstrated through the development of an integrated GPS/INS navigation system. This system acquires both global position data and inertial body data, to provide optimal estimates of current position and attitude states. The optimal states are estimated using a Kalman filter. The state estimation system will include appropriate error models for the measurement hardware. The results of this work will lead to the development of a "black-box" state estimation system that supplies current motion information (position and attitude states) that can be used to carry out guidance and control strategies. This black-box state estimation system is developed independent of the vehicle dynamics and therefore is directly applicable to a variety of vehicles. Issues in system modeling and application of Kalman filtering techniques are investigated and presented. These issues include linearized models of equations of state, models of the measurement sensors, and appropriate application and parameter setting (tuning) of the Kalman filter. The general model and subsequent algorithm is developed in Matlab for numerical testing. The results of this system are demonstrated through application to data from the X-33 Michael's 9A8 mission and are presented in plots and simple animations.

  5. Onboard navigation - The near-earth options

    NASA Technical Reports Server (NTRS)

    Kurzhals, P. S.; Fuchs, A. J.

    1980-01-01

    This paper summarizes anticipated onboard navigation accuracies and user system characteristics for near-earth spacecraft. Alternate onboard systems configurations using inputs from the Tracking and Data Relay Satellite System (TDRSS) and the DOD NAVSTAR Global Positioning System (GPS) are described. Initial simulation results indicate that TDRSS will provide accuracies of 100 meters or less, and GPS can permit user spacecraft orbit determination to within 10 meters. Specific GPS user equipment developments for Landsat-D and Shuttle are outlined, along with future low-cost versions of these systems.

  6. Application of differential GPS to civil helicopter terminal guidance

    NASA Technical Reports Server (NTRS)

    Denaro, R. P.

    1984-01-01

    NASA is conducting a research program to evaluate differential Global Positioning System (GPS) concepts for civil helicopter navigation. It is pointed out that the civil helicopter community will probably be an early user of GPS because of the unique mission operations in areas where precise navigation aids are not available. Applications with very demanding accuracy requirements are related to remote area search and rescue, offshore oil platform approach, remote area precision landing, and other precise navigation operations. Differential GPS appears to provide a solution for meeting the accuracy requirements involved in the considered operations. The present investigation is concerned with results obtained in three areas studied in connection with the conducted research program. Attention is given to mission-tailored satellite selection, a satellite selection algorithm concept, satellite selection algorithm simulation results, and differential GPS ground station design.

  7. SDR/STRS Flight Experiment and the Role of SDR-Based Communication and Navigation Systems

    NASA Technical Reports Server (NTRS)

    Reinhart, Richard C.

    2008-01-01

    This presentation describes an open architecture SDR (software defined radio) infrastructure, suitable for space-based radios and operations, entitled Space Telecommunications Radio System (STRS). SDR technologies will endow space and planetary exploration systems with dramatically increased capability, reduced power consumption, and less mass than conventional systems, at costs reduced by vigorous competition, hardware commonality, dense integration, minimizing the impact of parts obsolescence, improved interoperability, and software re-use. To advance the SDR architecture technology and demonstrate its applicability in space, NASA is developing a space experiment of multiple SDRs each with various waveforms to communicate with NASA s TDRSS satellite and ground networks, and the GPS constellation. An experiments program will investigate S-band and Ka-band communications, navigation, and networking technologies and operations.

  8. Field Results of a GPS/INS-Based Approach to Measuring Ship Flexure Onboard an Aircraft

    E-print Network

    Calgary, University of

    Field Results of a GPS/INS-Based Approach to Measuring Ship Flexure Onboard an Aircraft Carrier M extensively on the integration of GPS and inertial navigation systems for precise aircraft positioning. Dr and Landing System (JPALS) aims to deliver automatic landing capabilities to inbound aircraft aboard aircraft

  9. 12. LOCK, ELECTRICAL SYSTEM, LOCK, DAM, AND NAVIGATION LIGHTING UNITS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. LOCK, ELECTRICAL SYSTEM, LOCK, DAM, AND NAVIGATION LIGHTING UNITS (October 1935) - Mississippi River 9-Foot Channel Project, Lock & Dam No. 18, Upper Mississippi River, Gladstone, Henderson County, IL

  10. 76. LOCK, ELECTRICAL SYSTEM, LOCK, DAM AND NAVIGATION LIGHTING UNITS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    76. LOCK, ELECTRICAL SYSTEM, LOCK, DAM AND NAVIGATION LIGHTING UNITS. February 1938 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 17, Upper Mississippi River, New Boston, Mercer County, IL

  11. Cyclone Global Navigation Satellite System (CYGNSS) Mission Overview

    E-print Network

    Eustice, Ryan

    Cyclone Global Navigation Satellite System (CYGNSS) Mission Overview Ta007961_CYGNSS between ocean surface properties, moist atmospheric thermodynamics,radiation,andconvectivedynamicsintheinnercoreofaTropicalCyclone thermodynamics,radiation,andconvectivedynamicsintheinnercoreofaTropicalCyclone(TC). CYGNSS coverage map overlaid

  12. Enhancing Outdoor Navigation Sys-tems through Vibrotactile Feedback

    E-print Network

    are wearing helmets visual feedback is often difficult due to lighting conditions, and audio feedback is lim available for pedestrians, bikes, and motorcycles. However, navigation systems for motorcyclists are of- ten

  13. The Role of Trust and Interaction in GPS Related Accidents: A Human Factors Safety Assessment of the Global Positioning System (GPS)

    E-print Network

    Johnson, Chris

    of the Global Positioning System (GPS) Chris. W. Johnson, DPhil; Department of Computing Science, University of Glasgow, Scotland, UK. Christine Shea, PhD; ESR Technology Ltd, Birchwood Park, Warrington, Cheshire, UK

  14. GPS error and its effects on movement analysis

    E-print Network

    Ranacher, Peter; Van der Spek, Stefan Christiaan; Reich, Siegfried

    2015-01-01

    Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), are among the most important sensors in movement analysis. GPS data loggers are widely used to record the movement trajectories of vehicles, animals or human beings. However, these trajectories are inevitably affected by GPS measurement error, which influences conclusion drawn about the behavior of the moving objects. In this paper we investigate GPS measurement error and discuss its influence on movement parameters such as speed, direction or distance. We identify three characteristic properties of GPS measurement error: it follows temporal (1) and spatial (2) autocorrelation and causes a systematic overestimation of distances (3). Based on our findings we give recommendations on how to collect movement data in order to minimize the influence of error. We claim that these recommendations are essential for designing an appropriate sampling strategy for collecting movement data by means of a GPS.

  15. VIBANASS (VIsion BAsed NAvigation Sensor System) System Test Results

    NASA Astrophysics Data System (ADS)

    Hausmann, G.; Muhlbauer, Q.; Rank, P.; Kaiser, C.

    2013-08-01

    Future Active Debris Removal missions will require vision sensors both to support guidance, navigation and control and to examine the targeted debris object prior to capture. With this scenario in mind, Kayser-Threde has developed the VIsion BAsed NAvigation Sensor System (VIBANASS). A demonstrator model representative of the flight hardware was built for execution of a space qualification program and subjected to an extensive test campaign at the European Proximity Operations Simulator (EPOS). It was shown that VIBANASS is able to perform its tasks reliably in vision-based Rendezvous and Docking maneuvers under a wide variety of illumination conditions. These tests included image processing algorithms for target distance evaluation and a closed-loop rendezvous experiment.

  16. C/NOFS: a demonstration system to forecast equatorial ionospheric scintillation that adversely affects navigation, communication, and surveillance systems

    NASA Astrophysics Data System (ADS)

    Rich, Frederick J.; de La Beaujardiere, Odile; Retterer, John M.; Basu, Bamandas; Groves, Keith; Jeong, Laila S.; Beach, Theodore; Hunton, Donald; Mellein, Jason; Kachner, Kimberlee

    2004-10-01

    The purpose of the Communication/Navigation Outage Forecasting System (C/NOFS) is to detect and forecast ionospheric irregularities that adversely impact communication, navigation and surveillance systems. The C/NOFS consists of ground sites that monitor the radio link to geosynchronous and GPS spacecraft, a fully-instrumented monitoring satellite scheduled for launch in 2005 and a central data collection facility that creates scintillation warnings in near real-time. The C/NOFS spacecraft will be launched into a low inclination (13°), elliptical (~ 375 x 710 km) orbit. Sensors on the C/NOFS spacecraft measure the ambient ionosphere near the equator and detect density fluctuations which cause scintillation. Ionospheric irregularities often occur after sunset within +/-20° of the magnetic equator. These irregularities can be fairly benign, causing a small amount of radio scintillation and perturbing only UHF/VHF communications, or they can be very severe, causing L-band scintillation that interfere with the functioning of GPS receivers. In these severe cases, the ionospheric irregularities can extend beyond 1000 km altitude. One of the challenges of this project is to go beyond detecting irregularities and to predict scintillation-producing irregularities up to 8 hours into the future and estimating changes in the climatology 24 hours or more into the future.

  17. Integration of GPS/INS and Magnetic Markers for Advanced Vehicle Control

    E-print Network

    Farrell, Jay; Barth, Matthew

    2001-01-01

    integrated navigation system reliably calculates the trajectory relative vehiclevehicle control by designing, analyzing, developing, and evaluating an integratedvehicle control based on the Two-Antenna GPS/INS integrated

  18. Navigation for space shuttle approach and landing using an inertial navigation system augmented by data from a precision ranging system or a microwave scan beam landing guidance system

    NASA Technical Reports Server (NTRS)

    Mcgee, L. A.; Smith, G. L.; Hegarty, D. M.; Merrick, R. B.; Carson, T. M.; Schmidt, S. F.

    1970-01-01

    A preliminary study has been made of the navigation performance which might be achieved for the high cross-range space shuttle orbiter during final approach and landing by using an optimally augmented inertial navigation system. Computed navigation accuracies are presented for an on-board inertial navigation system augmented (by means of an optimal filter algorithm) with data from two different ground navigation aids; a precision ranging system and a microwave scanning beam landing guidance system. These results show that augmentation with either type of ground navigation aid is capable of providing a navigation performance at touchdown which should be adequate for the space shuttle. In addition, adequate navigation performance for space shuttle landing is obtainable from the precision ranging system even with a complete dropout of precision range measurements as much as 100 seconds before touchdown.

  19. The future of GPS-based electric power system measurements, operation and control

    SciTech Connect

    Rizy, D.T.; Wilson, R.E.; Martin, K.E.; Litzenberger, W.H.; Hauer, J.F.; Overholt, P.N.; Sobajic, D.J.

    1998-11-01

    Much of modern society is powered by inexpensive and reliable electricity delivered by a complex and elaborate electric power network. Electrical utilities are currently using the Global Positioning System-NAVSTAR (GPS) timekeeping to improve the network`s reliability. Currently, GPS synchronizes the clocks on dynamic recorders and aids in post-mortem analysis of network disturbances. Two major projects have demonstrated the use of GPS-synchronized power system measurements. In 1992, the Electric Power Research Institute`s (EPRI) sponsored Phase Measurements Project used a commercially available Phasor Measurements Unit (PMU) to collect GPS-synchronized measurements for analyzing power system problems. In 1995, Bonneville Power Administration (BPA) and Western Area Power Administration (WAPA) under DOE`s and EPRI`s sponsorship launched the Wide Area Measurements (WAMS) project. WAMS demonstrated GPS-synchronized measurements over a large area of their power networks and demonstrated the networking of GPS-based measurement systems in BPA and WAPA. The phasor measurement technology has also been used to conduct dynamic power system tests. During these tests, a large dynamic resistor was inserted to simulate a small power system disturbance.

  20. Precise time and Time Interval (PTTI) measurements from the navigation technology satellites and the GPS NAVSTAR-4 satellite

    NASA Technical Reports Server (NTRS)

    Buisson, J. A.; Mccaskill, T., B.; Oaks, O. J.; Jeffries, M. M.; Stebbins, S. B.

    1979-01-01

    A time domain estimate for the NAVSTAR-4 SV clock offset was obtained for each SV pass over the GPS monitor sites, using a smoothed reference ephemeris, with corrections for ionospheric delay, tropospheric delay, earth rotation and relativistic effects. Conversion from the time domain to the frequency domain was made using the two sample Allan Variance; sigma-tau plots used to identify the noise processes. Estimates of flicker and white frequency noise for the NAVSTAR-4 rubidium frequency standard were obtained. The contribution of the reference ground clocks and other error sources to the frequency stability estimates were also considered.

  1. GPS Augmentation with Pseudolites for

    E-print Network

    Calgary, University of

    GPS Augmentation with Pseudolites for Navigation in Constricted Waterways T. MORLEY Stanford transmitters, or pseudolites (PLs) (pseudo- satellites), to augment the existing space-borne GPS satellite the effect of increasing mask angle on GPS availability, accuracy, and reliability measures. Up to three PLs

  2. High-Accurate Deformation Monitoring System Based on GPS and COMPASS

    NASA Astrophysics Data System (ADS)

    Xiao, Yugang; Jiang, Weiping; Xi, Ruijie; Peng, Lifeng

    2014-05-01

    The results of deformation monitoring system can be significantly enhanced in accuracy and availability with multiple GNSS systems. Phase II of COMPASS has completed a constellation of 14 satellites, 5 GEO satellites, 5 IGSO satellites and 4 MEO satellites, before the end of 2012 and can provide navigation services in Asia-Pacific areas now. Along with the release of the Interface Control Document (ICD), there are more combinations for us to select. In this study, we have developed a new deformation monitoring system based on two GNSS systems, GPS and COMPASS, with the strategy of double-difference and a wide variety of systematic error corrections. During the process of research and development, reliable methods of data preprocessing and bias fixing were used. We took advantage of the geometry-free observables (LG), Melbourne-Wubbena observables (MW) and single-difference residuals of ionosphere-free observables (LC) to detect the cycle slips of raw data, and then solved all of these cycle slips as bias parameters in the process of Least Square Algorithm to avoid the wrong repairs. As for the bias fixing, We utilized the method of bootstrap and decision function to solve the bias parameters as an integer one by one. Several steps were adopted to ensure the result of bias fixing was correct. The solution was given by 3 components of the baselines and their variances respectively, which could be used to evaluate the quality of the data-processing. Comparisons between the new system and systems which is based on single GNSS system show that the results are improved remarkably in accuracy and availability, especially in Asia-Pacific region, where the accuracy of mm-level for short baselines can be achieved easily. Along with more satellites being launched in the future, COMPASS will make more contribution to the deformation monitoring application worldwide. In addition, the solution can be further enhanced with more and more error correction models being put into effect.

  3. GPS Radio Occultation as Part of the Global Observing System for Atmosphere

    NASA Technical Reports Server (NTRS)

    Mannucci, Anthony J.; Ao, C. O.; Iijima, B. A.; Wilson, B. D.; Yunck, T. P.; Kursinski, E. R.

    2008-01-01

    Topics include: The Measurement (Physical retrievals based on time standards), GPS Retrieval Products, Retrievals and Radiances: CLARREO Mission, GPS RO and AIRS, GPS RO and Microwave, GPS RO and Radiosondes, GPS/GNSS Science, and Conclusions.

  4. Expected Navigation Flight Performance for the Magnetospheric Multiscale (MMS) Mission

    NASA Technical Reports Server (NTRS)

    Olson, Corwin; Wright, Cinnamon; Long, Anne

    2012-01-01

    The Magnetospheric Multiscale (MMS) mission consists of four formation-flying spacecraft placed in highly eccentric elliptical orbits about the Earth. The primary scientific mission objective is to study magnetic reconnection within the Earth s magnetosphere. The baseline navigation concept is the independent estimation of each spacecraft state using GPS pseudorange measurements (referenced to an onboard Ultra Stable Oscillator) and accelerometer measurements during maneuvers. State estimation for the MMS spacecraft is performed onboard each vehicle using the Goddard Enhanced Onboard Navigation System, which is embedded in the Navigator GPS receiver. This paper describes the latest efforts to characterize expected navigation flight performance using upgraded simulation models derived from recent analyses.

  5. Ideas for Future GPS Timing Improvements

    NASA Technical Reports Server (NTRS)

    Hutsell, Steven T.

    1996-01-01

    Having recently met stringent criteria for full operational capability (FOC) certification, the Global Positioning System (GPS) now has higher customer expectations than ever before. In order to maintain customer satisfaction, and the meet the even high customer demands of the future, the GPS Master Control Station (MCS) must play a critical role in the process of carefully refining the performance and integrity of the GPS constellation, particularly in the area of timing. This paper will present an operational perspective on several ideas for improving timing in GPS. These ideas include the desire for improving MCS - US Naval Observatory (USNO) data connectivity, an improved GPS-Coordinated Universal Time (UTC) prediction algorithm, a more robust Kalman Filter, and more features in the GPS reference time algorithm (the GPS composite clock), including frequency step resolution, a more explicit use of the basic time scale equation, and dynamic clock weighting. Current MCS software meets the exceptional challenge of managing an extremely complex constellation of 24 navigation satellites. The GPS community will, however, always seek to improve upon this performance and integrity.

  6. A Dynamical System Approach to Orbit Down-Selection of Earth-Moon Autonomous Navigation Constellations

    NASA Astrophysics Data System (ADS)

    Villac, Benjamin; Chow, Channing; Lo, Martin; Hintz, Gerald

    2011-07-01

    The article develops a method for the exploration of a concept of autonomous navigation constellations in the Earth-Moon system. This concept consists of using autonomous GPS-like beacons on three-body periodic orbits to provide navigation services to an end-user in the larger Earth-Moon neighborhood. The autonomy of the constellation spacecraft would be achieved using LiAISON navigation as introduced by Hill, Born, and Lo. The article focuses on the problem of orbit down-selection for such a concept, which is approached by formulating an optimization problem. The discussion of potential cost functions and the resulting simplifications of the problem are addressed. A continuation based method that leverages the structure of periodic orbits in the circular restricted three-body problem is then proposed to analyze the problem. The method allows notably for a succinct representation of the solution space as a one-dimensional graph that highlights local and global extrema of the optimization problem. Illustration of the method using a simplified down-selection metric is discussed to balance the strengths and limitations of the approach.

  7. A navigational guidance system in the human brain

    PubMed Central

    Spiers, Hugo J.; Maguire, Eleanor A.

    2008-01-01

    Finding your way in large-scale space requires knowing where you currently are and how to get to your goal destination. While much is understood about the neural basis of one’s current position during navigation, surprisingly little is known about how the human brain guides navigation to goals. Computational accounts argue that specific brain regions support navigational guidance by coding the proximity and direction to the goal, but empirical evidence for such mechanisms is lacking. Here, we scanned subjects with functional MRI (fMRI) as they navigated to goal destinations in a highly accurate virtual simulation of a real city. Brain activity was then analysed in combination with metric measures of proximity and direction to goal destinations which were derived from each individual subject’s coordinates at every second of navigation. We found that activity in the medial prefrontal cortex was positively correlated, and activity in a right subicular/entorhinal region was negatively correlated with goal proximity. By contrast, activity in bilateral posterior parietal cortex was correlated with egocentric direction to goals. Our results provide empirical evidence for a navigational guidance system in the human brain, and define more precisely the contribution of these three brain regions to human navigation. In addition, these findings may also have wider implications for how the brain monitors and integrates different types of information in the service of goal-directed behaviour in general. PMID:17492693

  8. Earth orbit navigation study. Volume 2: System evaluation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An overall systems evaluation was made of five candidate navigation systems in support of earth orbit missions. The five systems were horizon sensor system, unkown landmark tracking system, ground transponder system, manned space flight network, and tracking and data relay satellite system. Two reference missions were chosen: a low earth orbit mission and a transfer trajectory mission from low earth orbit to geosynchronous orbit. The specific areas addressed in the evaluation were performance, multifunction utilization, system mechanization, and cost.

  9. Formations of Autonomous Vehicles Using Global Positioning Systems (GPS)

    E-print Network

    Arabshahi, Payman

    for education and investigation into low-cost formation control. The low cost testbed is to be used formations based upon the GPS data the PC had received. The idea for this project was a joint decision between Western New England College and the Jet Propulsion Laboratory (JPL). A team of three students

  10. The Nuclear Detonation Detection System on the GPS satellites

    SciTech Connect

    Higbie, P.R.; Blocker, N.K.

    1993-07-27

    This article begins with a historical perspective of satellite usage in monitoring nuclear detonations. Current capabilities of the 24 GPS satellites in detecting the light, gamma rays, x-rays and neutrons from a nuclear explosion are described. In particular, an optical radiometer developed at Sandia National Laboratories is characterized. Operational information and calibration procedures are emphasized.

  11. Autonomous Flight in GPS-Denied Environments Using Monocular Vision and Inertial Sensors

    E-print Network

    Kaess, Michael

    Autonomous Flight in GPS-Denied Environments Using Monocular Vision and Inertial Sensors Allen D-aided inertial navigation system that enables autonomous flight of an aerial vehicle in GPS-denied environments Measurement Unit (IMU) forward in time. An Extended Kalman filter framework is proposed for performing

  12. 75 FR 68701 - Establishment and Amendment of Area Navigation (RNAV) Routes; Alaska

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    ...based on RNAV, for use by aircraft having instrument flight rules (IFR)-approved Global Positioning System (GPS)/Global Navigation Satellite System (GNSS) equipment, or Distance Measuring Equipment (DME)/DME Inertial...

  13. 75 FR 32120 - Proposed Establishment and Amendment of Area Navigation (RNAV) Routes; Alaska

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-07

    ...based on RNAV, for use by aircraft having instrument flight rules (IFR)-approved Global Positioning System (GPS)/ Global Navigation Satellite System (GNSS) equipment, or Distance Measuring Equipment (DME)/DME Inertial...

  14. Current GPS/GLONASS time reference and UTC

    NASA Technical Reports Server (NTRS)

    Daly, Peter

    1990-01-01

    The world's two global satellite navigation systems, GPS and GLONASS, will both become operational during the early 1990's. Each will offer, independently of the other, precise location and time transfer continuously anywhere in the world and indeed in space itself. Many potential users, in particular the civil aviation community, are keenly interested in a joint GPS/GLONASS operation since it would offer substantial advantages in defining and maintaining the integrity of the navigation aid. The question arises of compatibility of GPS/GLONASS from the point of view of satellite on-board clocks, their system references, their national standards and ultimately UTC. Results are presented on the characterization of GLONASS system and spacecraft clocks as compared to their Navstar GPS counterparts.

  15. A T-DMB navigation system for seamless positioning in both indoor and outdoor environments

    NASA Astrophysics Data System (ADS)

    Moon, Gong Bo; Chun, Se Bum; Hur, Moon Beom; Jee, Gyu-In

    2014-12-01

    The conventional global positioning system (GPS) can often fail to provide position determination for a mobile user in indoor and urban environments. To cope with GPS failure in such environments, a new navigation system which utilizes a terrestrial digital multimedia broadcasting (T-DMB) signal to obtain the mobile user's position is presented. Since the T-DMB transmitters in Korea construct a single frequency network (SFN), which forces the transmitters to be synchronized, the mobile user can measure a time difference of arrival (TDOA) for all audible T-DMB transmitter pairs. The time difference between T-DMB transmitters is converted to a distance difference by multiplying the time difference by the speed of light. Using these measurements and a TDOA positioning method, the mobile user position can be estimated. An experiment with a T-DMB receiver and a data acquisition (DAQ) board is performed in Seoul to analyze the error characteristic of TDOA measurements. It is certified that the measurement error is bounded under 300 m and can be used to determine the mobile user's position with a small standard deviation.

  16. Low-frequency radio navigation system

    NASA Technical Reports Server (NTRS)

    Wallis, D. E. (inventor)

    1983-01-01

    A method of continuous wave navigation using four transmitters operating at sufficiently low frequencies to assure essentially pure groundwave operation is described. The transmitters are keyed to transmit constant bursts (1/4 sec) in a time-multiplexed pattern with phase modulation of at least one transmitter for identification of the transmitters and with the ability to identify the absolute phase of the modulated transmitter and the ability to modulate low rate data for transmission. The transmitters are optimally positioned to provide groundwave coverage over a service region of about 50 by 50 km for the frequencies selected in the range of 200 to 500 kHz, but their locations are not critical because of the beneficial effect of overdetermination of position of a receiver made possible by the fourth transmitter. Four frequencies are used, at least two of which are selected to provide optimal resolution. All transmitters are synchronized to an average phase as received by a monitor receiver.

  17. An Application of UAV Attitude Estimation Using a Low-Cost Inertial Navigation System

    NASA Technical Reports Server (NTRS)

    Eure, Kenneth W.; Quach, Cuong Chi; Vazquez, Sixto L.; Hogge, Edward F.; Hill, Boyd L.

    2013-01-01

    Unmanned Aerial Vehicles (UAV) are playing an increasing role in aviation. Various methods exist for the computation of UAV attitude based on low cost microelectromechanical systems (MEMS) and Global Positioning System (GPS) receivers. There has been a recent increase in UAV autonomy as sensors are becoming more compact and onboard processing power has increased significantly. Correct UAV attitude estimation will play a critical role in navigation and separation assurance as UAVs share airspace with civil air traffic. This paper describes attitude estimation derived by post-processing data from a small low cost Inertial Navigation System (INS) recorded during the flight of a subscale commercial off the shelf (COTS) UAV. Two discrete time attitude estimation schemes are presented here in detail. The first is an adaptation of the Kalman Filter to accommodate nonlinear systems, the Extended Kalman Filter (EKF). The EKF returns quaternion estimates of the UAV attitude based on MEMS gyro, magnetometer, accelerometer, and pitot tube inputs. The second scheme is the complementary filter which is a simpler algorithm that splits the sensor frequency spectrum based on noise characteristics. The necessity to correct both filters for gravity measurement errors during turning maneuvers is demonstrated. It is shown that the proposed algorithms may be used to estimate UAV attitude. The effects of vibration on sensor measurements are discussed. Heuristic tuning comments pertaining to sensor filtering and gain selection to achieve acceptable performance during flight are given. Comparisons of attitude estimation performance are made between the EKF and the complementary filter.

  18. Global positioning system pseudolite-based relative navigation.

    SciTech Connect

    Monda, Eric W.

    2004-03-01

    Though the Global Positioning System has revolutionized navigation in the modern age, it is limited in its capability for some applications because an unobstructed line of sight to a minimum of four satellites is required. One way of augmenting the system in small areas is by employing pseudolites to broadcast additional signals that can be used to improve the user's position solution. At the Navigation Systems Testing Laboratory (NSTL) at NASA's Johnson Space Center in Houston, TX, research has been underway on the use of pseudolites to perform precision relative navigation. Based on the findings of previous research done at the NSTL, the method used to process the pseudolite measurements is an extended Kalman filter of the double differenced carrier phase measurements. By employing simulations of the system, as well as processing previously collected data in a real time manner, sub-meter tracking of a moving receiver with carrier phase measurements in the extended Kalman filter appears to be possible.

  19. Integrated INS/GPS attitude determination for manned space flight

    NASA Technical Reports Server (NTRS)

    Anderman, Alfred

    1991-01-01

    The promise and technical feasibility of a GPS sensor updating inertial attitude for the guidance, navigation, and control (GN&C) and the flight control system functions of spacecraft are demonstrated. Attitude control simulations are reported which suggest that GPS/INS systems will be as suitable as astroinertial GN&C systems of future space vehicle navigation. However, arcsec attitude accuracy star trackers will still be required for special payloads. HT need for international cooperation and agreements before worldwide implementation can be achieved is emphasized.

  20. Autonomous Spacecraft Navigation With Pulsars

    NASA Astrophysics Data System (ADS)

    Becker, Werner

    2014-08-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. We will describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  1. Autonomous Spacecraft Navigation With Pulsars

    E-print Network

    Becker, Werner; Jessner, Axel

    2013-01-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  2. Autonomous Spacecraft Navigation With Pulsars

    NASA Astrophysics Data System (ADS)

    Becker, Werner; Bernhardt, Mike G.; Jessner, Axel

    2013-11-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. ?e unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  3. Briefing highlights space weather risks to GPS

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-07-01

    Solar storms, which are expected to increase as the Sun nears the most active phase of the solar cycle, can disrupt a variety of technologies on which society relies. Speakers at a 22 June briefing on Capitol Hill in Washington, D. C., focused on how space weather can affect the Global Positioning System (GPS), which is used in a wide range of industries, including commercial air travel, agriculture, national security, and emergency response. Rocky Stone, chief technical pilot for United Airlines, noted that GPS allows more aircraft to be in airspace, saves fuel, and helps aircraft move safely on runways. “Improvements in space weather forecasting need to be pursued,” he said. Precision GPS has also “changed the whole nature of farming,” said Ron Hatch, Director of Navigation Systems, NavCom Technology/John Deere. GPS makes it possible for tractors to be driven in the most efficient paths and for fertilizer and water to be applied precisely to the areas that most need them. Space weather-induced degradation of GPS signals can cause significant loss to farms that rely on GPS. Elizabeth Zimmerman, Deputy Associate Administrator for the Office of Response and Recovery at the Federal Emergency Management Agency (FEMA), described how FEMA relies on GPS for disaster recovery. The agency is developing an operations plan for dealing with space weather, she said.

  4. GPS Interferometry

    NASA Technical Reports Server (NTRS)

    Vangrass, Frank

    1992-01-01

    This semi-annual progress report provides an overview of the work performed during the first six months of Grant NAG 1 1423, titled 'GPS Interferometry'. The Global Positioning System (GPS) is a satellite-based positioning and timing system. Through the use of interferometric processing techniques, it is feasible to obtain sub-decimeter position accuracies for an aircraft in flight. The proposed duration of this Grant is three years. During the first year of the Grant, the efforts are focussed on two topics: (1) continued development of GPS Interferometry core technology; and (2) rapid technology demonstration of GPS interferometry through the design and implementation of a flight reference/autoland system. Multipath error has been the emphasis of the continued development of GPS Interferometry core technology. The results have been documented in a Doctoral Dissertation and a conference paper. The design and implementation of the flight reference/autoland system is nearing completion. The remainder of this progress report summarizes the architecture of this system.

  5. An Indoor Navigation System for the Visually Impaired

    PubMed Central

    Guerrero, Luis A.; Vasquez, Francisco; Ochoa, Sergio F.

    2012-01-01

    Navigation in indoor environments is highly challenging for the severely visually impaired, particularly in spaces visited for the first time. Several solutions have been proposed to deal with this challenge. Although some of them have shown to be useful in real scenarios, they involve an important deployment effort or use artifacts that are not natural for blind users. This paper presents an indoor navigation system that was designed taking into consideration usability as the quality requirement to be maximized. This solution enables one to identify the position of a person and calculates the velocity and direction of his movements. Using this information, the system determines the user's trajectory, locates possible obstacles in that route, and offers navigation information to the user. The solution has been evaluated using two experimental scenarios. Although the results are still not enough to provide strong conclusions, they indicate that the system is suitable to guide visually impaired people through an unknown built environment. PMID:22969398

  6. An indoor navigation system for the visually impaired.

    PubMed

    Guerrero, Luis A; Vasquez, Francisco; Ochoa, Sergio F

    2012-01-01

    Navigation in indoor environments is highly challenging for the severely visually impaired, particularly in spaces visited for the first time. Several solutions have been proposed to deal with this challenge. Although some of them have shown to be useful in real scenarios, they involve an important deployment effort or use artifacts that are not natural for blind users. This paper presents an indoor navigation system that was designed taking into consideration usability as the quality requirement to be maximized. This solution enables one to identify the position of a person and calculates the velocity and direction of his movements. Using this information, the system determines the user's trajectory, locates possible obstacles in that route, and offers navigation information to the user. The solution has been evaluated using two experimental scenarios. Although the results are still not enough to provide strong conclusions, they indicate that the system is suitable to guide visually impaired people through an unknown built environment. PMID:22969398

  7. A summary of the GPS system performance for STARS Mission 3

    SciTech Connect

    Creel, E.E.

    1997-08-01

    This paper describes the performance of the GPS system on the most recent flight of the STARS missile, STARS Mission 3 (M3). This mission was conducted under the Ballistic Missile Defense Organization`s (BMDO`s) Consolidated Targets Program. The United States Army Space and Strategic Defense Command (USASSDC) is the executing agent for this mission and the Department of Energy`s (DOE`s) Sandia National Laboratories (SNL) is the vehicle developer and integrator. The M3 flight, dually designated as the MSX Dedicated Targets II (MDT-II) mission occurred on August 31, 1996. This mission was conducted for the specific purpose of providing targets for viewing by the MSX satellite. STARS M3 was the first STARS flight to use GPS-derived data for missile guidance, and proved to be instrumental in the procurement of a wealth of experimental data which is still undergoing analysis by numerous scientific agencies within the BMDO complex. GPS accuracy was required for this mission because of the prescribed targeting requirements for the MDT-II payload deliveries with respect to the MSX satellite flight path. During the flight test real time GPS-derived state vector data was also used to generate pointing angles for various down range sensors involved in the experiment. Background information describing the STARS missile, GPS subsystem architecture, and the GPS Kalman filter design is presented first, followed by a discussion of the telemetry data records obtained from this flight with interpretations and conclusions.

  8. Global Positioning System (GPS) Precipitable Water in Forecasting Lightning at Spaceport Canaveral

    NASA Technical Reports Server (NTRS)

    Kehrer, Kristen C.; Graf, Brian; Roeder, William

    2006-01-01

    This paper evaluates the use of precipitable water (PW) from Global Positioning System (GPS) in lightning prediction. Additional independent verification of an earlier model is performed. This earlier model used binary logistic regression with the following four predictor variables optimally selected from a candidate list of 23 candidate predictors: the current precipitable water value for a given time of the day, the change in GPS-PW over the past 9 hours, the KIndex, and the electric field mill value. This earlier model was not optimized for any specific forecast interval, but showed promise for 6 hour and 1.5 hour forecasts. Two new models were developed and verified. These new models were optimized for two operationally significant forecast intervals. The first model was optimized for the 0.5 hour lightning advisories issued by the 45th Weather Squadron. An additional 1.5 hours was allowed for sensor dwell, communication, calculation, analysis, and advisory decision by the forecaster. Therefore the 0.5 hour advisory model became a 2 hour forecast model for lightning within the 45th Weather Squadron advisory areas. The second model was optimized for major ground processing operations supported by the 45th Weather Squadron, which can require lightning forecasts with a lead-time of up to 7.5 hours. Using the same 1.5 lag as in the other new model, this became a 9 hour forecast model for lightning within 37 km (20 NM)) of the 45th Weather Squadron advisory areas. The two new models were built using binary logistic regression from a list of 26 candidate predictor variables: the current GPS-PW value, the change of GPS-PW over 0.5 hour increments from 0.5 to 12 hours, and the K-index. The new 2 hour model found the following for predictors to be statistically significant, listed in decreasing order of contribution to the forecast: the 0.5 hour change in GPS-PW, the 7.5 hour change in GPS-PW, the current GPS-PW value, and the KIndex. The new 9 hour forecast model found the following five independent variables to be statistically significant, listed in decreasing order of contribution to the forecast: the current GPSPW value, the 8.5 hour change in GPS-PW, the 3.5 hour change in GPS-PW, the 12 hour change in GPS-PW, and the K-Index. In both models, the GPS-PW parameters had better correlation to the lightning forecast than the K-Index, a widely used thunderstorm index. Possible future improvements to this study are discussed.

  9. Travel patterns during pregnancy: comparison between Global Positioning System (GPS) tracking and questionnaire data

    PubMed Central

    2013-01-01

    Background Maternal exposures to traffic-related air pollution have been associated with adverse pregnancy outcomes. Exposures to traffic-related air pollutants are strongly influenced by time spent near traffic. However, little is known about women’s travel activities during pregnancy and whether questionnaire-based data can provide reliable information on travel patterns during pregnancy. Objectives Examine women’s in-vehicle travel behavior during pregnancy and examine the difference in travel data collected by questionnaire and global positioning system (GPS) and their potential for exposure error. Methods We measured work-related travel patterns in 56 pregnant women using a questionnaire and one-week GPS tracking three times during pregnancy (<20 weeks, 20–30 weeks, and >30 weeks of gestation). We compared self-reported activities with GPS-derived trip distance and duration, and examined potentially influential factors that may contribute to differences. We also described in-vehicle travel behavior by pregnancy periods and influences of demographic and personal factors on daily travel times. Finally, we estimated personal exposure to particle-bound polycyclic aromatic hydrocarbon (PB-PAH) and examined the magnitude of exposure misclassification using self-reported vs. GPS travel data. Results Subjects overestimated both trip duration and trip distance compared to the GPS data. We observed moderately high correlations between self-reported and GPS-recorded travel distance (home to work trips: r?=?0.88; work to home trips: r?=?0.80). Better agreement was observed between the GPS and the self-reported travel time for home to work trips (r?=?0.77) than work to home trips (r?=?0.64). The subjects on average spent 69 and 93 minutes traveling in vehicles daily based on the GPS and self-reported data, respectively. Longer daily travel time was observed among participants in early pregnancy, and during certain pregnancy periods in women with higher education attainment, higher income, and no children. When comparing self-reported vs. GPS data, we found that estimated personal exposure to PB-PAH did not differ remarkably at the population level, but the difference was large at an individual level. Conclusion Self-reported home-to-work data overestimated both trip duration and trip distance compared to GPS data. Significant differences in PAH exposure estimates were observed at individual level using self-reported vs. GPS data, which has important implications in air pollution epidemiological studies. PMID:24107241

  10. Performance analysis of an integrated GPS/inertial attitude determination system. M.S. Thesis - MIT

    NASA Technical Reports Server (NTRS)

    Sullivan, Wendy I.

    1994-01-01

    The performance of an integrated GPS/inertial attitude determination system is investigated using a linear covariance analysis. The principles of GPS interferometry are reviewed, and the major error sources of both interferometers and gyroscopes are discussed and modeled. A new figure of merit, attitude dilution of precision (ADOP), is defined for two possible GPS attitude determination methods, namely single difference and double difference interferometry. Based on this figure of merit, a satellite selection scheme is proposed. The performance of the integrated GPS/inertial attitude determination system is determined using a linear covariance analysis. Based on this analysis, it is concluded that the baseline errors (i.e., knowledge of the GPS interferometer baseline relative to the vehicle coordinate system) are the limiting factor in system performance. By reducing baseline errors, it should be possible to use lower quality gyroscopes without significantly reducing performance. For the cases considered, single difference interferometry is only marginally better than double difference interferometry. Finally, the performance of the system is found to be relatively insensitive to the satellite selection technique.

  11. Evaluation of Relative Navigation Algorithms for Formation-Flying Satellites

    NASA Technical Reports Server (NTRS)

    Kelbel, David; Lee, Taesul; Long, Anne; Carpenter, J. Russell; Gramling, Cheryl

    2001-01-01

    Goddard Space Flight Center is currently developing advanced spacecraft systems to provide autonomous navigation and control of formation flyers. This paper discusses autonomous relative navigation performance for formations in eccentric, medium, and high-altitude Earth orbits using Global Positioning System (GPS) Standard Positioning Service (SPS) and intersatellite range measurements. The performance of several candidate relative navigation approaches is evaluated. These analyses indicate that the relative navigation accuracy is primarily a function of the frequency of acquisition and tracking of the GPS signals. A relative navigation position accuracy of 0.5 meters root-mean-square (RMS) can be achieved for formations in medium-attitude eccentric orbits that can continuously track at least one GPS signal. A relative navigation position accuracy of better than 75 meters RMS can be achieved for formations in high-altitude eccentric orbits that have sparse tracking of the GPS signals. The addition of round-trip intersatellite range measurements can significantly improve relative navigation accuracy for formations with sparse tracking of the GPS signals.

  12. Image-based 3D scene analysis for navigation of autonomous airborne systems

    NASA Astrophysics Data System (ADS)

    Jaeger, Klaus; Bers, Karl-Heinz

    2001-10-01

    In this paper we describe a method for automatic determination of sensor pose (position and orientation) related to a 3D landmark or scene model. The method is based on geometrical matching of 2D image structures with projected elements of the associated 3D model. For structural image analysis and scene interpretation, a blackboard-based production system is used resulting in a symbolic description of image data. Knowledge of the approximated sensor pose measured for example by IMU or GPS enables to estimate an expected model projection used for solving the correspondence problem of image structures and model elements. These correspondences are presupposed for pose computation carried out by nonlinear numerical optimization algorithms. We demonstrate the efficiency of the proposed method by navigation update approaching a bridge scenario and flying over urban area, whereas data were taken with airborne infrared sensors in high oblique view. In doing so we simulated image-based navigation for target engagement and midcourse guidance suited for the concepts of future autonomous systems like missiles and drones.

  13. Potential GPS user architecture for the NASA Space Station based on Landsat 4/5 experience

    NASA Technical Reports Server (NTRS)

    Korenstein, David A.

    1987-01-01

    A Landsat 4/5 GPS system is described which uses an inertial reference attitude control system and precision real-time ephemeris generation to achieve precision earth pointing. The system has application to the validation of the use of GPS for the low earth orbit navigation of the Space Station. The present system consists of a receiver/processor assembly (R/PA), an L-band GPS antenna, a precision oscillator, and the Landsat computer. The R/PA is integrated with a GPS receiver which selects, acquires, tracks, times, and decodes navigation signals from GPS satellites in order to derive ephemerides. Ephemeris estimates were found to be accurate to better than 50 meters.

  14. Think GPS offers high security? Think again.

    SciTech Connect

    Johnston, R. G.; Warner, J. S.

    2004-01-01

    The Global Positioning System (GPS) is being increasingly used for a variety of important applications. These include public safety services (police, fire, rescue, and ambulance), marine and aircraft navigation, vehicle theft monitoring, cargo tracking, and critical time synchronization for utility, telecommunications, banking, and computer industries. Civilian GPS signals-the only ones available to business and to most of the federal government-are high-tech, but not high-security. They were never meant for critical or security applications. Unlike the military GPS signals, civilian GPS satellite signals are unencrypted and unauthenticated. This makes it easy for even relatively unsophisticated adversaries to jam or counterfeit them. Counterfeiting ('spoofing') of civilian GPS signals is particularly troublesome because it is totally surreptitious, and (as we have demonstrated) surprisingly simple. The U.S. Department of Transportation (DOT) has warned of vulnerabilities and looming problems associated with over-reliance and over-confidence in civilian GPS. Few GPS users appear to be paying attention.

  15. Triply redundant integrated navigation and asset visibility system

    SciTech Connect

    Smith, Stephen F.; Moore, James A.

    2011-11-29

    Methods and apparatus are described for a navigation system. A method includes providing a global positioning system fix having a plurality of tracking parameters; providing a theater positioning system fix; monitoring the plurality of tracking parameters for predetermined conditions; and, when the predetermined conditions are met, sending a notifying signal and switching to the theater positioning system fix as a primary fix. An apparatus includes a system controller; a global positioning system receiver coupled to the system controller; a radio frequency locating receiver coupled to the system controller; and an operator interface coupled to the system controller.

  16. Triply redundant integrated navigation and asset visibility system

    SciTech Connect

    Smith, Stephen F.; Moore, James A.

    2013-01-22

    Methods and apparatus are described for a navigation system. A method includes providing a global positioning system fix having a plurality of tracking parameters; providing a theater positioning system fix; monitoring the plurality of tracking parameters for predetermined conditions; and, when the predetermined conditions are met, sending a notifying signal and switching to the theater positioning system fix as a primary fix. An apparatus includes a system controller; a global positioning system receiver coupled to the system controller; a radio frequency locating receiver coupled to the system controller; and an operator interface coupled to the system controller.

  17. Data Analysis Techniques for a Lunar Surface Navigation System Testbed

    NASA Technical Reports Server (NTRS)

    Chelmins, David; Sands, O. Scott; Swank, Aaron

    2011-01-01

    NASA is interested in finding new methods of surface navigation to allow astronauts to navigate on the lunar surface. In support of the Vision for Space Exploration, the NASA Glenn Research Center developed the Lunar Extra-Vehicular Activity Crewmember Location Determination System and performed testing at the Desert Research and Technology Studies event in 2009. A significant amount of sensor data was recorded during nine tests performed with six test subjects. This paper provides the procedure, formulas, and techniques for data analysis, as well as commentary on applications.

  18. Autonomous navigation system for the Marsokhod rover project

    NASA Technical Reports Server (NTRS)

    Proy, C.; Lamboley, M.; Rastel, L.

    1994-01-01

    This paper presents a general overview of the Marsokhod rover mission. The autonomous navigation for a Mars exploration rover is controlled by a vision system which has been developed on the basis of two CCD cameras, stereovision and path planning algorithms. Its performances have been tested on a Mars-like experimentation site.

  19. AIDE: An Automatic User Navigation System for Interactive Data Exploration

    E-print Network

    Diao, Yanlei

    , and revision of results at various points in the process. To make the most of the increasingly complex big data interesting data areas based on her rel- evance feedback on database samples, aiming to achieve the goalAIDE: An Automatic User Navigation System for Interactive Data Exploration Yanlei Diao± , Kyriaki

  20. A MVC prototype for the landmarke firefighter navigation system

    E-print Network

    Beigl, Michael

    A MVC prototype for the landmarke firefighter navigation system Markus Scholz, Leonardo Ramirez Berning, Matthias Budde, Dimana Shishkova, Till Riedel and Michael Beigl I. INTRODUCTION FirefightersIT@Work project was to search for alternative approaches to support firefighters. From their work

  1. Portable device to assess dynamic accuracy of global positioning systems (GPS) receivers used in agricultural aircraft

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A device was designed to test the dynamic accuracy of Global Positioning System (GPS) receivers used in aerial vehicles. The system works by directing a sun-reflected light beam from the ground to the aircraft using mirrors. A photodetector is placed pointing downward from the aircraft and circuitry...

  2. TRIANGULATION OF LH SYSTEMS' ADS40 IMAGERY USING ORIMA GPS/IMU L. Hinsken a

    E-print Network

    Giger, Christine

    TRIANGULATION OF LH SYSTEMS' ADS40 IMAGERY USING ORIMA GPS/IMU L. Hinsken a , S. Miller b , U, Three-Line, Aerial, Mathematics, Bundle, Triangulation, Orientation, Calibration, Adjustment, Software for the triangulation of the ADS40. The ADS40 Airborne Digital Sensor is LH Systems' multi-line scanner (Röser, 2000

  3. Use of global positioning system (GPS) technology to map cross country pipelines

    SciTech Connect

    Barrett, J.P.

    1998-12-31

    Using Global Positioning System (GPS) to map pipelines could improve public safety, emergency response, protection of the environment, and reduce operational, regulatory, and asset integrity costs. Sub-meter to meter-level GPS accuracy can be a low-cost mapping technique to capture far more data than traditional meets-and-bound surveys. This paper will address some of the steps in determining what equipment, process, data dictionary, and data collection techniques would best fit the user`s application. Discussion will include the step-increase in costs for accuracy, equipment options, overall survey costs, data collection processes, and benefits of implementing a cost-effective mapping program using Global Positioning System (GPS) technology.

  4. ION GPS '99, 14-17 September 1999, Nashville, TN Virtual Differential GPS & Road

    E-print Network

    Faulds, James E.

    ION GPS '99, 14-17 September 1999, Nashville, TN Virtual Differential GPS & Road Reduction company specializing in GPS and GIS R&D, and is also a lecturer in Geographical Information Science Fellowship to research GPS and digital mapping integra- tion for vehicle tracking and navigation. Professor

  5. Vision-aided inertial navigation system for robotic mobile mapping

    NASA Astrophysics Data System (ADS)

    Bayoud, Fadi; Skaloud, Jan

    2008-04-01

    A mapping system by vision-aided inertial navigation was developed for areas where GNSS signals are unreachable. In this framework, a methodology on the integration of vision and inertial sensors is presented, analysed and tested. The system employs the method of “SLAM: Simultaneous Localisation And Mapping” where the only external input available to the system at the beginning of the mapping mission is a number of features with known coordinates. SLAM is a term used in the robotics community to describe the problem of mapping the environment and at the same time using this map to determine the location of the mapping device. Differing from the robotics approach, the presented development stems from the frameworks of photogrammetry and kinematic geodesy that are merged in two filters that run in parallel: the Least-Squares Adjustment (LSA) for features coordinates determination and the Kalman filter (KF) for navigation correction. To test this approach, a mapping system-prototype comprising two CCD cameras and one Inertial Measurement Unit (IMU) is introduced. Conceptually, the outputs of the LSA photogrammetric resection are used as the external measurements for the KF that corrects the inertial navigation. The filtered position and orientation are subsequently employed in the photogrammetric intersection to map the surrounding features that are used as control points for the resection in the next epoch. We confirm empirically the dependency of navigation performance on the quality of the images and the number of tracked features, as well as on the geometry of the stereo-pair. Due to its autonomous nature, the SLAM's performance is further affected by the quality of IMU initialisation and the a-priory assumptions on error distribution. Using the example of the presented system we show that centimetre accuracy can be achieved in both navigation and mapping when the image geometry is optimal.

  6. Influence of Ephemeris Error on GPS Single Point Positioning Accuracy

    NASA Astrophysics Data System (ADS)

    Lihua, Ma; Wang, Meng

    2013-09-01

    The Global Positioning System (GPS) user makes use of the navigation message transmitted from GPS satellites to achieve its location. Because the receiver uses the satellite's location in position calculations, an ephemeris error, a difference between the expected and actual orbital position of a GPS satellite, reduces user accuracy. The influence extent is decided by the precision of broadcast ephemeris from the control station upload. Simulation analysis with the Yuma almanac show that maximum positioning error exists in the case where the ephemeris error is along the line-of-sight (LOS) direction. Meanwhile, the error is dependent on the relationship between the observer and spatial constellation at some time period.

  7. TOUCHLESS MEDICAL IMAGE NAVIGATION SYSTEM FOR SURGERY

    E-print Network

    Xu, Dana N.

    room management system to select the patient. 100% DICOM compatible. Fluid can read any kind of medical SENSOR ROOM 1 VIDEO MATRIX PACS OR AGENDA THERAPIXEL SERVER Each room is controlled by an independent PC;8 Instant access. Image prefetching allows for instant access to all data. Zero loading time on the PACS

  8. Vehicle health management for guidance, navigation and control systems

    NASA Astrophysics Data System (ADS)

    Radke, Kathleen; Frazzini, Ron; Bursch, Paul; Wald, Jerry; Brown, Don

    The objective of the program was to architect a vehicle health management (VHM) system for space systems avionics that assures system readiness for launch vehicles and for space-based dormant vehicles. The platforms which were studied and considered for application of VHM for guidance, navigation and control (GN&C) included the Advanced Manned Launch System (AMLS), the Horizontal Landing-20/Personnel Launch System (HL-20/PLS), the Assured Crew Return Vehicle (ACRV) and the Extended Duration Orbiter (EDO). This set was selected because dormancy and/or availability requirements are driving the designs of these future systems.

  9. GPS L1 Indoor Fading Characterization using Block Processing Techniques

    E-print Network

    Calgary, University of

    Satellite Systems (GNSS) R&D projects since 1980, ranging from RTK positioning to indoor location and GNSS receivers. When propagating indoors, Global Navigation Satellite System (GNSS) signals experi- ence bothGPS L1 Indoor Fading Characterization using Block Processing Techniques Shashank Satyanarayana

  10. International Conference on Advanced Robotics, Budapest, Hungary, August 2001. 1 A Local-Area GPS Pseudolite-Based

    E-print Network

    Stanford University

    to a full GPS satellite constellation. This concept is illustrated in Figure 1. Figure 1: Mars SCPA One-Area GPS Pseudolite-Based Mars Navigation System Edward A. LeMaster and Stephen M. Rock Stanford University Durand Bldg. Rm. 250, Stanford, CA 94305 Abstract Tasks envisioned for future generation Mars rovers

  11. On-Board Perception System For Planetary Aerobot Balloon Navigation

    NASA Technical Reports Server (NTRS)

    Balaram, J.; Scheid, Robert E.; T. Salomon, Phil

    1996-01-01

    NASA's Jet Propulsion Laboratory is implementing the Planetary Aerobot Testbed to develop the technology needed to operate a robotic balloon aero-vehicle (Aerobot). This earth-based system would be the precursor for aerobots designed to explore Venus, Mars, Titan and other gaseous planetary bodies. The on-board perception system allows the aerobot to localize itself and navigate on a planet using information derived from a variety of celestial, inertial, ground-imaging, ranging, and radiometric sensors.

  12. Kalman Filtering USNO's GPS Observations for Improved Time Transfer Predictions

    NASA Technical Reports Server (NTRS)

    Hutsell, Steven T.

    1996-01-01

    The Global Positioning System (GPS) Master Control Station (MCS) performs the Coordinated Universal Time (UTC) time transfer mission by uploading and broadcasting predictions of the GPS-UTC offset in subframe 4 of the GS navigation message. These predictions are based on only two successive daily data points obtained from the US Naval Observatory (USNO). USNO produces these daily smoothed data points by performing a least-squares fit on roughly 38 hours worth of data from roughly 160 successive 13-minute tracks of GPS satellites. Though sufficient for helping to maintain a time transfer error specification of 28 ns (1 Sigma), the MCS's prediction algorithm does not make the best use of the available data from from USNO, and produces data that can degrade quickly over extended prediction spans. This paper investigates how, by applying Kalman filtering to the same available tracking data, the MCS could improve its estimate of GPS-UTC, and in particular, the GPS-UTC A(sub 1) term. By refining the A(sub 1) (frequency) estimate for GPS-UTC predictions, error in GPS time transfer could drop significantly. Additional, the risk of future spikes in GPS's time transfer error could similarly be minimized, by employing robust Kalman filtering for GPS-UTC predictions.

  13. Real-time ultrasound-guided PCNL using a novel SonixGPS needle tracking system.

    PubMed

    Li, Xiang; Long, Qingzhi; Chen, Xingfa; He, Dalin; Dalin, He; He, Hui

    2014-08-01

    SonixGPS is a successful ultrasound guidance position system. It helps to improve accuracy in performing complex puncture operations. This study firstly used SonixGPS to perform kidney calyx access in PCNL to investigate its effectiveness and safety. This was a prospectively randomized controlled study performed from September 2011 to October 2012. A total of 97 patients were prospectively randomized into two groups using random number generated from SAS software. 47 Patients were enrolled in conventional ultrasound-guided (US-guided) group and 50 patients were classified into SonixGPS-guided group. Nine patients were lost during follow-up. Hence, a total of 88 patients were qualified and analyzed. Preoperative examinations included urine analysis, urine culture, kidney function, coagulation profile and routine analysis of blood. Ultrasonography was used to evaluate the degree of hydronephrosis. The intraoperative findings, including blood loss, operating time, time to successful puncture, the number of attempts for successful puncture and hospital stay were recorded. The stone clearance rate and complications were analyzed. The present study showed no significant difference between the two groups in terms of demographic data, preoperative markers, stone clearance rate and the stone composition. However, the time to successful puncture, the number of trials for successful puncture, operating time and hospital length of stay were significantly decreased in the SonixGPS-guided group. Furthermore, the hemoglobin decrease was also obviously lower in the SonixGPS group than that in conventional US-guided group. SonixGPS needle tacking system guided PCNL is safe and effective in treating upper urinary tract stones. This novel technology makes puncturing more accuracy and can significantly decrease the incidence of relative hemorrhage and accelerate recovery. PMID:24965272

  14. Measuring Orientation Of The Earth With GPS

    NASA Technical Reports Server (NTRS)

    Freedman, Adam P.

    1992-01-01

    Report discusses feasibility of using Global Positioning System (GPS) to resolve short-term fluctuations (days or hours) in locations of points on crust of Earth to within centimeters or millimeters. With full constellation of satellites and ground receiving stations, system provides rapid (within 12 hours) determinations of variations in orientation. Measurements used to enhance precision of spacecraft navigation and in geophysical and meteorological studies of daily exchanges of angular momentum among fluid core, crust and mantle, oceans, and atmosphere.

  15. Algorithms for spacecraft formation flying navigation based on wireless positioning system measurements

    NASA Astrophysics Data System (ADS)

    Goh, Shu Ting

    Spacecraft formation flying navigation continues to receive a great deal of interest. The research presented in this dissertation focuses on developing methods for estimating spacecraft absolute and relative positions, assuming measurements of only relative positions using wireless sensors. The implementation of the extended Kalman filter to the spacecraft formation navigation problem results in high estimation errors and instabilities in state estimation at times. This is due to the high nonlinearities in the system dynamic model. Several approaches are attempted in this dissertation aiming at increasing the estimation stability and improving the estimation accuracy. A differential geometric filter is implemented for spacecraft positions estimation. The differential geometric filter avoids the linearization step (which is always carried out in the extended Kalman filter) through a mathematical transformation that converts the nonlinear system into a linear system. A linear estimator is designed in the linear domain, and then transformed back to the physical domain. This approach demonstrated better estimation stability for spacecraft formation positions estimation, as detailed in this dissertation. The constrained Kalman filter is also implemented for spacecraft formation flying absolute positions estimation. The orbital motion of a spacecraft is characterized by two range extrema (perigee and apogee). At the extremum, the rate of change of a spacecraft's range vanishes. This motion constraint can be used to improve the position estimation accuracy. The application of the constrained Kalman filter at only two points in the orbit causes filter instability. Two variables are introduced into the constrained Kalman filter to maintain the stability and improve the estimation accuracy. An extended Kalman filter is implemented as a benchmark for comparison with the constrained Kalman filter. Simulation results show that the constrained Kalman filter provides better estimation accuracy as compared with the extended Kalman filter. A Weighted Measurement Fusion Kalman Filter (WMFKF) is proposed in this dissertation. In wireless localizing sensors, a measurement error is proportional to the distance of the signal travels and sensor noise. In this proposed Weighted Measurement Fusion Kalman Filter, the signal traveling time delay is not modeled; however, each measurement is weighted based on the measured signal travel distance. The obtained estimation performance is compared to the standard Kalman filter in two scenarios. The first scenario assumes using a wireless local positioning system in a GPS denied environment. The second scenario assumes the availability of both the wireless local positioning system and GPS measurements. The simulation results show that the WMFKF has similar accuracy performance as the standard Kalman Filter (KF) in the GPS denied environment. However, the WMFKF maintains the position estimation error within its expected error boundary when the WLPS detection range limit is above 30km. In addition, the WMFKF has a better accuracy and stability performance when GPS is available. Also, the computational cost analysis shows that the WMFKF has less computational cost than the standard KF, and the WMFKF has higher ellipsoid error probable percentage than the standard Measurement Fusion method. A method to determine the relative attitudes between three spacecraft is developed. The method requires four direction measurements between the three spacecraft. The simulation results and covariance analysis show that the method's error falls within a three sigma boundary without exhibiting any singularity issues. A study of the accuracy of the proposed method with respect to the shape of the spacecraft formation is also presented.

  16. A reactive system for open terrain navigation: Performance and limitations

    NASA Technical Reports Server (NTRS)

    Langer, D.; Rosenblatt, J.; Hebert, M.

    1994-01-01

    We describe a core system for autonomous navigation in outdoor natural terrain. The system consists of three parts: a perception module which processes range images to identify untraversable regions of the terrain, a local map management module which maintains a representation of the environment in the vicinity of the vehicle, and a planning module which issues commands to the vehicle controller. Our approach is to use the concept of 'early traversability evaluation', and on the use of reactive planning for generating commands to drive the vehicle. We argue that our approach leads to a robust and efficient navigation system. We illustrate our approach by an experiment in which a vehicle travelled autonomously for one kilometer through unmapped cross-country terrain.

  17. Pilot factors guidelines for the operational inspection of navigation systems

    NASA Technical Reports Server (NTRS)

    Sadler, J. F.; Boucek, G. P.

    1988-01-01

    A computerized human engineered inspection technique is developed for use by FAA inspectors in evaluating the pilot factors aspects of aircraft navigation systems. The short title for this project is Nav Handbook. A menu-driven checklist, computer program and data base (Human Factors Design Criteria) were developed and merged to form a self-contained, portable, human factors inspection checklist tool for use in a laboratory or field setting. The automated checklist is tailored for general aviation navigation systems and can be expanded for use with other aircraft systems, transports or military aircraft. The Nav Handbook inspection concept was demonstrated using a lap-top computer and an Omega/VLF CDU. The program generates standardized inspection reports. Automated checklists for LORAN/C and R NAV were also developed. A Nav Handbook User's Guide is included.

  18. GPS Ephemeris Verification for Local Area Augmentation System (LAAS) Ground Stations

    E-print Network

    Rotkowitz, Michael C.

    GPS Ephemeris Verification for Local Area Augmentation System (LAAS) Ground Stations Shuichi ephemeris messages that do not correspond to true satellite locations, can be difficult to detect by a Local antennas that are very close together. Although ephemeris failures large enough to threaten LAAS user

  19. Tractor-mounted, GPS-based spot fumigation system manages Prunus replant disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our research goal was to use recent advances in global positioning system (GPS) and computer technology to apply just the right amount of fumigant where it is most needed (i.e., in a small target treatment zone in and around each tree replanting site) to control Prunus replant disease (PRD). We deve...

  20. Rapid determination of earthquake magnitude using GPS for tsunami warning systems

    E-print Network

    Faulds, James E.

    Rapid determination of earthquake magnitude using GPS for tsunami warning systems Geoffrey Blewitt Sumatra earthquake (Mw 9.2­9.3) generated the most deadly tsunami in history. Yet within the first hour, the true danger of a major oceanwide tsunami was not indicated by seismic magnitude estimates, which were

  1. A relativistic navigation system for space

    E-print Network

    Angelo Tartaglia; Matteo Luca Ruggiero; Emiliano Capolongo

    2011-09-28

    We present here a method for the relativistic positioning in spacetime based on the reception of pulses from sources of electromagnetic signals whose worldline is known. The method is based on the use of a four-dimensional grid covering the whole spacetime and made of the null hypersurfaces representing the propagating pulses. In our first approach to the problem of positioning we consider radio-pulsars at infinity as primary sources of the required signals. The reason is that, besides being very good clocks, pulsars can be considered as being fixed stars for reasonably long times. The positioning is obtained linearizing the worldline of the observer for times of the order of a few periods of the signals. We present an exercise where the use of our method applied to the signals from four real pulsars permits the reconstruction of the motion of the Earth with respect to the fixed stars during three days. The uncertainties and the constraints of the method are discussed and the possibilities of using moving artificial sources carried around by celestial bodies or spacecrafts in the Solar System is also discussed.

  2. A Low Cost GPS System for Real-Time Tracking of Sounding Rockets

    NASA Technical Reports Server (NTRS)

    Markgraf, M.; Montenbruck, O.; Hassenpflug, F.; Turner, P.; Bull, B.; Bauer, Frank (Technical Monitor)

    2001-01-01

    This paper describes the development as well as the on-ground and the in-flight evaluation of a low cost Global Positioning System (GPS) system for real-time tracking of sounding rockets. The flight unit comprises a modified ORION GPS receiver and a newly designed switchable antenna system composed of a helical antenna in the rocket tip and a dual-blade antenna combination attached to the body of the service module. Aside from the flight hardware a PC based terminal program has been developed to monitor the GPS data and graphically displays the rocket's path during the flight. In addition an Instantaneous Impact Point (IIP) prediction is performed based on the received position and velocity information. In preparation for ESA's Maxus-4 mission, a sounding rocket test flight was carried out at Esrange, Kiruna, on 19 Feb. 2001 to validate existing ground facilities and range safety installations. Due to the absence of a dedicated scientific payload, the flight offered the opportunity to test multiple GPS receivers and assess their performance for the tracking of sounding rockets. In addition to the ORION receiver, an Ashtech G12 HDMA receiver and a BAE (Canadian Marconi) Allstar receiver, both connected to a wrap-around antenna, have been flown on the same rocket as part of an independent experiment provided by the Goddard Space Flight Center. This allows an in-depth verification and trade-off of different receiver and antenna concepts.

  3. General aviation Omega navigation in the national airspace system

    E-print Network

    Wischmeyer, Carl Edward

    1976-01-01

    Introduction: Omega navigation has great potential as a navigation sensor for general aviation aircraft. Advantages of Omega navigation include signal availability at all altitudes, and no need for overflying of various ...

  4. Indoor inertial navigation application for smartphones with Android

    NASA Astrophysics Data System (ADS)

    Kami?ski, ?.; Tarapata, G.

    2015-09-01

    Inertial navigation is widely used by the military, in logistics and sailing. In mobile devices, inertial sensors are mostly used as a support for GPS and Wi-Fi-based navigation systems. Inertial-based navigation might prove useful on mobile devices running Android OS. At present, in spite of the accelerometer sensor's precision having been greatly improved, as well as the devices' computing power continuously rising, inertial navigation's precision still suffers. For smartphones, the key solution seems to be the usage of sensor fusion and signal smart filtering, both discussed in this paper. The paper also describes implementation of inertial navigation in Android devices, their analysis as well as test results.

  5. Improvement in the observation system for the GPS/A seafloor positioning

    NASA Astrophysics Data System (ADS)

    Fujimoto, H.; Kido, M.; Osada, Y.

    2010-12-01

    GPS/Acoustic seafloor positioning has become an indispensable geodetic observation for the monitoring of crustal activities near plate boundaries. There remain, however, substantial differences from GPS observation on land. Our group in Tohoku University has been working to cope with the problems under the program of the DONET, JAMSTEC.One of critical problems regarding the present GPS/A observation lies in the campaign style observation spending one or two days to measure the position of an array of acoustic transponders (PXPs) once or twice a year. It is similar to the triangulation observation on land before the age of the GPS. Chadwell et al. (2009, AGU Fall Meeting) made a step forward for this problem by carrying out a continuous GPS/A observation with a moored buoy. We are also developing a system using a moored small buoy. Precision of seafloor positioning by GPS/A is another critical problems. Considering that plate motions are several centimeters per year in most cases, precision of a few centimeters by GPS/A is a big difference from a few millimeters by GPS on land. We estimate that lateral variations in the sound velocity in the ocean can be a key to improve the precision in the positioning and to reduce the required time for the measurement, we have tried to estimate the lateral variations in the acoustic velocity by using 4-5 PXPs (Kido et al., 2006; Kido et al., this meeting). Long-term attitude stability of the position of a PXP deployed on thick sediment has been a basic problem in the GPS/A observation. While a pillar of a GPS antenna for an observation point is set up firmly on the ground, a PXP is deployed on the seafloor after a free fall from the sea surface. It is a serious problem to detect coseismic crustal movements on the seafloor. M7-class earthquakes occurred in 2004 off Kii Peninsula, Central Japan, gave us an opportunity to study the problem. By using an ROV (remotely operated vehicle), we visually observed ten PXPs in 2006, seven of which had been used to detect coseismic seafloor crustal movements of 20 cm or more as was reported by Kido et al. (2006) and by Tadokoro et al. (2006). The diving survey confirmed that all of the seven PXPs stood stably on the flat sediment, no effects of the earthquakes being recognized. Even if slight tilts of the PXPs were caused by the earthquakes, the effect on the seafloor positioning by GPS/A was estimated to be 1 cm or less (Fujimoto et al., in press). A PXP has been deployed for a permanent (actually several to 10 years) use. Therefore, it is not equipped with a recovery system as is used for an ocean bottom seismometers or pressure recorders. From our experience we have often wished to retrieve a PXP to revise its performance, to slightly change its position, or to reuse it after the battery is exhausted. We tried to use a long-life acoustic recovery system for three PXPs. We successfully recovered all of them 4.5 years after their deployment.

  6. In Proceedings 2010 Integrated Communications Navigation and Surveillance (ICNS) Conference, May 11-13, 2010 ANALYSIS OF PERFORMANCE OF Q ROUTES FOR ESTABLISHING

    E-print Network

    In Proceedings 2010 Integrated Communications Navigation and Surveillance (ICNS) Conference, May 11 Equipment (DME)/DME/IRU or /and Global Positioning System (GPS)/ Global Navigation Satellite Systems (GNSS 2010 Integrated Communications Navigation and Surveillance (ICNS) Conference, May 11-13, 2010

  7. Robust low-frequency spread-spectrum navigation system

    SciTech Connect

    Smith, Stephen F; Moore, James A

    2012-10-30

    Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.

  8. Robust low-frequency spread-spectrum navigation system

    SciTech Connect

    Smith, Stephen F.; Moore, James A.

    2009-12-01

    Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.

  9. Robust low-frequency spread-spectrum navigation system

    DOEpatents

    Smith, Stephen F. (Loudon, TN); Moore, James A. (Powell, TN)

    2012-01-03

    Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.

  10. Robust low-frequency spread-spectrum navigation system

    SciTech Connect

    Smith, Stephen F.; Moore, James A.

    2011-01-25

    Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.

  11. Fault detection and exclusion in multisensor navigation systems

    NASA Technical Reports Server (NTRS)

    Bernath, Gregory N.

    1995-01-01

    In order for a multisensor navigation system to meet integrity requirements, there must be a way of detecting erroneous measurements, using only data from those measurements. This can be accomplished using a parity space estimation algorithm. Erroneous measurements must then be removed from the position solution; the entire process is called fault detection and exclusion (FDE). A baseline FDE algorithm has been determined, and is capable of working in real time on present affordable hardware.

  12. Improved Modeling in a Matlab-Based Navigation System

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Bar-Itzhack, Itzhack; Harman, Rick; Larimore, Wallace E.

    1999-01-01

    An innovative approach to autonomous navigation is available for low earth orbit satellites. The system is developed in Matlab and utilizes an Extended Kalman Filter (EKF) to estimate the attitude and trajectory based on spacecraft magnetometer and gyro data. Preliminary tests of the system with real spacecraft data from the Rossi X-Ray Timing Explorer Satellite (RXTE) indicate the existence of unmodeled errors in the magnetometer data. Incorporating into the EKF a statistical model that describes the colored component of the effective measurement of the magnetic field vector could improve the accuracy of the trajectory and attitude estimates and also improve the convergence time. This model is identified as a first order Markov process. With the addition of the model, the EKF attempts to identify the non-white components of the noise allowing for more accurate estimation of the original state vector, i.e. the orbital elements and the attitude. Working in Matlab allows for easy incorporation of new models into the EKF and the resulting navigation system is generic and can easily be applied to future missions resulting in an alternative in onboard or ground-based navigation.

  13. DESIGN AND PERFORMANCE ANALYSIS OF A LOW-COST AIDED DEAD RECKONING NAVIGATION SYSTEM

    E-print Network

    Stanford University

    DESIGN AND PERFORMANCE ANALYSIS OF A LOW-COST AIDED DEAD RECKONING NAVIGATION SYSTEM D. Gebre navigation system based on the fusion of inexpensive inertial, air data and magnetic sensors aided by a skeletal network of radio-navigation aids. In the future National Airspace System of the United States

  14. A Navigation System for Robot Soccer Brett Browning, Gordon Wyeth and Ashley Tews

    E-print Network

    Browning, Brett

    A Navigation System for Robot Soccer Brett Browning, Gordon Wyeth and Ashley Tews Computer Science describes the navigation system used for the UQ RoboRoos robot soccer team, runner up in the 1998 world RoboCup championships. The navigation system has been developed to cope with the dynamic environment of robot soccer

  15. Sensitivity of Magnetospheric Multi-Scale (MMS) Mission Navigation Accuracy to Major Error Sources

    NASA Technical Reports Server (NTRS)

    Olson, Corwin; Long, Anne; Car[emter. Russell

    2011-01-01

    The Magnetospheric Multiscale (MMS) mission consists of four satellites flying in formation in highly elliptical orbits about the Earth, with a primary objective of studying magnetic reconnection. The baseline navigation concept is independent estimation of each spacecraft state using GPS pseudorange measurements referenced to an Ultra Stable Oscillator (USO) with accelerometer measurements included during maneuvers. MMS state estimation is performed onboard each spacecraft using the Goddard Enhanced Onboard Navigation System (GEONS), which is embedded in the Navigator GPS receiver. This paper describes the sensitivity of MMS navigation performance to two major error sources: USO clock errors and thrust acceleration knowledge errors.

  16. Multipath characteristics of GPS signals as determined from the Antenna and Multipath Calibration System

    NASA Astrophysics Data System (ADS)

    Park, K.-D.; Davis, J. L.; Jarlemark, P. O. J.; Elosegui, P.; Normandeau, J. E.; Corey, B. E.; Niell, A. E.; Meertens, C. E.; Andreatta, V. A.

    2002-09-01

    Geophysical applications of the Global Positioning System (GPS) for studies such as global sea level change and glacial isostatic adjustment require very high accuracy (1 mm?yr-1) determinations of site velocity, especially of its vertical component. Despite the many efforts devoted by investigators to the calibration of site-specific errors, signal scattering and multipath remain an unsolved problem. We have developed an Antenna and Multipath Calibration System (AMCS) for characterizing site-specific GPS phase measurement errors. The system consists of a high-gain, multipath-free, 3-m diameter parabolic antenna, a test antenna, and two Trimble GPS receivers. There are two modes of operating the AMCS: Zero-baseline (ZBL) and AMCS modes. In ZBL-mode, the two receivers simultaneously record the signal from the test GPS antenna. In this operating mode, one can determine the receiver clock synchronization error and the phase biases for each satellite. Typical RMS accuracies of ZBL-mode phase residuals are sub-millimeter level, ranging from 0.4 to 0.7 mm. In the AMCS-mode, one GPS receiver records the signal received at the test antenna, and the other records the signal from the parabola. Thus, one can compare the phases from the two receivers, and determine the antenna and multipath calibration errors of the test antenna. In our test cases with the test antenna located in a multipath-rich environment, the phase residuals obtained by tracking the same satellite over several days show large amplitude variations over small elevation angle ranges with highly repeatable patterns. The amplitude is 4-6 mm for low elevation angles and 1-2 mm for high elevation angles. Modeling and subtracting the repeating patterns from the phase residuals results in RMS of about 1 mm. We have recently installed a second GPS antenna at a nearby location where the multipath effects are presumably less significant than at the location of the first GPS antenna. To further reduce multipath effects, all-weather microwave absorbers surrounded the second antenna. The amplitude of the phase residuals obtained for the second antenna location is significantly smaller than for the first antenna, implying that the second antenna is less affected by multipath. These independent results also served to confirm that the origin of the phase patterns measured is multipath.

  17. Precursor systems analyses of automated highway systems. Carrier phase GPS for AHS vehicle control. Resource materials. Final report, September 1993-November 1994

    SciTech Connect

    Galijan, R.C.

    1996-01-01

    This report describs the results of a PSA contract awarded to SRI International to analyze applications of advanced Global Positioning System (GPS) measurement techniques to provide data for lateral and longitudinal control of AHS vehicles. The report includes: (1) a review of control sensor requirements suggested by other PSA contractors and AHS researchers; (2) an indepth discussion of GPS principles of operation, advanced techniques for achieving extremely accurate GPS positioning and velocity data, and techniques for augmenting GPS to provide continuous high-accuracy data; (3) current and expected GPS capabilities and performance; (4) a review of other proposed sensor types for providing lateral and longitudinal control data; (5) a description of a notional architecture and operation of an AHS incorporating GPS; and (6) a preliminary evaluation by SRI of GPS operation in a typical AHS roadway environment.

  18. A Simple Method to Improve Autonomous GPS Positioning for Tractors

    PubMed Central

    Gomez-Gil, Jaime; Alonso-Garcia, Sergio; Gómez-Gil, Francisco Javier; Stombaugh, Tim

    2011-01-01

    Error is always present in the GPS guidance of a tractor along a desired trajectory. One way to reduce GPS guidance error is by improving the tractor positioning. The most commonly used ways to do this are either by employing more precise GPS receivers and differential corrections or by employing GPS together with some other local positioning systems such as electronic compasses or Inertial Navigation Systems (INS). However, both are complex and expensive solutions. In contrast, this article presents a simple and low cost method to improve tractor positioning when only a GPS receiver is used as the positioning sensor. The method is based on placing the GPS receiver ahead of the tractor, and on applying kinematic laws of tractor movement, or a geometric approximation, to obtain the midpoint position and orientation of the tractor rear axle more precisely. This precision improvement is produced by the fusion of the GPS data with tractor kinematic control laws. Our results reveal that the proposed method effectively reduces the guidance GPS error along a straight trajectory. PMID:22163917

  19. A simple method to improve autonomous GPS positioning for tractors.

    PubMed

    Gomez-Gil, Jaime; Alonso-Garcia, Sergio; Gómez-Gil, Francisco Javier; Stombaugh, Tim

    2011-01-01

    Error is always present in the GPS guidance of a tractor along a desired trajectory. One way to reduce GPS guidance error is by improving the tractor positioning. The most commonly used ways to do this are either by employing more precise GPS receivers and differential corrections or by employing GPS together with some other local positioning systems such as electronic compasses or Inertial Navigation Systems (INS). However, both are complex and expensive solutions. In contrast, this article presents a simple and low cost method to improve tractor positioning when only a GPS receiver is used as the positioning sensor. The method is based on placing the GPS receiver ahead of the tractor, and on applying kinematic laws of tractor movement, or a geometric approximation, to obtain the midpoint position and orientation of the tractor rear axle more precisely. This precision improvement is produced by the fusion of the GPS data with tractor kinematic control laws. Our results reveal that the proposed method effectively reduces the guidance GPS error along a straight trajectory. PMID:22163917

  20. Implementation of a vector-based tracking loop receiver in a pseudolite navigation system.

    PubMed

    So, Hyoungmin; Lee, Taikjin; Jeon, Sanghoon; Kim, Chongwon; Kee, Changdon; Kim, Taehee; Lee, Sanguk

    2010-01-01

    We propose a vector tracking loop (VTL) algorithm for an asynchronous pseudolite navigation system. It was implemented in a software receiver and experiments in an indoor navigation system were conducted. Test results show that the VTL successfully tracks signals against the near-far problem, one of the major limitations in pseudolite navigation systems, and could improve positioning availability by extending pseudolite navigation coverage. PMID:22163552