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1

Autonomous navigation system based on GPS and magnetometer data  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

2

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Navigation Equipment Using the Global Positioning System (GPS) AGENCY: Federal...Navigation Equipment Using the Global Positioning System (GPS), and request for...Navigation Equipment Using the Global Positioning System (GPS). The effect...

2011-08-16

3

Investigation and evaluation of shuttle/GPS navigation system  

NASA Technical Reports Server (NTRS)

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.

Nilsen, P. W.

1977-01-01

4

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

5

Flight evaluation of differential GPS aided inertial navigation systems  

NASA Technical Reports Server (NTRS)

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.)

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

1992-01-01

6

OEM4 Inertial: A Tightly Integrated Decentralised Inertial\\/GPS Navigation System  

Microsoft Academic Search

The synergy between GPS and inertial navigation has been well known in the industry since the inception of GPS. In theory, the continuity of the inertial system can both fill in positioning gaps left by GPS satellite outages and reduce the effect of high frequency GPS errors, while the unbiased nature of the GPS signals can limit the size of

Tom Ford; Janet Neumann; Pat Fenton; Mike Bobye; Jason Hamilton

7

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Devices, Navigation and Display Systems, Radar Systems, Navigational Aids, Mapping Systems...devices, navigation and display systems, radar systems, navigational aids, mapping systems...devices, navigation and display systems, radar systems, navigational aids, mapping...

2013-11-15

8

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

PubMed Central

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

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

2013-01-01

9

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

PubMed

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

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

2013-01-01

10

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

NASA Technical Reports Server (NTRS)

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,

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

11

An integrated Relative Navigation system using GPS\\/VISNAV for ultra-close spacecraft formation flying  

Microsoft Academic Search

To improve the accuracy and better fault-tolerant performance for ultra-close spacecraft formation flying, a Global Position System (GPS)\\/Vision based Navigation (VISNAV) integrated Relative Navigation and Attitude Determination (RNAD) approach was presented in this paper. Onboard GPS was used for RNAD for formation spacecraft by multi-antennas configuration. The same RNAD information was also achieved by VISNAV system separately by using multiple

Junli Chen; Xiaoliang Wang; Xiaowei Shaotand; Dengping Duan

2010-01-01

12

FPGA-based real-time embedded system for RISS/GPS integrated navigation.  

PubMed

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

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

2012-01-01

13

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

14

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

NASA Technical Reports Server (NTRS)

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.

Truong, Son H.

1999-01-01

15

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

NASA Technical Reports Server (NTRS)

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.

Truong, S. H.

1999-01-01

16

A LOW-COST GPS AIDED INERTIAL NAVIGATION SYSTEM FOR VEHICLE APPLICATIONS  

Microsoft Academic Search

In this paper an approach for integration between GPS and inertial navigation systems (INS) is described. The continuous-time nav- igation and error equations for an earth-centered earth-fixed INS system are presented. Using zero order hold sampling, the set of equations is discretized. An extended Kalman filter for closed loop integration between the GPS and INS is derived. The filter propa-

Isaac Skog; Peter H

17

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

18

GPS navigation experiment using high precision GPS timing receivers  

NASA Technical Reports Server (NTRS)

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.

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

19

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)

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.

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

2005-10-01

20

Design and flight test of a differential GPS/inertial navigation system for approach/landing guidance  

NASA Technical Reports Server (NTRS)

NASA-Langley has conducted a flight test program evaluating a differential GPS/inertial navigation system's (DGPS/INS) utility as an approach/landing aid. The DGPS/INS airborne and ground components are based on off-the-shelf transport aircraft avionics, namely a global positioning/inertial reference unit (GPIRU) and two GPS sensor units (GPSSUs). Systematic GPS errors are measured by the ground GPSSU and transmitted to the aircraft GPIRU, allowing the errors to be eliminated or greatly reduced in the airborne equipment. Over 120 landings were flown; 36 of these were fully automatic DGPS/INS landings.

Vallot, Lawrence; Snyder, Scott; Schipper, Brian; Parker, Nigel; Spitzer, Cary

1991-01-01

21

High accuracy navigation and landing system using GPS\\/IMU system integration  

Microsoft Academic Search

In this paper, the accuracy, integrity and continuity of function requirements for automatic landing systems using satellite navigation systems are discussed. Such a landing system is the integrated navigation and landing system (INLS) developed by Deutsche Aerospace (DASA\\/Ulm, Germany). The system concepts of the INLS are presented. It is shown how an INLS, based on system integration of a satellite

J. Meyer-Hilberg; T. Jacob

1994-01-01

22

Geoid profile determination by direct integration of GPS inertial navigation system vector gravimetry  

NASA Astrophysics Data System (ADS)

Analogous to astrogeodetic methods, the geoid undulation may be determined along profiles by integrating the horizontal components of the gravity vector estimated by airborne GPS inertial navigation system. This has the advantage of obviating large regional surveys of the vertical gravity component that are required in the usual boundary value problem approach. Two data sets were tested, one over the Canadian Rocky Mountains and one over the North Atlantic Ocean. Comparisons with the Canadian geoid model and an Arctic geoid model, respectively, showed better than 10 cm (SD) agreement in the relative geoid, with resolution judged to be between 10 and 20 km. The geoid estimation was found to be sensitive to the curvature of the geopotential field in the mountainous region, and, in the ocean area, the estimates clearly revealed the difference between the geoid and the mean sea surface at this resolution and accuracy.

Jekeli, Christopher; Kwon, Jay H.

2002-10-01

23

Evaluating the velocity accuracy of an integrated GPS\\/INS system: Flight test results. [Global positioning system\\/inertial navigation systems (GPS\\/INS)  

Microsoft Academic Search

Verifying the velocity accuracy of a GPS receiver or an integrated GPS\\/INS system in a dynamic environment is a difficult proposition when many of the commonly used reference systems have velocity uncertainities of the same order of magnitude or greater than the GPS system. The results of flight tests aboard an aircraft in which multiple reference systems simultaneously collected data

T. E. Owen; R. Wardlaw

1991-01-01

24

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

NASA Technical Reports Server (NTRS)

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.

Devito, D. M.

1981-01-01

25

GPS Navigation for Outdoor and Indoor Environments  

E-print Network

of this would matter. #12;i ABSTRACT The Global Positioning System (GPS) is an accurate positioning system..................................................................................................... 1 2 GLOBAL POSITIONING SYSTEM OVERVIEW .............................................. 2 3 GPS

Abidi, Mongi A.

26

Low cost GPS\\/INS sensor fusion system for UAV navigation  

Microsoft Academic Search

The performance of UAV is dependent greatly upon onboard sensors due to its characteristics of unmanned operated vehicle. The navigation sensor, which informs where UAV is flying, also is one of those onboard sensors. Small UAV needs the navigation system with the compact, light, cheap and precise navigation solution. As the inertial sensor for precise air navigation is very expensive,

Chang-Sun Yoo; Iee-Ki Ahn

2003-01-01

27

Evaluation of the impact of ionospheric disturbances on air navigation augmentation system using multi-point GPS receivers  

NASA Astrophysics Data System (ADS)

In recent years, GPS has been utilized for navigation system for airplanes. Propagation delays in the ionosphere due to total electron content (TEC) between GPS satellite and receiver cause large positioning errors. In precision measurement using GPS, the ionospheric delay correction is generally conducted using both GPS L1 and L2 frequencies. However, L2 frequency is not internationally accepted as air navigation band, so it is not available for positioning directly in air navigation. In air navigation, not only positioning accuracy but safety is important, so augmentation systems are required to ensure the safety. Augmentation systems such as the satellite-based augmentation system (SBAS) or the ground-based augmentation system (GBAS) are being developed and some of them are already in operation. GBAS is available in a relatively narrow area around airports. In general, it corrects for the combined effects of multiple sources of positioning errors simultaneously, including satellite clock and orbital information errors, ionospheric delay errors, and tropospheric delay errors, using the differential corrections broadcast by GBAS ground station. However, if the spatial ionospheric delay gradient exists in the area, correction errors remain even after correction by GBAS. It must be a threat to GBAS. In this study, we use the GPS data provided by the Geographical Survey Institute in Japan. From the GPS data, TEC is obtained every 30 seconds. We select 4 observation points from 24.4 to 35.6 degrees north latitude in Japan, and analyze TEC data of these points from 2001 to 2011. Then we reveal dependences of Rate of TEC change Index (ROTI) on latitude, season, and solar activity statistically. ROTI is the root-mean-square deviation of time subtraction of TEC within 5 minutes. In the result, it is the midnight of the spring and the summer of the solar maximum in the point of 26.4 degrees north latitude that the value of ROTI becomes the largest. We think it is caused by plasma bubbles, and the maximum value of ROTI is about 6 TECU/min. Since it is thought that ROTI is an index representing the spatial ionospheric delay gradient, we can evaluate the effect of spatial ionospheric delay gradient to GBAS. In addition, we will discuss azimuth angle dependence of ROTI. We have found that ROTI tends to be high when the GPS satellites are seen westward. Initial analysis results in Indonesia show a similar feature. This feature could arise from the westward tilt of the plasma bubbles with altitude. More detailed results will be reported in this presentation.

Omatsu, N.; Otsuka, Y.; Shiokawa, K.; Saito, S.

2013-12-01

28

Multiple mobile robot navigation using the indoor global positioning system (iGPS)  

Microsoft Academic Search

We propose a practical method of multiple mobile robot navigation aimed at the realization of service robots that deliver letters, parcels and documents in an office building. For robust execution of delivery tasks by mobile robots, navigation is important, and localization of robots is a key function for designing robust navigation. We developed a global positioning system for indoor mobile

Yoshiro HADA; Kunikatsu TAKASE

2001-01-01

29

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

E-print Network

Abstract--There is an increasing demand for use of the Global Positioning System (GPS) to navigate--Forest, Global Positioning System, Image processing, Otsu' algorithm I. INTRODUCTION here is an increasing demand for use of the Global Positioning System (GPS) in the forest environment. For example, tree harvesters

Washington at Seattle, University of

30

NAVIGATION PERFORMANCE IN HIGH EARTH ORBITS USING NAVIGATOR GPS RECEIVER  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

31

DARPA looks beyond GPS for positioning, navigating, and timing  

SciTech Connect

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.

Kramer, David

2014-10-01

32

Method and apparatus for relative navigation using reflected GPS signals  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

33

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

SciTech Connect

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.

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

1999-06-24

34

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

PubMed

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

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

2015-01-01

35

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

PubMed Central

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

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

2015-01-01

36

Autonomous GPS/INS navigation experiment for Space Transfer Vehicle  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

37

High Sensitivity GPS Velocity Updates For Personal Indoor Navigation Using Inertial  

E-print Network

High Sensitivity GPS Velocity Updates For Personal Indoor Navigation Using Inertial Navigation been working in the area of satellite and inertial navigation since receiving his BSc from the same extensively on the integration of GPS and inertial navigation systems for precise aircraft positioning. Dr

Calgary, University of

38

Satellite Navigation Systems  

NSDL National Science Digital Library

The Global Positioning System (GPS) has been in operation for several years, and its use is continually rising. GPS is the main satellite navigation system developed by the United States. There are countless applications of this technology, and numerous international efforts are currently underway.The Topcon Positioning Systems company provides an excellent introduction to GPS technology in its online book (1). The first couple chapters describe the evolution of GPS and its fundamentals, and the remaining material focuses on some specific issues. A more advanced tutorial is given through the IBM Web site (2). A brief, free registration is required to view it, and some familiarity with Java is recommended. The European Space Agency provides this page about satellite navigation (3), which describes, among other things, Galileo. This is not the astronomer; Galileo is Europe's version of GPS, scheduled for completion in 2008. Another system, developed by Russia, is detailed on the Space and Technology Web site (4). The short summary describes the 20-year history of the Global Navigation Satellite System (GLONASS), as well as upgrades that are in progress. Differential GPS, a service that is more accurate than standard GPS in areas with poor coverage, is operated by the US Coast Guard Navigation Center (5). Some information about the status of nationwide DGPS expansion is given. Several research and development projects, technology highlights, and GPS implementations are covered on the UNAVCO home page (6). The facility primarily fosters work to expand the applications of satellite navigation. With the wave of kidnapping cases reported across the country, a novel use of GPS is being marketed to keep track of children (7). These portable devices can be worn on the wrist, like a watch, so parents can always know where their kids are. Another news story describes the use of GPS in mining operations (8). The technology allows operators of huge three-story dump trucks to detect obstacles and maneuver the vehicle with only limited visibility.

Leske, Cavin.

2002-01-01

39

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

40

A GPS sonobuoy localization system  

Microsoft Academic Search

A GPS localization system is described that uses the precision navigation signal but does not require a SAASM decoding unit in the sonobuoy. The system operates by retransmitting a selected 1 MHz portion of the GPS L1 or L2 signal spectrum from the sonobuoy to a Master Control Station (MCS). By offsetting the selected spectrum about 2 MHz from the

Harper J. Whitehouse; J. M. Alsup; A. Leese de Escobar; Shelby F. Sullivan

2004-01-01

41

A GPS/Shuttle orbital navigation experiment  

NASA Astrophysics Data System (ADS)

A proposal is made to fly a Texas Instruments GPS geodetic receiver (GEOSTAR) on the Space Shuttle to evaluate its ability to perform autonomous orbit determination. GEOSTAR receiver and recorder units would be flown in the Shuttle's middeck for the purposes of computing real-time solutions and recording tracking data for post-flight analysis. Feasibility study results are presented which show that the GEOSTAR should be able to withstand flight induced loads, and to acquire and track GPS satellites in an orbital dynamic environment. Real-time navigation accuracies from 20 m to 400 m are anticipated.

Peters, G.

1984-08-01

42

GPS - Global Positioning System. Theory and practice  

Microsoft Academic Search

This book shows in comprehensive manner how the Global Positioning System (GPS) works. The use of GPS for precise measurements (i.e. surveying) is treated as well as navigation and attitude determination. The basic mathematical models for various modes of GPS operations and detailed explanation of the practical use of GPS are developed precisely in this book. Additionally, the text shows

B. Hofmann-Wellenhof; H. Lichtenegger; J. Collins

1997-01-01

43

GPS compound eye attitude and navigation sensor and method  

NASA Technical Reports Server (NTRS)

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.

Quinn, David A. (Inventor)

2003-01-01

44

GPS Auto-Navigation Design for Unmanned Air Vehicles  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

45

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

E-print Network

(inertial, air- data and magnetometers) is shown to provide an af- fordable area navigation capability-DME infrastructure is around $84 Million 3]. Eliminating or reducing the num- ber of active ground based navigaitonal

Stanford University

46

Satellite systems for maritime navigation  

NASA Astrophysics Data System (ADS)

The principles underlying the design of Doppler satellite navigation systems are examined, and the characteristics of existing and proposed satellite systems for maritime navigation are described. Particular attention is given to the COSPAS-SARSAT system, GPS/Navstar, and the Navsat, Granas, and Geostar projects. The features of shipboard navigation instruments are examined.

Bogdanov, Valerii Anatol'evich; Sorochinskii, Valentin Alekseevich; Iakshevich, Evgenii Viktorovich

47

GPS Navigation for the Magnetospheric Multi-Scale Mission  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

48

A Leapfrog Navigation System  

NASA Astrophysics Data System (ADS)

There are times 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 altogether. The goal of the Leapfrog Navigation System (LNS) is to provide localized positioning services for such cases. The concept behind leapfrog navigation is to advance a group of navigation units teamwise into an area of interest. In a practical 2-D case, leapfrogging assumes known initial positions of at least two currently stationary navigation units. Two or more mobile units can then start to advance into the area of interest. The positions of the mobiles are constantly being calculated based on cross-range distance measurements to the stationary units, as well as cross-ranges among the mobiles themselves. At some point the mobile units stop, and the stationary units are released to move. This second team of units (now mobile) can then overtake the first team (now stationary) and travel even further towards the common goal of the group. Since there always is one stationary team, the position of any unit can be referenced back to the initial positions. Thus, LNS provides absolute positioning. I developed navigation algorithms needed to solve leapfrog positions based on cross-range measurements. I used statistical tools to predict how position errors would grow as a function of navigation unit geometry, cross-range measurement accuracy and previous position errors. Using this knowledge I predicted that a 4-unit Leapfrog Navigation System using 100 m baselines and 200 m leap distances could travel almost 15 km before accumulating absolute position errors of 10 m (1sigma). Finally, I built a prototype leapfrog navigation system using 4 GPS transceiver ranging units. I placed the 4 units in the vertices a 10m x 10m square, and leapfrogged the group 20 meters forwards, and then back again (40 m total travel). Average horizontal RMS position errors never exceeded 16 cm during these field tests.

Opshaug, Guttorm Ringstad

49

Fault tolerant GPS\\/Inertial System design  

Microsoft Academic Search

The use of a GPS\\/Inertial integrated system in future launch vehicles motivates the described design of the present fault-tolerant system. The robustness of the navigation system is enhanced by integrating the GPS with an inertial fault-tolerant system. Three layers of failure detection and isolation are incorporated to determine the nature of flaws in the inertial instruments, the GPS receivers, or

Alison K. Brown; Mark A. Sturza; Franco Deangelis; David A. Lukaszewski

1990-01-01

50

Passive GPS-Free Navigation for Small UAVs Jack Langelaan  

E-print Network

-free navigation of a small Unmanned Aerial Vehicle with a minimal sensor suite (limited to an inertial measurement objects on the ground we can obtain a navigation solution. Fusing inertial measurements with bearingsPassive GPS-Free Navigation for Small UAVs Jack Langelaan Steve Rock Department of Aeronautics

Langelaan, Jack W.

51

Sensor data fusion for inertial navigation of trains in GPS-dark areas  

Microsoft Academic Search

The motivation of the presented work is to develop a robust navigation system for accurate localization of trains on railway tracks in the cases where the GPS-based navigation is not temporally available. As the final solution of the train locator naturally takes into consideration the satellite-based navigation, the satellite signal needs not to be available all along the railway. The

R. Mazl; L. Preucil

2003-01-01

52

Global Positioning System Tutorial: All About GPS  

NSDL National Science Digital Library

The Global Positioning System (GPS) is a very popular and useful tool, whether you're navigating on a long hike or just driving through an unfamiliar town. A good tutorial that introduces the basics of the technology is found on the Web site of a leading GPS company, Trimble. It starts by describing the underlying concepts of GPS and how it compares to other positioning systems. Then, the principle of satellite triangulation is explained with as little technical jargon as possible. A large section of the tutorial covers differential GPS, a developing technology with profound implications. Lastly, some applications that use GPS are mentioned, and a glossary clarifies a few special terms.

2007-03-06

53

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

is on the integration of GPS with medium accuracy inertial navigation systems. Dr. M. Elizabeth Cannon is Professor as the integration of GPS with inertial navigation systems for wide variety of applications. She is a Past President of the Institute of Navigation. ABSTRACT The combination of the Global Positioning System (GPS) and an Inertial

Calgary, University of

54

Navigation Overview Types of Navigation  

E-print Network

Navigation ­ Inertial Navigation System (INS) · Satellite Navigation Systems ­ Global Positioning System (GPS latitude, longitude, groundpseed, ..." · Accelerometers exhibit drift over time ­ Global Positioning System

55

Navigation in GPS Challenged Environments Based Upon Ranging Imagery  

NASA Astrophysics Data System (ADS)

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.

Markiel, J. N. Nikki

56

Inertial navigation aided with GPS information  

Microsoft Academic Search

This paper presents a dynamic alignment algorithm for a six-degree of freedom inertial unit. A differential GPS is used as external sensor. It provides decorrelated range position and Doppler velocity information. A simplified error model valid for a local area is also presented. An indirect Kalman filter approach is used to fuse high frequency inertial information with low frequency GPS

E. Nebot; S. Sukkarieh; H. Durrant-Whyte

1997-01-01

57

A LEO Satellite Navigation Algorithm Based on GPS and Magnetometer Data  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

58

A Leo Satellite Navigation Algorithm Based on GPS and Magnetometer Data  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

59

Perspective\\/navigation-The Global Positioning System  

Microsoft Academic Search

A brief history of navigation is given, highlighting the needs that led ultimately to the development of 3-D satellite based navigation. The evolution of Navstar, commonly known as GPS (Global Positioning System), is traced from its initial conception in 1960. The use of bandwidth compression to overcome the SNR problem is discussed. An explanation of how the GPS works is

1993-01-01

60

A LEAPFROG NAVIGATION SYSTEM A DISSERTATION  

E-print Network

and places where conventional navigation systems, such as the Global Positioning System (GPS altogether. The goal of the Leapfrog Navigation System (LNS) is to provide localized positioning servicesA LEAPFROG NAVIGATION SYSTEM A DISSERTATION SUBMITTED TO THE DEPARTMENT OF AERONAUTICS

Stanford University

61

GPS system simulation methodology  

NASA Technical Reports Server (NTRS)

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.

Ewing, Thomas F.

1993-01-01

62

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

E-print Network

1 Abstract--There is an increasing demand for use of the Global Positioning System (GPS--Forest, Global Positioning System, Image processing, Otsu' algorithm I. INTRODUCTION here is an increasing demand for use of the Global Positioning System (GPS) in the forest environment. For example, tree harvesters

Wang, Yinhai

63

GPS Navigation Results from the Low Power Transceiver CANDOS Experiment on STS-107  

NASA Technical Reports Server (NTRS)

This paper presents the Global Positioning System (GPS) navigation results from the Communications and Savigation Demonstration on Shuttle (CANDOS) experiment flown on STS- 107. The CAkDOS experiment consisted of the Low Power Transceiver (LPT) that hosted the GPS Enhanced Orbit Determination Experiment (GEODE) orbit determination software. All CANDOS test data were recovered during the mission using the LPT's Tracking and Data Relay Satellite System (TDRSS) uplinh'downlink communications capabilit! . An overview of the LPT's navigation software and the GPS experiment timeline is presented. In addition. this paper discusses GEODE performance results. including comparisons ibith the Best Estimate of Trajectory (BET). N.ASA Johnson Space Center (JSC) real-time ground navigation vectors. and post-processed solutions using the Goddard Trajectory Determination System (GTDS).

Haas, Lin; Massey, Chris; Baraban, Dmitri; Kelbel, David; Lee, Taesul; Long, Anne; Carpenter, J. Russell

2003-01-01

64

GPS World, Innovation: Autonomous Navigation at High Earth Orbits  

NASA Technical Reports Server (NTRS)

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.

Bamford, William; Winternitz, Luke; Hay, Curtis

2005-01-01

65

High integrity GPS/INS filter for precise relative navigation  

NASA Astrophysics Data System (ADS)

A GPS/INS filter design for absolute and relative state estimation is discussed. The GPS code and Doppler measurements are used for absolute state estimation while the GPS carrier phase and Doppler measurements are used for relative state estimation. Real-time results obtained from a Hardware-in-the-Loop Simulation and actual F-18 flight tests are presented. To ensure accurate state estimation, the observability of the GPS/INS system is analyzed analytically when the system is at rest and during maneuvers. The system observability enhancement during two different maneuvers is discussed. Simulation results illustrating the observability of the system during the different stages of the GPS/INS system operation are also presented. To allow successful use of the high-accuracy carrier phase measurements, two methods for resolving GPS integer ambiguity are introduced. The first combines an efficient method for obtaining the admissible integer ambiguity hypotheses within a probabilistic volume with an integer hypothesis testing method to reduce the convergence time with high probability to the GPS carrier phase integers. The second GPS integer ambiguity resolution method is based on a log-formulation of the Multiple Hypothesis Wald Sequential Probability Test (MHWSPT). The computational time requirement of the latter method is shown to be smaller than the former method. Real-time results are presented to show the performance of the two methods introduced.

Abdel-Hafez, Mamoun F.

66

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

E-print Network

Using GPS and GPS/INS Systems to Assess Relative Antenna Motion Onboard an Aircraft Carrier navigation systems for precise aircraft positioning. Dr. Cannon is a Past President of the ION. ABSTRACT provide auto-landing capability for an inbound aircraft. An inherent requirement therefore is to know

Calgary, University of

67

Multi-Flight-Phase GPS Navigation Filter Applications to Terrestrial Vehicle Navigation and Positioning  

NASA Technical Reports Server (NTRS)

A candidate onboard space navigation filter demonstrated excellent performance (less than 8 meter level RMS semi-major axis accuracy) in performing orbit determination of a low-Earth orbit Explorer satellite using single-frequency real GPS data. This performance is significantly better than predicted by other simulation studies using dual-frequency GPS data. The study results revealed the significance of two new modeling approaches evaluated in the work. One approach introduces a single-frequency ionospheric correction through pseudo-range and phase range averaging implementation. The other approach demonstrates a precise axis-dependent characterization of dynamic sample space uncertainty to compute a more accurate Kalman filter gain. Additionally, this navigation filter demonstrates a flexibility to accommodate both perturbational dynamic and observational biases required for multi-flight phase and inhomogeneous application environments. This paper reviews the potential application of these methods and the filter structure to terrestrial vehicle and positioning applications. Both the single-frequency ionospheric correction method and the axis-dependent state noise modeling approach offer valuable contributions in cost and accuracy improvements for terrestrial GPS receivers. With a modular design approach to either 'plug-in' or 'unplug' various force models, this multi-flight phase navigation filter design structure also provides a versatile GPS navigation software engine for both atmospheric and exo-atmospheric navigation or positioning use, thereby streamlining the flight phase or application-dependent software requirements. Thus, a standardized GPS navigation software engine that can reduce the development and maintenance cost of commercial GPS receivers is now possible.

Park, Young W.; Montez, Moises N.

1994-01-01

68

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

E-print Network

evaluates the performance of a shoe/foot mounted inertial system for pedestrian navigation application. Two a six degree-of- freedom (DOF) navigation solution. Such a system is referred to as an Inertial Navigation in a Signal Degraded Environment S. Godha, G. Lachapelle, and M. E. Cannon Positioning Location

Calgary, University of

69

Robust Real-Time Wide-Area Differential GPS Navigation  

NASA Technical Reports Server (NTRS)

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.

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

70

Networked differential GPS system  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

71

Differential GPS/inertial navigation approach/landing flight test results  

NASA Technical Reports Server (NTRS)

In November of 1990 a joint Honeywell/NASA-Langley differential GPS/inertial flight test was conducted at Wallops Island, Virginia. The test objective was to acquire a system performance database and demonstrate automatic landing using an integrated differential GPS/INS (Global Positioning System/inertial navigation system) with barometric and radar altimeters. The flight test effort exceeded program objectives with over 120 landings, 36 of which were fully automatic differential GPS/inertial landings. Flight test results obtained from post-flight data analysis are discussed. These results include characteristics of differential GPS/inertial error, using the Wallops Island Laser Tracker as a reference. Data on the magnitude of the differential corrections and vertical channel performance with and without radar altimeter augmentation are provided.

Snyder, Scott; Schipper, Brian; Vallot, Larry; Parker, Nigel; Spitzer, Cary

1992-01-01

72

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

E-print Network

knowledge of the vehicle location is required, this algorithm presents a powerful navigation augmentation in information form (negative log-likelihood) for communication. Experimental results are provided using computer Systems (TANS) as an alternative to relieve the dependency on GPS is an active area [5]-[8]. This type

Kim, Jonghyuk "Jon"

73

Global Navigation Satellite Systems (GNSSs) for Monitoring Long Suspension Bridges  

E-print Network

, Nanjing, China 1 A Brief Introduction to the Global Positioning System 1 2 GPS for Structural Health 16 1 A BRIEF INTRODUCTION TO THE GLOBAL POSITIONING SYSTEM 1.1 GPS constellation The full term of the well-known acronym GPS is NAVSTAR global positioning system, where NAVSTAR stands for NAVigation System

Santerre, Rock

74

SPACECRAFT NAVIGATION USING THE MODERNIZED GLOBAL POSITIONING SYSTEM SIGNAL  

E-print Network

SPACECRAFT NAVIGATION USING THE MODERNIZED GLOBAL POSITIONING SYSTEM SIGNAL E. G. Lightsey and R. B The utility of the Global Positioning System (GPS) for spacecraft navigation and timing has been widely

Lightsey, Glenn

75

Flight Test of Attitude Determination System using Multiple GPS Antennae  

Microsoft Academic Search

Small Unmanned Aerial Vehicles (UAVs) or inexpensive airplanes, such as a Cessna single engine aircraft, require a navigation system with a cheap, compact and precise sensor. Over the past ten years, GPS receivers have begun to be used as primary or alternative navigation sensors, because their use can significantly reduce the overall system cost. This paper describes a navigation system

Jaegyu Jang; Changdon Kee

2006-01-01

76

A LEO Satellite Navigation Algorithm Based on GPS and Magnetometer Data  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

77

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

78

Vertical Component of Satellite Navigation Systems  

NASA Astrophysics Data System (ADS)

The altitude is one of four coordinates of the user's position obtained from Satellite Navigation System (SNS) measurements. The distributions (in per cent) of VDOP coefficient value for different constellations of three SNS - GPS, GLONASS and Galileo - for different masking elevation angles for different user's latitudes are presented in the paper. The results of the measurements of GPS position and vertical accuracy in mode "3D" and position accuracy in mode "2D" for different GPS receivers and different receiver's antenna heights are demonstrated also. Additionally the use of vertical component of SNS in maritime navigation like the determination highly accurate sea-floor depths is presented.

Januszewski, Jacek

2010-01-01

79

GPSIM: A Personal Computer-Based GPS Simulator System  

NASA Astrophysics Data System (ADS)

Global Positioning Systems (GPS) are now in use in many applications, ranging from GIS to route guidance, automatic vehicle location (AVL), air, land, and marine navigation, and many other transportation and geographical based applications. In many applications, the GPS receiver is connected to some form of intelligent electronic system which receives the positional data from the GPS unit and then performs the required operation. When developing and testing GPS-based systems, one of the problems is that it is usually necessary to create GPS-compatible geographical data to simulate a GPS operation in real time. This paper provides the details of a Personal Computer (PC)-based GPS simulator system called GPSIM. The system receives user way-points and routes from Windows-based screen forms and then simulates a GPS operation in real time by generating most of the commonly used GPS sentences. The user-specified waypoints are divided into a number of small segments, each segment specifying a small distance in the direction of the original waypoint. The GPS sentence corresponding to the geographical coordinates of each segment is then sent out of the PC serial port. The system described is an invaluable testing tool for GPS-based system developers and also for people training to learn to use GPS-based products.

Ibrahim, D.

80

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

NASA Technical Reports Server (NTRS)

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.

Hodge, W. F.

1980-01-01

81

Embedded Low Cost Inertial Navigation System 1  

Microsoft Academic Search

This paper will discuss the design and implementation of an embedded low cost inertial navigation system (INS) using an inertial measurement unit (IMU), digital compass, GPS, and an embedded computer system. The INS is capable of providing continuous estimates of a vehicle's position and orientation. Typically IMU's are very expensive systems, however this INS will use \\

Kevin J. Walchko; Michael C. Nechyba; Eric Schwartz; Antonio Arroyo

82

Testing the Preliminary X-33 Navigation System  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

83

Application of aircraft navigation sensors to enhanced vision systems  

NASA Technical Reports Server (NTRS)

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.

Sweet, Barbara T.

1993-01-01

84

An Inertial Navigation System for Small Autonomous Underwater Vehicles  

Microsoft Academic Search

A small AUV navigation system (SANS) has been developed at the Naval Postgraduate School. The SANS is an integrated GPS\\/INS navigation system composed of low-cost, small-size components. It is designed to demonstrate the feasibility of using a low-cost inertial measurement unit to navigate between intermittent GPS fixes. This paper reports recent improvements to the SANS hardware, latest testing results after

Xiaoping Yun; Eric R. Bachmann; Suat Arslan

2000-01-01

85

Institute of Navigation National Technical Meeting/Anaheim, CA/January 26-28,2000 1 LOW COST INS/GPS INTEGRATION  

E-print Network

, and has worked extensively on the integration of GPS and inertial navigation systems for precise aircraft of inertial units is the main obstacle for their inclusion in precision navigation systems to support a variety of application areas. Standard inertial navigation systems (INS) use precise gyro

Calgary, University of

86

Regional Navigation System Using Geosynchronous Satellites and Stratospheric Airships  

E-print Network

he or she is at. Now the Global Positioning System (GPS) provides the ultimate solution is possible. Because there already exists a fully functional global positioning system (i.e., GPS), we propose navigation using just this augmented system without the aid of the existing global positioning system

Won, Chang-Hee

87

Conceptual deliberations on the global use of satellite navigation systems  

NASA Astrophysics Data System (ADS)

The increase in demand for navigation services worldwide is reviewed, and the use of satellite navigation systems to help satisfy navigation-related needs is discussed. The applications and availabiilty of GPS are addressed, and the roles of the FAA National Airspace System, Glonass, Inmarsat, Geostar/Locstar are described.

Hartl, Ph.

88

Inertial navigation systems analysis.  

NASA Technical Reports Server (NTRS)

This volume offers the avionic systems engineer a fundamental exposition of the mechanization and error analysis of inertial navigation systems. While the material is applicable to spacecraft and undersea navigation, emphasis is placed upon terrestrial applications on or slightly above the earth's surface. As a result, practical considerations are geared toward those aircraft navigation systems of particular current interest. Extensive use is made of perturbation techniques to develop linearized system equations, whose solutions closely approximate those obtained by nonlinear differential equations. A unified error analysis technique is developed that is applicable to virtually all system configurations. The technique provides a greatly simplified method for comparing the performance of competing system configurations.

Britting, K. R.

1971-01-01

89

A derivative UKF for tightly coupled INS/GPS integrated navigation.  

PubMed

The tightly coupled INS/GPS integration introduces nonlinearity to the measurement equation of the Kalman filter due to the use of raw GPS pseudorange measurements. The extended Kalman filter (EKF) is a typical method to address the nonlinearity by linearizing the pseudorange measurements. However, the linearization may cause large modeling error or even degraded navigation solution. To solve this problem, this paper constructs a nonlinear measurement equation by including the second-order term in the Taylor series of the pseudorange measurements. Nevertheless, when using the unscented Kalman filter (UKF) to the INS/GPS integration for navigation estimation, it causes a great amount of redundant computation in the prediction process due to the linear feature of system state equation, especially for the case with system state vector in much higher dimension than measurement vector. To overcome this drawback in computational burden, this paper further develops a derivative UKF based on the constructed nonlinear measurement equation. The derivative UKF adopts the concise form of the original Kalman filter (KF) to the prediction process and employs the unscented transformation technique to the update process. Theoretical analysis and simulation results demonstrate that the derivative UKF can achieve higher accuracy with a much smaller computational cost in comparison with the traditional UKF. PMID:25467307

Hu, Gaoge; Gao, Shesheng; Zhong, Yongmin

2014-11-10

90

Indoor Navigation System for Mobile Robot using Wireless Sensor Network  

Microsoft Academic Search

We describe an algorithm for indoor mobile robot navigation using wireless sensor network. In our navigation system, a robot can navigate autonomously without the need for a map, a compass, or GPS. We use only several sensor nodes with ultrasonic sensors. Sensor nodes are deployed in an indoor environment and each sensor node has routing paths to all available destination-nodes

Wooyong Lee; Minkyu Kim; Wonhee Yee; Dooseop Eom

91

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

PubMed Central

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 410 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

Islam, Md. Rashedul; Kim, Jong-Myon

2014-01-01

92

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

PubMed

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

Islam, Md Rashedul; Kim, Jong-Myon

2014-01-01

93

gpsTunes controlling navigation via audio feedback Steven Strachan1  

E-print Network

Global Positioning System (GPS) with that of an MP3 player, implemented on a PocketPC, to produce example of a pocket-sized location aware system, based on GPS (Global Positioning System) signals, which

Murray-Smith, Roderick

94

Alternatives to GPS  

Microsoft Academic Search

The U.S. Navy is currently pursuing several approaches to improving the reliability of precision navigation systems, including those that would still permit precision navigation in the event that the Global Positioning System (GPS) is denied or unavailable. This paper examines two alternatives to GPS: bathymetric and celestial navigation. Bathymetric navigation, a non-deniable source of position, determines a position by correlating

F. Pappalardi; S. J. Dunham; M. E. LeBlang; T. E. Jones; J. Bangert; G. Kaplan

2001-01-01

95

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

NASA Astrophysics Data System (ADS)

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.

Celik, Koray

96

Digital image georeferencing from a multiple camera system by GPS\\/INS  

Microsoft Academic Search

In this paper, the development and testing of an airborne fully digital multi-sensor system for digital mapping data acquisition is presented. The system acquires two streams of data, namely, navigation (georeferencing) data and imaging data. The navigation data are obtained by integrating an accurate strapdown inertial navigation system with a differential GPS system (DGPS). The imaging data are acquired by

Mohamed M. R. Mostafa; Klaus-Peter Schwarz

2001-01-01

97

Use of a Reduced IMU to Aid a GPS Receiver with Adaptive Tracking Loops for Land Vehicle Navigation  

E-print Network

/IMU integration; Reduced IMU; Inertial-aided GPS receiver; Adaptive loop filter; Land vehicle navigation Introduction In land vehicle navigation (LVN) applications, reduced inertial measurement units (IMU) canUse of a Reduced IMU to Aid a GPS Receiver with Adaptive Tracking Loops for Land Vehicle Navigation

Calgary, University of

98

Shuttle Global Positioning (GPS) System design study  

NASA Technical Reports Server (NTRS)

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.

Nilsen, P.; Huth, G. K.

1980-01-01

99

Integrated GPS and dead reckoning for low-cost vehicle navigation and tracking  

Microsoft Academic Search

GPS (global positioning system) for the private car, which spends most of its time in cities, requires augmentation by dead reckoning (DR) sensors. Comparative results are given for GPS alone, loosely coupled with DR, and tightly coupled, based on tests in Paris and England. An implementation is described where GPS, DR, route planning algorithms and map display can all run

P. G. Mattos

1994-01-01

100

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

SciTech Connect

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.

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

1997-03-01

101

Accuracy analysis of strapdown inertial navigation systems  

NASA Astrophysics Data System (ADS)

This paper discusses correction methods of INS/GPS systems. Different schemes are considered: open loop correction scheme, scheme with estimated instrumental errors feedback, scheme with state space feedback and scheme with navigation parameter errors feedback INS correction is considered as the process of control on the base of combined method. Nonlinear equations of INS angular errors in quaternion form are obtained. Nonliear and linear equations of navigation and orientation parameters errors are presented. Observability and detectability of linear equations of INS errors at different component combination of error vector are evaluated. Precision analysis of instrumental errors compensation is carried out. The results of testing INS/GPS systems on laboratory bench and car are presented.

Kortunov, V.; Dybska, I.; Proskura, G.; Trachsel, T.

102

Cloud Absorption Radiometer Autonomous Navigation System - CANS  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

103

A simple visual navigation system for an UAV  

Microsoft Academic Search

We present a simple and robust monocular camera-based navigation system for an autonomous quadcopter. The method does not require any additional infrastructure like radio beacons, artificial landmarks or GPS and can be easily combined with other navigation methods and algorithms. Its computational complexity is independent of the environment size and it works even when sensing only one landmark at a

Tomas Krajnik; Matias Nitsche; Sol Pedre; Libor Preucil; Marta E. Mejail

2012-01-01

104

IMU/GPS System Provides Position and Attitude Data  

NASA Technical Reports Server (NTRS)

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.

Lin, Ching Fang

2006-01-01

105

Geostar - Navigation location system  

NASA Astrophysics Data System (ADS)

The author describes the Radiodetermination Satellite Service (RDSS). The initial phase of the RDSS provides for a unique service enabling central offices and headquarters to obtain position-location information and receive short digital messages from mobile user terminals throughout the contiguous United States, southern Canada, and northern Mexico. The system employs a spread-spectrum, CDMA modulation technique allowing multiple customers to use the system simultaneously, without preassigned coordination with fellow users. Position location is currently determined by employing an existing radio determination receiver, such as Loran-C, GPS, or Transit, in the mobile user terminal. In the early 1990s position location will be determined at a central earth station by time-differential ranging of the user terminals via two or more geostationary satellites. A brief overview of the RDSS system architecture is presented with emphasis on the user terminal and its diverse applications.

Keyser, Donald A.

106

Assessing the Security of a Navigation System: A Case Study using Enhanced Loran  

E-print Network

the Global Positioning System (GPS) in the event of an outage or disruption in service [2]." Europe has also Positioning System (GPS) Laboratory. He is the Associate Investigator for the Stanford University efforts Laboratory and the Center for Position, Navigation and Time. 1.0 INTRODUCTION Global Navigation Satellite

Stanford University

107

A new multi-position calibration method for MEMS inertial navigation systems  

Microsoft Academic Search

The Global Positioning System (GPS) is a worldwide navigation system that requires a clear line of sight to the orbiting satellites. For land vehicle navigation, a clear line of sight cannot be maintained all the time as the vehicle can travel through tunnels, under bridges, forest canopies or within urban canyons. In such situations, the augmentation of GPS with other

Z F Syed; P Aggarwal; C Goodall; X Niu; N El-Sheimy

2007-01-01

108

76 FR 63714 - Technical Standard Order (TSO)-C129a, Airborne Supplemental Navigation Equipment Using the Global...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Navigation Equipment Using the Global Positioning System (GPS) AGENCY: Federal...Navigation Equipment Using the Global Positioning System (GPS...Navigation Equipment Using the Global Positioning System (GPS) effective...

2011-10-13

109

Extended Kalman filter synthesis for integrated global positioning\\/inertial navigation systems  

Microsoft Academic Search

The integrated global position system (GPS)\\/inertial navigation system (INS) is a cost-effective way of providing an accurate and reliable navigation system for civil and military aviation. These systems also provide low cost solutions to mid-course navigation and guidance of medium- and long-range weapon systems. In this paper, an error model developed earlier is used for GPS\\/INS filter mechanization (F.A. Faruqi,

Farhan A. Faruqi; Kenneth J. Turner

2000-01-01

110

Pulsar Navigation in the Solar System  

E-print Network

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...

Dong, Jiang

2008-01-01

111

Civil satellite navigation systems  

NASA Astrophysics Data System (ADS)

The use of satellite navigation for civil purposes is examined critically to compare the merits and costs of existing and practical satellite systems. Accuracy and range considerations are reviewed, and the basic requirements of radionavigation systems are set forth. Specific data are given regarding coverage area, integration with ground-based systems, monitoring and control, and accuracy. Systems reviewed include 'Starfix,' Inmarsat, EVA Vavsat, and Geostar/Locstar/Omnitracs, and extensive illustrations are provided to demonstrate constellation geometries. When in view, two or three geosynchronous satellites can provide acceptable fixing, and 9 satellites can provide global coverage. It is argued that systems such as 'Starfix' are commercially viable with less than 100 users, and Inmarsat is identified as an effective European civil system.

Blanchard, Walter F.

1991-07-01

112

Navigating low altitude satellites using the current four Navstar\\/GPS satellites  

Microsoft Academic Search

It is shown that Landsat 4 can be quite accurately navigated over CONUS throughout most of the year using only the four fully operational GPS satellites. It is noted that the Landsat 4 mission covers only a very small fraction of the earth's surface. Typically, only two out of the roughly fourteen and one-half orbits per day are used and

S. Jorgensen

1983-01-01

113

GPS/Magnetometer Based Satellite Navigation and Attitude Determination  

NASA Technical Reports Server (NTRS)

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).

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

2001-01-01

114

Application of GPS systems on a mobile robot  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to describe the use of Global Positioning Systems (GPS) as geographic information and navigational system for a ground based mobile robot. Several low cost wireless systems are now available for a variety of innovative automobile applications including location, messaging and tracking and security. Experiments were conducted with a test bed mobile robot, Bearcat II, for point-to-point motion using a Motorola GPS in June 2001. The Motorola M12 Oncore GPS system is connected to the Bearcat II main control computer through a RS232 interface. A mapping program is used to define a desired route. Then GPS information may be displayed for verification. However, the GPS information is also used to update the control points of the mobile robot using a reinforcement learning method. Local position updates are also used when found in the environment. The significance of the method is in extending the use of GPS to local vehicle control that requires more resolution that is available from the raw data using the adaptive control method.

Cao, Peter; Saxena, Mayank; Tedder, Maurice; Mischalske, Steve; Hall, Ernest L.

2001-10-01

115

The Honeywell\\/DND helicopter integrated navigation system (HINS)  

Microsoft Academic Search

The development of prototype of a high-performance, fault-tolerant navigation system for Canada's anti-submarine-warfare helicopter is discussed. HINS consists of three primary navigation subsystems (an F 3INS, a five channel P-code GPS (global positioning system), and a Doppler velocity sensor) and three secondary sensors (a strapdown magnetometer, a vertical gyro, and an air data system). The system is designed to blend

G. West-Vukovich; J. Zywiel; B. M. Scherzinger; H. Russell; S. Burke

1989-01-01

116

Mobile GPS tracking system using Holger Vmel  

E-print Network

be recorded from launch site (or DSRC!) to avoid drop outs. · Need cell phone communication #12;Mobile GPS tracking system using STRATO Holger Vömel University of Colorado, CIRES and NOAA/CMDL #12;Mobile GPS tracking system using STRATO Huntsville soundings : November 1, 2002 November 2, 2002

Vömel, Holger

117

Drishti: An Integrated Navigation System for Visually Impaired and Disabled  

Microsoft Academic Search

Drishti is a wireless pedestrian navigation system. It integrates several technologies including wearable computers, voice recognition and synthesis, wireless networks, Geographic Information System (GIS) and Global positioning system (GPS). Drishti augments contextual information to the visually impaired and computes optimized routes based on user preference, temporal constraints (e.g. traffic congestion), and dynamic obstacles (e.g. ongoing ground work, road blockade for

Abdelsalam Helal; Steven Edwin Moore; Balaji Ramachandran

2001-01-01

118

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

119

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

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

120

Shuttle Global Positioning System (GPS) system design study  

NASA Technical Reports Server (NTRS)

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.

Nilsen, P. W.

1979-01-01

121

ASRS Database Report Set Global Positioning System (GPS) Reports  

E-print Network

ASRS Database Report Set Global Positioning System (GPS) Reports Report Set Description.........................................A variety of reports referencing use of Global Positioning System (GPS) devices. Update Number

122

Institute of Navigation National Technical Meeting/Anaheim, CA/January 26-28,2000 1 Analysis of Multiple GPS Antennas for  

E-print Network

extensively on the integration of GPS and inertial navigation systems for precise aircraft positioning. Dr of position aware safety systems for road vehicle. He holds a BA in physics from Princeton University the integrated position solution. The objective of this paper is to assess the feasibility of using multiple

Calgary, University of

123

NORAD TLE Type Orbit Determination of LEO Satellites Using GPS Navigation Solutions  

NASA Astrophysics Data System (ADS)

NORAD Two Line Elements (TLE) are widely used for the increasing number of small satellite mission operations and analysis. However, due to the irregular periodicity of generation of the NORAD TLE, a new TLE that is independent of NORAD is required. A TLE type Orbit Determination (TLEOD) has been developed for the generation of a new TLE. Thus, the TLEOD system can provide an Antenna Control Unit (ACU) with the orbit determination result in the type of a TLE, which provides a simple interface for the commercialized ACU system. For the TLEOD system, NORAD SGP4 was used to make a new orbit determination system. In addition, a least squares method was implemented for the TLEOD system with the GPS navigation solutions of the KOMPSAT-1. Considering both the Orbit Propagation (OP) difference and the tendency of B* value, the preferable span of the day in the observation data was selected to be 3 days. Through the OD with 3 days observation data, the OP difference was derived and compared with that of Mission Analysis and Planning (MAPS) for the KOMPSAT-1. It has the extent from 2 km after six days to 4 km after seven days. This is qualified enough for the efficiency of an ACU in image reception and processing center of the KOMPSAT-2.

Cho, Chang-Hwa; Lee, Byoung-Sun; Lee, Jeong-Sook; Kim, Jae-Hoon; Choi, Kyu-Hong

2002-09-01

124

Wellborne inertial navigation system  

SciTech Connect

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.

Kelsey, J.R.

1983-01-01

125

Wireless sensor network system helping navigation of the visually impaired  

E-print Network

Wireless sensor network system helping navigation of the visually impaired Kamal Beydoun, Violeta of the visually impaired, which addresses both orientation and obstacle negotiation. The proposed system is GPS for the visually impaired people and especially for blind individuals. Existing electronic travel aids (ETAs

Paris-Sud XI, Université de

126

GPS Basics  

NSDL National Science Digital Library

The Federal Aviation Administration maintains the graphically impressive Global Positioning System (GPS) Basics Web site. From the history of the global positioning system and how it works to governmental policy that controls its use, this site does a good job of explaining all facets of what GPS is about without being overly technical. Interested visitors can explore some of the other links that cover satellite navigation topics as well, such as GPS programs; a library of documents, fact sheets, press releases, and news; frequently asked questions; links; and more. Anyone interested in mapping, navigation, or similar subjects will enjoy exploring the interesting information provided on this well designed site.

127

Applicable Tracking Data Arcs for NORAD TLE Orbit Determination of the KOMPSAT-1 Satellite Using GPS Navigation Solutions  

NASA Astrophysics Data System (ADS)

NORAD Two Line Element (TLE) is very useful to simplify the ground station antenna pointing and mission operations. When a satellite operations facility has the capability to determine NORAD type TLE which is independent of NORAD, it is important to analyze the applicable tracking data arcs for obtaining the best possible orbit. The applicable tracking data arcs for NORAD independent TLE orbit determination of the KOMPSAT-1 using GPS navigation solutions was analyzed for the best possible orbit determination and propagation results. Data spans of the GPS navi gation solutions from 1 day to 5 days were used for TLE orbit determination and the results were used as initial orbit for SGP4 orbit propagation. The operational orbit determination results using KOMPSAT-1 Mission Analysis and Planning System (MAPS) were used as references for the comparisons. The best-matched orbit determination was obtained when 3 days of GPS navigation solutions were used. The resulting 4 days of orbit propagation results were within 2 km of the KOMPSAT-1 MAPS results.

Lee, Byoung-Sun

2005-09-01

128

Analysis of Spaceborne GPS Systems  

NASA Technical Reports Server (NTRS)

A reasonable amount of literature can be found on the general topic of GPS receiving antennas, but very little has been published on spaceborne GPS receiving antennas. This very new topic seems to be so far more of interest for the industrial world than for the academic community. For satellite applications, microstrip antennas are usually preferred over other types of antennas mainly because of their non-electrical characteristics, such as small size, relatively lightweight, shape, possibility of integration with microwave integrated circuits, and relatively low costs. Careful design of patch antennas could meet all the requirements (electrical and non-electrical) of GPS receiving antenna to be mounted on a tethered satellite.

Cosmo, Mario L.; Davis, James L.; Elosegui, Pedro; Hill, Michael; ScireScapuzzo, Francesca

1998-01-01

129

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...

130

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

NASA Technical Reports Server (NTRS)

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).

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

1997-01-01

131

NASA tracking ship navigation systems  

NASA Technical Reports Server (NTRS)

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.

Mckenna, J. J.

1976-01-01

132

Hybrid Kalman\\/H?filter in designing optimal navigation of vehicle in PRT System  

Microsoft Academic Search

PRT( Personal Rapid Transit ) system is a automated operation, so that it is important exactly finding position of vehicle. Many of PRT system has accepted the GPS system for a position, speed, and direction. in this paper, we propose a combination of Kalman Filter and H? Filter known as Hybrid Kalman\\/ H? Filter for applying to GPS navigation algorithm.

Hyunsoo Kim; Hoang Hieu Nguyen; Phi Long Nguyen; Han Sil Kim; Young Hwan Jang; Myungseon Ryu; Changho Choi

2007-01-01

133

Space shuttle navigation analysis. Volume 2: Baseline system navigation  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

134

Differential GPS\\/inertial navigation approach\\/landing flight test results  

Microsoft Academic Search

In November 1990, a differential GPS\\/inertial flight test was conducted to acquire a system performance database and demonstrate automatic landing using an integrated differential GPS\\/INS with barometric and radar altimeters. Flight test results obtained from postflight data analysis are presented. These results include characteristics of DGPS\\/inertial error, using a laser tracker as a reference. In addition, data are provided on

S. Snyder; B. Schipper; L. Vallot; N. Parker; C. Spitzer

1992-01-01

135

Simplified Orbit Determination Algorithm for Low Earth Orbit Satellites Using Spaceborne Gps Navigation Sensor  

NASA Astrophysics Data System (ADS)

In this paper, the main work is focused on designing and simplifying the orbit determination algorithm which will be used for Low Earth Orbit (LEO) navigation. The various data processing algorithms, state estimation algorithms and modeling forces were studied in detail, and simplified algorithm is selected to reduce hardware burden and computational cost. This is done by using raw navigation solution provided by GPS Navigation sensor. A fixed step-size Runge-Kutta 4th order numerical integration method is selected for orbit propagation. Both, the least square and Extended Kalman Filter (EKF) orbit estimation algorithms are developed and the results of the same are compared with each other. EKF algorithm converges faster than least square algorithm. EKF algorithm satisfies the criterions of low computation burden which is required for autonomous orbit determination. Simple static force models also feasible to reduce the hardware burden and computational cost.

Tukaram Aghav, Sandip; Achyut Gangal, Shashikala

2014-06-01

136

14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...  

Code of Federal Regulations, 2012 CFR

...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....

2012-01-01

137

14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...  

Code of Federal Regulations, 2013 CFR

...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....

2013-01-01

138

14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...  

Code of Federal Regulations, 2014 CFR

...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....

2014-01-01

139

14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...  

Code of Federal Regulations, 2010 CFR

...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....

2010-01-01

140

14 CFR Special Federal Aviation... - Special Operating Rules for the Conduct of Instrument Flight Rules (IFR) Area Navigation (RNAV...  

Code of Federal Regulations, 2011 CFR

...Components of the GNSS include GPS, the Global Orbiting Navigation Satellite System, and WAAS satellites. Global Positioning System (GPS). GPS is a satellite-based radio navigational, positioning, and time transfer system....

2011-01-01

141

A Constructive and Autonomous Integration Scheme of Low-Cost GPS\\/MEMS IMU for Land Vehicular Navigation Applications  

Microsoft Academic Search

The integration of GPS and INS provides a system that has superior performance in comparison with either a GPS or an INS stand-alone systems. Most integrated GPS\\/INS positioning systems have been implemented using Kalman Filter (KF) technique. Although of being widely used, KF has some drawbacks related to computation load, immunity to noise effects and observability. In addition, KF only

Kai-Wei Chiang; Semah Nassar; Naser El-Sheimy

2006-01-01

142

Real-time integration of a tactical-grade IMU and GPS for high-accuracy positioning and navigation  

NASA Astrophysics Data System (ADS)

The integration of the Global Positioning System (CPS) and Inertial Navigation Systems (INSs) is often used to provide accurate positioning and navigation information. For applications requiring the highest accuracy, the quality of the inertial sensors required is usually assumed to be very high. This dissertation investigates the integration of CPS with a tactical-grade Inertial Measurement Unit (IMU) for centimetre-level navigation in real-time. Different GPS/INS integration strategies are investigated to assess their relative performance in terms of position and velocity accuracy during partial and complete data outages, carrier phase ambiguity resolution after such data outages, and the overall statistical reliability of the system. In terms of statistical reliability, the traditional equations used in dynamic systems are redeveloped in light of some practical considerations, including centralized and decentralized filter architectures, and sequential versus simultaneous measurement updating. Results show that the integrated solution outperforms the GPS-only approach in all areas. The difference between loose and tight integration strategies was most significant for ambiguity resolution and system reliability. The integrated solution is capable of providing decimetre-level accuracy or better for durations of about five or ten seconds when a complete or partial CPS outage is simulated. This level of accuracy, extended over longer time intervals, is shown to reduce the time required to resolve the L1 ambiguities by an average of about 50% or more for data outages as long as 30 seconds when using a tight integration strategy. More importantly, the reliability of the ambiguity resolution process is improved with the integrated system. Statistical reliability parameters are also dramatically better when using the integrated system with the ability of detecting a single-cycle cycle slip being better and more consistent, relative to GPS-only. The effect of undetected blunders on the final system is also significantly reduced. Two real-time tests are analyzed and results show that directly resolving the L1 ambiguities is still unreliable in suburban environments, even with the integrated system. However, using the widelane phase observable, sub-decimetre navigation is demonstrated in suburban and pseudo-urban environments, despite the relatively adverse operational conditions encountered.

Petovello, Mark G.

2003-10-01

143

The Performance Analysis of a 3d Map Embedded Ins/gps Fusion Algorithm for Seamless Vehicular Navigation in Elevated Highway Environments  

NASA Astrophysics Data System (ADS)

In this study, a 3D Map Matching (3D MM) algorithm is embedded to current INS/GPS fusion algorithm for enhancing the sustainability and accuracy of INS/GPS integration systems, especially the height component. In addition, this study propose an effective solutions to the limitation of current commercial vehicular navigation systems where they fail to distinguish whether the vehicle is moving on the elevated highway or the road under it because those systems don't have sufficient height resolution. To validate the performance of proposed 3D MM embedded INS/GPS integration algorithms, in the test area, two scenarios were considered, paths under the freeways and streets between tall buildings, where the GPS signal is obstacle or interfered easily. The test platform was mounted on the top of a land vehicle and also systems in the vehicle. The IMUs applied includes SPAN-LCI (0.1 deg/hr gyro bias) from NovAtel, which was used as the reference system, and two MEMS IMUs with different specifications for verifying the performance of proposed algorithm. The preliminary results indicate the proposed algorithms are able to improve the accuracy of positional components in GPS denied environments significantly with the use of INS/GPS integrated systems in SPP mode.

Lee, Y. H.; Chiang, K. W.

2012-07-01

144

Integrated communications and optical navigation system  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

145

Flight Test of Attitude Determination System using Multiple GPS Antennae  

NASA Astrophysics Data System (ADS)

Small Unmanned Aerial Vehicles (UAVs) or inexpensive airplanes, such as a Cessna single engine aircraft, require a navigation system with a cheap, compact and precise sensor. Over the past ten years, GPS receivers have begun to be used as primary or alternative navigation sensors, because their use can significantly reduce the overall system cost. This paper describes a navigation system incorporating a velocity-based attitude estimation system with an attitude determination system using multiple antennae, which was implemented and tested using a UAV. The main objective was to obtain precise attitude information using low cost GPS OEM boards and antennae. Attitude boundaries are derived from the relationship between the body frame and the wind coordinates, which are used to validate the resolved cycle ambiguity in an Euler angle domain. Angular rate based on Doppler measurements was used to exclude the degenerate pseudo-roll angle information during severe uncoordinated flight. Searching for cycle ambiguity at every epoch of the flight showed that the developed system gave reliable cycle integer solutions, although the carrier phase measurement was subject to additional errors, such as multipath, external interference, and phase centre variation. A flight test was performed using a 1/4-scale Piper J3 Cub model, CMC Allstar OEM boards, OEM AT575-70 antennae, and 700 MHz PC104 board.

Jang, Jaegyu; Kee, Changdon

2006-01-01

146

Non-linear mathematical model for integrated global positioning\\/inertial navigation systems  

Microsoft Academic Search

In recent years there has been a major upsurge of interest in the integrated global positioning system (GPS)\\/inertial navigation system (INS) as a cost-effective way of providing accurate and reliable navigation aid for civil and military vehicles (ships, aircrafts, land vehicles). In this paper an error model is developed which can be used for GPS\\/INS filter mechanization. It is shown

Farhan A. Faruqi

2000-01-01

147

Software for a GPS-Reflection Remote-Sensing System  

NASA Technical Reports Server (NTRS)

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).

Lowe, Stephen

2003-01-01

148

Miniaturized GPS/MEMS IMU integrated board  

NASA Technical Reports Server (NTRS)

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.

Lin, Ching-Fang (Inventor)

2012-01-01

149

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Committee 159: Global Positioning System (GPS) AGENCY: Federal...Committee 159 meeting: Global Positioning System (GPS...Special Committee 159: Global Positioning System (GPS). DATES: The...

2010-05-20

150

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Committee 159: Global Positioning System (GPS) AGENCY: Federal...Committee 159 meeting: Global Positioning System (GPS...Special Committee 159: Global Positioning System (GPS). DATES: The...

2011-05-12

151

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Committee 159: Global Positioning System (GPS) AGENCY: Federal...Committee 159 meeting: Global Positioning System (GPS...Special Committee 159: Global Positioning System (GPS). DATES: The...

2011-06-07

152

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Committee 159: Global Positioning System (GPS) AGENCY: Federal...Committee 159 meeting: Global Positioning System (GPS...Special Committee 159: Global Positioning System (GPS). DATES: The...

2010-01-15

153

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Committee 159: Global Positioning System (GPS) AGENCY: Federal...Committee 159 meeting: Global Positioning System (GPS...Special Committee 159: Global Positioning System (GPS) 87th meeting....

2011-10-28

154

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Committee 159: Global Positioning System (GPS). AGENCY: Federal...Committee 159 meeting: Global Positioning System (GPS...Special Committee 159: Global Positioning System (GPS). DATES: The...

2010-10-06

155

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Committee 159, Global Positioning System (GPS) AGENCY: Federal...Special Committee 159, Global Positioning System (GPS...Special Committee 159, Global Positioning System (GPS). DATES: The...

2012-02-28

156

VI-Navi: a novel indoor navigation system for visually impaired people  

Microsoft Academic Search

We propose an indoor navigation system to aid visually impaired people using a GPS like environment created inside a building using Infrared transmitters. It assists visually impaired people in navigation, orientation and independent movement in an enclosed surrounding. Our focus is to develop a low cost, portable and easy to install system. This system includes plug and play transmitter node

Parth Mehta; Pavas Kant; Poojan Shah; Anil K. Roy

2011-01-01

157

Differential GPS/inertial navigation approach/landing flight test results  

NASA Technical Reports Server (NTRS)

Results of a joint Honeywell/NASA-Langley differential GPS/inertial flight test conducted in November 1990 are discussed focusing on postflight data analysis. The test was aimed at acquiring a system performance database and demonstrating automatic landing based on an integrated differential GPS/INS with barometric and radar altimeters. Particular attention is given to characteristics of DGPS/inertial error and the magnitude of the differential corrections and vertical channel performance with and without altimeter augmentation. It is shown that DGPS/inertial integrated with a radar altimeter is capable of providing a precision approach and autoland guidance of manned return space vehicles within the Space Shuttle accuracy requirements.

Snyder, Scott; Schipper, Brian; Vallot, Larry; Parker, Nigel; Spitzer, Cary

1992-01-01

158

Wireless-enabled GPS indoor geolocation system  

Microsoft Academic Search

In this paper we discuss a wireless-enabled GPS indoor geolocation system which will provide centimeter level position level accuracy 99.999% of the time and meet the integrity requirements in the tough areas such as indoors, undergrounds, and in tunnels in direct response to President Obama's call for building nation's best E911 infrastructure emergency response system in the world.

Ilir F. Progri; Worcester MA

2010-01-01

159

On-line smoothing for an integrated navigation system with low-cost MEMS inertial sensors.  

PubMed

The integration of the Inertial Navigation System (INS) and the Global Positioning System (GPS) is widely applied to seamlessly determine the time-variable position and orientation parameters of a system for navigation and mobile mapping applications. For optimal data fusion, the Kalman filter (KF) is often used for real-time applications. Backward smoothing is considered an optimal post-processing procedure. However, in current INS/GPS integration schemes, the KF and smoothing techniques still have some limitations. This article reviews the principles and analyzes the limitations of these estimators. In addition, an on-line smoothing method that overcomes the limitations of previous algorithms is proposed. For verification, an INS/GPS integrated architecture is implemented using a low-cost micro-electro-mechanical systems inertial measurement unit and a single-frequency GPS receiver. GPS signal outages are included in the testing trajectories to evaluate the effectiveness of the proposed method in comparison to conventional schemes. PMID:23443403

Chiang, Kai-Wei; Duong, Thanh Trung; Liao, Jhen-Kai; Lai, Ying-Chih; Chang, Chin-Chia; Cai, Jia-Ming; Huang, Shih-Ching

2012-01-01

160

Navigating the System  

MedlinePLUS

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

161

Tight coupling of GPS, laser scanner, and inertial measurements for navigation in urban environments  

Microsoft Academic Search

Many applications can be envisioned for accurate, robust, and reliable navigation solution in challenging urban environments. Examples of existing and prospective applications include, but are not limited to, navigation, guidance, and control of autonomous vehicles (including both ground and aerial vehicles) for urban surveillance and reconnaissance; collection of geographical information system (GIS) data in cities; monitoring of urban infrastructure for

Andrey Soloviev

2008-01-01

162

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

PubMed

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

Holland, Richard; Filannino, Caterina; Gagliardo, Anna

2013-06-15

163

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

164

Optimizing of ANFIS for estimating INS error during GPS outages  

Microsoft Academic Search

Global positioning system (GPS) has been extensively used for land vehicle navigation systems. However, GPS is incapable of providing permanent and reliable navigation solutions in the presence of signal evaporation or blockage. On the other hand, navigation systems, in particular, inertial navigation systems (INSs), have become important components in different military and civil applications due to the recent advent of

Ahmed Mudheher Hasan; Khairulmizam Samsudin; Abdul Rahman Ramli

2011-01-01

165

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

E-print Network

Global Positioning System (GPS) Bias Correction and Habitat Analysis of Mountain Goats Oreamnos, shall not be allowed without my written permission. Signature Date #12;Global Positioning System (GPS to the difficulties of monitoring animal movement in all months of the year. The use of global positioning system (GPS

Wallin, David O.

166

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

NASA Technical Reports Server (NTRS)

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).

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

2002-01-01

167

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

NASA Astrophysics Data System (ADS)

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.

Moafipoor, Shahram

168

Environmental applications of GPS  

SciTech Connect

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.

Vigil, S.A.; Zueck, D.

1999-07-01

169

The Evolution of Global Positioning System (GPS) Technology.  

ERIC Educational Resources Information Center

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

Kumar, Sameer; Moore, Kevin B.

2002-01-01

170

Performance of Hybrid Positioning System Combining GPS and Television Signals  

Microsoft Academic Search

In spite of the global coverage and the penetration into a daily life of GPS (global positioning system), GPS receivers have not been able to overcome the critical weakness of a GPS signal in indoor and urban areas due to its low signal power level after a long journey from satellites. One of the best solutions to this problem is

Matthew Rabinowitz; P. Enge

2006-01-01

171

Low cost inertial\\/GPS integrated position and orientation system for marine applications  

Microsoft Academic Search

This paper describes the low cost position and orientation system (LCPOS), comprising the integration of a low cost tactical grade inertial measurement unit with GPS position, velocity and heading aiding data. LCPOS was designed to be a cost-effective alternative to a high performance costly ship INS (SINS). The demonstrated accuracy of the LCPOS integrated navigation solution is comparable to that

Bruno M. Scherzinger; Joseph J. Hutton; J. Christopher McMillan

1996-01-01

172

Efficient authentication mechanisms for navigation systems a radio-navigation case  

E-print Network

Global Positioning System (GPS) Laboratory. He is the Associate Investigator for the Stanford University is a research associate at the Stanford University Global Positioning System (GPS) Laboratory. He received his M

Stanford University

173

Autonomous navigation system. [gyroscopic pendulum for air navigation  

NASA Technical Reports Server (NTRS)

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.

Merhav, S. J. (inventor)

1981-01-01

174

GPS: A New Constellation  

NSDL National Science Digital Library

This Air and Space Museum website provides detailed information about how GPS (Global Positioning System) works. Beginning with technology that existed before GPS, such as the sextant and the TRANSIT satellite, it provides information about land, air, and sea navigation, Earth mapping, land management, and scientific applications.

2008-09-03

175

GPS Measurement Of Attitude  

NASA Technical Reports Server (NTRS)

Signals transmitted by satellites of Global Positioning System (GPS) measure orientation of baseline on ship, aircraft, or other vehicle with accuracy. Two GPS antennas and receivers placed at well separated points on platform. Receivers measure positions of ends of baseline as functions of time. Output processor computes vector difference between two positions and determines orientation of baseline. Combined with conventional GPS data, orientation data allows more precise navigation and mapping and enhances calculations related to performance and control of vehicle.

Dinardo, S. J.; Hushbeck, E. L.; Meehan, T. K.; Munson, T. N.; Purcell, G. H.; Srinivasan, J. M.; Young, L. E.; Yunck, T. P.

1992-01-01

176

Quantifying Improvements from the Integration of GPS and a Tactical Grade INS in High  

E-print Network

of satellite and inertial navigation since that time. Some of his past research includes integration of GPS on the integration of GPS and inertial navigation systems for precise aircraft positioning. Dr. Cannon is a Past. INTRODUCTION The integration of Global Positioning System (GPS) receivers with Inertial Navigation Systems (INS

Calgary, University of

177

Innovative use of global navigation satellite systems for flight inspection  

NASA Astrophysics Data System (ADS)

The International Civil Aviation Organization (ICAO) mandates flight inspection in every country to provide safety during flight operations. Among many criteria of flight inspection, airborne inspection of Instrument Landing Systems (ILS) is very important because the ILS is the primary landing guidance system worldwide. During flight inspection of the ILS, accuracy in ILS landing guidance is checked by using a Flight Inspection System (FIS). Therefore, a flight inspection system must have high accuracy in its positioning capability to detect any deviation so that accurate guidance of the ILS can be maintained. Currently, there are two Automated Flight Inspection Systems (AFIS). One is called Inertial-based AFIS, and the other one is called Differential GPS-based (DGPS-based) AFIS. The Inertial-based AFIS enables efficient flight inspection procedures, but its drawback is high cost because it requires a navigation-grade Inertial Navigation System (INS). On the other hand, the DGPS-based AFIS has relatively low cost, but flight inspection procedures require landing and setting up a reference receiver. Most countries use either one of the systems based on their own preferences. There are around 1200 ILS in the U.S., and each ILS must be inspected every 6 to 9 months. Therefore, it is important to manage the airborne inspection of the ILS in a very efficient manner. For this reason, the Federal Aviation Administration (FAA) mainly uses the Inertial-based AFIS, which has better efficiency than the DGPS-based AFIS in spite of its high cost. Obviously, the FAA spends tremendous resources on flight inspection. This thesis investigates the value of GPS and the FAA's augmentation to GPS for civil aviation called the Wide Area Augmentation System (or WAAS) for flight inspection. Because standard GPS or WAAS position outputs cannot meet the required accuracy for flight inspection, in this thesis, various algorithms are developed to improve the positioning ability of Flight Inspection Systems (FIS) by using GPS and WAAS in novel manners. The algorithms include Adaptive Carrier Smoothing (ACS), optimizing WAAS accuracy and stability, and reference point-based precise relative positioning for real-time and near-real-time applications. The developed systems are WAAS-aided FIS, WAAS-based FIS, and stand-alone GPS-based FIS. These systems offer both high efficiency and low cost, and they have different advantages over one another in terms of accuracy, integrity, and worldwide availability. The performance of each system is tested with experimental flight test data and shown to have accuracy that is sufficient for flight inspection and superior to the current Inertial-based AFIS.

Kim, Eui-Ho

178

12.215 Modern Navigation, Fall 2002  

E-print Network

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 ...

Herring, T. (Thomas)

179

In-flight detection of errors for enhanced aircraft flight safety and vertical accuracy improvement using digital terrain elevation data with an inertial navigation system, global positioning system and radar altimeter  

Microsoft Academic Search

This dissertation discusses integration architectures using digital terrain elevation data (DTED) with an inertial navigation system (INS), a global positioning system (GPS) and a radar altimeter. Two integration architectures are considered: DTED with INS, GPS and radar altimeter for aircraft vertical accuracy improvement during the final approach; and DTED with kinematic GPS (KGPS) and a radar altimeter for enhanced aircraft

Robert Anthony Gray

1999-01-01

180

GPS Signal-in-Space Integrity Performance Evolution in the  

E-print Network

, Fellow, IEEE Stanford University Knowledge of the Global Positioning System (GPS) signal-in-space (SIS Global Positioning System (GPS) is so far the most widely used space-based positioning, navigation

Stanford University

181

Integrated Global Positioning Systems (GPS) Laboratory  

NASA Technical Reports Server (NTRS)

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.

Brown, Dewayne Randolph

2002-01-01

182

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...

183

SOANFIS assisted GPS\\/MEMS-INS integrated positioning errors prediction  

Microsoft Academic Search

To solve the problem that GPS\\/MEMS-INS (micro-electro-mechanical system - inertial navigation system) integrated positioning errors accumulate rapidly with time during GPS outages, a kind of SOANFIS (self-organizing adaptive neuro-fuzzy inference system) is proposed to predict the positioning errors of GPS\\/MEMS-INS integrated navigation system. When GPS is available, not only the parameters of SOANFIS are tuned, but also its structure is

Li Cong; Honglei Qin; Juhong Xing

2010-01-01

184

Inertial/multisensor navigation  

NASA Technical Reports Server (NTRS)

A Multisensor Navigation System as proposed by the Ohio University Avionics Engineering Center is illustrated. The proposed system incorporates radio (Lorac-C), satellite (Global Positioning System) and an inertial navigation system (INS). The inertial part of the system will be of a low grade since the INS will be used primarily for filtering the GPS data and for short term stability. Loran-C and GPS will be used for long term stability.

Alikiotis, Dimitri

1987-01-01

185

Autonomous navigation system and method  

SciTech Connect

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.

Bruemmer, David J. (Idaho Falls, ID) [Idaho Falls, ID; Few, Douglas A. (Idaho Falls, ID) [Idaho Falls, ID

2009-09-08

186

GENESIS: GPS Environmental and Earth Science Information System  

NASA Technical Reports Server (NTRS)

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.

Hajj, George

1999-01-01

187

Time and Frequency Measurements Using the Global Positioning System (GPS)  

Microsoft Academic Search

This paper describes how Global Positioning System (GPS) satellite signals are used in time and frequency metrology. It discusses how a GPS receiver can provide a reference signal for frequency calibrations and time synchronization. It also explains the several types of time and frequency measurements that utilize GPS signals. These include one-way or direct reception measurements, single and multi-channel common-view

Michael A. Lombardi; Lisa M. Nelson; Andrew N. Novick; Victor S. Zhang

188

Comparison of robust H ? filter and Kalman filter for initial alignment of inertial navigation system  

Microsoft Academic Search

There are many filtering methods that can be used for the initial alignment of an integrated inertial navigation system. This\\u000a paper discussed the use of GPS, but focused on two kinds of filters for the initial alignment of an integrated strapdown inertial\\u000a navigation system (SINS). One method is based on the Kalman filter (KF), and the other is based on

Yan-Ling Hao; Ming-Hui Chen; Liang-Jun Li; Bo Xu

2008-01-01

189

A wellbore inertial navigation system  

SciTech Connect

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.

Kelsey, J.R.

1983-02-01

190

Performance of Hybrid Positioning System Combining GPS and Television Signals  

E-print Network

solutions to this problem is the adoption of powerful terrestrial signals such as television, Wi the benefits of a hybrid positioning system combining GPS and television signals, a prototype of TV signalPerformance of Hybrid Positioning System Combining GPS and Television Signals Ju-Yong Do Electrical

Stanford University

191

Navigation Systems -Nolan, Chap 2  

E-print Network

Altitude (MDA) · Pilot maintains MDA on runway center-line to Missed Approach Point (MAP) · If runway MDA · If runway in sight at DH, then land · If runway not in sight at DH, then Missed Approach Segment FAF MDA MAP IAF FAF DH MAP #12;13 #12;14 Grand Forks ­ GPS RWY 26 ­ Initial Approach Segment: · EYWUS

192

Basic Mars Navigation System For Local Areas  

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

193

The Role of Trust and Interaction in GPS Related Accidents: A Human Factors Safety Assessment of the Global Positioning System (GPS)  

E-print Network

of the Global Positioning System (GPS) Chris. W. Johnson, DPhil; Department of Computing Science, University; accident analysis; organisational safety. Abstract The Global Positioning System (GPS) uses a network

Johnson, Chris

194

The GPS Space Service Volume  

NASA Technical Reports Server (NTRS)

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.

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

195

Hybrid Kalman/H?filter in designing optimal navigation of vehicle in PRT System  

NASA Astrophysics Data System (ADS)

PRT( Personal Rapid Transit ) system is a automated operation, so that it is important exactly finding position of vehicle. Many of PRT system has accepted the GPS system for a position, speed, and direction. in this paper, we propose a combination of Kalman Filter and H? Filter known as Hybrid Kalman/ H? Filter for applying to GPS navigation algorithm. For disturbance cancellation, Kalman Filter is optimal but it requires the statistical information about process and measurement noises while H? Filter only minimizes the "worst-case" error and requires that the noises are bounded. The new Hybrid Filter is expected to reduce the worst-case error and exploit the incomplete knowledge about noises to provide a better estimation. The experiment shows us the ability of Hybrid Filter in GPS navigation algorithm.

Kim, Hyunsoo; Nguyen, Hoang Hieu; Nguyen, Phi Long; Kim, Han Sil; Jang, Young Hwan; Ryu, Myungseon; Choi, Changho

2007-12-01

196

Autonomous Navigation System Using a Fuzzy Adaptive Nonlinear H? Filter  

PubMed Central

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

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

2014-01-01

197

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

PubMed

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

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

2014-01-01

198

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

#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

Kamat, Vineet R.

199

Navigation radar signal acquisition and measurement system  

Microsoft Academic Search

In the course of navigation, radar is a very important navigation aids. However, different types of radar always have different signal definition. In this paper, a kind of method on radar signal acquisition and measurement based on embedded system is proposed. The system, which could automatically detect some common radar signal parameter, is consist of CPLD, ARM micro processor, ADC

Shaowei Li; Xinqing Zhuang

2009-01-01

200

Optimum Reset of Ship's Inertial Navigation System  

Microsoft Academic Search

Optimum linear filter and control theory is applied to the practical problem of supplementing an inertial navigation system with discrete reference information. The information takes the form of position obtained from Loran C or Decca, for example, and occasional azimuth fixes obtained from star sightings. In particular, optimum use of this information is discussed for the Ship's Inertial Navigation System

B. E. Bona; Robert J. Smay

1966-01-01

201

Inertial navigation system aided by aircraft dynamics  

Microsoft Academic Search

In this work the possibility of using the model of aircraft dynamics as a means for aiding an inertial navigation system is studied. The method is of particular interest for low-grade inertial navigating system (INS). The aiding formulation is introduced, its corresponding mathematical model is derived and used in the design of an appropriate extended Kalman filter. Sensitivity analysis of

M. Koifman; I. Y. Bar-Itzhack

1999-01-01

202

A STOL terminal area navigation system  

NASA Technical Reports Server (NTRS)

The mechanization and performance of a STOL terminal area navigation system are described. The purpose of the navigation system is to allow flying with precision 4D-guidance along complex flight paths in the terminal area, and to develop requirements for STOL operations in the 1980s. The navigation aids include an experimental microwave landing system, MODILS. The systems description begins with the navigation aids. It is shown how the data are transformed and combined with other data to obtain position and velocity estimates. Also presented are some of the design changes and other features that were introduced as a result of flight testing. The various ways of displaying navigation-derived data are given. Finally, simulator and flight test results are discussed.

Neuman, F.; Warner, D. N., Jr.

1974-01-01

203

New vision system and navigation algorithm for an autonomous ground vehicle  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

204

Civil satellite navigation and location systems  

NASA Astrophysics Data System (ADS)

The use of satellites for civil navigation and location, including satellites not necessarily launched for that purpose, is reviewed. In particular, attention is given to differences between civil and military satellites; civil use of military systems and the associated commercial considerations and regulatory issues; the use of communication satellites; and radiodetermination satellite service based on geostationary satellites. The discussion also covers integration with ground-based radio-navigation systems; existing radio-navigation satellite systems; and the Starfix, Geostar/Locstar, Starfind, Navsat, and Rexstar systems.

Blanchard, W. F.

1989-05-01

205

Navigation Systems -Enroute Nolan, Chap 2  

E-print Network

1 Navigation Systems - Enroute Nolan, Chap 2 #12;2 En-route Navigation Visual Flight Rules Pilotage/Dead-Reckoning Aircraft Instruments: ·Magnetic Compass/ ·Heading Indicator Aeronautic Charts Forecast Wind Instrument Flight Rules Land-based Space-based Aircraft-based VOR VOR/DME Theta/Theta Rho/Theta ·Airways, Waypoints

206

GPS RISK ASSESSMENT STUDY FINAL REPORT  

E-print Network

-based system using signals provided by the Department of Defense's Global Positioning System (GPS). However-jam technologies. KEYWORDS: National Airspace System Global Positioning System Navigation #12;v TABLE OF CONTENTS

Ladkin, Peter B.

207

NTNU Java: How GPS works  

NSDL National Science Digital Library

This applet describes and demonstrates how GPS works. The Global Positioning System (GPS) is actually a constellation of 27 Earth-orbiting satellites (24 in operation and three extras in case one fails)implemented by the U.S. military for military navigation.

Hwang, Fu-Kwun

2008-07-07

208

Accurate aircraft wind measurements using the global positioning system (GPS)  

SciTech Connect

High accuracy measurements of the spatial distribution of wind speed are required in the study of turbulent exchange between the atmosphere and the earth. The use of a differential global positioning system (GPS) to determine the sensor velocity vector component of wind speed is discussed in this paper. The results of noise and rocking testing are summarized, and fluxes obtained from the GPS-based methods are compared to those measured from systems on towers and airplanes. The GPS-based methods provided usable measurements that compared well with tower and aircraft data at a significantly lower cost. 21 refs., 1 fig., 2 tabs.

Dobosy, R.J.; Crawford, T.L., McMillen, R.T., Dumas, E.J. [Atmospheric Turbulence and Diffusion Div., Oak Ridge, TN (United States)

1996-11-01

209

A comparative analysis of area navigation systems for general aviation  

E-print Network

Within the next decade area navigation is to become the primary method of air navigation within the United States. There are numerous radio navigation systems that offer the capabilities of area navigation to general ...

Dodge, Steven Malcolm

1973-01-01

210

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

USGS Publications Warehouse

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.

Sanchez, Richard D.; Hothem, Larry D.

2002-01-01

211

Gravity aided inertial navigation system (GAINS)  

NASA Astrophysics Data System (ADS)

The paper describes a new autonomous covert INS uniquely suited to underwater applications. Unlike the conventional INS, schuler and siderial errors are bounded without external navigation aids or active instrumentation of ground speed. As a result, the system exhibits excellent long-term navigation performance while maintaining the inherent covertness of the INS system. A conventional INS is integrated with a gravity gradiometer capable of measuring gravity field components independently of platform accelerations. This new integration scheme takes advantage of navigation system velocity error observability. Parametric performance results are presented for GAINS, varying gyro, gravimeter, gradiometer, depth sensor quality, and gravity field activity.

Jircitano, Albert; Dosch, Daniel E.

212

Sigma-point Kalman filtering for integrated GPS and inertial navigation  

Microsoft Academic Search

A sigma-point Kalman filter is derived for integrating GPS measurements with inertial measurements from gyros and accelerometers to determine both the position and the attitude of a moving vehicle. Sigma-point filters use a carefully selected set of sample points to more accurately map the probability distribution than the linearization of the standard extended Kalman filter (KKF), leading to faster convergence

J. L. Crassidis

2006-01-01

213

Digital image georeferencing from a multiple camera system by GPS/INS  

NASA Astrophysics Data System (ADS)

In this paper, the development and testing of an airborne fully digital multi-sensor system for digital mapping data acquisition is presented. The system acquires two streams of data, namely, navigation (georeferencing) data and imaging data. The navigation data are obtained by integrating an accurate strapdown inertial navigation system with a differential GPS system (DGPS). The imaging data are acquired by two low-cost digital cameras, configured in such a way so as to reduce their geometric limitations. The two cameras capture strips of overlapping nadir and oblique images. The GPS/INS-derived trajectory contains the full translational and rotational motion of the carrier aircraft. Thus, image exterior orientation information is extracted from the trajectory, during post-processing. This approach eliminates the need for ground control (GCP) when computing 3D positions of objects that appear in the field of view of the system imaging component. Two approaches for calibrating the system are presented, namely, terrestrial calibration and in-flight calibration. Test flights were conducted over the campus of The University of Calgary. Testing the system showed that best ground point positioning accuracy at 1:12,000 average image scale is 0.2 m (RMS) in easting and northing and 0.3 m (RMS) in height. Preliminary results indicate that major applications of such a system in the future are in the field of digital mapping, at scales of 1:5000 and smaller, and in the generation of digital elevation models for engineering applications.

Mostafa, Mohamed M. R.; Schwarz, Klaus-Peter

214

Color night vision system for ground vehicle navigation  

NASA Astrophysics Data System (ADS)

Operating in a degraded visual environment due to darkness can pose a threat to navigation safety. Systems have been developed to navigate in darkness that depend upon differences between objects such as temperature or reflectivity at various wavelengths. However, adding sensors for these systems increases the complexity by adding multiple components that may create problems with alignment and calibration. An approach is needed that is passive and simple for widespread acceptance. Our approach uses a type of augmented display to show fused images from visible and thermal sensors that are continuously updated. Because the raw fused image gave an unnatural color appearance, we used a color transfer process based on a look-up table to replace the false colors with a colormap derived from a daytime reference image obtained from a public database using the GPS coordinates of the vehicle. Although the database image was not perfectly registered, we were able to produce imagery acquired at night that appeared with daylight colors. Such an approach could improve the safety of nighttime navigation.

Ali, E. A.; Qadir, H.; Kozaitis, S. P.

2014-06-01

215

The role of adaptive antenna systems when used with GPS  

NASA Astrophysics Data System (ADS)

The possible effects of jamming on the operation of the GPS is examined, and possible ways of dealing with this problem are discussed. In particular, it is shown that Controlled Reception Pattern Antennas are capable of greatly increasing the jamming levels for which GPS can be used. Nulls of the order of 40 dB can be generated in high dynamic applications. It is expected that such systems will find increased applications in the air, at sea, and on land.

Johannessen, Rolf

216

GPS-RDS enabled location based smart transit  

Microsoft Academic Search

The GPS (Global Positioning System) is Global Navigation Satellite system used for navigation purposes. Now days, GPS enables the vehicle drivers to check the real time position of there vehicle onto a preloaded map with features like, mapping of way to a location etc. The RDS (Radio Data System) is the best and cheapest way of broadcasting digital information over

A. Agarwal; N. Goel

2009-01-01

217

Inertial navigation system for bladder endoscopy.  

PubMed

The usage of video endoscopes in cystoscopic interventions of the urinary bladder impedes an intuitive navigation. Although image-based solutions such as panorama images can provide extended views of the surgical field, a real-time 3-D navigation is not supported. Furthermore, the integration of common tracking systems in ambulant clinics is often hindered due to low usability and high costs. Thus, we discuss in this paper a first low-cost inertial navigation system. Our evaluation results show that in spite of lower sensor accuracies, mean errors between < 1 and 4 are achieved for solid angles. Using endoscopes with different view angles we apply an extended endoscope model for an adaptive displacement correction. Furthermore, we implement a first guided navigation tool for tumor re-identification in real-time. PMID:22255553

Behrens, Alexander; Grimm, Jonathan; Gross, Sebastian; Aach, Til

2011-01-01

218

GPS Time Synchronization System for K2K  

E-print Network

The K2K (KEK E362) long-baseline neutrino oscillations experiment requires synchronization of clocks with ~100 nsec accuracy at the near and far detector sites (KEK and Super-Kamiokande, respectively), which are separated by 250 km. The Global Positioning 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 (1PPS) signal whose leading edge is synchronized with GPS seconds rollovers to well within the required accuracy. For each beam spill trigger at KEK, and each event trigger at Super-Kamiokande, 50 MHz free-running Local Time Clock (LTC) modules at each site provide fractional-second data with 20 nsec ticks. At each site, two GPS clocks run in parallel, providing hardware backup as well as data quality checks.

H. G. Berns; R. J. Wilkes

1999-09-13

219

Significance of Waterway Navigation Positioning Systems On Ship's Manoeuvring Safety  

NASA Astrophysics Data System (ADS)

The main goal of navigation is to lead the ship to the point of destination safety and efficiently. Various factors may affect ship realisating this process. The ship movement on waterway are mainly limited by water area dimensions (surface and depth). These limitations cause the requirement to realise the proper of ship movement trajectory. In case when this re requirement cant't fulfil then marine accident may happend. This fact is unwanted event caused losses of human health and life, damage or loss of cargo and ship, pollution of natural environment, damage of port structures or blocking the port of its ports and lost of salvage operation. These losses in same cases can be catas- trophical especially while e.i. crude oil spilling could be place. To realise of safety navigation process is needed to embrace the ship's movement trajectory by waterways area. The ship's trajectory is described by manoeuvring lane as a surface of water area which is require to realise of safety ship movement. Many conditions affect to ship manoeuvring line. The main are following: positioning accuracy, ship's manoeuvring features and phenomena's of shore and ship's bulk common affecting. The accuracy of positioning system is most important. This system depends on coast navigation mark- ing which can range many kinds of technical realisation. Mainly used systems based on lights (line), radionavigation (local system or GPS, DGPS), or radars. If accuracy of positiong is higer, then safety of navigation is growing. This article presents these problems exemplifying with approaching channel to ports situated on West Pomera- nian water region.

Galor, W.

220

Low-Cost INS/GPS Integration: Concepts and Testing  

E-print Network

of inertial units is the main obstacle for their inclusion in precision navigation systems to support a variety of application areas. Standard inertial navigation systems (INS) use precise gyro inclusion of these sensors to augment GPS in precision navigation systems. Standard inertial navigation

Calgary, University of

221

The Mathematics of Navigating the Solar System  

NASA Technical Reports Server (NTRS)

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.

Hintz, Gerald

2000-01-01

222

Navigation of robotic system using cricket motes  

NASA Astrophysics Data System (ADS)

This paper presents a novel algorithm for self-mapping of the cricket motes that can be used for indoor navigation of autonomous robotic systems. The cricket system is a wireless sensor network that can provide indoor localization service to its user via acoustic ranging techniques. The behavior of the ultrasonic transducer on the cricket mote is studied and the regions where satisfactorily distance measurements can be obtained are recorded. Placing the motes in these regions results fine-grain mapping of the cricket motes. Trilateration is used to obtain a rigid coordinate system, but is insufficient if the network is to be used for navigation. A modified SLAM algorithm is applied to overcome the shortcomings of trilateration. Finally, the self-mapped cricket motes can be used for navigation of autonomous robotic systems in an indoor location.

Patil, Yogendra J.; Baine, Nicholas A.; Rattan, Kuldip S.

2011-06-01

223

Global navigation satellite system receiver for weak signals under all dynamic conditions  

NASA Astrophysics Data System (ADS)

The ability of the Global Navigation Satellite System (GNSS) receiver to work under weak signal and various dynamic conditions is required in some applications. For example, to provide a positioning capability in wireless devices, or orbit determination of Geostationary and high Earth orbit satellites. This dissertation develops Global Positioning System (GPS) receiver algorithms for such applications. Fifteen algorithms are developed for the GPS C/A signal. They cover all the receiver main functions, which include acquisition, fine acquisition, bit synchronization, code and carrier tracking, and navigation message decoding. They are integrated together, and they can be used in any software GPS receiver. They also can be modified to fit any other GPS or GNSS signals. The algorithms have new capabilities. The processing and memory requirements are considered in the design to allow the algorithms to fit the limited resources of some applications; they do not require any assisting information. Weak signals can be acquired in the presence of strong interfering signals and under high dynamic conditions. The fine acquisition, bit synchronization, and tracking algorithms are based on the Viterbi algorithm and Extended Kalman filter approaches. The tracking algorithms capabilities increase the time to lose lock. They have the ability to adaptively change the integration length and the code delay separation. More than one code delay separation can be used in the same time. Large tracking errors can be detected and then corrected by a re-initialization and an acquisition-like algorithms. Detecting the navigation message is needed to increase the coherent integration; decoding it is needed to calculate the navigation solution. The decoding algorithm utilizes the message structure to enable its decoding for signals with high Bit Error Rate. The algorithms are demonstrated using simulated GPS C/A code signals, and TCXO clocks. The results have shown the algorithms ability to reliably work with 15 dB-Hz signals and acceleration over 6 g.

Ziedan, Nesreen Ibrahim

224

Flight-control/navigation inertial reference system  

NASA Technical Reports Server (NTRS)

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.

Ebner, R. E.

1977-01-01

225

Inertial navigation sensor integrated obstacle detection system  

NASA Technical Reports Server (NTRS)

A system that incorporates inertial sensor information into optical flow computations to detect obstacles and to provide alternative navigational paths free from obstacles. The system is a maximally passive obstacle detection system that makes selective use of an active sensor. The active detection typically utilizes a laser. Passive sensor suite includes binocular stereo, motion stereo and variable fields-of-view. Optical flow computations involve extraction, derotation and matching of interest points from sequential frames of imagery, for range interpolation of the sensed scene, which in turn provides obstacle information for purposes of safe navigation.

Bhanu, Bir (Inventor); Roberts, Barry A. (Inventor)

1992-01-01

226

Microwave Landing System Area Navigation  

Microsoft Academic Search

The International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARPS) states that the Time Reference Scanning Beam (TRSB) Microwave Landing System will supplant the existing Instrument Landing System (ILS) as the recognized international standard as early as 1995. The MLS provides the ability to determine the aircraft's position in three dimensional space over a large coverage volume in the

James Remer; Barry Billmann

1987-01-01

227

A simple dead-reckoning navigational system  

NASA Technical Reports Server (NTRS)

Simple navigation system is designed for vehicles operating in remote locations where it is not feasible to transport extensive equipment. System consists of four main components: directional gyrocompass to establish inertial direction; odometer to measure distance; signal processor to combine measured distance and direction; and sun compass to determine initial direction.

Walls, B. F.; Mastin, W. C.; Broussard, P., Jr.

1972-01-01

228

Inertial navigation system for mobile land vehicles  

Microsoft Academic Search

This paper describes a prototype of an inertial navigation system for use in mobile land vehicles, such as cars or mobile robots. The complete system is composed by sensors, their mechanical mount and cabling, these connect to a PC card with local processing and memory, based on a Intel 80C196KC microcontroller. The sensors used were a piezoelectric vibrating gyroscope, two

Jorge Lobo; Paulo Lucas; Jorge Dias; A. Traca de Almeida

1995-01-01

229

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

E-print Network

or distract her/his attention [6, 7 and 8]. It is known that visual and auditory information channels are performed in virtual environments under two different sensory conditions (auditory alone and auditory auditory noise and distraction exist in the environment, the navigation errors (making a wrong turn

Basdogan, Cagatay

230

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

PubMed

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

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

2013-01-01

231

Navigation in Antarctica Today: The Global Positioning System  

NSDL National Science Digital Library

After researching how the Global Positioning System is used in Antarctica and across the globe, students learn how GPS works. Throughout this weeklong activity, students collect their findings in a portfolio. The comprehensive curriculum materials contain teacher tools, which include individually downloadable readings, detailed daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, a project rubric sheet, and additional readings. Students investigate the use of the Global Positioning System (GPS)in Antarctica and across the globe. They conduct research on the Web to understand how and why GPS is used today. Students also complete a hands-on activity that is based on spatial principles similar to those used by GPS; they learn how GPS works by doing on paper the work of GPS satellites in space.

232

Performance Analysis and Architectures for INS-Aided GPS Tracking Loops  

E-print Network

characteristics, which have been exploited in the design of integrated GPS-inertial navigation and guidance from GPS and an Inertial Navigation System using either loose integration (i.e., integration are in the areas of navigation, guidance and control with an emphasis on sensor fusion and system integration

Stanford University

233

Investigation of GPS/IMU Positioning System for Mining Equipment  

SciTech Connect

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.

Ken L. Stratton

2006-09-13

234

A programmable FPGA implementation of a multi-coded BOC(m,n) signal generator for navigation systems  

Microsoft Academic Search

A new signal will be used within the modernized satellites for the global positioning system (GPS) as well as within the launch of the new European global navigation satellite system (GNSS) called Galileo, this signal will use the binary offset carrier (BOC) modulation scheme. BOC signals have very attractive features such as better tracking and immunity to multipath, as well

Mohammad S. Sharawi; Daniel N. Aloi

2008-01-01

235

INTERACTION DESIGN ISSUES FOR CAR NAVIGATION SYSTEMS Paul Curzon  

E-print Network

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

Curzon, Paul

236

Observability studies of inertial navigation systems  

NASA Technical Reports Server (NTRS)

The present work deals with an undamped three-channel inertial-navigation-system error model. It is shown that it is possible to fully observe, and thus estimate, all the states of the system. This is in contrast to a previous two-channel system, in which it was impossible to fully observe and estimate all the states of the system. The conclusions of the analysis are verified through covariance simulation, which yields identical results.

Bar-Itzhack, I. Y.; Goshen-Meskin, D.

1989-01-01

237

ION GPS '99, 14-17 September 1999, Nashville, TN Virtual Differential GPS & Road  

E-print Network

of these systems use the Global Positioning System (GPS) to initially determine the position of a ve- hicle. The Global Positioning System has become the most ex- tensively used positioning and navigation tool A novel method of map matching using the Global Posi- tioning System (GPS) has been developed for civilian

Tingley, Joseph V.

238

International GPS (Global Positioning System) Service for Geodynamics  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

239

Autonomous system for cross-country navigation  

NASA Astrophysics Data System (ADS)

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.

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

1993-05-01

240

An advanced, low cost, GPS-based animal tracking system  

Technology Transfer Automated Retrieval System (TEKTRAN)

An improved GPS-based animal tracking system is needed to meet quickly-evolving ecological research and natural resource management demands. Commercially-available tracking systems lack the data storage capacity needed to frequently collect animal location data (e.g., at less than 5-minute interval...

241

Design of gyroscope-free navigation systems  

Microsoft Academic Search

We examine the feasibility of designing a gyroscope-free inertial navigation system (INS) that uses only accelerometers to compute the linear and angular motions of a rigid body. The accelerometer output equation is derived to relate the linear and angular motions of a rigid body relative to a fixed inertial frame. A sufficient condition is given to determine if a configuration

Chin-Woo Tan; K. Mostov; P. Varaiya

2001-01-01

242

Applications of Magnetoresistive Sensors in Navigation Systems  

Microsoft Academic Search

Most navigation systems today use some type of compass to determine heading direction. Using the earths magnetic field, electronic compasses based on magnetoresistive (MR) sensors can electrically resolve better than 0.1 degree rotation. Discussion of a simple 8- point compass will be described using MR sensors. Methods for building a one degree compass using MR sensors will also be discussed.

Michael J. Caruso

243

Multiposition alignment of strapdown inertial navigation system  

Microsoft Academic Search

The authors demonstrate that the stationary alignment of strapdown inertial navigation system (SDINS) can be improved by employing the multiposition\\/technique. Using an observability analysis, it is shown that an optimal two-position alignment not only satisfies complete observability conditions but also minimizes alignment errors. This is done by analytic rank testing of the stripped observability matrix and numerical calculation of the

J. G. Lee; C. G. Park; H. W. Park

1993-01-01

244

Meta-image navigation augmenters for unmanned aircraft systems (MINA for UAS)  

NASA Astrophysics Data System (ADS)

GPS is a critical sensor for Unmanned Aircraft Systems (UASs) due to its accuracy, global coverage and small hardware footprint, but is subject to denial due to signal blockage or RF interference. When GPS is unavailable, position, velocity and attitude (PVA) performance from other inertial and air data sensors is not sufficient, especially for small UASs. Recently, image-based navigation algorithms have been developed to address GPS outages for UASs, since most of these platforms already include a camera as standard equipage. Performing absolute navigation with real-time aerial images requires georeferenced data, either images or landmarks, as a reference. Georeferenced imagery is readily available today, but requires a large amount of storage, whereas collections of discrete landmarks are compact but must be generated by pre-processing. An alternative, compact source of georeferenced data having large coverage area is open source vector maps from which meta-objects can be extracted for matching against real-time acquired imagery. We have developed a novel, automated approach called MINA (Meta Image Navigation Augmenters), which is a synergy of machine-vision and machine-learning algorithms for map aided navigation. As opposed to existing image map matching algorithms, MINA utilizes publicly available open-source geo-referenced vector map data, such as OpenStreetMap, in conjunction with real-time optical imagery from an on-board, monocular camera to augment the UAS navigation computer when GPS is not available. The MINA approach has been experimentally validated with both actual flight data and flight simulation data and results are presented in the paper.

Ҫelik, Koray; Somani, Arun K.; Schnaufer, Bernard; Hwang, Patrick Y.; McGraw, Gary A.; Nadke, Jeremy

2013-05-01

245

Space shuttle navigation analysis  

NASA Technical Reports Server (NTRS)

A detailed analysis of space shuttle navigation for each of the major mission phases is presented. A covariance analysis program for prelaunch IMU calibration and alignment for the orbital flight tests (OFT) is described, and a partial error budget is presented. The ascent, orbital operations and deorbit maneuver study considered GPS-aided inertial navigation in the Phase III GPS (1984+) time frame. The entry and landing study evaluated navigation performance for the OFT baseline system. Detailed error budgets and sensitivity analyses are provided for both the ascent and entry studies.

Jones, H. L.; Luders, G.; Matchett, G. A.; Sciabarrasi, J. E.

1976-01-01

246

Obstacle-avoiding navigation system  

DOEpatents

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.

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

1991-01-01

247

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

NASA Technical Reports Server (NTRS)

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.

Psiaki, Mark L.

2003-01-01

248

Automobile navigation system using beacon information  

Microsoft Academic Search

A navigation and communication system utilizing roadside beacons is under development. The functions and infrastructure of the Road\\/Automobile Communication System are outlined, the in-vehicle equipment is described and the results of field tests conducted in the Tokyo\\/Yokohama area are reported. The system provides the driver with such information as present location and traffic conditions, plots optimum and alternative routes to

T. Saito; J. Shima; H. Kanemitsu; Y. Tanaka

1989-01-01

249

WiFi GPS based Combined positioning Algorithm Soumaya Zirari, Philippe Canalda  

E-print Network

POSITIONING SYSTEM The Global Positioning System [3] is a passive Global Navigation Satellite System territories where traditional (and basic) positioning system (GPS, gsm or WiFi) and hybrid ones (GPS- gsm, GPS direction of the signal depending on the applications and the positioning system. In the sequel we present

Paris-Sud XI, Université de

250

Satellite emission radio interferometric earth surveying series - GPS geodetic system  

NASA Technical Reports Server (NTRS)

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.

Macdoran, P. F.

1979-01-01

251

An Inexpensive and Robust GPS/INS Attitude System for Automobiles  

E-print Network

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

Stanford University

252

Evaluating the velocity accuracy of an integrated GPS\\/INS system: Flight test results  

Microsoft Academic Search

Verifying the velocity accuracy of a GPS receiver or an integrated GPS\\/INS system in a dynamic environment is a difficult proposition when many of the commonly used reference systems have velocity uncertainities of the same order of magnitude or greater than the GPS system. The results of flight tests aboard an aircraft in which multiple reference systems simultaneously collected data

T. E. Owen; R. Wardlaw

1991-01-01

253

Satellite Navigation Systems: Policy, Commercial and Technical Interaction.  

NASA Astrophysics Data System (ADS)

This book adopts a broad perspective on positioning and navigation systems which rely on Earth orbiting satellites for their successful operation. The first of such global systems was the US Global Positioning System (GPS), and the next the Russian GLONASS system. Now studies relating to Europe's future Galileo system are gaining momentum and other nations are planning regional augmentation systems. All such systems are discussed here, particularly relating to political, commercial, legal and technical issues. The opportunities - and also the problems - of having three similar systems in operation simultaneously are examined, and several novel applications are proposed. These range from improved vehicular transport by land, sea and air, to more accurate surveying, more efficient agricultural practices and safer operations in mountainous regions. Everyone who is challenged by these topics will find this volume invaluable. ISU WWW Server; http://www.isunet.edu. Further information on ISU Symposia may also be obtained by e-mail from symposium@isu.isunet.edu Link: http://www.wkap.nl/prod/b/1-4020-1678-6

Rycroft, M.

2003-12-01

254

GOES image navigation and registration system  

NASA Astrophysics Data System (ADS)

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.

Kamel, Ahmed

1996-10-01

255

Visual navigation system for autonomous indoor blimps  

NASA Astrophysics Data System (ADS)

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.

Campos, Mario F.; de Souza Coelho, Lucio

1999-07-01

256

On intelligent transportation system based on GPS and data mining  

Microsoft Academic Search

On the basis of the effective using of the satellite information offered by GPS, this paper sets up the database of the real-time information of traffic conditions that combined road information acquired by various types of vehicles in ITS and exploit data mining software of analytical work, construct the more advanced intellectual traffic system of city in order to help

Yan Bo; Huang Yehua; Ma Xinjun

2008-01-01

257

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

NASA Astrophysics Data System (ADS)

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.

Zhang, Xiaoyue; Lin, Zhili; Zhang, Chunxi

2014-07-01

258

New mechanization equations for aided inertial navigation systems  

NASA Technical Reports Server (NTRS)

Inertial navigation equations are developed which use area navigation (RNAV) waypoints and runway references as coodinate centers. The formulation is designed for aided inertial navigation systems and gives a high numerical accuracy through all phases of flight. A new formulation of the error equations for inertial navigation systems is also presented. This new formulation reduces numerical calculations in the use of Kalman filters for aided inertial navigation systems.

Schmidt, S. F.; Bjorkman, W. S.; Conrad, B.

1973-01-01

259

Temporal and spatial precursors in the ionospheric global positioning system (GPS) total electron content observed  

E-print Network

Temporal and spatial precursors in the ionospheric global positioning system (GPS) total electron maps of the TEC derived from worldwide groundbased receivers of the global positioning system (GPS in the ionospheric global positioning system (GPS) total electron content observed before the 26 December 2004 M9

Chen, Yuh-Ing

260

Effects of Multipath and Signal Blockage on GPS Navigation in the Vicinity of the International Space Station (ISS)  

Microsoft Academic Search

A number of studies have examined GPS relative navi- gation for spacecraft performing rendezvous and docking with the International Space Station (ISS). However, these studies have not accounted for degradation in GPS naviga- tion performance due to multipath signals being reflected off of the ISS or blockage of GPS signals by the ISS. The objective of this study is to

David E. Gaylor; E. Glenn Lightsey; Kevin W. Key

261

Lunar Navigation Determination System - LaNDS  

NASA Technical Reports Server (NTRS)

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.

Quinn, David; Talabac, Stephen

2012-01-01

262

Inertial navigation systems for mobile robots  

Microsoft Academic Search

A low-cost solid-state inertial navigation system (INS) for mobile robotics applications is described. Error models for the inertial sensors are generated and included in an extended Kalman filter (EKF) for estimating the position and orientation of a moving robot vehicle. Two different solid-state gyroscopes have been evaluated for estimating the orientation of the robot. Performance of the gyroscopes with error

Billur Barshan; Hugh F. Durrant-Whyte

1995-01-01

263

The changing world of global navigation satellite systems  

NASA Astrophysics Data System (ADS)

The world of global navigation satellite systems (GNSS) has been changing very rapidly during the last years. New constellations are being developed in Europe (Galileo), India (IRNSS), Japan (QZNSS) and China (Compass), while both the US GPS and the Russian GLONASS programmes are engaged in very significant mediumto long-term improvements, which will make them even more valuable in the coming years to an ever wider range of civilian users. In addition, powerful regional augmentation systems are becoming (or have already become) operational, providing users with important real time information concerning the integrity of the signals being broadcast by those two systems: these include the US WAAS, the European EGNOS, the Japanese MSAS, the Indian GAGAN and others. Following a number of United Nations sponsored regional workshops, a report by an ad hoc UN "GNSS Action Team" and several preparatory meetings, the International Committee on GNSS (ICG) was established in December 2005 in Vienna, Austria. The ICG is an informal body with the main objective of promoting cooperation on matters of mutual interest related to civil satellite-based positioning, navigation, timing, and value-added services, as well as compatibility and interoperability among the GNSS systems. A further important objective is to encourage the use of GNSS to support sustainable development, particularly in the developing countries. The United Nations Office for Outer Space Affairs (UNOOSA) plays a key role in facilitating the work of the ICG. The members of the Committee are GNSS system providers, while international organisations representing users of GNSS can qualify for participation in the work of the Committee as associate members or observers. The interests of the space geodetic, mapping and timing communities are represented in particular through ICG associate membership of the IGS, IAG, FIG, IERS, while BIPM is an ICG observer. This paper will highlight the background of these developments and focus on the concerns of the ICG, especially from the point of view of the user organisations.

Dow, John M.; Neilan, Ruth E.; Higgins, Matt; Arias, Felicitas

264

Study of Ionospheric Response to Space Weather Disturbances in Three Dimensions Using the GPS Observation System  

Microsoft Academic Search

The Global Positioning System GPS satellites and global as well as regional networks of hundreds to thousands of ground-based permanent GPS receiver stations have become an unprecedented space weather observation system since the beginning of the new millennium The GPS observables namely carrier phase and pseudorange as well as signal power can be processed to retrieve ionospheric measurements along the

X. Pi; A. J. Mannucci; B. A. Iijima; A. Komjathy

2006-01-01

265

Global Positioning System (GPS) Time Dissemination for Real-Time Applications  

Microsoft Academic Search

This paper presents an overview of the Global Positioning System (GPS) for the potential precise time and time interval user with special reference to real -time systems. An overview of GPS operation is presented and GPS error sources are described as they relate to the timing user. A review of receiver types and receiver tasks provides the basis for understanding

Peter H. Dana

1997-01-01

266

DESIGN AND PERFORMANCE OF A ROBUST GPS/INS ATTITUDE SYSTEM FOR AUTOMOBILE  

E-print Network

DESIGN AND PERFORMANCE OF A ROBUST GPS/INS ATTITUDE SYSTEM FOR AUTOMOBILE APPLICATIONS cars has led to a growing number of GPS applications in the automobile industry. In addition of an inexpensive and ro- bust attitude system based on GPS and inertial sensors, suitable for use in automobiles

Stanford University

267

Fiber optic gyroscopes for vehicle navigation systems  

NASA Astrophysics Data System (ADS)

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.

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

1994-03-01

268

Inertial navigation system for directional surveying  

SciTech Connect

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.

Kohler, S.M.

1982-09-01

269

GPS Timing and Control System of the HAWC Detector  

E-print Network

The design and performance of the GPS Timing and Control (GTC) System of the High Altitude Water Cerenkov (HAWC) gamma ray observatory is described. The GTC system provides a GPS synchronized absolute timestamp, with an accuracy better than 1$\\mu$s, for each recorded event in HAWC. In order to avoid any slack between the recorded data and the timestamp, timestamps are injected to the main data acquisition (DAQ) system after the Front-end Electronic Boards (FEBs). When HAWC is completed, the HAWC main DAQ will use 10 time to digital converters (TDCs). In order to keep all the TDCs in sync, the GTC system provides a synchronized clock signal, coordinated trigger signal, and control signals to all TDCs.

Abeysekara, Anushka Udara; Edmunds, Dan; Linnemanna, James; Imranc, Asif; Kunded, Gerd; Wisher, Ian

2014-01-01

270

A GPS Real Time Earthquake and Tsunami (GREAT) Alert System  

Microsoft Academic Search

The GREAT Alert is a NASA-sponsored, real-time prototype system designed to enhance natural hazard warning capability and damage assessment. The system takes advantage of the increasingly available global and regional real-time GPS data, as well as advanced fault and ocean dynamics models to enable more accurate and timely assessment of the magnitude and mechanism of large earthquakes, and the magnitude

Yoaz Bar-Sever

2010-01-01

271

An Heuristic Method for GPS Surveying Stefka Fidanova  

E-print Network

, to analyze and improve the efficiency of the design of Global Positioning System (GPS) surveying networks of computational effort. The Global Positioning System is a satellite-based radio-navigation system that permits. The most widely known space systems are: the American Global Positioning System (GPS), the Russian GLObal

Fidanova, Stefka

272

National aerospace meeting of the Institute of Navigation  

NASA Astrophysics Data System (ADS)

The program for this year's aerospace meeting of The Institute of Navigation addressed developments in the evolving Global Positioning System (GPS) of navigation satellites, inertial navigation systems, and other electronic navigation systems and their applications. Also included in the program were a limited number of papers addressing the geodetic use of the GPS system.The Global Positioning System is a constellation of 18 navigation satellites being developed by the Department of Defense to provide instantaneous worldwide navigation. The system will support a multitude of military applications. The first paper by Jacobson reviewed the engineering development of GPS navigation receivers stressing the use of common hardware and software modules. A later paper by Ould described the mechanization of a digital receiver for GPS applications designed for faster acquisition of the spread spectrum satellite transmissions than analog receivers. The paper by Brady discussed the worldwide coverage that is provided by the limited number of satellites that will constitute the GPS constellation through 1983. The capability provided by the satellites presently on orbit would support a variety of experiments at almost any location. Tables of multiple satellite availability are provided for numerous worldwide locations. For civil aviation applications, Vogel addressed the satellite geometry considerations for low cost GPS user equipment, Esposito described the Federal Aviation Administration acceptance tests of a GPS navigation receiver, and Hopkins discussed the design and capability of an integrated GPS strapdown attitude and heading reference system for avionics.

Fell, Patrick

273

GPS Animations  

NSDL National Science Digital Library

This site features Flash animations that illustrate how the Global Positioning System (GPS) works. The animations depict how GPS signals are derived, compare geostationary and polar orbits, and explain satellites, ground control, and user segments, which comprise the three main GPS components. These resources are suitable for use in lectures, labs, or other teaching activities.

2008-09-12

274

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

USGS Publications Warehouse

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.

Sanchez, Richard D.

2004-01-01

275

Research on web-based ship navigation system  

Microsoft Academic Search

According to the convenient condition of wireless Internet service along inland rivers in China, the paper researched a web-based ship navigation system for inland river navigation. The system is developed with three-tier network architecture, and runs on web browsers. Based on an electronic channel chart platform developed by COM and JSP, the system provides comprehensive navigation service for ship users,

Ming-yang Pan; Bin Zhang; Jing-feng Hu

2010-01-01

276

Factor Graph Based Incremental Smoothing in Inertial Navigation Systems  

E-print Network

Factor Graph Based Incremental Smoothing in Inertial Navigation Systems Vadim Indelman, Stephen Abstract--This paper describes a new approach for informa- tion fusion in inertial navigation systems. INTRODUCTION Information fusion in inertial navigation systems is essential for any practical application

Kaess, Michael

277

Effects of Geodetic Uncertainties on a Damped Inertial Navigation System  

Microsoft Academic Search

Gravity uncertainties are an inexorable source of error in all inertial navigation systems and are particularly important in high-quality inertial navigation systems. In this paper the steady-state rms errors that are excited in a damped inertial navigation system are analytically determined for four gravity uncertainty models and two vehicle maneuver models. The statistical approach used in this paper is compared

Stanley Jordan

1973-01-01

278

Assessment of Step Determination in a GPS/Compass/IMU System for Personal  

E-print Network

in electrical engineering from National University of Colombia, Bogotá, Colombia. Currently, she is working implemented location techniques for vehicles or robots. The combination of GPS with sensors like environment is provided by GPS receivers whose accuracy range is in meters. The GPS system does not provide

279

GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System  

Microsoft Academic Search

We present a new approach to remote sensing of water vapor based on the global positioning system (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is

Michael Bevis; Steven Businger; Thomas A. Herring; Christian Rocken; Richard A. Anthes; Randolph H. Ware

1992-01-01

280

IEEE PLANS '90 - Position Location and Navigation Symposium, Las Vegas, NV, Mar. 20-23, 1990, Record  

NASA Astrophysics Data System (ADS)

Various papers on position, location, and navigation are presented. The general topics addressed include: space-based navigation systems; inertial sensor development; other radio navigation system technologies; surveying, mapping, and digital electronics technology; positioning, pointing, and stabilization of space systems; inertial systems development and applications; integrated communicaiton/navigration systems and standard avionics; application of statistical filtering to navigation technology; GPS applications and equipment in civil, governmental, and commercial areas. Also discussed are: integrated navigation and targeting systems; civil aviation and marine navigation/traffic control; geodesy, gravity measurement, and earth reference systems; GPS military applications and equipment; integrated aircraft navigation and flight control; land vehicle navigation, positioning, and information systems; differential GPS; GPS/inertial navigation; terrain aided air vehicle navigation.

281

Managing wildlife: A spatial information system for GPS collars data  

Microsoft Academic Search

ISAMUD (Integrated System for Analysis and Management of Ungulate Data) is an integrated and modular software platform developed to manage GPS collar data for wildlife management. It is based on an open source spatial database (PostgreSQL and PostGIS) and includes open source data management, geo-statistical analysis and Web services modules (R, QGIS, GRASS, MapServer, Ka-Map) and a proprietary database front-end

Francesca Cagnacci; Ferdinando Urbano

2008-01-01

282

Autonomous underwater pipeline monitoring navigation system  

NASA Astrophysics Data System (ADS)

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.

Mitchell, Byrel; Mahmoudian, Nina; Meadows, Guy

2014-06-01

283

The REFSAT approach to low-cost GPS terminals  

NASA Technical Reports Server (NTRS)

A concept utilizing a geostationary reference satellite (REFSAT) that broadcasts navigation aiding signals to low cost civil user terminals which employ the constellation of 24 NAVSTAR Global Positioning System (GPS) satellites for position determination is described. The signal acquisition, tracking and position fixing properties of such low cost, dual channel, L-band, civil user receiver designed to receive both GPS navigation and REFSAT navigation aiding signals is presented. REFSAT reduces the cost of user equipment.

Sennott, J. W.; Choudhury, A. K.; Taylor, R. E.

1979-01-01

284

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

PubMed

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

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

2014-01-01

285

INTRODUCTION The integration of GPS receivers with inertial  

E-print Network

INTRODUCTION The integration of GPS receivers with inertial navigation systems (INS) has been well only at using high-end, navigation-grade inertial systems for high-accuracy (centimeter with inertial sensors can provide many benefits for navigation, from improved accuracy to increased reliability

Calgary, University of

286

Libration Point Navigation Concepts Supporting the Vision for Space Exploration  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

287

An Autonomous Vehicle Navigation System using Panoramic Machine Vision Techniques  

E-print Network

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

Spacek, Libor

288

Automatic alignment and calibration of an inertial navigation system  

Microsoft Academic Search

In this paper we derive a simple six degree of freedom navigator, Earth-surface navigator, for terranean vehicle application, using low grade gyros. The calibration and alignment of the navigator are investigated when the system is at rest. Based on the observability of the error model when the system is at rest, a state transformation is presented. This transformation decouples the

Samer S. Saab; Kristjan T. Gunnarsson

1994-01-01

289

Synthesis of a Very Accurate Inertial Navigation System  

Microsoft Academic Search

A philosophy for the synthesis of a very accurate inertial navigation system is developed here. First, the requirements for a spherical earth navigator are determined, and the basis for a navigator error analysis is developed through the use of mathematical error models. Four types of redundant information are then considered in sequence: external speed information, redundant system gyro, external discrete

Arthur Gelb

1965-01-01

290

Tuning and Robustness Analysis for the Orion Absolute Navigation System  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

291

A LAGRANGIAN DRIFTER WITH INEXPENSIVE WIDE AREA DIFFERENTIAL GPS POSITIONING  

E-print Network

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

Kurapov, Alexander

292

Plot Your Course - Navigation  

NSDL National Science Digital Library

In this unit, students learn the very basics of navigation, including the different kinds of navigation and their purposes. The concepts of relative and absolute location, latitude, longitude and cardinal directions are explored, as well as the use and principles of maps and a compass. Students discover the history of navigation and learn the importance of math and how it ties into navigational techniques. Understanding how trilateration can determine one's location leads to a lesson on the global positioning system and how to use a GPS receiver. The unit concludes with an overview of orbits and spacecraft trajectories from Earth to other planets.

Integrated Teaching And Learning Program

293

Constrained navigation algorithms for strapdown inertial navigation systems with reduced set of sensors  

Microsoft Academic Search

This paper develops a family of algorithms for low-cost strapdown inertial navigation system for land vehicles. Constraints on the motion of land vehicles are defined. They include constraints on vehicle's orientation relative to the Earth surface, and relationship between vehicle's attitude and its velocity direction. Navigation equations are derived that assume validity of these constraints on the vehicle's motion. Compared

Aleksandr Brandt; John F. Gardner

1998-01-01

294

A Recommendation on SLR Ranging to Future Global Navigation Satellite Systems  

NASA Astrophysics Data System (ADS)

The multi-agency US Geodetic Requirements Working Group has recommended that Satellite Laser Retro- reflectors be installed on GPS III satellites as a principal component of the Positioning, Navigation, and Timing mandate of the Global Positioning System. The Working Group, which includes NASA, NGA, NOAA, NRL, USGS, and the USNO, echoes the Global Geodetic Observing System recommendation that SLR retro- reflectors be installed on all GNSS satellites. It is further recommended that the retro-reflectors conform to and hopefully exceed the minimum standard of the International Laser Ranging Service for retro-reflector cross sections of 100 million square meters for the HEO GNSS satellites to insure sufficiently accurate ranging by the global network of satellite laser ranging systems. The objective of this recommendation is to contribute to the improvement in the International Terrestrial Reference Frame, and its derivative the WGS84 reference frame, through continuing improvements in the characterization of the GPS orbits and clocks. Another objective is to provide an independent means of assessing the interoperability and accuracy of the GNSS systems and regional augmentation systems. The ranging to GNSS-mounted retro-reflectors will constitute a significant new means of space-based collocation to constrain the tie between the GPS and SLR networks that constitute over 50% of the data from which the ITRF is derived. The recommendation for the installation of SLR retro-reflectors aboard future GPS satellites is one of a number of efforts aimed at improving the accuracy and stability of ITRF. These steps are being coordinated with and supportive of the efforts of the GGOS and its services such at the VLBI2010 initiative, developing a next generation geodetic network, near real-time GPS positioning and EOP determination, and numerous efforts in the improvement of geodetic algorithms for GPS, SLR, VLBI, DORIS, and the determination of the ITRF. If past is prologue, the requirements of accuracy placed upon GNSS systems will continue to evolve at a factor of ten per decade for the lifetime of the GPS III, extending to 2025 and beyond. Global societal priorities such as sea level change measurement already require a factor of ten or more improvement in the accuracy and stability of the ITRF. Increasing accuracy requirements by civilian users for precision positioning and time keeping will certainly continue to grow at an exponential rate. The PNT accuracy of our GNSS systems will keep pace with these societal needs only if we equip the GNSS systems with the capability to identify and further reduce systematic errors.

Labrecque, J. L.; Miller, J. J.; Pearlman, M.

2008-12-01

295

A Micromechanical INS/GPS System for Small Satellites  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

296

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

E-print Network

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

297

Integrated vision\\/inertial navigation system design using nonlinear filtering  

Microsoft Academic Search

Addresses the problem of navigation system design for autonomous aircraft landing. New nonlinear filter structures are introduced to estimate the position of an aircraft with respect to a possibly moving landing site, such as a naval vessel, based on measurements provided by airborne vision and inertial sensors. By exploring the geometry of the navigation problem, the navigation filter dynamics are

I. Kaminer; A. Pascoal; Wei Kang

1999-01-01

298

The QuakeSim System for GPS Time Series Analysis  

NASA Astrophysics Data System (ADS)

We present a system for analysis of GPS time series data available to geosciences users through a web services / web portal interface. The system provides two time series analysis methods, one based on hidden Markov model (HMM) segmentation, the other based on covariance descriptor analysis (CDA). In addition, it provides data pre-processing routines that perform spike noise removal, linear de-trending, sum-of-sines removal, and common mode removal using probabilistic principle components analysis (PPCA). These components can be composed by the user into the desired series of processing steps for analysis through an intuitive graphical interface. The system is accessed through a web portal that allows both micro-scale (individual station) and macro-scale (whole network) exploration of data sets and analysis results via Google Maps. Users can focus in on or scroll through particular spatial or temporal time windows, or observe dynamic behavior by created movies that display the system state. Analysis results can be exported to KML format for easy combination with other sources of data, such as fault databases and InSAR interferograms. GPS solutions for California member stations of the plate boundary observatory from both the SOPAC and JPL gipsy context groups are automatically imported into the system as that data becomes available. We show the results of the methods as applied to these data sets for an assortment of case studies, and show how the system can be used to analyze both seismic and aseismic signals.

Granat, R. A.; Gao, X.; Pierce, M.; Wang, J.

2010-12-01

299

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

E-print Network

--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

Ge, Shuzhi Sam

300

A novel laser Doppler velocimeter and its integrated navigation system with strapdown inertial navigation  

NASA Astrophysics Data System (ADS)

In order to suppress the error accumulation effect of inertial navigation system (INS), an idea of building an integrated navigation system using a laser Doppler velocimeter (LDV) together with strapdown inertial navigation (SIN) is proposed. The basic principle of LDV is expounded while a novel LDV with advanced optical structure is designed based on the split and reuse technique, and the process of dead reckoning using an integrated system which consists of LDV and SIN is discussed detailedly. The results of theory and experiment show that: the split and reuse type LDV has great advantages of high accuracy and signal-to-noise ratio, which has greatly enhanced the position accuracy of the navigation system. The position error has been decreased from 1166 m in 2 h with pure SIN to 20 m in 2 h with the integrated system.

Zhou, Jian; Nie, Xiaoming; Lin, Jun

2014-12-01

301

A precise GPS-based time and frequency system  

NASA Technical Reports Server (NTRS)

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.

Mcnabb, Jack; Fossler, Earl

1993-01-01

302

Memetic Simulated Annealing for the GPS Surveying Problem  

E-print Network

Memetic Simulated Annealing for the GPS Surveying Problem Stefka Fidanova, Enrique Alba~na {eat,guillermo}@lcc.uma.es Abstract. In designing Global Positioning System (GPS) surveying net- work) is a satellite-based radio-navigation system that permits land, sea, and airborne users to determine their three

Fidanova, Stefka

303

Institute of Navigation, Annual Meeting, 46th, Atlantic City, NJ, June 26-28, 1990, Proceedings  

NASA Astrophysics Data System (ADS)

Topics presented include test results of GPS integration with Carrier Aircraft Inertial Navigation System, the Decimeter Positioning System, safety implications of automobile navigation systems, and precision electronic navigation in restricted waterways. Also presented are marine inertial navigation into the 21st century, some environmental effects on the differential GPS, the effect of geometry on integrity monitoring performance, and production development of small fiber optic gyros.

304

Navigation satellites  

NASA Astrophysics Data System (ADS)

The evolution, capabilities and uses of satellite-based navigation systems are explored, with emphasis on the accompanying space- and earth-based technologies. Early measurements of the Doppler shifts of Sputnik signals spurred development of the Transit satellite system as a precision navigation aid for Polaris submarines. The development of gravimetric programs to project the actual position of the satellites and the use of high frequency signals to offset ionospheric interference are noted. The design features, performances, and numerous launch and operational failures, of successive Transit spacecraft, i.e., the 5BN, 5C1 and Oscar satellites, are summarized. Details of the operational parameters and design features of the prototype and planned NAVSTAR GPS system are outlined, and plans for a SARSAT search and rescue satellite and the commercial GEOSTAR radionavigation and positioning system are described.

Weiffenbach, George C.

305

Recent developments in the HUGIN AUV terrain navigation system  

Microsoft Academic Search

This paper describes recent developments in the HUGIN AUV terrain navigation system, which uses terrain measurements in order to provide submerged position updates for the main inertial navigation system. In previous versions of the system, a prior bathymetric map database has been required, sometimes restricting the use of the system. To relax this requirement, a real-time map generator has been

Kjetil Bergh Cnonsen; Ove Kent Hagen

2011-01-01

306

Application of GPS attitude determination to gravity gradient stabilized spacecraft  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

307

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

PubMed

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

Przemyslaw, Baranski; Pawel, Strumillo

2012-01-01

308

A visual navigation system for autonomous land vehicles  

Microsoft Academic Search

A modular system architecture has been developed to support visual navigation by an autonomous land vehicle. The system consists of vision modules performing image processing, three-dimensional shape recovery, and geometric reasoning, as well as modules for planning, navigating, and piloting. The system runs in two distinct modes, bootstrap and feedforward. The bootstrap mode requires analysis of entire images to find

ALLEN M. WAXMAN; JACQUELINE J. LEMOIGNE; LARRY S. DAVIS; BABU SRINIVASAN; TODD R. KUSHNER; Eli Liang; THARAKESH SIDDALINGAIAH

1987-01-01

309

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

E-print Network

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 in all, with three satellites in GEO stationary and four in GEO synchronous orbits (Kibe & Gowrishankar

Calgary, University of

310

33 CFR 164.72 - Navigational-safety equipment, charts or maps, and publications required on towing vessels.  

Code of Federal Regulations, 2012 CFR

...position-fixing device. An electronic position-fixing device, a satellite navigational system such as the Global Positioning System (GPS) as required by 164.41, if the vessel engages in towing seaward of navigable waters of the...

2012-07-01

311

33 CFR 164.72 - Navigational-safety equipment, charts or maps, and publications required on towing vessels.  

Code of Federal Regulations, 2014 CFR

...position-fixing device. An electronic position-fixing device, a satellite navigational system such as the Global Positioning System (GPS) as required by 164.41, if the vessel engages in towing seaward of navigable waters of the...

2014-07-01

312

33 CFR 164.72 - Navigational-safety equipment, charts or maps, and publications required on towing vessels.  

Code of Federal Regulations, 2013 CFR

...position-fixing device. An electronic position-fixing device, a satellite navigational system such as the Global Positioning System (GPS) as required by 164.41, if the vessel engages in towing seaward of navigable waters of the...

2013-07-01

313

33 CFR 164.72 - Navigational-safety equipment, charts or maps, and publications required on towing vessels.  

Code of Federal Regulations, 2011 CFR

...position-fixing device. An electronic position-fixing device, a satellite navigational system such as the Global Positioning System (GPS) as required by 164.41, if the vessel engages in towing seaward of navigable waters of the...

2011-07-01

314

GPS as an orbit determination subsystems  

NASA Technical Reports Server (NTRS)

This paper evaluates the use of Global Positioning System (GPS) receivers as a primary source of tracking data for low-Earth orbit satellites. GPS data is an alternative to using range, azimuth, elevation, and range-rate (RAER) data from the Air Force Satellite Control Network antennas, the Space Ground Link System (SGLS). This evaluation is applicable to missions such as Skipper, a joint U.S. and Russian atmosphere research mission, that will rely on a GPS receiver as a primary tracking data source. The Detachment 2, Space and Missile Systems Center's Test Support Complex (TSC) conducted the evaluation based on receiver data from the Space Test Experiment Platform Mission O (STEP-O) and Advanced Photovoltaic and Electronics Experiments (APEX) satellites. The TSC performed orbit reconstruction and prediction on the STEP-0 and APEX vehicles using GPS receiver navigation solution data, SGLS RAER data, and SGLS anglesonly (azimuth and elevation) data. For the STEP-O case, the navigation solution based orbits proved to be more accurate than SGLS RAER based orbits. For the APEX case, navigation solution based orbits proved to be less accurate than SGLS RAER based orbits for orbit prediction, and results for orbit reconstruction were inconclusive due to the lack of a precise truth orbit. After evaluating several different GPS data processing methods, the TSC concluded that using GPS navigation solution data is a viable alternative to using SGLS RAER data.

Fennessey, Richard; Roberts, Pat; Knight, Robin; Vanvolkinburg, Bart

1995-01-01

315

GPS pseudolites: Theory, design, and applications  

NASA Astrophysics Data System (ADS)

Pseudolites (ground-based pseudo-satellite transmitters) can initialize carrier-phase differential GPS (CDGPS) navigation systems in seconds to perform real-time dynamic positioning with one-sigma errors as low as 1 cm. Previous CDGPS systems were rarely used due to cumbersome initialization procedures requiring up to 30 minutes; initialization of the carrier-phase integer ambiguities via pseudolite removes these constraints. This work describes pseudolites optimized for this application which cost two orders of magnitude less than previous pseudolites. Synchrolites (synchronized pseudolites) which derive their timing from individual Global Positioning System (GPS) satellites are also described. Synchrolites can replace the CDGPS reference station and datalink, while simultaneously serving to initialize CDGPS navigation. A cluster of well-placed synchrolites could enable CDGPS navigation even if only one GPS satellite signal is available. A prototype CDGPS system initialized by pseudolites and synchrolites was designed and tested. The goal of this system, known as the Integrity Beacon Landing System (IBLS), was to provide navigation accurate and reliable enough to land aircraft in bad weather. Flight test results for prototype pseudolite and synchrolite systems, including results from 110 fully automatic landings of a Boeing 737 airliner controlled by IBLS, are presented. Existing pseudolite applications are described, including simulation of the GPS constellation for indoor navigation experiments. Synchrolite navigation algorithms are developed and analyzed. New applications for pseudolites and synchrolites are proposed. Theoretical and practical work on the near/far problem is presented.

Cobb, H. Stewart

316

Differential GPS for air transport: Status  

NASA Technical Reports Server (NTRS)

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.

Hueschen, Richard M.

1993-01-01

317

GPS/INS integration by functional partitioning  

NASA Astrophysics Data System (ADS)

It is shown that a GPS/INS system integrated by functional partitioning can satisfy all of the RTCA navigation requirements and goals. This is accomplished by accurately calibrating the INS using GPS after the inertial instruments are thermally stabilized and by exploiting the very slow subsequent error growth in the INS information. In this way, autonomous integrity monitoring can be achieved using only existing or presently planned systems.

Diesel, John W.

318

The Cyclone Global Navigation Satellite System: An 8-Satellite Constellation Mission  

NASA Astrophysics Data System (ADS)

Recently, NASA selected the Cyclone Global Navigation Satellite System (CYGNSS) mission for the Earth Venture Space System. The scientific goal of CYGNSS is to better understand the development of strong winds within the core of tropical cyclones. It will allow scientists to achieve this goal by inferring the surface winds through the use of reflected Global Position Satellite (GPS) signals off the ocean surface. Each of the eight CYGNSS satellites measures both direct and indirect GPS signals. These electromagnetic waves specularly reflect off of the ocean surface, allowing the roughness to be determined. This roughness is proportional to the surface wind speed. One of the important features of using GPS signals is that they are not attenuated by heavy rain fall, allowing the wind to be inferred throughout a tropical cyclone. The eight microsats will be launched by a single launch vehicle and will spread out across their orbit over about two weeks. After this, they will provide coverage of the wind speeds within 35 degrees of the equator with relatively rapid repeat times. This talk will present the scientific goals of CYGNSS, the characteristics of the eight microsats their orbit, and the status of the mission.

Ridley, A. J.; Ruf, C. S.; Rose, R.; Scherrer, J.

2012-12-01

319

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

ERIC Educational Resources Information Center

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

Guccione, Sam

2005-01-01

320

RoSES: Robust Self-configuring Embedded Systems  

E-print Network

Institute for Complex Engineered Systems Inertial Navigation CAN Embedded Network GPS Navigation Data Collection Vehicle Stability Control Precision Navigation Synthesis Wireless Andrew CANalyzer Test Tool Experimental Testbed > > > > Application: Navigation, then Active Vehicle Stability Control Simulation testbed

Koopman, Philip

321

Development of a Water Vapor Tomography System Using Low Cost L1 GPS Receivers  

Microsoft Academic Search

A system of low cost Global Positioning System (GPS) stations is being developed to measure the three- dimensional (3-D) structure of tropospheric water vapor over a small ground network. The concept is to deploy 20 GPS stations in a network spanning 10 km to 20 km. For each of the 20 stations, we will measure the integrated water vapor from

J. Braun; C. Rocken; C. Meertens; R. Ware

322

Evaluation of the 1984 Alaska global positioning system campaign with the Bernese GPS software  

Microsoft Academic Search

During the summer of 1984 five TI-4100 global positioning system (GPS) receivers were used to measure an eight-station network in Alaska and Canada, previously measured with mobile very long baseline interferometry (VLBI) systems, with baselines ranging from 300 km to almost 2700 km. The observations have been processed in the network mode with the Bernese GPS software using orbit improvement

G. Beutler; I. Bauersima; W. Gurtner; M. Rothacher; T. Schildknecht; G. L. Mader; M. D. Abell

1987-01-01

323

GPS-Optimal Micro Air Vehicle Navigation in Degraded Environments* Jason T. Isaacs1, Ceridwen Magee2, Anantharaman Subbaraman1, Francois Quitin3, Kingsley Fregene2,  

E-print Network

, a greedy algorithm is shown to exhibit a global recurrence property. Simulations supplied with actual GPS. INTRODUCTION Unmanned Aircraft Systems (UAS) are becoming preva- lent in many civilian and military to their lower size, weight, required power, cost and ease of deployment/maintenance, the class of UAS

Hespanha, João Pedro

324

Fiber-based rotary strapdown inertial navigation system  

NASA Astrophysics Data System (ADS)

Navigation involves the integration of methodologies and systems for estimating the time-varying attitude of moving objects. A fiber strapdown inertial navigation system (FSINS) is presently used in several applications related to vehicle navigation. However, the absolute attitude and position from FSINS contain an error that increases with time. In order to improve the performance of FSINS based on our present inertial sensors, the auto-compensation of inertial sensor bias in rotation error modulation was proposed. The aim is to develop a rotary FSINS, in which the significant sensor bias is automatically compensated by rotating the inertial measurement unit (IMU), to offer the comparable navigation performance to navigation-grade IMU. In the proposed rotational technology, the IMU is rotated back and forth in azimuth through four orthogonal positions relative to the vehicle's longitudinal axis. Simulation and experimental testing are conducted for the prototype, and the results showed that the rotary FSINS's navigation performance is improved.

Sun, Wei; Gao, Yang

2013-07-01

325

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

NASA Astrophysics Data System (ADS)

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.

Doyle, Patrick T.

2013-03-01

326

A Real Time Differential GPS Tracking System for NASA Sounding Rockets  

NASA Technical Reports Server (NTRS)

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.

Bull, Barton; Bauer, Frank (Technical Monitor)

2000-01-01

327

Global Positioning System (GPS) location accuracy improvement due to Selective Availability removal  

Microsoft Academic Search

Global Positioning System (GPS) is an important new technology for spatio-temporal behaviour studies of animals. Differential correction improves location accuracy. Previously, it mostly removed partially the influence of Selective Availability (SA). SA was deactivated in May 2000. The aim of this study was to quantify the influence of SA cancellation on location accuracy of various GPS receivers. We tested the

Christophe Adrados; Irne Girard; Jean-Paul Gendner; Georges Janeau

2002-01-01

328

Analysis of a choke ring groundplane for multipath control in Global Positioning System (GPS) applications  

Microsoft Academic Search

In this paper a computational scheme is presented for accurately predicting the farfield amplitude and phase characteristics of Global Positioning System (GPS) antennas flush-mounted to a corrugated groundplane. The algorithm developed is particularly well-suited in beamshaping of (GPS) antennas in order to provide a high level of multipath rejection. The usefulness of the analytical model has been verified by the

James M. Tranquilla; J. P. Carr; Hussain M. Al-Rizzo

1994-01-01

329

Global Positioning System (GPS) estimates of crustal deformation in the Marmara Sea region, Northwestern Anatolia  

Microsoft Academic Search

In the Marmara Sea region the relative motion between the Anatolian and Eurasian lithosphere has been measured by means of the modern techniques of space geodesy using the Global Positioning System (GPS). In order to resolve in detail the kinematic field within the active earthquake belts of Northwestern Anatolia, two GPS campaigns were carried out across a dense network consisting

Christian Straub; Hans-Gert Kahle

1994-01-01

330

Integrating Inertial Sensors With Global Positioning System (GPS) for Vehicle Dynamics Control  

Microsoft Academic Search

This paper demonstrates a method of estimating several key vehicle statessideslip angle, longitudinal velocity, roll and gradeby combining automotive grade inertial sen- sors with a Global Positioning System (GPS) receiver. Kinematic Kalman filters that are independent of uncertain vehicle parameters integrate the inertial sensors with GPS to provide high update estimates of the vehicle states and the sensor biases. Using

Jihan Ryu; J. Christian Gerdes

2004-01-01

331

Development of an Integrated Low-Cost GPS/Rate Gyro System  

E-print Network

Development of an Integrated Low-Cost GPS/Rate Gyro System for Attitude Determination Chaochao Wang of Calgary) The use of low-cost GPS receivers and antennas for attitude determination can significantly, the carrier phase measurements from low-cost equipment are subject to additional carrier phase measurement

Calgary, University of

332

Strapdown inertial navigation system algorithms based on dual quaternions  

Microsoft Academic Search

The design of strapdown inertial navigation system (INS) algorithms based on dual quaternions is addressed. Dual quaternion is a most concise and efficient mathematical tool to represent rotation and translation simultaneously, i.e., the general displacement of a rigid body. The principle of strapdown inertial navigation is represented using the tool of dual quaternion. It is shown that the principle can

Yuanxin Wu; Xiaoping Hu; Dewen Hu; Tao Li; Junxiang Lian

2005-01-01

333

Epipolar Constraints for Vision-Aided Inertial Navigation  

Microsoft Academic Search

This paper describes a new method to improve inertial navigation using feature-based constraints from one or more video cameras. The proposed method lengthens the period of time during which a human or vehicle can navigate in GPS-deprived environments. Our approach integrates well with existing navigation systems, because we invoke general sensor models that represent a wide range of available hard-

David D. Diel; Paul Debitetto; Seth J. Teller

2005-01-01

334

A GPS Receiver for Lunar Missions  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

335

Navigation Flight Test Results from the Low Power Transceiver Communications and Navigation Demonstration on Shuttle (CANDOS) Experiment  

NASA Technical Reports Server (NTRS)

This paper presents the Global Positioning System (GPS) navigation results from the Communications and Navigation Demonstration on Shuttle (CANDOS) experiment flown on STS-107. This experiment was the initial flight of a Low Power Transceiver (LPT) that featured high capacity space- space and space-ground communications and GPS- based navigation capabilities. The LPT also hosted the GPS Enhanced Orbit Determination Experiment (GEODE) orbit determination software. All CANDOS test data were recovered during the mission using LPT communications links via the Tracking and Data Relay Satellite System (TDRSS). An overview of the LPT s navigation software and the GPS experiment timeline is presented, along with comparisons of test results to the NASA Johnson Space Center (JSC) real-time ground navigation vectors and Best Estimate of Trajectory (BET).

Haas, Lin; Massey, Christopher; Baraban, Dmitri

2003-01-01

336

A Navigation System for Computer Assisted Unicompartmental Arthroplasty  

Microsoft Academic Search

http:\\/\\/www.ior.it\\/biomec\\/ Abstract. This work presents an overview of a prototype navigation system for computer assisted unicompartmental arthroplasty. The navigation system allows the surgeon to use a minimally invasive surgical technique, solving the problems due to a restricted knee exposure with an augmented reality environment. The key feature of the system is an interactive graphical interface in which a 3D model

Maurilio Marcacci; Oliver Tonet; Giuseppe Megali; Paolo Dario; Maria Chiara Carrozza; Laura Nofrini; Pier Francesco La Palombara

2000-01-01

337

A robust data fusion scheme for integrated navigation systems employing fault detection methodology augmented with fuzzy adaptive filtering  

NASA Astrophysics Data System (ADS)

Integrated navigation systems for various applications, generally employs the centralized Kalman filter (CKF) wherein all measured sensor data are communicated to a single central Kalman filter. The advantage of CKF is that there is a minimal loss of information and high precision under benign conditions. But CKF may suffer computational overloading, and poor fault tolerance. The alternative is the federated Kalman filter (FKF) wherein the local estimates can deliver optimal or suboptimal state estimate as per certain information fusion criterion. FKF has enhanced throughput and multiple level fault detection capability. The Standard CKF or FKF require that the system noise and the measurement noise are zero-mean and Gaussian. Moreover it is assumed that covariance of system and measurement noises remain constant. But if the theoretical and actual statistical features employed in Kalman filter are not compatible, the Kalman filter does not render satisfactory solutions and divergence problems also occur. To resolve such problems, in this paper, an adaptive Kalman filter scheme strengthened with fuzzy inference system (FIS) is employed to adapt the statistical features of contributing sensors, online, in the light of real system dynamics and varying measurement noises. The excessive faults are detected and isolated by employing Chi Square test method. As a case study, the presented scheme has been implemented on Strapdown Inertial Navigation System (SINS) integrated with the Celestial Navigation System (CNS), GPS and Doppler radar using FKF. Collectively the overall system can be termed as SINS/CNS/GPS/Doppler integrated navigation system. The simulation results have validated the effectiveness of the presented scheme with significantly enhanced precision, reliability and fault tolerance. Effectiveness of the scheme has been tested against simulated abnormal errors/noises during different time segments of flight. It is believed that the presented scheme can be applied to the navigation system of aircraft or unmanned aerial vehicle (UAV).

Ushaq, Muhammad; Fang, Jiancheng

2013-10-01

338

Precise time and Time Interval (PTTI) measurements from the navigation technology satellites and the GPS NAVSTAR-4 satellite  

NASA Technical Reports Server (NTRS)

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.

Buisson, J. A.; Mccaskill, T., B.; Oaks, O. J.; Jeffries, M. M.; Stebbins, S. B.

1979-01-01

339

Franz BLAUENSTEINER: GPS/IMU Integration for the precise determination of high kinematic flighttrajectories  

E-print Network

navigation system (IMU) are mounted on and within the aircraft. Without an inertial navigation of the inertial navigation system, a proper densification of the obtained parameters is ensured. Both be solved using measurements of different sensors. Therefore a GPS/GLONASS receiver and an inertial

Schuh, Harald

340

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...

341

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 producers farm near Plains, Texas, in 2006. The field test identi...

342

How Do Global Positioning Systems, or GPS, Work?  

NSDL National Science Digital Library

A movie of students interviewing a NASA expert, who explains basic GPS principles. Simple, but clear description of how trilateration works with a two-dimensional model vs 3-D. Appropriate for the 6-8 grade range.

Nasa; Knockout, Video C.

343

GPS instrumentation performance as an ICBM guidance system evaluator  

NASA Astrophysics Data System (ADS)

GPS performance on two Minuteman III flight tests is analyzed. It is shown how data of this quality can provide superior evaluation of total guidance error and can be used to identify inflight guidance anomalies. The GPS data on these flights exhibit short-term accuracy equal to the predicted levels. Typically, random errors on the order of 2 ft and .01 ft/sec (for a one-second average) are obtained. This makes possible a direct observation of PIGA magnetic sensitivity effects during the PBV period by an external sensor. The absolute accuracy is less easily evaluated owing to a lack of suitable standard. The GPS is found to be clearly more accurate than the radars that also tracked the missile, and the post-fit residuals are found to be consistent with a high level of total accuracy. It is concluded that the total accuracy is consistent with the predicted GPS performance.

Barkley, R. L., Jr.; Hietzke, W. H.

344

Cyclone Global Navigation Satellite System (CYGNSS) Mission Overview  

E-print Network

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

Eustice, Ryan

345

Discrete-time observers for inertial navigation systems  

E-print Network

In this thesis, we derive an exact deterministic nonlinear observer to compute the continuous-time states of inertial navigation system based on partial discrete measurements, the so-called strapdown problem. Nonlinear ...

Zhao, Yong, 1980-

2004-01-01

346

Neural network correction of a vector gravitoinertial navigation system  

NASA Astrophysics Data System (ADS)

The concept and model of correction of a 3D inertial navigation system capable of estimating earth's gravitational field anomalies are suggested. The results of the computational experiment are presented.

Devyatisil'nyi, A. S.

2013-12-01

347

In-field calibration of the Navigation Dosimetry System (NAVIDOS) during solar minimum conditions  

NASA Astrophysics Data System (ADS)

The NAVIgation DOsimetry System (NAVIDOS) comprises a complete readout system for a radiation detector, an air pressure sensor and a GPS receiver. The detector system DOSTEL uses silicon detectors which make NAVIDOS light weighted and compact in size. Therefore, NAVIDOS is well suited to be installed on board aircraft. The calibration of NAVIDOS in terms of ambient dose equivalent is done by an in-field comparison with the PTB reference instrument ?DOS. We also show that the dependence of these results on the vertical cut-off rigidity can be explained by the low response of the silicon detectors for neutrons. Therefore, in-flight measurements have been performed together with the PTB reference instrument ?DOS. The dose rates, calculated using the PTB code FDOScalc, were verified with these ?DOS measurements. The calibration of NAVIDOS was done with FDOScalc and results in calibration factors between 3.4 in the polar and 2.4 in the equator region.

Mller, T.; Burda, O.; Burmeister, S.; Heber, B.; Langner, F.; Wissmann, F.

2012-06-01

348

System and method for generating attitude determinations using GPS  

NASA Technical Reports Server (NTRS)

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.

Cohen, Clark E. (Inventor)

1996-01-01

349

Fault Tolerance of the Global Navigation SatelliteSystem using System-LevelDiagnosis  

E-print Network

. With augmentations based in other countries, the GNSS becomes a truly global positioning system, able to track known probabilistic approach. Introduction The Global Positioning System (GPS) is a space- based

Thulsiraman, Krishnaiyan

350

The Effect of Helicopter Rotors on GPS Signal Reception  

NASA Astrophysics Data System (ADS)

This paper presents the results of an experiment to investigate the impact of helicopter rotor blades on GPS signal reception. An offshore transport helicopter was equipped with a measurement system including a TSO-C129 compliant receiver and a custom research receiver. GPS signals passing through rotor discs of this aircraft were found to suffer a reduction in received signal strength, leading to potential navigation and RAIM availability concerns. The phenomenon will vary between installations and receiver types. Test procedures to identify the occurrence of the phenomenon in operational GPS installations are presented, together with possible in-service monitoring programs to assess the impact on the navigation function.

Brodin, Gary; Cooper, John; Walsh, David; Stevens, Jeff

2005-09-01

351

ION NTM 2006, January 18-20, 2006, Monterey, CA GPS and Galileo Performance Evaluations for  

E-print Network

and the modernization of the current Global Positioning System (GPS) will substantially increase the available signals Global Positioning System (GPS) and Galileo will provide users with new positioning capabilities to Global Navigation Satellite Systems (GNSS) users. Past simulation studies have shown that Galileo

Calgary, University of

352

Low-frequency radio navigation system  

NASA Technical Reports Server (NTRS)

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.

Wallis, D. E. (inventor)

1983-01-01

353

Context-Aware Indoor Navigation  

Microsoft Academic Search

Over the past few years, several technological advances have been made to enable locating people in indoor settings, where\\u000a way finding is something we do on a daily basis. In a similar way as it happened with GPS and todays popular outdoor navigation\\u000a systems, indoor navigation is set to become one of the first, truly ubiquitous services that will make

Fernando Lyardet; Diego Wong Szeto; Erwin Aitenbichler

2008-01-01

354

Using Ontologies for Adaptive Navigation Support in Educational Hypermedia Systems  

Microsoft Academic Search

Educational hypermedia systems seek to provide adaptive naviga- tion, whereas intelligent web-based learning systems seek to provide adaptive courseware generation. The design of powerful frameworks by merging the ap- proaches used in the above mentioned systems is recognized as one of the most interesting questions in adaptive web-based educational systems. In this paper we address adaptive navigation support in educational

Pythagoras Karampiperis; Demetrios Sampson

2004-01-01

355

GPS meteorology - Remote sensing of atmospheric water vapor using the Global Positioning System  

NASA Technical Reports Server (NTRS)

We present a new approach to remote sensing of water vapor based on the Global Positioning System (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is retrieved by stochastic filtering of the GPS data. Given surface temperature and pressure readings at the GPS receiver, the retrieved ZWD can be transformed with very little additional uncertainty into an estimate of the integrated water vapor (IWV) overlying that receiver. Networks of continuously operating GPS receivers are being constructed by geodesists, geophysicists, and government and military agencies, in order to implement a wide range of positioning capabilities. These emerging GPS networks offer the possibility of observing the horizontal distribution of IWV or, equivalently, precipitate water with unprecedented coverage and a temporal resolution of the order of 10 min. These measurements could be utilized in operational weather forecasting and in fundamental research into atmospheric storm systems, the hydrologic cycle, atmospheric chemistry, and global climate change.

Bevis, Michael; Businger, Steven; Herring, Thomas A.; Rocken, Christian; Anthes, Richard A.; Ware, Randolph H.

1992-01-01

356

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)

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.

Mcgee, L. A.; Smith, G. L.; Hegarty, D. M.; Merrick, R. B.; Carson, T. M.; Schmidt, S. F.

1970-01-01

357

Robust GPS autonomous signal quality monitoring  

NASA Astrophysics Data System (ADS)

The Global Positioning System (GPS), introduced by the U.S. Department of Defense in 1973, provides unprecedented world-wide navigation capabilities through a constellation of 24 satellites in global orbit, each emitting a low-power radio-frequency signal for ranging. GPS receivers track these transmitted signals, computing position to within 30 meters from range measurements made to four satellites. GPS has a wide range of applications, including aircraft, marine and land vehicle navigation. Each application places demands on GPS for various levels of accuracy, integrity, system availability and continuity of service. Radio frequency interference (RFI), which results from natural sources such as TV/FM harmonics, radar or Mobile Satellite Systems (MSS), presents a challenge in the use of GPS, by posing a threat to the accuracy, integrity and availability of the GPS navigation solution. In order to use GPS for integrity-sensitive applications, it is therefore necessary to monitor the quality of the received signal, with the objective of promptly detecting the presence of RFI, and thus provide a timely warning of degradation of system accuracy. This presents a challenge, since the myriad kinds of RFI affect the GPS receiver in different ways. What is required then, is a robust method of detecting GPS accuracy degradation, which is effective regardless of the origin of the threat. This dissertation presents a new method of robust signal quality monitoring for GPS. Algorithms for receiver autonomous interference detection and integrity monitoring are demonstrated. Candidate test statistics are derived from fundamental receiver measurements of in-phase and quadrature correlation outputs, and the gain of the Active Gain Controller (AGC). Performance of selected test statistics are evaluated in the presence of RFI: broadband interference, pulsed and non-pulsed interference, coherent CW at different frequencies; and non-RFI: GPS signal fading due to physical blockage and multipath. Results are presented which verify the effectiveness of these proposed methods. The benefits of pseudolites in reducing service outages due to interference are demonstrated. Pseudolites also enhance the geometry of the GPS constellation, improving overall system accuracy. Designs for pseudolites signals, to reduce the near-far problem associated with pseudolite use, are also presented.

Ndili, Awele Nnaemeka

358

Presented at ION NTM 2005 San Diego, CA January 24-26, 2005 1/12 Performance Comparison of Kinematic GPS  

E-print Network

research areas since 1998, including satellite-based navigation, inertial navigation, reliability analysis, and has worked extensively on the integration of GPS and inertial navigation systems for precise aircraft and a tactical- grade inertial navigation system (INS) have previously been investigated using the Honeywell HG

Calgary, University of

359

Navigating at the Speed of Satellites  

NSDL National Science Digital Library

For thousands of years, navigators have looked to the sky for direction. Today, celestial navigation has simply switched from using natural objects to human-created satellites. A constellation of satellites, called the Global Positioning System, and hand-held receivers allow for very accurate navigation. In this lesson, students investigate the fundamental concepts of GPS technology trilateration and using the speed of light to calculate distances.

Integrated Teaching And Learning Program

360

Overview of how the Global Positioning System (GPS) is used to study earthquakes  

NSDL National Science Digital Library

This module allows students to interactively explore the use of the Southern California Integrated GPS Network (SCIGN) and its data in earthquake studies. The four major sections, Plate Tectonics, Earthquakes, Global Positioning Systems (GPS), and Space Technology at Work, include background material and activities; the first three sections focus primarily on introducing satellite technology and tectonic phenomena, and the final section serves to integrate knowledge learned in the first three by allowing students to use real SCIGN data in their investigations into plate tectonics, earthquakes, and GPS.

Glasscoe, Maggie

361

Overview of How the Global Positioning System (GPS) is Used to Study Earthquakes  

NSDL National Science Digital Library

This module allows students to interactively explore the use of the Southern California Integrated GPS Network (SCIGN) and its data in earthquake studies. The four major sections, Plate Tectonics, Earthquakes, Global Positioning Systems (GPS), and Space Technology at Work, include background material and activities; the first three sections focus primarily on introducing satellite technology and tectonic phenomena, and the final section serves to integrate knowledge learned in the first three by allowing students to use real SCIGN data in their investigations into plate tectonics, earthquakes, and GPS.

Glasscoe, Maggi

2011-05-17

362

The future of GPS-based electric power system measurements, operation and control  

SciTech Connect

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.

Rizy, D.T. [Oak Ridge National Lab., TN (United States); Wilson, R.E. [Western Area Power Administration, Golden, CO (United States); Martin, K.E.; Litzenberger, W.H. [Bonneville Power Administration, Portland, OR (United States); Hauer, J.F. [Pacific Northwest National Lab., Richland, WA (United States); Overholt, P.N. [Dept. of Energy, Washington, DC (United States); Sobajic, D.J. [Electric Power Research Inst., Palo Alto, CA (United States)

1998-11-01

363

Vision-based augmented reality computer assisted surgery navigation system  

NASA Astrophysics Data System (ADS)

A vision-based Augmented Reality computer assisted surgery navigation system is presented in this paper. It applies the Augmented Reality technique to surgery navigation system, so the surgeon's vision of the real world is enhanced. In the system, the camera calibration is adopted to calculate the cameras projection matrix, and then make the virtual-real registration by using the transformation relation. The merging of synthetic 3D information into user's vision is realized by texture technique. The experiment results demonstrate the feasibility of the system we have designed.

Sun, Lei; Chen, Xin; Xu, Kebin; Li, Xin; Xu, Wei

2007-12-01

364

A goggle navigation system for cancer resection surgery  

NASA Astrophysics Data System (ADS)

We describe a portable fluorescence goggle navigation system for cancer margin assessment during oncologic surgeries. The system consists of a computer, a head mount display (HMD) device, a near infrared (NIR) CCD camera, a miniature CMOS camera, and a 780 nm laser diode excitation light source. The fluorescence and the background images of the surgical scene are acquired by the CCD camera and the CMOS camera respectively, co-registered, and displayed on the HMD device in real-time. The spatial resolution and the co-registration deviation of the goggle navigation system are evaluated quantitatively. The technical feasibility of the proposed goggle system is tested in an ex vivo tumor model. Our experiments demonstrate the feasibility of using a goggle navigation system for intraoperative margin detection and surgical guidance.

Xu, Junbin; Shao, Pengfei; Yue, Ting; Zhang, Shiwu; Ding, Houzhu; Wang, Jinkun; Xu, Ronald

2014-02-01

365

A T-DMB navigation system for seamless positioning in both indoor and outdoor environments  

NASA Astrophysics Data System (ADS)

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.

Moon, Gong Bo; Chun, Se Bum; Hur, Moon Beom; Jee, Gyu-In

2014-12-01

366

A sonar-based mapping and navigation system  

Microsoft Academic Search

This paper describes a sonar-based mapping and navigation system for autonomous mobile robots operating in unknown and unstructured surroundings. The system uses sonar range data to build a multileveled description of the robot's environment. Sonar maps are represented in the system along several dimensions: the Abstraction axis, the Geographical axis, and the Resolution axis. Various kinds of problem-solving activities can

A. Elfes

1986-01-01

367

Automated Endoscope Navigation and Advisory System from medical imaging  

Microsoft Academic Search

In this paper, we present a review of the research conducted by our group to design an automatic endoscope navigation and advisory system. The whole system can be viewed as a two-layer system. The first layer is at the signal level, which consists of the processing that will be performed o n a series of images to extract all the

Chee Keong Kwoh; Gul Nawaz Khan; Duncan Fyfe Gillies

1999-01-01

368

Automated endoscopic navigation and advisory system from medical image  

Microsoft Academic Search

In this paper, we present a review of the research conducted by our group to design an automatic endoscope navigation and advisory system. The whole system can be viewed as a two-layer system. The first layer is at the signal level, which consists of the processing that will be performed on a series of images to extract all the identifiable

Chee K. Kwoh; Gul N. Khan; Duncan F. Gillies

1999-01-01

369

Performance evaluation system for inertial navigation equipment  

NASA Technical Reports Server (NTRS)

Testing system studies inertial characteristics of gyroscopic devices. System consisting of instrument support package, dynamic test table, torque control electronics, and real-time computer evaluates performance of prototype gyroscopic strapdown units in inertial-grade attitude-reference systems. System is applicable to commercial aircraft.

Mc Kern, R. A.

1971-01-01

370

An improved high precision ionospheric total electron content modeling using GPS  

Microsoft Academic Search

Space-based radio navigation systems such as the Global Positioning System (GPS) can provide us with a unique opportunity to study the effect of the ionosphere as the signals propagate from the satellites to the GPS receivers. Based on a modified version of the University of New Brunswick's (UNB) DIPOP software package, the authors enhanced the algorithm to model ionospheric total

Attila Komjathy; George H. Born; David N. Anderson

2000-01-01

371

Global positioning system pseudolite-based relative navigation.  

SciTech Connect

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.

Monda, Eric W. (University of Texas, Austin, TX)

2004-03-01

372

Realization of the Terrestrial Reference System by a reprocessed global GPS network  

Microsoft Academic Search

We present a GPS-only reference frame named PDR05 (Potsdam-Dresden-Reprocessing TRF 2005) based on the results of a homogeneous reprocessing of a global GPS network over the time span 1994.02006.0. The reference frame is realized in the center of mass (CM) system. This implies that a self-consistent model considering the reference frame and loading dynamics has been applied. The determined set

A. Rlke; R. Dietrich; M. Fritsche; M. Rothacher; P. Steigenberger

2008-01-01

373

Realization of the Terrestrial Reference System by a reprocessed global GPS network  

Microsoft Academic Search

We present a GPS-only reference frame named PDR05 (Potsdam-Dresden-Reprocessing TRF 2005) based on the results of a homogeneous reprocessing of a global GPS network over the time span 1994.0-2006.0. The reference frame is realized in the center of mass (CM) system. This implies that a self-consistent model considering the reference frame and loading dynamics has been applied. The determined set

A. Rlke; R. Dietrich; M. Fritsche; M. Rothacher; P. Steigenberger

2008-01-01

374

CARDIOSMART: intelligent cardiology monitoring system using GPS\\/GPRS networks  

Microsoft Academic Search

Cardiosmart project is based on a portable terminal for the acquisition, pre-processing and transmission of cardiac signals and the GPRS network (PAC) used to send the ECG signal to a host computer in the medical services provider centre or a specialist consulting room. The PAC terminal includes a GPRS modem for data transmission, a GPS device to provide an accurate

M. Elena; J. M. Quero; S. L. Toral; C. L. Tarrida; J. A. Segovia; L. G. Franquelo

2002-01-01

375

An Application of UAV Attitude Estimation Using a Low-Cost Inertial Navigation System  

NASA Technical Reports Server (NTRS)

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.

Eure, Kenneth W.; Quach, Cuong Chi; Vazquez, Sixto L.; Hogge, Edward F.; Hill, Boyd L.

2013-01-01

376

Ideas for Future GPS Timing Improvements  

NASA Technical Reports Server (NTRS)

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.

Hutsell, Steven T.

1996-01-01

377

Desktop-VR system for preflight 3D navigation training  

NASA Astrophysics Data System (ADS)

Crews who inhabit spacecraft with complex 3D architecture frequently report inflight disorientation and navigation problems. Preflight virtual reality (VR) training may reduce those risks. Although immersive VR techniques may better support spatial orientation training in a local environment, a non-immersive desktop (DT) system may be more convenient for navigation training in "building scale" spaces, especially if the two methods achieve comparable results. In this study trainees' orientation and navigation performance during simulated space station emergency egress tasks was compared while using immersive head-mounted display (HMD) and DT-VR systems. Analyses showed no differences in pointing angular-error or egress time among the groups. The HMD group was significantly faster than DT group when pointing from destination to start location and from start toward different destination. However, this may be attributed to differences in the input device used (a head-tracker for HMD group vs. a keyboard touchpad or a gamepad in the DT group). All other 3D navigation performance measures were similar using the immersive and non-immersive VR systems, suggesting that the simpler desktop VR system may be useful for astronaut 3D navigation training.

Aoki, Hirofumi; Oman, Charles M.; Buckland, Daniel A.; Natapoff, Alan

378

Causal Analysis Methodology of Multisensor Systems based on GNSS  

E-print Network

(Global Navigation Satellite Sys- tems) like the GPS (Global Positioning System) or the future Galileo Systems) - the GPS (Global Positioning System) - was designed by the DoD (Department of Defense) of United

Boyer, Edmond

379

Borehole survey system utilizing strapdown inertial navigation  

SciTech Connect

A signal processing method is described for use in borehole surveys, consisting of: (a) transforming the acceleration signals in the first coordinate system to obtain inertial signals representative of movement of the probe in a second coordinate system that is fixed relative to the earth, the inertial signals in the second coordinate system including probe velocity signals; (b) generating a signal representative of the amount of cable being fed into the entrance opening of the borehole; (c) processing the signal representative of the amount of cable being feed into the entrance opening of the borehole; (d) transforming the inertial signals representative of movement of the probe in the second coordinate system into inertial signals representative of movement of the probe in the first coordinate system; (e) combining the signal representative of the progress of the probe along the borehole with the inertial signals representative of movement of the probe in the first coordinate system to obtain error signals; (f) transforming the error signals into the second coordinate system to obtain error correction signals; (g) combining the error correction signals with the inertial signals representative of movement of the probe in the second coordinate system to obtain corrected probe velocity signals; and (h) integrating the corrected probe velocity signals to obtain signals representative of the course of the borehole relative to the second coordinate system.

Hulsing, R.H.

1989-03-14

380

Synthetic Aperture Digital Beamsteering Array for Global Positioning System Interference Mitigation: A Study on Array Topology  

E-print Network

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...

Harms, Joel K

2014-05-20

381

An Integrated System for Autonomous Off-Road Navigation  

Microsoft Academic Search

In this paper, we report on experiments with 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 main- tains a representation of the environment in the vicinity of the vehicle, and a planning

Dirk Langer; Julio K. Rosenblatt; Martial Hebert

1994-01-01

382

A Reactive System For Off-Road Navigation  

Microsoft Academic Search

In this paper; we describe a core system for autonomous navigation in outdoor natural ter- rain. 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 main- tains a representation of the environment in the vicinity of the vehicle, and a planning module which

D. Langer; J. K. Rosenblatt; M. Hebert

1994-01-01

383

An integrated system for autonomous off-road navigation  

Microsoft Academic Search

In this paper, we report on experiments with 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

D. Langer; J. K. Rosenblatt; M. Hebert

1994-01-01

384

A behavior-based system for off-road navigation  

Microsoft Academic Search

We describe a core system for autonomous navigation in outdoor natural terrain. The system consists of three parts: a perception module that processes range images to identify untraversable regions of the terrain, a local map management module that maintains a representation of the environment in the vicinity of the vehicle, and a planning module that issues commands to the vehicle

D. Langer; J. K. Rosenblatt; M. Hebert

1994-01-01

385

Taux: A System for Evaluating Sound Feedback in Navigational Tasks  

ERIC Educational Resources Information Center

This thesis presents the design and development of an evaluation system for generating audio displays that provide feedback to persons performing navigation tasks. It first develops the need for such a system by describing existing wayfinding solutions, investigating new electronic location-based methods that have the potential of changing these

Lutz, Robert J.

2008-01-01

386

Expected Navigation Flight Performance for the Magnetospheric Multiscale (MMS) Mission  

NASA Technical Reports Server (NTRS)

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.

Olson, Corwin; Wright, Cinnamon; Long, Anne

2012-01-01

387

Accounting for GalileoGPS inter-system biases in precise satellite positioning  

NASA Astrophysics Data System (ADS)

Availability of two overlapping frequencies L1/E1 and L5/E5a of the signals transmitted by GPS and Galileo systems offers the possibility of tightly combining observations from both systems in a single observational model. A tightly combined observational model assumes a single reference satellite for all observations from both Galileo and GPS systems. However, when inter-system double-differenced observations are created, receiver inter-system bias is introduced. This study presents the results and the methodology for estimation and accounting for phase and code GPS-Galileo inter-system bias in precise relative positioning. The research investigates the size and temporal stability of the estimated bias for different receiver pairs as well as examines the influence of accounting for the inter-system bias on the user position solution. The obtained numerical results are based on four experiments carried out at different locations and time periods using both real and simulated GNSS data.

Paziewski, Jacek; Wielgosz, Pawel

2015-01-01

388

Approximate Nonlinear Filtering and its Application in Navigation B. Azimi-Sadjadi  

E-print Network

for a combination of inertial navigation system (INS) and global positioning system (GPS), referred to as integratedApproximate Nonlinear Filtering and its Application in Navigation B. Azimi-Sadjadi and P regular particle filtering in navigation performance, and extended Kalman filter as well when satellite

Del Moral , Pierre

389

Selected bibliography of OMEGA, VLF and LF techniques applied to aircraft navigation systems  

NASA Technical Reports Server (NTRS)

A bibliography is presented which includes references to the OMEGA navigation system, very low frequencies, time-frequency measurements, air traffic control, radio navigation, and applications of OMEGA.

1974-01-01

390

Simulation of an Inertial Acoustic Navigation System With Range Aiding for an Autonomous Underwater Vehicle  

Microsoft Academic Search

This paper presents an integrated navigation system for underwater vehicles to improve the performance of a conventional inertial acoustic navigation system by introducing range measurement. The integrated navigation system is based on a strapdown inertial navigation system (SDINS) accompanying range sensor, Doppler velocity log (DVL), magnetic compass, and depth sensor. Two measurement models of the range sensor are derived and

Pan-Mook Lee; Bong-Huan Jun; Kihun Kim; Jihong Lee; Taro Aoki; Tadahiro Hyakudome

2007-01-01

391

Magnetometer and differential carrier phase GPS-aided INS for advanced vehicle control  

Microsoft Academic Search

This paper describes the design, analysis, implementation, and experimental results of a triple redundancy navigation system incorporating magnetometer, inertial, and carrier phase differential Global Positioning System (GPS) measurements. The navigation system is able to accurately estimate vehicle attitude (including yaw) as long as the vehicle velocity is not zero. The motivating application was lateral vehicle control for intelligent highway systems.

Yunchun Yang; Jay A. Farrell

2003-01-01

392

GPS Interferometry  

NASA Technical Reports Server (NTRS)

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.

Vangrass, Frank

1992-01-01

393

An integrated GPS\\/INS\\/baro and radar altimeter system for aircraft precision approach landings  

Microsoft Academic Search

Currently, the Department of Defense (DOD) and the commercial airline industry are utilizing the Instrument Landing System (ILS) during aircraft landings for precision approaches. The replacement system for the aging ILS was thought to be the Microwave Landing System (MLS). Instead, use of the Global Positioning System (GPS) is now thought to be a viable replacement for ILS precision approaches.

Robert A. Gray; Peter S. Maybeck

1995-01-01

394

Triply redundant integrated navigation and asset visibility system  

SciTech Connect

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.

Smith, Stephen F.; Moore, James A.

2013-01-22

395

Triply redundant integrated navigation and asset visibility system  

SciTech Connect

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.

Smith, Stephen F. (Loudon, TN); Moore, James A. (Powell, TN)

2011-11-29

396

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Air Traffic Service (ATS) route structure to be used by suitably equipped helicopters having IFR- approved Global Positioning System (GPS)/Global Navigation Satellite System (GNSS) equipment. Additionally, the FAA is proposing to...

2011-03-08

397

Potential of Global Positioning System (GPS) to measure frequencies of oscillations of engineering structures  

NASA Astrophysics Data System (ADS)

Global Positioning System (GPS) has been successfully used to measure displacements of oscillating flexible civil engineering structures such as long suspension bridges and high-rise buildings, and to derive their modal frequencies, usually up to 1 Hz, but there is evidence that these limits can be exceeded using high frequency GPS receivers. Based on systematic experiments in computer controlled oscillations with one- and three-degrees of freedom we investigated the potential of GPS, first to record higher oscillation frequencies, at least up to 4 Hz at the minimum resolution level of this instrument for kinematic applications (?5 mm), and second, to identify more than one dominant frequency. Data were processed using least squares-based spectral analysis and wavelet techniques which permit to analyze entire time series, even those of too short duration or those characterized by gaps, in both the frequency and the time domain. The ability of GPS to accurately measure frequencies of oscillations of relatively rigid (modal frequencies 1-4 Hz) civil engineering structures is demonstrated in the cases of two bridges. The outcome of this study is that GPS is suitable for the identification of dynamic characteristics of even relatively rigid (modal frequencies up to 4 Hz) civil engineering structures excited by various loads (wind, traffic, earthquakes, etc.) if displacements are above the uncertainty level of the method (?5 mm). Structural health monitoring of a wide range of structures appears therefore a promising field of application of GPS.

Psimoulis, Panos; Pytharouli, Stella; Karambalis, Dimitris; Stiros, Stathis

2008-12-01

398

Global Positioning System (GPS) Precipitable Water in Forecasting Lightning at Spaceport Canaveral  

NASA Technical Reports Server (NTRS)

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.

Kehrer, Kristen C.; Graf, Brian; Roeder, William

2006-01-01

399

Image-based 3D scene analysis for navigation of autonomous airborne systems  

NASA Astrophysics Data System (ADS)

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.

Jaeger, Klaus; Bers, Karl-Heinz

2001-10-01

400

Current GPS/GLONASS time reference and UTC  

NASA Technical Reports Server (NTRS)

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.

Daly, Peter

1990-01-01

401

Data Analysis Techniques for a Lunar Surface Navigation System Testbed  

NASA Technical Reports Server (NTRS)

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.

Chelmins, David; Sands, O. Scott; Swank, Aaron

2011-01-01

402

Multiband Pyramidal Antenna for Radio Navigation and Telemetry Systems  

E-print Network

elements, the antenna radiates either right-hand (RH) or left-hand (LH) circularly polarized (CPMultiband Pyramidal Antenna for Radio Navigation and Telemetry Systems Sami Hebib*(1,2) , Hervé Noordwijk ZH, the Netherlands nelson.fonseca@esa.int Abstract--A novel multi-band pyramidal antenna

Boyer, Edmond

403

Autonomous navigation system for the Marsokhod rover project  

NASA Technical Reports Server (NTRS)

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.

Proy, C.; Lamboley, M.; Rastel, L.

1994-01-01

404

Conceptual fuzzy sets-based navigation system for Yahoo!  

Microsoft Academic Search

In this paper, we propose a menu navigation system which conceptually matches input keywords and paths. For conceptual matching, we use conceptual fuzzy sets (CFSs) based on radial basis function (RBF) networks. In a CFS, the meaning of a concept is represented by the distribution of the activation values of the other concepts. To expand input keywords the propagation of

Ryosuke Ohgaya; Tomohiro Takagi; Kouta Fukano; Koji Taniguchi; Akiko Aizawa; Masoud Nikravesh

2002-01-01

405

CRCHD PNP Project: Improving Patient Outcomes Through System Navigation  

Cancer.gov

The overall goal of the Improving Patient Outcomes Through System Navigation project is to work with two community partners, the University of Colorado Comprehensive Cancer Center and the AMC Cancer Research Center, to reduce cancer health disparities experienced by many minorities and underserved patients, approximately half without health insurance, living in the Rocky Mountain region.

406

Tightly Coupled Visual-Inertial Navigation System Using Optical Flow  

E-print Network

Tightly Coupled Visual-Inertial Navigation System Using Optical Flow Simon Lynen Sammy Omari to be known a-priori and is also estimated at run-time. The estimation framework fuses visual and inertial measurements in an Extended Kalman Filter (EKF). Experiments using a hand-held visual-inertial sensor

Daraio, Chiara

407

Design of accelerometer-based inertial navigation systems  

Microsoft Academic Search

We examine the feasibility of designing an accelerometer-based (or gyroscope-free) inertial navigation system that uses only accelerometer measurements to compute the linear and angular motions of a rigid body. The accelerometer output equation is derived to relate the linear and angular motions of a rigid body relative to a fixed inertial frame. A sufficient condition is given to determine if

Chin-Woo Tan

2005-01-01

408

Autonomous Spacecraft Navigation With Pulsars  

NASA Astrophysics Data System (ADS)

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.

Becker, Werner

2014-08-01

409

The NavChair Assistive Wheelchair Navigation System  

Microsoft Academic Search

The NavChair Assistive Wheelchair Navigation System is being developed to reduce the cognitive and physical requirements of operating a power wheelchair for people with wide ranging impairments that limit their access to powered mobility. The NavChair is based on a commercial wheelchair system with the addition of a DOS-based computer system, ultrasonic sensors, and an interface module interposed between the

Simon P. Levine; David A. Bell; Lincoln A. Jaros; Richard C. Simpson; Yoram Koren; Johann Borenstein

1999-01-01

410

Briefing highlights space weather risks to GPS  

NASA Astrophysics Data System (ADS)

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.

Tretkoff, Ernie

2011-07-01

411

GPS Integrity Channel RTCA Working Group recommendations  

NASA Astrophysics Data System (ADS)

Recommendations made by a working group established by the Radio Technical Commission for Aeronautics are presented for the design of a wide-area broadcast service to provide indications on the status of GPS satellites. The integrity channel requirements and operational goals are outlined. Six integrity channel system concepts are considered and system design and time-to-alarm considerations are examined. The recommended system includes the broadcast of a coarse range measurement for each satellite which will enable the on-board GPS receiver to determine whether or not the navigation accuracy is within prescribed limits.

Kalafus, Rudolph M.

412

Direct Exterior Orientation Of Airborne Sensors - An Accuracy Investigation of an integrated GPS/inertial system  

E-print Network

By direct georeferencing, i.e. the direct measurement of the exterior orientation of an imaging sensor using an integrated system consisting of receivers of the Global Positioning System (GPS) and a strap-down Inertial Measurement Unit (IMU), many applications can be realized more efficiently and economically due to the reduction or elimination of required ground control and tie point information. Within this article a well controlled test comparing standard aerial triangulation and point determination with direct georeferencing is described to demonstrate the potential and accuracy of a commercially available integrated GPS/Inertial system.

Michael Cramer; Norbert Haala

1999-01-01

413

GPS on the Move  

NSDL National Science Digital Library

During a scavenger hunt and an art project, students learn how to use a handheld GPS receiver for personal navigation. Teachers can request assistance from the Institute of Navigation to find nearby members with experience in using GPS and in locating receivers to use. Visit the ION website (www.ion.org) for links to local ION sections and member contact information. (Note: Mention of specific receiver manufacturers or brands does not constitute an endorsement by the Institute of Navigation or the University of Colorado.)

Integrated Teaching And Learning Program

414

A DSRC Doppler-Based Cooperative Positioning Enhancement for Vehicular Networks With GPS Availability  

Microsoft Academic Search

Position information, as a fundamental element for many of the modern vehicle-based logistic applications, is comprehensively provided by Global Navigation Satellite Systems (GNSS) such as the Global Positioning System (GPS). A variety of applications, including navigation and intelligent transpiration systems, require position data with certain accuracy. However, the shortcomings of GNSS, such as limited accuracy and availability, have been a

Nima Alam; Asghar Tabatabaei Balaei; Andrew G. Dempster

2011-01-01

415

Vehicle health management for guidance, navigation and control systems  

NASA Technical Reports Server (NTRS)

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.

Radke, Kathleen; Frazzini, Ron; Bursch, Paul; Wald, Jerry; Brown, Don

1993-01-01

416

Analysis of test data on the simplex strapdown navigation system  

NASA Technical Reports Server (NTRS)

The results of a study of test data taken on the simplex strapdown navigation system were presented. That system consisted of the following components: strapdown platform, altimeter, digital computer, tape recorder, typewriter, and power source. The objective of these tests was to isolate error sources which may cause degradation of the system's accuracy and to recommend appropriate changes to the system test procedures or computer software. The following recommendations were made: (1) addition of a gyro compassing alignment program into the navigation program, (2) addition of line drivers at the signal processor end of the transmission line, (3) need for extensive laboratory testing to determine sensor misalignments, biases, and scale factors, (4) need to stabilize the power source to prevent transients during power transfer, (5) need to isolate and eliminate the source of the large noise inputs.

1976-01-01

417

Computer-assisted navigation system in intranasal surgery  

NASA Astrophysics Data System (ADS)

Due to anatomical variability and limited visibility of endoscopic image, endoscopic operations of nose and paranasal sinuses are ones of the most difficult surgical procedures. The field of operation often comprises anatomical structures, which often present anomalies. Computer-assisted navigational endoscopic surgery consists of routine tomography with the possibility of 3-axis projection allowing for localization of surgical instruments in proper relation to anatomic structures. This potential permits the surgeon to penetrate specific structures with surgical instruments and visualize their localization on computer tomography, which was earlier entered to the computer and projected. Projection of the images and endoscopic picture on the same monitor provides comfort to the operator and feeling of safety to the operated patient. The image analysis feature supplies a set of information necessary for safer and more effective procedure conduction and decreased number of complications. This technique may considerably contribute to training programs in endoscopic surgery. Computer-aided navigation in surgical procedures allows for precise biopsy specimen uptake for pathological examination, even in cases requiring precision up to 1 mm. The authors present an overview of surgical computer-aided navigation systems and their own experience in endoscopic ethmoid and maxillary sinus surgery performed with the use of computer-assisted navigation system.

Rapiejko, Piotr; Wojdas, Andrzej; Wawrzyniak, Zbigniew M.; Jurkiewicz, Dariusz

2005-02-01

418

On-Board Perception System For Planetary Aerobot Balloon Navigation  

NASA Technical Reports Server (NTRS)

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.

Balaram, J.; Scheid, Robert E.; T. Salomon, Phil

1996-01-01

419

Error Analysis of Space-Stable Inertial Navigation Systems  

Microsoft Academic Search

The error equations for a space-stable inertial navigation system are derived. This is done by directly perturbing the mechanization equations in the inertial frame and then transforming in open-loop fashion to the local-level frame. A rotating inertial platform and velocity and altitude damping are considered. The relations between errors in space-stable and local-level systems are noted. Numerical results are presented

Stephen Levine; Kenneth Roy

1971-01-01

420

Proposed wireless system could interfere with key GPS receivers, U.S. officials testify  

NASA Astrophysics Data System (ADS)

A proposed $14 billion network that would increase broadband wireless access poses significant interference problems for existing GPS signals used for some critical U.S. federal science and public safety systems, said officials from NASA, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Geological Survey (USGS) and other experts at an 8 September hearing of the House of Representatives' Committee on Science, Space, and Technology. The officials cautioned that a terrestrial wireless network plan proposed by LightSquared LLCwhich includes using frequencies adjacent to the GPS bandneeds additional testing before it is given a green light by the Federal Communications Commission (FCC). In addition, the officials said that although they hope there is a win-win solution to increasing broadband wireless options without harming GPS signals, a recently revised plan that LightSquared indicates would reduce interference to a large majority of GPS receivers still would present problems for a number of high-precision GPS systems.

Showstack, Randy

2011-09-01

421

EUROCONTROL's predictive RAIM tool for en-route aircraft navigation  

Microsoft Academic Search

The Navigation Division of the EUROCONTROL Agency, with STASYS Ltd and Delft University, has developed the AUGUR Programme for B-RNAV (Basic Area Navigation). AUGUR is providing aircraft operators with availability of Global Positioning System (GPS) Receiver Autonomous Integrity Monitoring (RAIM). Its design was a particular challenge, as an algorithm had to be defined which was a suitable representation of those

D. A. G. Harriman; J. Wilde; P. B. Ober

1999-01-01

422

ORIGINAL ARTICLE Navigation your way: from spontaneous independent exploration  

E-print Network

the arrival of GPS-capable mobile devices, however, digital navigation tools have improved to simplify- versions of car-based navigation systems) are now widely available on many mobile devices and becoming ever.williamson@glasgow.ac.uk R. Murray-Smith e-mail: roderick.murray-smith@glasgow.ac.uk M. Lindborg Nokia Devices, Nokia Mobile

Williamson, John

423

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...

424

Use of global positioning system (GPS) technology to map cross country pipelines  

SciTech Connect

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.

Barrett, J.P. [Conoco Inc., Ponca City, OK (United States)

1998-12-31

425

Global Positioning System Primer  

NSDL National Science Digital Library

The Global Positioning System (GPS) Primer, created by the Aerospace Corporation, gives basic information on how a GPS works and the many ways in which it is used. Supplying straight-forward text with a few graphics and illustrations, sections range from "What is Navigation?" to "Military Uses for GPS." Includes a search option and an organized selection of links to other GPS related sites. The GPS Primer is also downloadable (.pdf, 1618 KB).

426

A magnetic-resonance-imaging-compatible remote catheter navigation system.  

PubMed

A remote catheter navigation system compatible with magnetic resonance imaging (MRI) has been developed to facilitate MRI-guided catheterization procedures. The interventionalist's conventional motions (axial motion and rotation) on an input catheter - acting as the master - are measured by a pair of optical encoders, and a custom embedded system relays the motions to a pair of ultrasonic motors. The ultrasonic motors drive the patient catheter (slave) within the MRI scanner, replicating the motion of the input catheter. The performance of the remote catheter navigation system was evaluated in terms of accuracy and delay of motion replication outside and within the bore of the magnet. While inside the scanner bore, motion accuracy was characterized during the acquisition of frequently used imaging sequences, including real-time gradient echo. The effect of the catheter navigation system on image signal-to-noise ratio (SNR) was also evaluated. The results show that the master-slave system has a maximum time delay of 41 21 ms in replicating motion; an absolute value error of 2 2 was measured for radial catheter motion replication over 360 and 1.0 0.8 mm in axial catheter motion replication over 100 mm of travel. The worst-case SNR drop was observed to be 2.5%. PMID:23192485

Tavallaei, Mohammad Ali; Thakur, Yogesh; Haider, Syed; Drangova, Maria

2013-04-01

427

HelpMate autonomous mobile robot navigation system  

NASA Astrophysics Data System (ADS)

HelpMate is a mobile robotic materials transport system that performs fetch and carry tasks at Danbury Hospital. It autonomously navigates along the main arteries of the hospital crossing between buildings via interconnecting hallways and uses radio to communicate with the elevator. HelpMate uses sensor information to follow straight paths down hallways and to successfully reach its destination. Also HelpMate has the ability to sense obstacles in its path and plot a course around them. A two part vision system is employed on HelpMate to aid in navigation and obstacle avoidance. One part determines the vehicle''s orientation and position in the hallway by looking at the ceiling lights. The other part uses structured light projecting forward into the immediate path of the robot to detect obstacles.

King, Steven J.; Weiman, Carl F. R.

1991-03-01

428

General aviation Omega navigation in the national airspace system  

E-print Network

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 ...

Wischmeyer, Carl Edward

1976-01-01

429

Fault detection and exclusion in multisensor navigation systems  

NASA Technical Reports Server (NTRS)

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.

Bernath, Gregory N.

1995-01-01

430

Robust low-frequency spread-spectrum navigation system  

DOEpatents

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.

Smith, Stephen F. (Loudon, TN) [Loudon, TN; Moore, James A. (Powell, TN) [Powell, TN

2009-12-01

431

Robust low-frequency spread-spectrum navigation system  

DOEpatents

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.

Smith, Stephen F; Moore, James A

2012-10-30

432

Robust low-frequency spread-spectrum navigation system  

DOEpatents

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.

Smith, Stephen F. (Loudon, TN); Moore, James A. (Powell, TN)

2012-01-03

433

Robust low-frequency spread-spectrum navigation system  

DOEpatents

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.

Smith, Stephen F. (Loudon, TN); Moore, James A. (Powell, TN)

2011-01-25

434

An inertial navigation system for a mobile robot  

Microsoft Academic Search

A low-cost, solid-state inertial navigation system for robotics applications is described. Error models for the inertial sensors are generated and included in an extended Kalman filter (EKF) for estimating the position and orientation of a moving robot vehicle. A solid-state gyroscope and an accelerometer have been evaluated. Without error compensation, the error in orientation is between 5-15\\/min but can be

B. Barshan; H. F. Durrant-Whyte

1993-01-01

435

Self-calibration method based on navigation in high-precision inertial navigation system with fiber optic gyro  

NASA Astrophysics Data System (ADS)

A rotary inertial navigation system requires higher calibration accuracy of some error parameters owing to rotation. Conventional multiposition and rotation calibration methods are limited, for they do not consider sensors' actual operating condition. In order to achieve these parameters' values as closely as possible to their true values in application, their influence on navigation is analyzed, and a relevant new calibration method based on a system's velocity output during navigation is designed for the vital error parameters, including inertial sensors' installation errors and the scale factor error of fiber optic gyro. Most importantly, this approach requires no additional devices compared to the conventional method and costs merely several minutes. Experimental results from a real dual-axis rotary fiber optic gyro inertial navigation system demonstrate the practicability and higher precision of the suggested approach.

Wang, Lei; Wang, Wei; Zhang, Qian; Gao, Pengyu

2014-06-01

436

Global and regional reference system realization based on reprocessed GPS data: The Antarctic case  

NASA Astrophysics Data System (ADS)

Based on a homogeneous reprocessing of global GPS data dating back to 1994 the TRF realization for the Antarctic SCAR GPS network will be discusssed. For this purpose, we present the modelling and analysis approach applied within the GPS data processing. Following the approach for the global Terrestrial Reference System realization we discuss concepts for regional densifications with special focus on the Antarctic region. The main focus concerns the question on how to combine a regional and a global station network in an optimal way. Accuracy and consistency are discussued with regards to those station coordinates and velocities which are obtained from both global and regional network solutions. Our results confirm the essential need for a stable global reference frame to allow a reliable geophysical interpretation. The applied approach is valid also for other regional applications.

Ruelke, A.; Dietrich, R.; Fritsche, M.

2009-04-01

437

GPS Tutorials  

NSDL National Science Digital Library

This collection of links provides access to a number of tutorials on Global Positioning Systems (GPS). These materials instruct users on the basics of the technology and some of its uses, such as surveying. There are also links to another portal site and to a search engine for access to additional information.

438

Improved Modeling in a Matlab-Based Navigation System  

NASA Technical Reports Server (NTRS)

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.

Deutschmann, Julie; Bar-Itzhack, Itzhack; Harman, Rick; Larimore, Wallace E.

1999-01-01

439

DESIGN AND PERFORMANCE ANALYSIS OF A LOW-COST AIDED DEAD RECKONING NAVIGATION SYSTEM  

E-print Network

navigation system based on the fusion of inexpensive inertial, air data and magnetic sensors aided for General Aviation aircraft. Dead reckoning navigators mechanized using the classical inertial navigation that is mostly self-contained. A parametric study of navigation accuracy as a function of inertial sensor quality

Stanford University

440

Real-time ultrasound-guided PCNL using a novel SonixGPS needle tracking system.  

PubMed

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

Li, Xiang; Long, Qingzhi; Chen, Xingfa; Dalin, He; He, Hui

2014-08-01

441

Fault detection and isolation for multisensor navigation systems  

NASA Technical Reports Server (NTRS)

Increasing attention is being given to the problem of erroneous measurement data for multisensor navigation systems. A recursive estimator can be used in conjunction with a 'snapshot' batch estimator to provide fault detection and isolation (FDI) for these systems. A recursive estimator uses past system states to form a new state estimate and compares it to the calculated state based on a new set of measurements. A 'snapshot' batch estimator uses a set of measurements collected simultaneously and compares solutions based on subsets of measurements. The 'snapshot' approach requires redundant measurements in order to detect and isolate faults. FDI is also referred to as Receiver Autonomous Integrity Monitoring (RAIM).

Kline, Paul A.; Vangraas, Frank

1991-01-01

442

Hardware-software complex for determination of the Earth ionosphere parameters according to navigating systems  

NASA Astrophysics Data System (ADS)

Existing systems of distant short-wave communication provide the transfer of the information on long distances due to the reflection of radiowaves from the Earth ionosphere on the frequencies which do not exceed the critical frequency. To provide a sustainable functioning of such communication lines, first of all, it is required to know the highest frequency (maximum usable frequency - MUF) which can ensure at the reflection from the ionosphere the functioning of a radioline with higher reliability. With the help of common means of the short-wave band were conducted experimental studies on the use of a hardware-software complex for the problem-solving of the conditions' forecast for the radiowave propagation along the given line. The hardware-software complex includes a dual frequency navigating receiver working on GPS signals, and software solving a return problem of ionosphere radiotranslucence on the basis of the conjugate-gradient method. The radio-translucence method is based on the transformation of normalized phase difference for radio waves. Mathematically, it corresponds to the transformation of integral equations of first kind. Implementation of this method involves measurement of radio signal parameters along the path "satellite - ground receiver" carried out at one station. The radio-translucence method allows the creation of altitude profiles of ionosphere electron content distribution with sampling of GPS signal registration. Realization of this method is based on the decision of a return ill-posed task of an ionosphere radio-translucence by the conjugate-gradient method. It is a mathematically strict method for the solution of inverse problems, with imposed restrictions enabling us to obtain admissible solutions on convex sets. This method steadily works at the task decision with restrictions and presence of local maxima. The ill-posed nature of the problem of reconstructing electron content distribution using the results of radio-translucence does not allow us to obtain an exact solution for the main integral equation that would be stable under small variations in input data. In this case it is necessary to look for some approximate solution, choosing an acceptable solution from all the possible ones. Mathematical difficulties encountered when trying to apply this approach quite often force us to abandon the idea of obtaining a general solution to the problem of determining environmental parameter distribution. Most frequently, the problem is to be reduced to some elementary cases, for which acceptable results could be obtained. Continuous observations of navigating satellites of systems Glonass and GPS allows to receive values of time variations, both a maximum of an ionosphere, and its high-altitude structure of electronic concentration of an ionosphere simultaneously on several azimuthal directions. The high-altitude structures of the ionosphere received as a result of inversion of satellite measurement data are presented on fig. 3. These structures are received for the nearest distances of a projection of subionospheric points from receiver depending on time on observation of satellites. The opportunity to restore a full high-altitude structure of distribution of electronic concentration of an ionosphere allows analyzing time variations practically any part of an ionosphere. The restoration opportunity high-altitude structure of electronic concentration on observation on small time intervals allows to fix a big spatial the heterogeneity, observable in an ionosphere. Use of short time intervals of observation, sufficient for determination of a high-altitude structure of an ionosphere, allows localizing rather narrow areas of an ionosphere. Simulation results and the high-altitude structures of electronic concentration restored on real GPS data are presented. The results of the experimental studies have shown according to this method a relative error of the MUF's definition no more than 5 % for day time and 11 % for night time observation. These results were obtained for Moscow region.

Smirnov, V. M.; Malkovsky, A. P.; Smirnova, E. V.; Tynyankin, S. I.

2009-04-01

443

GPS Radio Occultation as Part of the Global Earth Observing System  

Microsoft Academic Search

Radio occultation measurements of the atmosphere using transmissions of the Global Positioning System (GPS) are discussed in the Decadal Survey for Earth Science released in 2007. Several successful examples of RO missions are currently in orbit: CHAMP, SAC-C, COSMIC and GRACE. RO retrievals have the fortunate characteristic of being based on time delay measurements, whose fundamental unitiquestthe secondiquestis absolutely calibrated

Anthony J. Mannucci; Chi O. Ao; Tom K. Meehan; Byron A. Iijima; Attila Komjathy; Thomas P. Yunck; Marc K. Pestana; Brian D. Wilson

2008-01-01

444

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...

445

Development of agriculture machinery aided guidance system based on GPS and GIS  

Microsoft Academic Search

The agriculture machinery guidance technology is one of precision agricultural important technologies. Based on GPS and GIS, it can raise working efficiency and improve the quality, reduce production costs, reduce driver working difficulty. This research's general goals realize the aided guidance function for agriculture machinery driving on road and straight line operation in the field by lightbar. The system uses

Zhuang Weidong; Wang Chun; Han Jing

2010-01-01

446

Influence of Ephemeris Error on GPS Single Point Positioning Accuracy  

NASA Astrophysics Data System (ADS)

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.

Lihua, Ma; Wang, Meng

2013-09-01

447

Fluoroscopy-based navigation system in spine surgery  

E-print Network

The variability in width, height, and spatial orientation of a spinal pedicle makes pedicle screw insertion a delicate operation. The aim of the current paper is to describe a computer-assisted surgical navigation system based on fluoroscopic X-ray image calibration and three-dimensional optical localizers in order to reduce radiation exposure while increasing accuracy and reliability of the surgical procedure for pedicle screw insertion. Instrumentation using transpedicular screw fixation was performed: in a first group, a conventional surgical procedure was carried out with 26 patients (138 screws); in a second group, a navigated surgical procedure (virtual fluoroscopy) was performed with 26 patients (140 screws). Evaluation of screw placement in every case was done by using plain X-rays and post-operative computer tomography scan. A 5 per cent cortex penetration (7 of 140 pedicle screws) occurred for the computer-assisted group. A 13 per cent penetration (18 of 138 pedicle screws) occurred for the non comp...

Merloz, Philippe; Vouaillat, Herv; Vasile, Christian; Tonetti, Jrme; Eid, Ahmad; Plaweski, Stphane

2007-01-01

448

Updating inertial navigation systems with VOR/DME information.  

NASA Technical Reports Server (NTRS)

Demonstration that updating an inertial navigation system (INS) with VOR/DME information (from one or two stations) by means of a maximum-likelihood filter results in substantial improvements in navigational accuracy over that obtained by the use of a single VOR/DME (current practice). When continuously updating, the use of a high-quality INS (0.01 deg/hr gyro drift) instead of a low-quality INS (1.0 deg/hr gyro drift) does not substantially improve position accuracy. In-flight alignment (or realignment) of an INS to an accuracy comparable to that of ground alignment can be accomplished by using two DMEs. Several reduced-order suboptimal filters were found to perform nearly optimally.

Bobick, J. C.; Bryson, A. E., Jr.

1972-01-01

449

The UNAVCO Real-time GPS Data Processing System and Community Reference Data Sets  

NASA Astrophysics Data System (ADS)

UNAVCO has constructed a real-time GPS (RT-GPS) network of 420 GPS stations. The majority of the streaming stations come from the EarthScope Plate Boundary Observatory (PBO) through an NSF-ARRA funded Cascadia Upgrade Initiative that upgraded 100 backbone stations throughout the PBO footprint and 282 stations focused in the Pacific Northwest. Additional contributions from NOAA (~30 stations in Southern California) and the USGS (8 stations at Yellowstone) account for the other real-time stations. Based on community based outcomes of a workshop focused on real-time GPS position data products and formats hosted by UNAVCO in Spring of 2011, UNAVCO now provides real-time PPP positions for all 420 stations using Trimble's PIVOT software and for 50 stations using TrackRT at the volcanic centers located at Yellowstone (Figure 1 shows an example ensemble of TrackRT networks used in processing the Yellowstone data), Mt St Helens, and Montserrat. The UNAVCO real-time system has the potential to enhance our understanding of earthquakes, seismic wave propagation, volcanic eruptions, magmatic intrusions, movement of ice, landslides, and the dynamics of the atmosphere. Beyond its increasing uses for science and engineering, RT-GPS has the potential to provide early warning of hazards to emergency managers, utilities, other infrastructure managers, first responders and others. With the goal of characterizing stability and improving software and higher level products based on real-time GPS time series, UNAVCO is developing an open community standard data set where data processors can provide solutions based on common sets of RT-GPS data which simulate real world scenarios and events. UNAVCO is generating standard data sets for playback that include not only real and synthetic events but also background noise, antenna movement (e.g., steps, linear trends, sine waves, and realistic earthquake-like motions), receiver drop out and online return, interruption of communications (such as, bulk regional failures due to specific carriers during an actual event), satellites rising and setting, various constellation outages and differences in performance between real-time and simulated (retroactive) real-time. We present an overview of the UNAVCO RT-GPS system, a comparison of the UNAVCO generated real-time data products, and an overview of available common data sets.

Sievers, C.; Mencin, D.; Berglund, H. T.; Blume, F.; Meertens, C. M.; Mattioli, G. S.

2013-12-01

450

A Topographical Lidar System for Terrain-Relative Navigation  

NASA Technical Reports Server (NTRS)

An imaging lidar system is being developed for use in navigation, relative to the local terrain. This technology will potentially be used for future spacecraft landing on the Moon. Systems like this one could also be used on Earth for diverse purposes, including mapping terrain, navigating aircraft with respect to terrain and military applications. The system has been field-tested aboard a helicopter in the Mojave Desert. When this system was designed, digitizers with sufficient sampling rate (2 GHz) were only available with very limited memory. Also, it was desirable to limit the amount of data to be transferred between the digitizer and the mass storage between individual frames. One of the novelty design features of this system was to design the system around the limited amount of memory of the digitizer. The system is required to operate over an altitude (distance) range from a few meters to approximately 1 km, but for each scan across the full field of view, the digitizer memory is only able to hold data for an altitude range no more than 100 m. Data acquisition methods in support of the limited 100 m wide altitude range are described.

Liebe, Carl Christian; Spiers, Gary; Bartman, Randy; Lam, Raymond; Alexander, James; Montgomery, James; Goldberg, Hannah; Johnson, Andrew; Meras, Patrick; Palacios, Peter

2008-01-01

451

Clarissa Spoken Dialogue System for Procedure Reading and Navigation  

NASA Technical Reports Server (NTRS)

Speech is the most natural modality for humans use to communicate with other people, agents and complex systems. A spoken dialogue system must be robust to noise and able to mimic human conversational behavior, like correcting misunderstandings, answering simple questions about the task and understanding most well formed inquiries or commands. The system aims to understand the meaning of the human utterance, and if it does not, then it discards the utterance as being meant for someone else. The first operational system is Clarissa, a conversational procedure reader and navigator, which will be used in a System Development Test Objective (SDTO) on the International Space Station (ISS) during Expedition 10. In the present environment one astronaut reads the procedure on a Manual Procedure Viewer (MPV) or paper, and has to stop to read or turn pages, shifting focus from the task. Clarissa is designed to read and navigate ISS procedures entirely with speech, while the astronaut has his eyes and hands engaged in performing the task. The system also provides an MPV like graphical interface so the procedure can be read visually. A demo of the system will be given.

Hieronymus, James; Dowding, John

2004-01-01

452

A Low Cost GPS System for Real-Time Tracking of Sounding Rockets  

NASA Technical Reports Server (NTRS)

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.

Markgraf, M.; Montenbruck, O.; Hassenpflug, F.; Turner, P.; Bull, B.; Bauer, Frank (Technical Monitor)

2001-01-01

453

TDRSS Onboard Navigation System (TONS) flight qualification experiment  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) is currently developing an operational Tracking and Data Relay Satellite (TDRS) System (TDRSS) Onboard Navigation System (TONS) to provide realtime, autonomous, high-accuracy navigation products to users of TDRSS. A TONS experiment was implemented on the Explorer Platform/Extreme Ultraviolet Explorer (EP/EUVE) spacecraft, launched June 7, 1992, to flight qualify the TONS operational system using TDRSS forward-link communications services. This paper provides a detailed evaluation of the flight hardware, an ultrastable oscillator (USO) and Doppler extractor (DE) card in one of the TDRSS user transponders and the ground-based prototype flight software performance, based on the 1 year of TONS experiment operation. The TONS experiment results are used to project the expected performance of the TONS 1 operational system. TONS 1 processes Doppler data derived from scheduled forward-link S-band services using a sequential estimation algorithm enhanced by a sophisticated process noise model to provide onboard orbit and frequency determination and time maintenance. TONS 1 will be the prime navigation system on the Earth Observing System (EOS)-AM1 spacecraft, currently scheduled for launch in 1998. Inflight evaluation of the USO and DE short-term and long-term stability indicates that the performance is excellent. Analysis of the TONS prototype flight software performance indicates that realtime onboard position accuracies of better than 25 meters root-mean-square are achievable with one tracking contact every one to two orbits for the EP/EUVE 525-kilometer altitude, 28.5 degree inclination orbit. The success of the TONS experiment demonstrates the flight readiness of TONS to support the EOS-AM1 mission.

Gramling, C. J.; Hart, R. C.; Folta, D. C.; Long, A. C.

1994-01-01

454

Using GPS in Geoscience Education  

NSDL National Science Digital Library

This site from SERC's Starting Point features an introduction to using Global Positioning System (GPS) in geoscience education. The site provides information as well as links to GPS history, types of receivers, recording data, downloading data, plus GPS references and examples of using GPS in education.

2007-02-08

455

Web API for biology with a workflow navigation system  

Microsoft Academic Search

ABSTRACT DNA Data Bank,of Japan,(DDBJ) provides,Web- based systems for biological analysis, called Web APIs for biology (WABI). So far, we have developed over,20 SOAP services,and,several,workflows,that consist,of a series,of method,invocations.,In this article, we present newly developed services of WABI, that is, REST-based Web services, additional workflows,and,a workflow,navigation,system. Each Web,service,and,workflow,can,be used,as a com- plete service or a building block for programmers,to construct,more,complex,information,processing

Yeondae Kwon; Yasumasa Shigemoto; Yoshikazu Kuwana; Hideaki Sugawara

2009-01-01

456

GPS\\/INS uses low-cost MEMS IMU  

Microsoft Academic Search

A description of the design, operation, and test results of a miniature, low-cost, integrated GPS\\/inertial navigation system that uses commercial off-the-shelf micro-electro-mechanical system (MEMS) accelerometers and gyroscopes. The MEMS inertial measurement unit (EMU) is packaged in a small size and provides the raw EMU data through a serial interface to a processor board where the inertial navigation solution and integrated

Alison K. Brown

2005-01-01

457

Development of an advanced intelligent robot navigation system  

SciTech Connect

As part of the US Department of Energy's Robotics for Advanced Reactors Project, the authors are in the process of assembling an advanced intelligent robotic navigation and control system based on previous work performed on this project in the areas of computer control, database access, graphical interfaces, shared data and computations, computer vision for positions determination, and sonar-based computer navigation systems. The system will feature three levels of goals: (1) high-level system for management of lower level functions to achieve specific functional goals; (2) intermediate level of goals such as position determination, obstacle avoidance, and discovering unexpected objects; and (3) other supplementary low-level functions such as reading and recording sonar or video camera data. In its current phase, the Cybermotion K2A mobile robot is not equipped with an onboard computer system, which will be included in the final phase. By that time, the onboard system will play important roles in vision processing and in robotic control communication.

Hai Quan Dai; Dalton, G.R.; Tulenko, J.; Crane, C.C. III (Univ. of Florida, Gainesville (United States))

1992-01-01

458

Wind speed measurement using forward scattered GPS signals  

Microsoft Academic Search

Instrumentation and retrieval algorithms are described which use the forward scattered range-coded signals from the global positioning system (GPS) radio navigation system for the measurement of sea surface roughness. This roughness has long been known to be dependent upon the surface wind speed. Experiments were conducted from aircraft along the TOPEX ground track and over experimental surface truth buoys. These

James L. Garrison; Attila Komjathy; Valery U. Zavorotny; Stephen J. Katzberg

2002-01-01

459

Improvement on an inertial-Doppler navigation system of underwater vehicles using a complementary range sonar  

Microsoft Academic Search

This work presents an improvement of an inertial-Doppler underwater navigation system for unmanned underwater vehicles (UUV) using a complementary range sonar. The inertial-Doppler navigation system is generally based on an inertial measurement unit (IMU) and a Doppler velocity log (DVL) accompanying a magnetic compass and a depth sensor. Although conventional navigation systems update bias errors of the inertial sensors, scale

Pan-Mook Lee; Sea-Moon Kim; Bong-Hwan Jeon; Hyun Taek Choi; Chong-Moo Lee

2004-01-01

460

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

E-print Network

SIG Technology Review · Summer 1994 57 Real-Time Navigation Using the Global Positioning System Real-Time Navigation Using the Global Positioning System Dan Simon and Hossny El-Sherief, TRW Ballistic Technology Review · Summer 1994 Real-Time Navigation Using the Global Positioning System introduces errors

Simon, Dan

461

Computer-assisted Preoperative Planning and Surgical Navigation System in Dental Implantology  

Microsoft Academic Search

This paper presents a construction of a computer assisted system in dental implantology. Preoperative planning and surgical navigation are two main sub-systems in our proposed system. In the preoperative planning subsystem, we provide different kinds of views to the surgeons based on CT data scanned for a specific patient. And the surgical navigation subsystem uses an infra-red light based navigation

Guangchao. Zheng; Lixu. Gu; Xiaobo. Li; Jingsi Zhang

2007-01-01

462

Observability Analysis of a Vision-aided Inertial Navigation System Using Planar Features on the Ground  

E-print Network

Observability Analysis of a Vision-aided Inertial Navigation System Using Planar Features-- In this paper, we present an observability analysis of a vision-aided inertial navigation system (VINS) in which-aided inertial navigation system (VINS)­without using the assump- tion of observing features in a plane­have been

Roumeliotis, Stergios I.

463

Experimental Evaluation of an Inertial Navigation System for Underwater Robotic Vehicles  

E-print Network

Experimental Evaluation of an Inertial Navigation System for Underwater Robotic Vehicles Giancarlo inertial navigation system (INS), and the effect of variations in the accuracy and the update rate of INS. INTRODUCTION Recent advances in inertial navigation systems (INS) tech- nology have enabled a new class

Whitcomb, Louis L.

464

[Study on intelligent system of hyper-spectral data gathering based on GPS in farm machinery].  

PubMed

In order to meet the precision agriculture needs that highly dense and overall farmland information is gathered, this system uses Visual Basic and Map-Objects to carry on integration of GPS, GIS and RS. On the one hand, the system can provide the space seat attribute of high precision for the spectral data gathered by way of integration GPS, and realizes integration in spectrum data gathering, orientation and storage. On the other hand, by way of integrated GIS, the system has realized the function of visualizing analysis and management of the spectrum data, displaying real-time trace of moving point, providing some related attribute of the moving point in map layers, and calculating crop derivative spectra and crop vegetation index NDVI etc. The sufficient information is put forward for expert system and decision support system of precision agriculture. PMID:16201388

Li, Zhi-wei; Pan, Jian-jun; Zhang, Jia-bao

2005-06-01

465

An enhanced inertial navigation system based on a low-cost IMU and laser scanner  

NASA Astrophysics Data System (ADS)

This paper describes an enhanced fusion method for an Inertial Navigation System (INS) based on a 3-axis accelerometer sensor, a 3-axis gyroscope sensor and a laser scanner. In GPS-denied environments, indoor or dense forests, a pure INS odometry is available for estimating the trajectory of a human or robot. However it has a critical implementation problem: a drift error of velocity, position and heading angles. Commonly the problem can be solved by fusing visual landmarks, a magnetometer or radio beacons. These methods are not robust in diverse environments: darkness, fog or sunlight, an unstable magnetic field and an environmental obstacle. We propose to overcome the drift problem using an Iterative Closest Point (ICP) scan matching algorithm with a laser scanner. This system consists of three parts. The first is the INS. It estimates attitude, velocity, position based on a 6-axis Inertial Measurement Unit (IMU) with both 'Heuristic Reduction of Gyro Drift' (HRGD) and 'Heuristic Reduction of Velocity Drift' (HRVD) methods. A frame-to-frame ICP matching algorithm for estimating position and attitude by laser scan data is the second. The third is an extended kalman filter method for multi-sensor data fusing: INS and Laser Range Finder (LRF). The proposed method is simple and robust in diverse environments, so we could reduce the drift error efficiently. We confirm the result comparing an odometry of the experimental result with ICP and LRF aided-INS in a long corridor.

Kim, Hyung-Soon; Baeg, Seung-Ho; Yang, Kwang-Woong; Cho, Kuk; Park, Sangdeok

2012-06-01

466

IMU-RGBD Camera Navigation using Point and Plane Features Chao X. Guo and Stergios I. Roumeliotis  

E-print Network

Abstract-- In this paper, we present a linear-complexity 3D inertial navigation algorithm using both point with this problem, most inertial navigation systems (INS) rely on GPS for bounding the estimation error used to aid the inertial sensors and improve the navigation accuracy. Compared to regular cameras, RGBD

Minnesota, University of

467

Wellbore inertial navigation system (WINS) software development and test results  

SciTech Connect

The structure and operation of the real-time software developed for the Wellbore Inertial Navigation System (WINS) application are described. The procedure and results of a field test held in a 7000-ft well in the Nevada Test Site are discussed. Calibration and instrumentation error compensation are outlined, as are design improvement areas requiring further test and development. Notes on Kalman filtering and complete program listings of the real-time software are included in the Appendices. Reference is made to a companion document which describes the downhole instrumentation package.

Wardlaw, R. Jr.

1982-09-01

468

Simulation and experiment analysis of dynamic deformation monitoring with the integrated GPS/pseudolite system  

NASA Astrophysics Data System (ADS)

The precision of displacement monitoring for deformable objects with global positioning system (GPS) is severely affected in highly occluded spaces, such as urban canyons and surface mines. This phenomenon is attributed to the presence of few visible GPS satellites with poor geometric structures, thus leading to ineffective positioning in severely occluded areas. An integrated GPS/pseudolite positioning technique is proposed in this paper as an effective solution for precision deformation monitoring in the abovementioned areas. This technique can effectively increase the number of visible satellites, optimize their geometric structure, and improve their positioning precision and reliability. This technique has been used in monitoring related deformable objects and has yielded favorable results. However, the majority of current studies have focused on static positioning, whereas dynamic positioning has largely been ignored. Furthermore, dynamic positioning requires further research to eliminate or reduce unmodeled systematic errors (particularly the multipath error). This paper explains the necessity and effectiveness of pseudolite introduction on the basis of the derivation of the basic deduction formula for integrated GPS/pseudolite positioning. Thereafter, the importance of pseudolite location selection by simulated test verification and analyses is discussed. Several methods for estimating and reducing the multipath error of pseudolite, which is affected by slow or small ground surface deformation and shows high spatial correlation, are also presented in this paper. A dynamic deformation monitoring model is proposed on the basis of the moving average method to improve the precision of dynamic positioning. The standard deviations of the baseline vectors in the X, Y, and Z directions are calculated at 14.0, 35.3, and 9.0?mm, respectively, thus indicating that the positioning precision is improved to different degrees in the proposed model compared with that of the separate GPS system (33.8, 54.4, and 22.3?mm for the X, Y, and Z directions, respectively), the integrated GPS/pseudolite dynamic positioning model prior to the elimination of the multipath errors of pseudolites (24.9, 56.4, and 13.3?mm for the X, Y, and Z directions, respectively), and the integrated GPS/pseudolite dynamic positioning model on the basis of the estimation of multipath error parameters (29.7, 47.