摘要:

ABSTRACTRecent advances in wide‐area differential GPS and dual‐frequency receiver technology have made dramatic accuracy improvements feasible for Precise Positioning Service (PPS) users. Through a set of distinct upgrades to the GPS control segment, signal‐in‐space (SIS) accuracy can be reduced to well under 1 m. Combined with optional user equipment upgrades, SIS error reduction makes submeter positioning accuracy achievable without the additional data link and reference receiver(s) generally required for differential systems.This paper focuses on the effectiveness of several SIS accuracy enhancement concepts. Results of parametric satellite monitoring experiments are used to divide control segment enhancements into subcategories based upon satellite monitoring accuracy and drift error characteristics. This parametric approach provides a framework for further comparisons of the various complementary and competing concepts under consideration. User‐related errors such as multipath and atmospheric delays are also discussed to place SIS accuracy in the context of the overall P

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb02574.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTIn earlier work, methods for using fast Fourier transform (FFT) techniques to process digitized GPS and GLONASS signals were presented. This paper presents data collected among the largest buildings in Hartford, Connecticut. Consistent with our laboratory findings, field analysis suggests that the FFT method is able to extract the times of arrival (TOAs) of the satellite signals given only brief glimpses of the signals, resulting in a receiver that can track more satellites than conventional receivers when operating in urban canyons. In addition, a method based on dynamic programming is presented which makes use of local maxima in the cross‐correlation functions to find the optimal trajectory, thereby further increasing fix availability. Finally, a method of implementing the optimum matched filter for colored noise and interference is described. It is shown that the filter improves performance even when noise and interference are limited to white noise and other satellites, and notching/filtering noise as wide as 1.44 MHz centered in the GPS band is illustrate

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb02575.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTAn interferometric fiber‐optic gyroscope (IFOG)‐based GPS Guidance Package (GGP) achieved 4 m spherical error probable (SEP) in an integrated GPS/inertial mode and 10 m error growth after 5 min without GPS reception under harsh field conditions. The 295 in3, 14 lb Phase 1 GGP systems were evaluated under controlled laboratory conditions and during van testing, as well as in a U.S. Army Fire Support Team Vehicle (FISTV). During the FISTV demonstration, the GGP significantly outperformed the Army's currently used equipment. The results of these tests validated the tightly coupled GPS/inertial design approach with fiber‐optic sensors and the system's suitability for applications with demanding environmental requirements. Current development is focused on 0.8 nmi/h inertial performance and miniaturization of the system to a 100 in3, 7 lb package. The Phase 2 design provides capabilities of high dynamics and low jamming susceptibility, as well as adaptability to multiple military and commercial applications with a low‐cost production

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb02576.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThis paper presents the design and flight test results of a tightly coupled, differential GPS/INS navigation system for precise tracking of medium‐range ballistic missiles on test ranges. It describes a 27‐state extended Kalman filter that blends data from a space‐stabilized inertial platform with DGPS pseudorange and pseudorange‐rate measurements to produce real‐time estimates of navigation and sensor errors. Navigation system performance results from simulation are presented, and the estimated degradation of reentry navigation accuracy due to the loss of DGPS updates over the course of the trajectory are detailed. System performance was validated with a 130 km flight test on a ballistic missile with a Pershing II reentry vehicle; results of this flight test are

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb02577.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTDifferential carrier‐phase positioning overcomes some of the operational limitations of carrier‐phase kinematic positioning in a real‐time environment. Unlike kinematic positioning, differential carrier‐phase positioning does not require time matching of reference and remote station data. The observation time matching adds the data link delay to the position latency and prevents positioning when the reference data transmission is interrupted. The differential carrier‐phase algorithm is based on determining and then applying the GPS carrier‐phase errors instead of direct observation differencing. The differential carrier‐phase method enables several‐centimeter positioning at a high rate dependent on the remote receiver observation rate, but relatively independent of the data link transmission rate. This paper discusses the design, successful implementation, and test results of a real‐time differential car

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb02578.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTWorking Group 5 of RTCA Special Committee (SC)‐159 has spent the past several years working on the problem of GPS fault detection and exclusion (FDE) for a primary‐means navigation system that can support oceanic en route through nonprecision approach modes of flight. The results of this working group's activities have been incorporated into RTCA/DO‐229, Minimum Operational Performance Standards (MOPS) for GPS/WAAS Airborne Equipment, and will also serve as a baseline for the GPS/GLONASS and GPS/INS MOPS. The purpose of this paper is to provide a history of the development of the FDE requirements, algorithms, and test procedures, as well as a summary of the main issues addressed by the GPS Integrity (FDE) Working

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb02579.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY