摘要:

ABSTRACTAn experimental DGPS precision approach and landing system was installed and flight tested on the NASA Langley Transport Systems Research Vehicle (TSRV). The GPS ground reference station and avionics units used 10‐channel, narrow‐correlator, C/A‐code tracking receiver engines. The avionics drove the aircraft flight control system with ILS “look‐alike” vertical and horizontal angular deviations derived solely from DGPS C/A‐code tracking position and velocity. The avionics did not make use of kinematic carrier‐phase tracking with on‐the‐fly cycle ambiguity resolution techniques.A total of 40 DGPS‐guided approaches and landings were performed at the NASA Wallops Flight Facility, 31 of them hands‐off, automatic landings. Total system error, measured by laser tracker, met the proposed Category III required navigation performance (RNP) or “tunnel concept” accuracy requirements by substantial margins. Touchdown dispersion for the 31 automatic landings also met Category III RNP requireme

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1994.tb02567.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTA new system based on GPSIntegrity Beacons(low‐power pseudolite marker beacon transmitters situated underneath the approach path) has been developed to provide the highest possible performance (including accuracy, integrity, and availability) for Category III precision landing using the Global Navigation Satellite System (GNSS). The landing system based on Integrity Beacons defines the Kinematic GNSS Landing System (KGLS). Two new developments are reported: first, real‐time, centimeter‐level kinematic satellite positioning using the integrity beacon is evaluated in flight testing, and second, a new paradigm for real‐time differential satellite positioning is introduced that eliminates the traditional data link. A special type of Integrity Beacon is the Omni Marker, which rebroadcasts each received satellite signal coherently using a new PRN code. An aircraft receiving both the direct signal and the rebroadcast is capable of differential ranging without a digital data link. The latency associated with traditional differential positioning is completely eli

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1994.tb02568.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTAlthough DGPS is inherently robust to space‐vehicle‐related ranging errors, failures in the differential station or airborne receiver can be a threat to continuous precise positioning. The stringent required navigation performance (RNP) for Category III precision landing, therefore, establishes the need for an active integrity verification system. Carrier tracking of ground‐based pseudolites can provide comprehensive integrity. The large geometry change that occurs during overflight of a ground‐based pseudolite and the great precision of carrier‐phase measurements can provide the leverage for effective autonomous integrity monitoring. The measurement residual statistic can be used to detect a wide range of conceivable fault scenarios occurring during the pseudolite overflight, including cycle slips, intentional tampering, and airborne database errors. The potential for autonomous integrity verification for Category III approach is demonstrated through analysis, simulation, and flight tests performed in a single‐engi

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1994.tb02569.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThe development of a real‐time positioning system using GPS carrier phase was formally initiated by the U.S. Army Corps of Engineers in 1988. The end goal of this effort was to have ready by 1993 an operational prototype capable of subdecimeter positions in three dimensions in real time. This goal has been met. Testing of this prototype began in March 1993. The first demonstration was in August 1993, with the first public demonstration following in October. The system typically resolves integer ambiguities on‐the‐fly (OTF) in 15 s or less, and requires no static initialization. It is robust and reliable to use for precisely positioning any mobile platform out to approximately 20 km. Testing has been performed under varying operating conditions to evaluate the limits of OTF ambiguity resolution for precisely positioning moving platforms. This paper summarizes the results of those tests. Early real‐time tests performed have shown accuracies of 1–3 cm in all three dimensions. Design of the final real‐time system and its integration with hydrographic survey platforms are als

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1994.tb02570.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTA new automatic dependent surveillance (ADS) system concept combining GPS‐based positions with Mode S data communications is described. Several potential applications of this concept are presented, with emphasis on surface surveillance at airports. The navigation and data link performance are analyzed. Compact ADS position formats are included. The results of the first tests at Hanscom Field, demonstrating the feasibility of the spontaneous broadcast of ADS positions using Mode S messages, are presented. Test aircraft, vehicles, avionics equipment, and the ground system configuration are described. Avionics standards and GPS interface requirements are discussed. Multipath and airport surface coverage issues are addressed. Further testing in an operational environment is continuing at Logan Airpor

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1994.tb02571.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTThis paper shows how coastal piloting observations can be cast in a form that allows them to be reduced using a celestial navigation algorithm. This is useful when navigating with a computer that can compute a position fix from celestial observations, but is not explicitly designed to handle coastal piloting. It is also a useful technique for incorporating piloting into a computer program without programming piloting and celestial techniques separately. We treat three cases: a range to a known object, a bearing to a known object, and a horizontal angle measured between two known objects.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1994.tb02572.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

ABSTRACTPreliminary descriptions and analyses of a precision lunar landing using various navigation scenarios are presented. The scenerios assume the Common Lunar Lander (CLL) as a reference mission. Current state‐of‐the‐art or off‐the‐shelf technology is emphasized to keep mission cost to a minimum—an important driver in the possible funding of future space missions. It is concluded that precision navigation sensor suites are required to meet certain stringent mission navigation r

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1994.tb02573.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY