摘要:

ABSTRACTA medium frequency (MF) radio system is being developed worldwide for the broadcast of differential corrections to users of GPS. TheseDGPS radiobeaconsuse groundwave propagation to carry the DGPS corrections to well beyond the radio horizon where the DGPS data is still valid. The International Association of Lighthouse Authorities (IALA) has established an international standard for the DGPS radiobeacon signal. Member countries have been extremely active in the development and installation of working systems. In particular, Iceland has just completed a nationwide DGPS service based on these radiobeacons and the IALA standard.This paper details the Icelandic goals and objectives for DGPS. It describes the resulting system architecture, including reference stations, integrity monitors, communications, and system control. It also predicts system performance in terms of coverage and availability. The paper then describes the validation effort, including sea, airborne, and overland trials. Finally, it provides a summary and conclusions.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1995.tb01906.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTAnalysis of the RTCA Special Committee (SC)‐159 baseline fault detection and exclusion (FDE) algorithm has been performed to determine whether a combined GPS/GLONASS system could satisfy availability requirements for a primary‐means air navigation system. The results presented in this paper are based on work performed in support of the RTCA SC‐159 GPS/GLONASS working group.These results demonstrate a substantial improvement in the availability of integrity over GPS alone, even if only a partial GLONASS constellation were to be available. Satellites were removed from both constellations to simulate operation under worst‐case conditions. It appears that an integrated GPS/GLONASS system could meet the availability requirement for a primary‐means air navigation system, even in cases where a number of satellites are out of service. Availability results are provided for oceanic, domestic en route, terminal, and nonprecision approach phases

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1995.tb01907.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTThe visibility of geostationary augmentation and GPS satellites from typical aircraft engaged in banked turning maneuvers is considered. First, the optical visibility from the GPS antenna location to the geostationary orbital arc is analyzed. It is shown that if two geostationary satellites at substantially different azimuths are available, they are blocked at different times during the aircraft turn, so that at no time during the maneuver is the aircraft without at least one geostationary's signal. Test flight data provided by Boeing for GPS satellites are then used to indicate that actual signal reception often continues well below the pessimistic optical mask. These considerations, as well as the operational fact that large banking angles do not occur in the final approach phase where integrity and continuity are most important, suggest that geostationary augmentation will remain effective at much higher latitudes than has been indicated in previous references.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1995.tb01908.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTA novel, high‐accuracy differential positioning technique for satellite‐based systems is presented. The technique does not require the use of code‐phase measurements. Integrated Doppler double difference () processing is used to converge the three‐dimensional position of a dynamic user to within 1 m of the true position after 1–2 min. Key elements of themethod are a very accurate propagation of the user position in combination with an iterative double difference processing scheme. The feasibility of theprocessing technique is demonstrated using both a computer simulation and actual flight test data. The technique requires measurements from seven or more satellites to achieve the short initialization time for dynamic users. This requirement can be satisfied with high availability by using all satellites from which the carrier phase can be tracked, in combination with a small reference station network that performs orbit determination for all satellites used in the position solution. Some applications and benefits of theprocessing technique are discusse

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1995.tb01909.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTGPS is capable of providing 100 m level accuracy for a great number of users worldwide. In GPS, range and range‐rate data can be used with satellite position and velocity to compute user position and velocity using an extended Kalman filter (EKF). However, the EKF is computationally intensive, leading to difficulties in broadband real‐time applications. Hence, it is necessary to resort to techniques to improve EKF speed. Therefore, in this paper, the EKF matrices are analyzed in detail, exploiting the sparsity and structure of the EKF matrices to reduce the number of computations.A typical trajectory is simulated, and a comparison of the computation speed of sequential implementations of EKF, both with and without the proposed reduction of computations, is reported. Further, an algorithm is developed to obtain an initial estimate of user position and velocity which is used to initialize the state vector of the EKF algori

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1995.tb01910.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTAlthough many mathematical approaches to the celestial fix problem have been published, all of them fundamentally assume a stationary observer. Since this situation seldom occurs in practice, methods have been developed that effectively remove the observer's motion from the problem before a fix is determined. As an alternative, this paper presents a development of celestial navigation that incorporates a moving observer as part of its basic construction. This development allows recovery of the information on the vessel's course and speed contained in the observations. Thus, it provides the means for determining, from a suitable ensemble of celestial observations, the values of all four parameters describing a vessel's rhumb‐line track across the earth: latitude and longitude at a specific time, course, and speed. In many cases, this technique will result in better fixes than traditional method

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1995.tb01911.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

ABSTRACTA review of the new Instrument Landing System (ILS) currently being deployed by the Federal Aviation Administration for use by pilots in making very low visibility landings is presented. The Mark‐20, as it is designated, is compatible with all present ILS receiving equipment and is intended principally as an upgrade to replace the first solid‐state transmitting equipment, which was typically placed in service approximately 25 years ago. New features such as remote control provisions and the novel components to accomplish this control are descri

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1995.tb01912.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY