摘要:

ABSTRACTThis paper addresses the requirement for an automatic dependent surveillance (ADS) function in oceanic areas. It includes a description of the present oceanic air traffic control (ATC) system and its functional limitations. It also provides a historical perspective on the National Airspace System, as well as background on oceanic ATC modernization and improvements leading to development of the FAA ADS program. Also included are a brief overview of the Oceanic Display and Planning System (ODAPS), which is the baseline for ADS, and a synopsis of the ADS function, program, demonstrations, implementation, and resulting benefits.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00968.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTNavigation, surveillance, and communications play an important role in most transportation activities in the Province of Ontario. This paper summarizes the present and future roles of these functions in various essential aviation activities that are performed by the provincial government. These activities include mapping, forest fire detection, wild life surveys, law enforcement, and health services. Particular emphasis is given to the expanding roles of Loran‐C for both navigation and dependent surveillance, and satellite communication

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00969.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTSimple closed‐form solutions for the statistics of coverage gaps (holidays) associated with parallel lane surveys are derived. In particular, theoretical results for mean holiday area, mean holiday dimensions, and frequency of encounter of random holidays are presented. For verification, the latter are compared with the results of computer simulations of first‐order Markov proces

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00970.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTToward the end of 1987, a question was raised regarding the treatment of special relativity for the case of intersatellite tracking of future replenishment GPS satellites. The question has to do with the manner in which moving clocks appear to slow down because of relativity. The effect appears to be quite different depending on how we define the observer. In one case, we consider the observer to be in the frame of the receiving satellite, with the clock on the transmitting satellite. In the other case, the observer is in earth‐centered inertial coordinates. The answer to the question regarding coordinate frames was found by considering classical Doppler together with special relativity. This paper shows that, since the dynamics of GPS is formulated in earth‐centered coordinates, it is necessary that special relativity also be formulated in this coordinate fr

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00971.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTThe GPS Joint Program Office has directed the delivery of GPS user equipment incorporating standard hardware and software. The resulting package, RCVR‐3A, is designed to provide specified navigation performance under a wide range of alternative avionics interface requirements and aircraft mission scenarios. However, various integration studies have demonstrated that some of the RCVR‐3A's potential performance is not realized because of the software design compromises made to accommodate standardization requirements. This is particularly the case when GPS measurements are integrated with INS outputs in RCVR‐3A INS‐mode operation. Therefore, some integrators have chosen to mechanize an independent navigation filter in a host vehicle mission computer when their system requirements exceed the GPS specifications.An alternative approach is to provide custom tuning for the RCVR‐3A navigation filter to improve the receiver's own estimates of velocity and platform alignment. This paper summarizes the results of studies indicating that filter tuning is a cost‐effective approach for certain combinations of INS and aircraft mission requirements. The paper concludes with a discussion of alternative means of mechanizing the RCVR

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00972.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTDuring the past two years, a hybrid Loran‐C/GPS receiver has been used in day‐to‐day navigation in a Beechcraft Bonanza Model S‐35. It has been an invaluable aid in learning about the capabilities of the hybrid system, as well as trying new features and options.In this paper, we first discuss the current capabilities and features of the hybrid receiver, with emphasis on the new digital Loran. Although the Loran receiver is designed as a marine product, many of the requirements of the aircraft market are similar. Second, we present data showing performance under several different circumstances, including both static and dynamic performance. Third, we discuss future enhancements and capabilities, with emphasis on the hybrid comb

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00973.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTGPS is currently being installed; when it is operational, five satellites will be in view virtually 100 percent of the time. However, the full constellation will not be in place for several years, and even then satellite failures may introduce coverage holes. Additionally, even with the full constellation, a GPS receiver will not always be able to monitor signal integrity unless some external aid is used.Loran‐C can be used effectively to aid GPS. A hybrid receiver can combine Loran lines of position with GPS lines of position to provide a system with great integrity, reliability, and time availability. Indeed, Loran is independent of GPS and can be used to detect GPS system or receiver failures. However, the hybrid receivers must include sophisticated Loran propagation models, which account for both the spatial and temporal anomalies of the propagation paths. Fortunately, GPS can be used to efficiently gather the data for these models. Additionally, GPS observations could be used to calibrate (or tune) these models in real time.This paper reviews the theory of Loran propagation and gives a basic Loran pseudorange model. It also presents some basic approaches for combining Loran and GPS pseudoranges in a position‐fixing receiver. Finally, it estimates the accuracy of the hybrid sys

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00974.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTThe advantages of a navigation system that can monitor its own integrity are obvious. Integrity monitoring requires that the navigation system detect faulty measurement sources before they corrupt the outputs. This paper describes a parity approach to measurement error detection when redundant measurements are available. The general form of the detector operating characteristic (DOC) is developed. This equation relates the probability of missed detection to the probability of false alarm, the measurement observation matrix, and the ratio of the detectable bias shift to the standard deviation of the measurement noise.Two applications are presented: skewed axis strapdown inertial navigation systems, where DOCs are used to compare the integrity monitoring capabilities of various redundant sensor strapdown system configurations; and GPS navigation sets, where DOCs are used to discuss GPS integrity monitoring for meeting non‐precision approach requirements. A fault identification algorithm is also presente

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00975.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00976.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY