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GLONASS performance in 1992: a review

Published in:
GPS World, Vol. 4, No. 5, May 1993, pp. 28-39.

Summary

Researchers at MIT's Lincoln Laboratory reviewed GLONASS developments during 1992, focusing on the requirements of civil aviation and the issues related to position estimation. The results show that the overall performance remains substantially the same as observed in 1991.
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Summary

Researchers at MIT's Lincoln Laboratory reviewed GLONASS developments during 1992, focusing on the requirements of civil aviation and the issues related to position estimation. The results show that the overall performance remains substantially the same as observed in 1991.

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An experimental GPS navigation receiver for general aviation: design and measured performance

Published in:
MIT Lincoln Laboratory Report ATC-121
Topic:

Summary

This report describes work performed by MIT Lincoln Laboratory between 1 October 1979 and 1 March 1983, to evaluate the use of the Global Positioning System (GPS) for low-cost civil air navigation. The report describes a GPS Test and Evaluation System developed jointly by MIT Lincoln Laboratory, Stanford Telecommunications, Inc., and Intermetrics, Inc., using techniques that could lead to low-cost commercial avionics. System performance results obtained in the laboratory and during flight tests are provided which demonstrate compliance with current and future navigation accuracy requirements for enroute, terminal, and non-precision flight paths. The report also includes functional specifications for a low-cost GPS navigation system for civil aircraft. The GPS Test and Evaluation system design was based on two important features: 1) automatic tracking of all visible satellites (rather than a minimum set of four) and 2) a dual-channel GPS C/A code receiver. Tracking all visible satellites allows the system to maintain continuous navigation when a satellite sets or is momentarily masked during aircraft maneuvers. The dual-channel receiver dedicates one channel to pseudo-range measurements, and the other channel to acquiring new satellites as they become visible. These two features, validated by flight test, allow the system to provide continuous navigation updates during critical aircraft maneuvers, such as non-precision approaches, and during satellite constellation changes.
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Summary

This report describes work performed by MIT Lincoln Laboratory between 1 October 1979 and 1 March 1983, to evaluate the use of the Global Positioning System (GPS) for low-cost civil air navigation. The report describes a GPS Test and Evaluation System developed jointly by MIT Lincoln Laboratory, Stanford Telecommunications, Inc...

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Alternate waveforms for a low-cost civil GPS receiver

Published in:
MIT Lincoln Laboratory Report ATC-86

Summary

This report examines the technical feasibility of alternate waveforms to perform the GPS functions and to result in less complex receivers than is possible with the GPS C/A waveform. The approach taken to accomplish this objective is (a) to identify, after a quick broad overview, a few promising waveforms, (b) to complete the architectural synthesis of a GPS system based on the new waveforms, (c) to analyze the performance of these systems in providing ranging and communication capability and (d) to assess the impact on receiver hardware and software. One conclusion is that the class of pulsed waveform, when combined with emerging matched filter technology, permits the use of a greatly simplified receiver design. Although very specific, the design was intended as a vehicle for performance analysis only and many refinements and alternatives within the same class are possible. Other classes of waveforms such as tome ranging and chirped FM waveforms, although adequate, do not seem superior to the present PN encoded CW waveform for GPS. Finally, if the "alternate" waveform is simply the present C/A waveform but with substantially increased power level, it is shown that with the present designs the performance will be greatly increased or, alternatively, performance margin can be traded for a simplified receiver implementation.
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Summary

This report examines the technical feasibility of alternate waveforms to perform the GPS functions and to result in less complex receivers than is possible with the GPS C/A waveform. The approach taken to accomplish this objective is (a) to identify, after a quick broad overview, a few promising waveforms, (b)...

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