Criteria for Military Certification of GPS for Sole Means Air Navigation

Edward C. Rish, Gary L. Noseworthy, George Lowenstein, Peter P. Fischer

Abstract:	The DOD navigation goal is to phase out the use of the existing TACAN, VOR/DME, OMEG4, Loran-C, and TRANSIT when GPS becomes fully operational and integrated in military aircraft, ships and ground units. In order to accomplish this the GPS replacement system must demonstrate that it is capable of meeting or exceeding the performance and key characteristics of the present systems. OMEGA, Loran-C, and TRANSIT are all geodetic referenced positioning systems that permit navigation in much the same manner as GPS. The primary differences are associated with the propagation of their carrier frequency and the inherent accuracy that is obtainable from each. The GPS L-Band signal will be available on a world wide basis 24 hours a day. GPS and the other geodetic positioning systems require a random area navigation (RNAV) computer associated with the basic sensor, to provide navigation and steering information to the pilot. Except for limited testing of Loran-C, previous testing of geodetic systems has not dealt with qualifying the entire system as a sole means air navigation system. TACAN and VOR/DME are qualified as sole means air navigation systems. Both of these systems are station referenced rather than geodetic referenced systems. Accurate radio bearing (radials) and ranging to a specific radio beacon are used to generate steering signals with sufficient accuracy to enable a pilot to perform safe flight. This includes enroute, terminal, and non-precision approach (up to the published decision height and range minimums) for any specific landing independent and without the aid of any other navigation system or mission computer. The use of geodetic referenced navigation systems in the sole means mode is not a new concept. DOD has not established specific guidance describing what constitutes a military, geodetic referenced, sole means air navigation capability. Basic requirements for civil use, however, are stated in AG 90-45A and RTCA/D0-187. DOD must also specify test criteria to certify that the described system will meet established guidelines for sole means air navigation within the National Airspace System. This paper will suggest guidance criteria for the definition and testing of a GPS equipped aircraft to enable certification by DOD.
Published in:	Proceedings of the 1988 National Technical Meeting of The Institute of Navigation January 26 - 29, 1988 Santa Barbara, CA
Pages:	130 - 137
Cite this article:	Rish, Edward C., Noseworthy, Gary L., Lowenstein, George, Fischer, Peter P., "Criteria for Military Certification of GPS for Sole Means Air Navigation," Proceedings of the 1988 National Technical Meeting of The Institute of Navigation, Santa Barbara, CA, January 1988, pp. 130-137.
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