A High Precision Dual-Band Solution to Airborne Navigation (Even in the Presence of Anti-Spoofing)

Xinhua Qin, Sergei A. Gourevitch, and Jonathan Ladd

Abstract:	The availability of high quality dual-frequency P-code (code and phase) observables has been responsible for many exciting developments in GPS geodesy and precision navigation over the last few years. Robust techniques for “on-the-fly” phase ambiguity resolution, resulting in sub-decimeter airborne differential navigation, promises to revolutionize precision approach and landing applications. Unfortunately, until very recently civilian users have been confronted with the fact that P-code quality tracking will essentially disappear when the government enacts full time Anti-Spoofing (AS). Ashtech has developed and patented a proprietary technique called Z-Tracking which produces “pure” high quality code and full wavelength carrier phase measurements in the presence of AS. Ashtech’s Z- Tracking technology will continue to provide civilian users with sufficient quality of data to support available P-code based techniques yet the technique does not conflict with DOD’S AS objectives. In parallel, Ashtech has developed a precise differential navigation software to provide sub-decimeter positioning. This is achievable using a combination of Ashtech’s “pure” high quality dual-frequency code and phase observables and “on-the-fly” phase ambiguity resolution techniques. We present the precision approach test results of such a system and highlight the accuracy comparison to laser tracking data and present results of on-the-fly centimeter level positioning during Anti- Spoofing.
Published in:	Proceedings of the 6th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1993) September 22 - 24, 1993 Salt Palace Convention Center Salt Lake City, UT
Pages:	885 - 891
Cite this article:	Qin, Xinhua, Gourevitch, Sergei A., Ladd, Jonathan, "A High Precision Dual-Band Solution to Airborne Navigation (Even in the Presence of Anti-Spoofing)," Proceedings of the 6th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1993), Salt Lake City, UT, September 1993, pp. 885-891.
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