ION Technical Content
Precision Survey With Ashtech XIX
| Abstract: | Several enhancements on GPS technology are presented. They encompass new data processing algorithms, enhanced application techniques, more hardware capabilities, and reduction in size and power con sumption. Cost reduction is a natural consequence. Use of Doppler measurements for instantaneous (every one second) stationary position fixes is introduced. This technique has the potential of reducing the effect of “Selective Availability” in static point positioning. It is shown that the combination of Doppler and code phase (pseudo-range) measurements can provide two dimensional deterministic static position fixes (and time) with only two satellites. It also can provide three dimensional position fixes (and time) with three satellites. The proposed techniques expand the usage of GPS in areas with low satellite visibility (e.g. forests) and in the interim period while the GPS satellite constellation is not complete. Definition and physical interpretation of GDOP for the hybrid use of Doppler and code phase are presented. The notion of “Multiple Ramp” smoothing of code phase with integrated Doppler is introduced. The result of implementation of this technique in Ashtech XII receivers for real-time differential GPS is given. Minimizing the errors in the use of GPS for aerial photogrammetry applications is discussed. A new technique implemented in Ashtech XII GPS receivers is presented. A new generation of GPS receiver (Ashtech M-XII) is introduced. It is capable of performing precision survey (static, kinematic, and pseudo-kinematic), navigation, and time transfer. The new 12 channel receiver employs higher level of hardware integration. The results of Ashtech XII Dual Frequency receivers on the FGCC test network are presented in this paper. The FGCC test happened to be performed during one of the most severe ionosphere activities of the decade. |
| Published in: |
Proceedings of the 1990 National Technical Meeting of The Institute of Navigation January 23 - 25, 1990 Princess Resort Hotel San Diego, CA |
| Pages: | 73 - 84 |
| Cite this article: | Ashjaee, Javad, "Precision Survey With Ashtech XIX," Proceedings of the 1990 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1990, pp. 73-84. |
| Full Paper: |
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