A Pointing System Requiring No Ambiguity Resolution: Theory, Design, and Performance

Lawrence Weill

Abstract:	Recently it has been shown by the author [31 that full 3-axis attitude determination is possible using a likelihood-function approach to the processing of GPS carrier phase measurements. The resulting attitude estimate is nearly optimal and does not require modeling of phase ambiguities. This paper presents the theory, design, and performance characteristics of a 2-axis (i.e., pointing) system using the aforementioned approach, in order to demonstrate the validity of the theoretical and design concepts in a practical system that could be used in space applications (such as antenna pointing) or ground applications (such as aiming of artillery). In addition to describing the simple and straightforward theory involved, the paper treats the design problem of selecting the antenna locations for optimum performance, and defines a geometrical figure of merit for attitude estimation which is similar to PDOP. It is shown that the performance characteristics of the resulting system agree closely with analytically derived results, and that “ambiguity resolution” is accomplished automatically without the need for special algorithms or mathematical modeling of any integer cycle uncertainties. The likelihood-function approach is equally valid for full 3-axis attitude determination. However, a 2- axis system is presented here because the results are much easier to visualize and interpret.
Published in:	Proceedings of the 1995 National Technical Meeting of The Institute of Navigation January 18 - 20, 1995 Disneyland Hotel Anaheim, CA
Pages:	803 - 812
Cite this article:	Weill, Lawrence, "A Pointing System Requiring No Ambiguity Resolution: Theory, Design, and Performance," Proceedings of the 1995 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 1995, pp. 803-812.
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