The Geometry of GPS Solutions

Jonathan S. Abel, James W. Chaffee

Abstract:	The geometry of point estimates of position computed from GPS pseudoranges is studied, and a new geometric model for GPS solutions is introduced. The new view- point is a departure from the standard idea of what con- stitutes a GPS solution in that the dependence of position on user clock bias is explicitly treated. GPS solutions, consisting of user position-user clock bias pairs, are seen to lie at the intersection of unit cones positioned according to the pseudorange measurements and satellite locations. One benefit of treating the bias dependence so explic- itly is that it makes clear the relationship between PDOP and TDOP by exhibiting the geometric relationship be- tween bias and position. It demonstrates the relation- ship between ranging, pseudoranging, and time of arrival differencing systems both qualitatively and with explicit error estimates.
Published in:	Proceedings of the 1992 National Technical Meeting of The Institute of Navigation January 27 - 29, 1992 Catamaran Resort Hotel San Diego, CA
Pages:	425 - 430
Cite this article:	Abel, Jonathan S., Chaffee, James W., "The Geometry of GPS Solutions," Proceedings of the 1992 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1992, pp. 425-430.
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