GPS-Network Analysis With BLIMPBE: A Less Biased Alternative To Least-Squares Adjustment

Kyle Snow and Burkhard Schaffrin

Abstract:	Geodetic Networks, when derived solely from observed GPS baseline vectors, have an inherent datum deficiency of dimension three due to the respective unknown translation parameters. Thus, estimated coordinates from a (weighted) least-squares adjustment will not be unique, although the adjusted baseline vectors are. Uniqueness without affecting the adjustment as such, can be achieved by introducing a minimum number of constraints for the coordinates, or by applying an objective function on the set of LEast-Squares Solutions (LESS) that fulfill the socalled “normal equations.” In both alternatives, bias control for some (or all) coordinate estimates has so far been treated only as a secondary issue. Here it is shown that the recently introduced estimator of type BLIMPBE – although generally not a LESS – can indeed be expected to be superior to all other linear estimators which minimize the bias for certain coordinates. This performance is demonstrated in a GPS-network that includes GPS receivers at several Continuously Operating Reference Stations (CORS).
Published in:	Proceedings of the 60th Annual Meeting of The Institute of Navigation (2004) June 7 - 9, 2004 Dayton Marriott Hotel Dayton, OH
Pages:	614 - 625
Cite this article:	Snow, Kyle, Schaffrin, Burkhard, "GPS-Network Analysis With BLIMPBE: A Less Biased Alternative To Least-Squares Adjustment," Proceedings of the 60th Annual Meeting of The Institute of Navigation (2004), Dayton, OH, June 2004, pp. 614-625.
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