Single-Epoch Weighting Adjustment of GPS Phase Observables

Joz Wu and Tien-fu Yeh

Peer Reviewed

Abstract: When observing the GPS satellites, a user receiver records the code pseudorange and carrier-phase measurements with differing precisions.A least-squares adjusting estimator was devised to investigate the respective pseudorange and carrier-phase variances on an epoch-by-epoch basis. As the inverse of a scaled covariance matrix represents a weighting matrix, the linear estimator of variance components can optimally determine the weights for any code and carrier-phase datasets. A feasibility study indicated that, for short-baseline vectors, four unknown variance factors can be associated with the single-epoch, dual-frequency GPS pseudoranges and carrier phases. With regard to resolution of the whole-cycle phase ambiguities, a decorrelating transformation method, based on some triangular factorizations, is described. There is also evidence that, when generated using the variance-component estimator, the resulting parameter covariance matrix will contribute to an effective ambiguity resolution.
Published in: NAVIGATION: Journal of the Institute of Navigation, Volume 52, Number 1
Pages: 39 - 48
Cite this article: Wu, Joz, Yeh, Tien-fu, "Single-Epoch Weighting Adjustment of GPS Phase Observables", NAVIGATION: Journal of The Institute of Navigation, Vol. 52, No. 1, Spring 2005, pp. 39-48.
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