Accuracy, Reliability and Repeatability of Kinematic GPS Single-Point and Differential Pseudorange Solutions

M. Abousalem, E.J. Krakiwsky, and D. Roberts

Abstract:	As quality control of information acquired from kinematic systems has, recently, become a prime concern to civil users in the field of vehicle navigation, more attention has been drawn to the precision accuracy and reliability of navigation systems output. Several RAIM techniques have been developed over the past few years to warn the users in case of receiving faulty GPS data. In this paper, a new methodology is proposed, and numerically quali- fied, which employs reliability theory and precision mea- sures to quantify theaccuracy, reliability and repeatability of a navigation solution. In real-time, GPS users can determine, by using this methodology, how acceptable and repeatable their solution is, depending on the avail- able satellite geometry, measurement accuracy, and sys- tem design. It isanasset, forhighquality GPS applications, to jointly use precision and reliability techniques, simply because DGP measures and precision of an estimated position, computed from the variance-covariance matrix of a GPS solution, is valid only if and only if no blunders were included in the data set employed; that is only random errors are assumed to exist. If an undetectable blunder exists in one of theobservations, the whole system is contaminated and its position output is no longer accu- rate nor reliable, although precise but yet not repeatable. In this paper, numerical and graphical illustrations, using QCKINrM software package, will be given to demonstrate the necessity of using reliability measures, hand-in-hand, with precision measures, e.g., DOPS, to ensure the quality of the system output for single-point, single-difference and double-difference GPS positioning techniques using Pseudorange observables. Accuracy, reliability and repeatability of GPS navigation solutions are a prerequisite in the field of positioning and navigation. The methodology discussed in this paper provides users with a measure of the quality of their navigation results.
Published in:	Proceedings of the 6th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1993) September 22 - 24, 1993 Salt Palace Convention Center Salt Lake City, UT
Pages:	529 - 529
Cite this article:	Abousalem, M., Krakiwsky, E.J., Roberts, D., "Accuracy, Reliability and Repeatability of Kinematic GPS Single-Point and Differential Pseudorange Solutions," Proceedings of the 6th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1993), Salt Lake City, UT, September 1993, pp. 529-529.
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