Validations of the SCORE Process

Gregory Bishop, Andrew Mazzella, Susan Rao, Andrew Batchelor, Peter Fleming, Nicholas Lunt and Leonard Kersley

Abstract:	The Self-Calibration Of pseudoRange Errors (SCORE, introduced at ION GPS-94 [ 11) algorithm uses ionospheric measurements to calibrate GPS two-frequency receivers for all system components’ contributions to pseudorange error [2]. To validate SCORE, the first logical choice is comparison to data obtained by other sensors such as ionosondes or computerized ionospheric tomography (CIT) networks. However, most of these techniques are either less precise than GPS measurements or measure over a different region than GPS, making it necessary to model or assume the contributions in the non-common region. Thus, in this paper we examine multiple approaches to validation of the SCORE technique. These include: accuracy of satellite bias errors, accuracy of receiver bias errors, credibility of derived regional ionosphere, comparison of overlapping GPS observations, comparison to another calibration technique, comparison to total electron content (TEC) measurements from the Navy Navigation Satellite System (NNSS, or Transit) satellites, credibility of day-to-day variations in regional ionosphere measurements, comparison to radar measurements, and comparison to TOPEX satellite measurements.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	289 - 296
Cite this article:	Bishop, Gregory, Mazzella, Andrew, Rao, Susan, Batchelor, Andrew, Fleming, Peter, Lunt, Nicholas, Kersley, Leonard, "Validations of the SCORE Process," Proceedings of the 1997 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1997, pp. 289-296.
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