Improving the Accuracy of C/A Code Systems

Javad M. Ashjaee

Abstract:	The accuracy of the single-frequency GPS systems are mostly limited by the ability to correct for the ionospheric delay. In this paper, we show that the ionospheric correction model, provided in ICD-200 ( 1), is not consistent with the uploaded parameters. The discrepancy is due to non-normalized coefficients of the cubic equation that must represent the normalized period of the model. The error degrades the performance of the single-frequency systems mostly during the night. We show that the corrected model provides about 30 meters of position fix and 90 nanoseconds of time transfer accuracy improvements. In this paper we also present data obtained in design and development of low-coat C/A code GPS receivers. The accuracy of the real time position fixes, with no differential corrections, are shown to be comparable to the published accuracy of dual frequency P-code receivers.
Published in:	Proceedings of the 1985 National Technical Meeting of The Institute of Navigation January 15 - 17, 1985 San Diego, CA
Pages:	92 - 100
Cite this article:	Ashjaee, Javad M., "Improving the Accuracy of C/A Code Systems," Proceedings of the 1985 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 1985, pp. 92-100.
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