A GPS Common-View Time Transfer Scheme considering the Code Bias

M.Y. Shin, D.J. Cho, S.H. Park, S.J. Lee

Abstract:	The common-view technique has long been used for international comparisons of time and frequency standards. The international time scales, TAI and UTC, are created by averaging data collected from more than 200 atomic clocks located in about 50 laboratories. Most of these data are collected using common-view GPS measurements. The common-view technique is a simple but elegant way to compare two clocks or oscillators to each other. In this paper, we analyze the performances and limitations of the common-view time transfer according to the measurement errors such as the ionospheric error, the ephemeris error and the code bias error on receiver. The code bias is generated because to the intra-frequency and inter-frequency differential delays of signal paths. So the code bias is the common-oscillator hardware or local environment delays for each observation. Generally, the code bias is identified initially but it is then neglected or assumed to be negligible. However the code bias has a time-varying property with different amount on each channel such that a proper removal method is necessary to improve the performance of the time transfer. This paper presents the effect of the code bias and shows the improved performance of the time transfer using a time-difference technique to reduce the effect of the code bias.
Published in:	Proceedings of the 2012 International Technical Meeting of The Institute of Navigation January 30 - 1, 2012 Marriott Newport Beach Hotel & Spa Newport Beach, CA
Pages:	509 - 512
Cite this article:	Shin, M.Y., Cho, D.J., Park, S.H., Lee, S.J., "A GPS Common-View Time Transfer Scheme considering the Code Bias," Proceedings of the 2012 International Technical Meeting of The Institute of Navigation, Newport Beach, CA, January 2012, pp. 509-512.
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