Estimating the Receiver Delay for Ionosphere-Free Code (P3) GPS Time Transfer

Victor Zhang

Abstract:	The ionosphere-free code (P3) GPS time transfer uses dual-frequency measurements from GPS geodetic receivers to minimize the errors in the ionospheric delay correction. The P3 GPS time transfer requires knowledge of the receiver delays on both the L1 and L2 frequencies (P3 receiver delay). Very few receivers used for P3 GPS time transfer are absolute calibrated, due to the complexity of the calibration. The BIPM has started regular calibration campaigns to determine the delay of the P3 receivers around the world against an absolute calibrated BIPM receiver. This paper presents a method to estimate the P3 receiver delay that uses a calibrated conventional GPS common-view receiver. The uncertainty of the estimated P3 receiver delay is about the same as that obtained by the differential calibration between two P3 receivers. Each timing laboratory with a calibrated common-view receiver can apply this method to estimate the delay of an on-site P3 receiver. This method can also be used to simplify the differential calibration of both the common-view receiver and the P3 receiver with one traveling common-view receiver.
Published in:	Proceedings of the 38th Annual Precise Time and Time Interval Systems and Applications Meeting December 7 - 9, 2006 Hyatt Regency Reston Town Center Reston, Virginia
Pages:	467 - 472
Cite this article:	Zhang, Victor, "Estimating the Receiver Delay for Ionosphere-Free Code (P3) GPS Time Transfer," Proceedings of the 38th Annual Precise Time and Time Interval Systems and Applications Meeting, Reston, Virginia, December 2006, pp. 467-472.
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