Analysis of the Integer Property of Ambiguity and Characteristics of Code and Phase Clocks in PPP using a Decoupled Clock Model

J. Shi, Y. Gao

Abstract:	GPS Precise Point Positioning (PPP) using a single receiver is able to obtain centimeter-level positioning accuracy for static applications. In order to achieve decimeter-level accuracy, half an hour or even longer convergence time is required. This long convergence time has limited the wide use of PPP technology to real-time kinematic applications. As a result, how to reduce this convergence time with satisfied positioning accuracy is a significant challenge. Like the double-difference applications benefitting from ambiguity resolution (AR), PPP AR has great potential to take advantages of ambiguity’s integer property and get improvements for both the convergence time and positioning accuracy. Literatures (Ge et al (2008), Wang & Gao (2006, 2007, and 2009), Geng (2009) and Geng et al (2009)) demonstrate that PPP with ambiguity resolution can improve float solutions with better positioning accuracy using a single-difference between satellites (SDBS) approach. In addition, Collins (2008) and Collins et al (2008) introduced another PPP AR method called decoupled clock (DC) model. Unlike the single-difference approach, this un-difference method uses un-difference code and phase observations but deals with separate code and phase clocks. The decoupled clock model has been tested feasible and applied in a tsunami warning system along Vancouver coastline (Collins et al (2009)). However, some aspects still remain uninvolved in the above-mentioned methods. First of all, most publications focus on analysis of reduced convergence time and improved positioning accuracy. Integer property of PPP ambiguity is not well assessed if it is theoretically recovered. Secondly, no clock analysis in both SDBS method and the decoupled clock model are performed from the timing perspective. Therefore, this paper will focus on these two topics and aim at analysis of the recovery of PPP ambiguity’s integer property and the characteristics of the decoupled code and phase clocks.
Published in:	Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010) September 21 - 24, 2010 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	2553 - 2564
Cite this article:	Shi, J., Gao, Y., "Analysis of the Integer Property of Ambiguity and Characteristics of Code and Phase Clocks in PPP using a Decoupled Clock Model," Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010), Portland, OR, September 2010, pp. 2553-2564.
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