A Study On Data Processing For Carrier-Phase Time Comparison Using GPS

The objective of this thesis is to study on cycle slip detection and repair and interpolation algorithm for precise ephemeredes, et al in GPS Carrier-Phase ( GPS CP ) time comparison, develop data processing software package, and solve out GPS CP key issue. The research emphasizes on cycle slip detection and repair and interpolation algorithm for precise ephemeredes. Based on the research, data processing Programming module is programmed, a time comparison experiment based on the Programming is carried out using raw GPS observation data, the results demonstrate that the algorithm used in this paper is credible. The core of the thesis includes the following:(1) The development history of the precise time comparison technologies is reviewed; the principle of GPS Common-View, Two-Way Satellite Time and Frequency Transfer and GPS Carrier-Phase are introduced, and they are compared in brief; the main error sources which limit the improvement of GPS CP time comparison, and several models for error correction and mitigation are analyzed;(2) Data processing methods are discussed, the study emphasizes on cycle slip detection and repair and interpolation algorithm for precise ephemeredes. Two Level Combination method of pseudorange/Carrier-Phase combination and dual frequency differenced Carrier-Phase, which suits dual-frequency receiver, is proposed to detect and correct cycle slip, two programs of TurboEdit and Two Level Combination methods are used in order to detect and fix cycle slip occurring in GPS CP time comparison; Sliding Lagrange polynomial interpolation algorithm is made use for precise ephemeredes, the reasonable polynomial order is investigated; phase smoothing pseudorange and fixing ambiguity algorithms are introduced;(3) The Programming module of data processing is developed using Fotran Programming language on Windows Operation System platform, blocking design is described with each sub-module function; a time comparison experiment based on the Programming is carried out using raw GPS observation data provided by IGS tracking stations, the results indicate that the precision of time comparison is up to sub-nanosecond , and a frequency stability of 7～8×10-15 is derived for averaging times of half-day.