GNSS Ambiguity Fixed Theory And Method Of Precise Point Positioning Research

Technology of Precise Point Positioning(Precise Point Positioning, PPP) is that a receiver can use single worldwide for dynamic or static independent observation, which can directly obtain the static centimeter level or dynamic metrics to centimeter level accuracy coordinates. As a result, it has been used in Leo satellite orbit determination, high precision navigation and Positioning, GNSS meteorology, precision timing, and other fields which has been widely used and development.Real-time performance and high precision is one of the research emphases and hotspot of precision positioning. As the real-time orbit determination precision clock difference and real-time estimate key core technology’s development and progress, such as precise point positioning technology has been gradually developed into the current methods of a high precision real-time positioning. In traditional precise point positioning, due to the phase delay of calibration deviation not decimal part FCBs(Fractional- cycle biases), the influence of solution for ambiguity parameters of real Numbers. Studies by many scholars both at home and abroad, precise point positioning is still up in the east of precision, which can be improved by the fuzzy degree of fixed. The use of regional or global reference station network, can restore its features, the difference degree of fuzzy integer implementation of rover PPP ambiguity in the area of search and fixed is a very meaningful and challenging work, and it is also a research focus in the field of GNSS scholars at home and abroad.This paper deeply studies the theoretical basis for precise point positioning technology,and detailed introduced the effect of all kinds of error and parameter estimation method and processing method. Starting from the most basic function model, that the phase ambiguity caused by the difference between non integer characteristic parameters and the relationship are analyzed in detail. Of precise point positioning and the influence has carried on the induction summary various error sources and processing methods, which gives the error correction model is commonly used in GPS data processing. Key for troposphere and clock error of these two kinds of time-varying parameter stochastic model are analyzed. At the same time according to the characteristics that caused the difference ambiguity integer phase calibration without delay in the deviation of the decimal part FCBs coupling properties of thedifferent with other parameters. That the system of the PPP ambiguity fixed algorithm at home and abroad were reviewed and the arrangement and classification, and make a detailed comparative analysis. Finally to the PPP ambiguity fixed algorithm based on FCBs. For example, the GPS data and compares the beidou data analysis, for carrying out a research into the beidou/GPS integrated positioning made basis.