The Theory Of Gnss Precise Point Positioning And Its Software Development

In the tens of millions of square kilometers or anywhere of worldwide, GNSS precise point positioning using single receiver can obtain millimeter-level accuracy positioning in static model and centimeter-level accuracy positioning in dynamic model. With the established of four navigation systems, positioning of multi-mode PPP has become a research focus. At present, Chinese GNSS precise point positioning software with high precision is rare, and our country mainly depend on foreign software, that greatly restricting Chinese satellite business. GNSS PPP technology will become the frontier research direction of GNSS positioning because of its simple operation, low cost and high precision.This paper is mainly focus on the following work about the theory of GNSS precise point positioning:(1) Introduction and comparison of four navigation system in the world; Summarize the types and applicabilities of the basic observation value and its combination form; Explain the transformation of time systems and coordinate systems of various navigation system in ppp solutions; Introduce the basic model of parameter estimation and ambiguity solution of GNSS PPP.(2) Analysis of the causes, features and corresponding error correction model of all kinds of error that effecting GNSS PPP. In the GNSS PPP, weaken or eliminate these errors is the way to improve positioning accuracy.(3) Analysis the function and design of multi-mode GNSS PPP software. Based on the VS2010 platform,a multi-mode GNSS positioning software that based on a windows platform,visual interface,and simple operation has been realized. Now it can conduct GPS/GLONASS PPP solutions; Test the GNSS PPP software’s calculation functions and coordinate conversion function and verify its reliability and precision.(4) Analysis the accuracy of IGU ephemeris orbit; Contrast the precision difference about the PPP of different navigation positioning system.