Research On GPS/GLONASS Precise Point Positioning Technology Model And Algorithm

GPS Precise Point Positioning (PPP) is a new satellite positioning technique, which can get the centimeter position solution by a dual-frequency GPS receiver. GPS is a satellite-based positioning system, its accuracy and reliability depend on the number of observable satellites. A good strategy is to integrate several positioning system, increase the number f visible satellites, and improve PPP's accuracy and reliability.With the GLONASS precise ephemeris, precise clock errors'occur, GPS/GLONASS PPP becomes possible. In this paper, the structure, the satellite signal and navigation data of GPS/GLONASS system are analyzed; then the time system, coordinate system's conversion method of GPS/GLONASS are discused; the GPS/GLONASS data processing method is researched; in GLONASS phase difference data processing, on the basis of remove the singular equation, derive the GLONASS ambiguity solving method. Researchs the key technology of the GPS/GLONASS single point positioning and GPS PPP, using the measured data in a manner, researchs the positioning accuracy of increasing the number of visible satellites, compares the positioning accuracy between using PPP and increasing the number of visible satellites, data analysis shows that, GPS/GLONASS is the best choice to improve the single point positioning accuracy. On the basis of the GPS PPP's research, this paper proposes the GPS/GLONASS PPP's mathematical model, using the Melbourne-Wubbena and L_GeometryFree combination observations, study the methods of removing gross error and repairing cycle slip, calculates the parameters by the method of least squares, derives the method of fixed weight, discuses the involved the error sources and the treatment, designs the data processing flow chart, achieve the GPS/GLONASS PPP by theory and methods.GPS/GLONASS PPP has the advantage of using a single receiver, high positioning accuracy, no distance limitations, data calculating speed fast, data processing simple, As a result, GPS/GLONASS PPP will be widely applied to the maintenance of high-accuracy frame, scientific investigation high-accuracy kinematic navigation and positioning, orbit determination of low orbit satellites high-accuracy engineering survey, sea surveying and so on.