Method for improving convergence speed of combined precise point positioning of GPS (Global Position System) and GLONASS

Abstract

The invention discloses a method for improving a convergence speed of combined precision single-point positioning (PPP) of a GPS (Global Position System) and a GLONASS. A plurality of independent 'time frequency bias' parameters are introduced into a function model to make up the defect in the prior art that GLONASS code inter-frequency bias is ignored in a modeling process; the convergence speed of the combined PPP of the GPS and the GLONASS is remarkably improved under the condition of not losing positioning precision. With the adoption of the method disclosed by the invention, a random model of GLONASS and GPS equal weight can be used for obtaining a code pseudo-range observation value when the PPP is combined, so that the defect that the weight ratio is determined by experiences in the prior art is avoided.

Description

technical field [0001] The invention relates to the technical field of satellite geodesy and navigation positioning, in particular to a method for improving the convergence speed of GPS and GLONASS combined precision single point positioning. Background technique [0002] With the continuous advancement of GLONASS modernization process, as of December 8, 2011, GLONASS has 24 satellites in orbit, and the system has resumed full operation. Unlike GPS, the current GLONASS system uses Frequency Division Multiple Access (FDMA) technology to distinguish signals from different satellites. The satellite signal will generate a corresponding hardware delay in the internal frequency channel of the receiver, which is generally divided into an average delay bias item and a delay bias item that varies depending on the channel frequency. The latter is also called Inter-Frequency Bias (IFB ). Because GLONASS adopts FDMA technology, satellite signals of different frequencies will enter the...

AI Technical Summary

Problems solved by technology

The main defect of the existing technology is that the introduced "system time difference" parameter only absorbs the average hardware delay of the receiver code, and the GLONASS code frequency deviation cannot be absorbed by the receiver clock difference parameter due to the difference between the satellite frequencies, and will eventually reflect In the residuals of code pseudorange observations

Neglecting the influence of code-frequency deviation in the combined PPP model will cause the accuracy of GLONASS code pseudo-range observations to be lower than its actual observation accuracy, especially when the value of the code-frequency deviation is much greater than the noise level of the code pseudo-range observations themselves. The convergence speed of GPS / GLONASS combined system PPP is not even as good as that of GPS single system PPP

The existing technology generally adopts the method of reducing the weight of GLONASS pseudo-range observations in the stochastic model to weaken the above-mentioned effects. have a certain understanding of the GLONASS code frequency deviation characteristics of the receiver, but most GNSS receiver manufacturers do not provide a priori value of this parameter. In actual operation, they mostly rely on the experience of data processing personnel to determine the weight ratio. Has a certain degree of blindness, theoretically imprecise

Images