Method for smoothing pseudo range by using Doppler frequency shift

Abstract

The invention discloses a method for smoothing the pseudo range by using a Doppler frequency shift, comprising the following steps: calculating the pseudo range of a measured epoch by using the code phase measurement value; calculating the change rate of the pseudo range of the measured epoch by using the Doppler frequency shift; calculating the estimation value of the pseudo range of the current epoch by using the smoothed value of the last epoch and the change rate of the pseudo range of the current measured epoch; and endowing the measurement value and the estimation value of the pseudo range of the current epoch with different weight to obtain the smoothed value of the pseudo range of the current epoch. Because the error on the pseudo range measured by using the code phase in single time is great, the Doppler frequency shift is used for smoothing the pseudo range. Therefore, the error on the pseudo range can be reduced effectively, and further the positioning accuracy of the GPS can be improved.

Description

technical field [0001] The invention belongs to GPS receiver positioning technology, relates to a method for improving the positioning accuracy of a GPS receiver, in particular to a method for smoothing pseudo-ranges using Doppler frequency shift information, which uses Doppler frequency shift information to smooth pseudo-ranges to obtain A method to obtain a pseudorange with a small error. Background technique [0002] The Global Positioning System (GPS) is a navigation system developed by the U.S. Department of Defense that uses satellite constellations for 24-hour positioning. The basic principle of GPS receiver positioning is to receive signals from at least four satellites, use the navigation message transmitted by the satellite to calculate the satellite position, and use the ranging code (C / A code and / or P code) transmitted by the satellite to calculate the distance between the user and the satellite. The line-of-sight distance with a certain deviation is called pseu...

AI Technical Summary

Problems solved by technology

The measured carrier phase (the carrier phase difference between the reproduced signal and the transmitted signal) is the carrier phase value of less than one full cycle, and the distance from the satellite to the receiver is the unknown number of full cycles and the phase sum of less than one full cycle. it has a whole week ambiguity problem

However, once the lock is lost halfway, it will cause a cycle slip phenomenon, so that the unknown integer number contained in the phase of the two measurements is different, and the unknown integer number cannot be eliminated through the difference

In the receiving environment of "urban canyons", the phenomenon of GPS signal being blocked is very common, and the phenomenon of cycle slips will keep losing lock and recapturing, and the filter will be initialized continuously, so that the application of this method is limited. limit

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