Open-loop GNSS (Global Navigation Satellite System) signal carrier tracking method and system

Abstract

The invention discloses an open-loop GNSS (Global Navigation Satellite System) signal carrier tracking method and an open-loop GNSS signal carrier tracking system with resource optimization. The method comprises the following steps that carrier stripping and pseudo-code correlation are performed on a GNSS signal received by a receiver, so as to obtain an I\Q integral value sequence, two groups of GNSS signal parameter estimated values are obtained in accordance with the I\Q integral value sequence, and a carrier generator and a pseudo-code generator are adjusted on the basis of the two groups of the GNSS signal parameter estimated values. The method has the advantages that FFT (Fast Fourier Transformation) is used for frequency estimation by an open-loop receiver, and optimization design is performed on the basis of the existing scheme. Compared with the FFT method, the method has the advantages that expenses of hardware resources are greatly reduced, and the complexity of hardware design is effectively reduced.

Description

technical field [0001] The invention relates to a satellite navigation and positioning system, in particular to an open-loop GNSS signal carrier tracking method and system for tracking weak satellite signals or rapidly changing signals in intensity in a high-sensitivity receiver. Background technique [0002] A GNSS (Global Navigation Satellite System) receiver receives satellite signals of normal strength in the open environment, and then acquires, tracks, and demodulates the signals. The satellite signal is composed of carrier, pseudo code and navigation message. Due to the relative motion between the satellite and the receiver, the carrier frequency of the satellite signal received by the receiver will be different from the nominal frequency of the satellite signal, that is, there is a Doppler effect. . Due to the existence of the Doppler effect, the pseudo-code phase will also change. The tracking of the receiver is to realize the estimation of the carrier Doppler freq...

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Problems solved by technology

[0005] Although more accurate frequency estimates can be obtained based on FFT transformation, performing FFT transformation directly in the hardware system is quite resource-intensive, inflexible and computationally intensive.

The Chinese patent with the notification number CN100399044C provides a method for open-loop tracking of GPS signals based on channelization filters. Although it is more flexible than the traditional open-loop FFT tracking method, it cannot reach the accuracy of the open-loop FFT tracking method. And because the square operation is not performed on the I\Q integral value, I\Q must be limited to one data bit when performing cumulative integration, which makes it difficult to further improve the sensitivity

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