GNSS (Global Navigation Satellite System) signal capturing method and device and computer storage medium

Abstract

The invention provides a GNSS (Global Navigation Satellite System) signal capturing method and device, and the method comprises the steps: carrying out the 1 / N-time code rate sampling of a spreading code, compressing the length of the spreading code into L, controlling the length of each segment to be L when the satellite data is segmented, and carrying out the frequency mixing with a local carrier wave, thereby obtaining zero-frequency data; searching a satellite data NH code phase, stripping an NH code from each segment of data, and performing coherent integration to obtain a compressed satellite signal with two spread spectrum period lengths; respectively carrying out FFT operation, complex number multiplication and IFFT operation on the processed spreading code and satellite data to obtain a cyclic correlation result; solving a modulus of the result and searching a maximum value, if the maximum value exceeds a preset first threshold, judging that coarse capture is successful, and calculating a satellite signal code phase, a Doppler value and an NH code phase; code phase accurate search is carried out at a 1 / 2 chip interval in left and right N / 2 ranges by taking a roughly captured satellite signal code phase as a center. The method is low in hardware resource consumption, and the capture signal-to-noise ratio and the capture code phase precision can be improved.

Description

technical field [0001] The invention relates to the technical field of satellite navigation, in particular to a GNSS signal acquisition method and device with a large number of spread spectrum code chips and with NH code modulation. Background technique [0002] In the design of GNSS receiver chip, the control of hardware resource usage not only involves cost control, but also affects the chip size and power consumption; in general, the most resource-consuming part is the acquisition module. Usually, the GNSS receiver hardware uses code-phase parallel frequency serial search (ie cyclic correlation algorithm) to achieve satellite signal acquisition, and its fast algorithm requires FFT-IFFT operation, and the length of the FFT will determine the number of registers and hardware area required by the hardware. and cost, so it is necessary to select the appropriate number of FFT operation points. However, the cyclic correlation is a correlation search for one cycle of the spread...

AI Technical Summary

Problems solved by technology

However, circular correlation is a correlation search for one cycle of the spreading code. When the number of chips in one cycle of the spreading code is large, a larger number of FFT points is necessary.

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