Acquisition method, bit synchronization method and device of bds non-geo satellite b1 signal

Abstract

A BDS non-GEO satellite B1 signal acquisition method, bit synchronization method and device, the acquisition method includes the following steps: in the received navigation signal, sliding sampling with the first preset time step to obtain a plurality of sampling data group, wherein the first data length contained in each sampling data group is greater than or equal to 20ms, and the product of the preset time step and the number of sampling data groups is greater than or equal to 20ms; each sampling data group and the local NH code are captured operation to obtain the capture correlation peak value of each sampling data group; if the maximum capture correlation peak value is greater than or equal to the first preset peak value threshold, it is determined that the capture is successful. The solution of the invention can capture based on the start time of the complete bit of the navigation signal, thereby reducing energy loss in the capture operation and improving capture sensitivity and accuracy.

Description

technical field [0001] The invention relates to the technical field of satellite navigation, in particular to a BDS non-GEO satellite B1 signal acquisition method, a bit synchronization method and a device. Background technique [0002] With the development of the global satellite navigation system and the increasing demand for location services, more and more attention has been paid to how to improve the accuracy and sensitivity of satellite signal acquisition and tracking. [0003] In the traditional navigation signal, a complete bit of the navigation message is 20ms, that is, a polarity change may occur every 20ms. Due to the long time interval, methods such as increasing the coherent integration time and increasing the number of non-coherent accumulations can be used to enhance signal capture. ability. [0004] However, since the Beidou Navigation Satellite System (BDS) non-geosynchronous orbit (GEO) satellite B1 signal is modulated by the Newman-Huffman code (referred ...

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Problems solved by technology

[0006] However, the start time of the navigation signal may not be the start time of a complete bit, that is, in every 20ms capture operation, in addition to the polarity reversal caused by the NH code, there may also be navigation signals at the bit transition edge polarity reversal of

Since the polarity of the spreading code at the corresponding position is also flipped after the position of the bit is flipped in the navigation data, and the result of multiplying the local spreading code becomes the opposite value of the original value, which will be partially canceled when the integral is accumulated to make the capture correlation The peak value is reduced, resulting in a decrease in the accuracy of the calculated peak value, and even when the signal is weak, making the correlation peak value less than the preset threshold, it may cause satellite signal acquisition failure

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