Double differential coherent detection method for capturing weak satellite signal

A satellite signal acquisition and coherent detection technology, applied in the field of navigation satellite signal acquisition, can solve the problems of increased calculation, no solution, and signal real-time processing obstacles, so as to improve the signal-to-noise ratio, reduce the probability of false capture, and improve The effect of accuracy

CN101806904BInactive Publication Date: 2012-06-27BEIHANG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2012-06-27
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a double differential coherent detection method for capturing a weak satellite signal. The signal comprises a pseudorange measurement code. The method comprises the following steps that: A. total quantity of search units is determined according to an inputted signal sampling rate and a correlation integral time; B. each potential satellite and each search unit are undertaken the correlation integral with the length of N millisecond, and relevant results of homodromous and orthogonal branch circuits are respectively recorded; C. data processed in step B is inputted into a double differential device to obtain a single differential result of each search unit; D. the result which is obtained in step C is accumulated for M times; E. the search unit corresponding to themaximum value of the outputted result in step D is found out; F. a signal-to-noise ratio corresponding to the result in step E is solved and is compared with a threshold to judge whether the signal exists or not. The double differential coherent detection method overcomes the phase influence in the traditional differential accumulation, has higher noise resistant performance compared with the traditional double differential method, and can improve the detected signal-to-noise ratio.
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Description

technical field

[0001] The invention relates to the field of navigation satellite signal capture, in particular to a double-difference coherent detection method suitable for weak satellite signal capture. Background technique

[0002] In recent years, satellite navigation and positioning systems have been more and more widely used. The general-purpose satellite navigation receiver can conveniently perform three-dimensional positioning and achieve positioning accuracy that meets the requirements. However, in harsh positioning environments such as indoors, forests, city centers, canyons, and tunnels, the navigation satellite signals are attenuated to varying degrees, making the received satellites The signal power is lower than ordinary satellite signals. For ordinary satellite navigation receivers, the capture of navigation satellite signals cannot be realized in this case, and the tracking and positioning calculation of signals cannot be performed. In order to break throug...

Examples

Embodiment Construction

[0027] The specific embodiment of the present invention is described in detail below in conjunction with accompanying drawing, and described description is example with capturing GPS weak signal, and weak GPS signal capture block diagram is as follows figure 1 shown.

[0028] The GPS intermediate frequency analog signal can be expressed as follows:

[0029] S IF ( t ) = Σ i = 1 N 2 P i D i ( t - τ i D ) C i ( t - τ i ) expj ( ...