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Spreading code cross-correlation optimization method of satellite navigation system based on greedy algorithm

A technology of satellite navigation system and greedy algorithm, which is applied in the field of satellite navigation, can solve the problems of non-polynomial complexity and inability to solve the spreading code of satellite navigation system, and achieve the effect of cross-correlation optimization

Inactive Publication Date: 2014-08-13
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

[0017] The purpose of the present invention is to solve the non-polynomial complexity of satellite navigation system spreading code cross-correlation optimization and the problem that cannot be solved within a limited time, and propose a satellite navigation system spreading code cross-correlation optimization method based on greedy algorithm

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  • Spreading code cross-correlation optimization method of satellite navigation system based on greedy algorithm
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  • Spreading code cross-correlation optimization method of satellite navigation system based on greedy algorithm

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[0039] In order to better illustrate the purpose and advantages of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. In this specific implementation manner, the US GPS system L5 signal spreading code will be used as an example for description.

[0040] The L5 signal of the GPS system is a new generation of navigation signals for life safety services. The L5 signal specification is defined in the IS-GPS-705B document published in 2011. The generation of the spreading code is based on the shift register. figure 2 As shown, the spreading code length L=10230 bits, there are 2 different initial states by XBi 13 -1=8191 kinds of combinations, based on balance, autocorrelation and spectrum characteristics, there are 107 remaining candidate spreading code words after deletion, that is, M=107, considering that the GPS basic configuration constellation requires a total o...

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Abstract

The invention relates to a spreading code cross-correlation optimization method of a satellite navigation system based on a greedy algorithm, and belongs to the technical field of satellite navigation. According to the method, the maximum value of odd and even cross-correlation function absolute values of two code words serves as the performance measure, and a cross-correlation measure matrix and a spreading code word index array are built; then the greedy algorithm is adopted to delete one spreading code word in a candidate code word set, and an obtained new matrix is utilized for updating the cross-correlation measure matrix. Code words in the candidate code word set are deleted by iteration until the optimal number of the code words is reached, a final spreading code word index array is obtained, and spreading codes of the corresponding serial numbers are extracted from the candidate code word set and serve as optimization results to be output. Compared with a conventional traversal search method, the spreading code cross-correlation optimization method has the advantages that the calculation complexity is decreased from the index complexity to the linear complexity, cross-correlation optimization of the spreading codes can be achieved rapidly, and meanwhile optimization of the spreading codes can be carried out on a greater candidate set.

Description

technical field [0001] The invention relates to a greedy algorithm-based cross-correlation optimization method for spreading codes of a satellite navigation system, which belongs to the technical field of satellite navigation. Background technique [0002] The code division multiple access (CDMA) system is the basis of the modern satellite navigation system, and the design and optimization of the spreading code is one of the important contents of the signal system design of the satellite navigation system. In the design and optimization of spreading codes, the correlation performance is the most important performance measurement, in which the autocorrelation function is related to the multipath interference of the signal. The ideal spreading code autocorrelation function should be 0 everywhere except the main lobe, and the mutual The correlation function is related to the multiple access interference of the signal. The ideal spreading code cross-correlation function should b...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J13/10
Inventor 王爱华朱建锋安建平杨杰周荣花樊芳芳
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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