基于随机共振的高灵敏度GPS信号捕获算法

High sensitive GPS signal acquisition algorithm based on stochastic resonance

针对微弱环境下全球定位系统(global position system,GPS)信号捕获问题,提出了基于随机共振(stochastic resonance,SR)的GPS信号捕获算法。该算法首先用部分匹配滤波器对GPS信号进行分段相关预处理,然后利用SR提高预处理后信号的信噪比(signal-to-noise ratio,SNR),SR中引入了二次采样和自适应技术,解决了传统SR不适合捕获大频率信号(频率远大于1 Hz的信号)及SR参数难以与被捕获信号匹配的难题,最后采用快速傅里叶变换(fast Fourier transform,FFT)谱分析技术,实现在较短的相关累积时间内获得较高的捕获灵敏度。实验表明,算法能明显提高系统捕获性能,在相关累积时间为10 ms,信号SNR为-38 dB的情况下,算法捕获GPS信号的正确检测率达到100%。

Aiming at the acquisition problem of weak global position system（GPS） signals,a GPS signal acquisition algorithm based on stochastic resonance（SR） is proposed.After a partial-matched filter is adopted in GPS signal pre-processing,the signal-to-noise ratio（SNR） is improved by employing SR.By introducing twice sampling and adaptive techniques in SR,signals with the large frequence can be acquired,and the parameters of SR can match up with the acquired siganls.Fast Fourier transform（FFT） spectrum analysis is used to realize higher sensitive acquisition of GPS signals in shorter coherent integration time.Experiment results show that the acquisition system improves acquiring performance obviously using the proposed algorithm,and it can be seen that correct detection probabilities achieve 100% for a coherent integration time of 10 ms and SNR of-38 dB.