基于小波变换的GPS微弱信号捕获组合算法

针对战场环境下GPS信号易受到敌方压制式干扰而产生严重衰减,提出了一种相干积分、非相干积分和小波降噪相结合的组合算法。该算法先通过相干积分和非相干积分结合的方法提高整体信号强度,避免导航数据位可能发生跳变的特性,然后采用小波降噪技术,克服信号与噪声的频带相互重叠时,滤波效果变差的问题,实现对弱信号的捕获。仿真结果表明,采用20 ms的相干积分时间、5次非相干积分和小波降噪,可以接收比传统方法低5 dB信噪比的微弱GPS信号。这种方法容易实现,预测可靠,具有实际应用价值。

Research on combination algorithm of weak GPS signal acquisition based on wavelet transform

According to the situation that the GPS signal is more influenced by the oppressive jamming and result in attenuation, an algorithm in combination with wavelet denoising algorithm,coherent integration and non-coherent integration is proposed. The whole signal strength is improved through the combination of coherent integration and non-coherent integration,thus to avoid the jumping of navigation data. Then wavelet denoising technology is adopted to overcome the problems of filtering effect deterioration when signal and noise overlap each other,and to realize the capture of weak signals. Simulation results show that weak GPS signal 5 dB SNR lower than traditional method can be received with 20 ms coherent integration,5 times non-coherent integration and wavelet denoising. This method is easy to be implemented,which has accurate estimation and practical application value.