低信噪比环境下短扩频码捕获性能的改善

Improvement of the Short Spread Spectrum Code Acquisition Performance in Low SNR Environment

介绍了低信噪比环境下基于FFT的扩频码捕获技术,提出了在相同累加段数情况下提高性能的方案。作为提高相干增益的两种方式,相干累加和非相干累加各有优缺点,在一定的数据长度内合理地设计累加方式对提高捕获性能大有帮助。基于两种累加方式的性能介绍了一种两路非相干积分的累加方式。对于GPS信号,在低信噪比的环境下的仿真证明,在一定长度下优化后的累加方式相比非相干累加和普通混合累加方式能够得到更好的捕获效果(更高的检测概率)。

This paper introduces the spread spectrum code acquisition technique using FFT in low SNR environment, and suggests a method to improve the detection performance in the same signal points. The coherent integration method and non -coherent integration method have different performance in code acquisition, so reasonably designing integration method can improve the detection performance. According to the two methods, a two - way non - coherent integration method is introduced. Based on the GPS signal, simulation results show that in the low SNR environment, the integration way ameliorated has better detection performance （higher detection probability） compared with the non -correlated integration and ordinary fixed integration method.