低信噪比高动态条件下P码直接捕获技术研究

Research of P-code Direct Acquisition Technology at Low Signal-to-Noise Rate in High Dynamic Condition

为了解决低信噪比高动态环境P码直捕问题,提出了将非相干累加与基于匹配滤波的部分相关值作FFT相结合的P码直捕系统。首先给出了捕获系统的实现方案,介绍了其工作原理,此后,以导航终端的具体应用环境为前提,推导了捕获系统检测概率与平均捕获时间的表达式,比较了应用非相干累加技术前后捕获系统的性能,研究表明此P码直捕系统能适应于低信噪比高动态环境。

For solving the problem that P-code direct acquisition with low signal-to-noise rate in high dynamic environment , the article provided a new P-code direct acquisition system that jointed non-coherent accumulate and FFT processing for part-correlation value based on matched filter. Firstly, realizable solution of acquisition system was given,and its principle was introduced. Subsequently, according to specific environment where navigation terminal worked, probability of detection and average acquisition time of acquisition system were deduced, and performance of acquisition system before applying non-coherent accumulate was compared with that after applying non-coherent accumulate. Research shows that the Pcode direct acquisition system works effectively at low signal-to-noise rate in high dynamic environment.