FFT捕获是伪码快速捕获的主要方式,伪随机码FFT快捕属于二元信号检测.通过相关输出最大相关值和门限比较来搜索伪码相位,这种情况下虚警捕获门限不能根据每个随机变量的分布来确定,而要根据最大值分布来确定门限.针对这一问题,推导了包络检波和平方检波伪随机码额域快捕恒虚警门限,并进行了仿真,验证了结论的正确性.%PN code acquisition based FFT is one kind of popular acquisition way, which belongs to two signal detection. PN code phase is searched by comparing the maximum output of correlation and the constant false alarm rate detection (CFAR) threshold, then the threshold need to be deter mined by using the distribution characteristics of the maximum output of correlation. Aim to the problem, the threshold of PN code acquisition based I IT with CFAR to envelope demodulation and square demodulation is derived in this paper, the simulation shows that it is correct.
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