Fast PN code acquisition for DSSS receiver in high dynamic situation
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摘要: 对于工作在高动态环境下的扩频接收机,在基于数字匹配滤波器的基础上,提出了一种高折叠倍数匹配滤波器和FFT相结合的捕获方法,将传统的基于信号载波频率和码相位的二维搜索过程变为基于码相位的一维搜索过程.给出了32折叠匹配滤波器在FPGA中的实现框架,通过对折叠倍数和占用系统资源的关系的仿真,可以看出,折叠倍数越大,占用系统资源越少.当输入信号的信噪比在-20 dB时,比传统采用二维搜索捕获方法的捕获速度有很大的提高.由于该方法具有捕获速度快和占用系统资源少的特点,经实际验证适用于高动态环境下的快速码捕获.Abstract: For direct sequence spectrum system(DSSS) receiver in high dynamic situation, a fast PN code acquisition method was proposed. The acquisition method based on high-folded digital matched filter(DMF) and FFT is able to convert the traditional two-dimensional search method to one-dimensional search. The realization frame of 32-folder DMF in FPGA was put forward. The simulation focused on the folder multiple and system resource shows that the larger the folder multiple is, the lesser the system resource costs. When the input signal SNR is -20 dB, the acquisition speed of this method is much faster than the traditional methods. This method has good characteristics of fast acquisition and system resource expended lower. Practical engineering verification shows that it can be used in high dynamic situation.
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