基于稀疏傅里叶变换的快速捕获方法

Fast acquisition methods based on sparse Fourier transform

卫星信号捕获是接收机内基带信号处理的关键步骤,捕获的速度严重影响接收机首次定位的时间(TTFF)。在基于快速傅里叶变换(FFT)的并行码相位捕获(PCPS)方法基础上,将具有亚线性运算量的稀疏傅里叶变换(SFT)引入捕获过程中,提出了基于SFT的快速捕获方法,通过优化捕获过程中相关运算的效率,提高捕获速度。仿真结果表明,与传统的基于FFT的捕获方法相比,基于SFT的快速捕获方法运算效率提高到原来的2倍,更好地满足了卫星信号对快速捕获的要求。

The acquisition of the satellite signals is the key step of baseband signal processing in the receiver. The speed of the acquisition has a serious effect on the time to first fix（TTFF）. According to the parallel code phase search（PCPS） method based on fast Fourier transform（FFT）,the sparse Fourier transform（SFT） which computes in sub-sampled time is applied to the PCPS algorithm to simplify the acquisition process. The fast acquisition method based on SFT is proposed. The faster acquisition is achieved by optimizing the efficiency of correlation operation. The simulation results show that the computation time of the proposed fast acquisition method based on SFT is 2 times faster than that of the conventional FFT-based acquisition method. And it can better meet the requirements of fast satellite signal acquisition.