高动态环境下长码扩频信号快捕算法

针对高速高动态接收机在长伪码周期、大频偏情况下的快速捕获问题，该文提出一种基于码相位压缩相关器与快速傅里叶变换(CCPC-FFT)的双驻留伪码快速捕获方法。在第一驻留阶段，利用码相位压缩相关器对相邻码相位进行快速、粗略的压缩搜索，同时利用FFT算法完成对多普勒频偏的并行捕获；在第二驻留阶段，利用传统的相关积分方法对第一驻留捕获的所有码相位进行逐个精确搜索。给出了系统性能的理论分析模型，并通过蒙特卡洛仿真验证了理论分析的正确性。最后仿真结果表明:新方法在平均捕获时间上比2维压缩相关(TDCC)捕获方法进一步缩短，同时提高了频偏的捕获带宽和精度，且针对长码的捕获比其他基于FFT的方法节省资源。

Rapid DSSS Signal Acquisition Algorithm under High Dynamic Environment

For high speed and high dynamic receiver, using long pseudo-noise code, seriously affected by Doppler frequency offset, this paper proposes a double dwell pseudo-noise code acquisition method based on Compressed Code Phase Correlator (CCPC) and FFT. In the first dwell search a rapid and rough compressed search is performed for some neighboring code phase using CCPC, and at the same time the parallel search for Doppler frequency offset using FFT is completed. In the second dwell, all the neighboring code phases acquired in the first dwell are searched accurately using conventional correlator. The theoretical performance analysis model for the proposed method is presented, whose correctness is validated by Monte Carlo simulation. The simulation result shows that the proposed method has obvious advantages compared to Two-Dimensional Compressed Correlator (TDCC) on Mean Acquisition Time (MAT), as well as on the bandwidth and precision of Doppler frequency. Less resources are consumed than other methods based on FFT when using long pseudo-noise code.