中文摘要：

利用卫星导航系统对高轨航天器进行自主导航与高精度定轨,对接收机的捕获灵敏度要求极高,双块补零（DBZP）算法是无辅助下卫星导航弱信号捕获的理想方案,然而受限于数据处理量大,DBZP实际应用难度大。在深入分析双块补零机理的基础上,结合矩阵重构的思想,提出了一种改进双块补零北斗导航接收机弱信号捕获方法。该方法对参与块内相关运算的基带信号和本地测距码分别进行重构,解决了块内点数与快速傅里叶变换输入点数之间的矛盾,提高了北斗导航接收机弱信号捕获性能。仿真实验结果分析表明,改进双块补零算法对信噪比没有损失,可以保证对低至15dB·Hz的弱信号进行有效捕获,能够满足高轨航天器定轨、室内外无缝导航等对接收机高灵敏度的需求。本方法是在块内运算层面对DBZP进行优化,具备良好的通用性和可移植性,与优化相干积分策略的各种改进DBZP算法可以无缝对接,进一步提高北斗导航接收机信号处理的效能。同时,重构的思想也适用于其他采用码分多址信号的卫星导航系统的弱信号检测和捕获,对提升多星座卫星导航系统的基带信号处理性能具有参考意义。

英文摘要：

The high altitude spacecraft autonomous navigation and orbit determination technology based on the global navigation satellite system has higher requirements for the acquisition sensitivity of the receiver.Double block zero padding（DBZP）method is an ideal solution for unaided satellite navigation receiver weak signal acquisition.But the classical DBZP has low engineering value to create barriers for its popularization and application.With the help of matrix reconfiguration,a new BeiDou weak signal acquisition method aided by block improved DBZP is proposed based on the analysis of the function realization mechanism.The baseband signal and local pseudo-random code are reconfigurated to solve the contradiction between the block points and fast Fourier transform input points,greatly improving the efficiency of weak signal acquisition.Performance analysis and simulation results show that the proposed method can realize the signal acquisition low to 15dB·Hz effectively without any loss of SNR,which can meet the requirement for high receiver sensitivity in high-altitude spacecraft orbit determination,and indoor and outdoor seamless navigation.The proposed method is the optimization on the level of DBZP block operation,and can seamlessly integrate with the other improved DBZP methods focusing on optimization of coherent integration scheme.The proposed method is thus of universal applicability and transplantability.Meanwhile,the idea of reconfiguration can be applied to any other global ravigation satellite system signal detection and acquisition based on code division multiple access,and can provide some reference to baseband signal processing of multi constellation navigation receiver.