基于平均分组和叠加相关的GPS信号捕获方法

GPS Signal Acquisition Method:Based on Average Grouping and Superposition Correlation

针对目前GPS软件接收机C/A码捕获信噪比门限高、捕获速度慢的问题,提出一种基于平均分组和叠加相关的GPS弱信号捕获方法。首先,基于平均相关处理技术降低C/A码捕获过程中的自相关损耗,提高对微弱信号的捕获能力;然后,利用叠加相关提高相干运算的运算效率,并采用线性插值提高自相关函数性能;最后,利用频偏校正和内插进一步提高C/A信号的捕获精度。理论分析和仿真实验均验证,该方法能够在较低的信噪比下实现GPS信号捕获,且精度较高、运算量较低。

Aiming at the problem that C/A code acquisition of GPS software receivers has a high signal-to-noise ratio threshold and slow acquisition speed,a GPS weak signal acquisition method based on average grouping and superposition correlation is proposed.First,autocorrelation loss is reduced and weak signal acquisition is improved based on the average correlation processing technique.Second,the superposition correlation is used to improve the operational efficiency of the coherent operation,and linear interpolation is used to improve the performance of the autocorrelation function.Finally,C/A signal acquisition accuracy is improved by frequency offset correction and interpolation.Theoretical analysis and simulation experiments both verify that the proposed acquisition method can achieve GPS signal acquisition at a lower signal-to-noise ratio with higher accuracy and lower computational load.