GPS信号C/A码快速精密捕获技术研究

Research on fast fine C/A code acquisition technique of GPS signal

提出了一种基于平均相关技术的快速精密的GPS信号C/A码捕获方案,该方案将接收到的中频信号和本地复制C/A码以高采样频率进行采样,然后通过对它们进行平均处理后以1 024点的FFT处理器计算相关能量值。与不经过平均处理的基于FFT的码捕获方案相比,该方案的运算复杂度约为1/22,可实现快速捕获的目的;与捕获精度为半个码片的常用码捕获方案相比,该方案的捕获灵敏度理论上提高约2.2 dB。最后通过仿真验证了该方案的可行性。

This paper presented a fast fine C/A code acquisition scheme of GPS signal based on averaging correlation tech- nique. In the proposed scheme, it sampled the received IF signal and the local C/A replica code at a high sampling frequen- cy, then both of them were dealt with averaging process and the value of correlation energy could be calculated by the 1 024- point FFT processor. It reduced the computational complexity in the proposed scheme to about 1/22 compared with the FFT- based code acquisition scheme without averaging process. It could realize the purpose of rapid acquisition. It improved the ac- quisition sensitivity of the proposed scheme theoretically by about 2.2 dB, compared to the conventional acquisition scheme with acquisition precision of half a chip. Finally, simulations performe to verify the feasibility of the proposed scheme.