基于分段折叠算法的北斗C_(B2I)码快速捕获

Beidou C_(B2I) code fast acquisition based on dividing and folding algorithm

以最新公布的北斗B2信号为研究对象,针对采样频率较高时,利用传统的并行码相位搜索捕获算法对北斗CB2I码进行捕获存在总运算量和单次FFT运算点数较大的问题,提出了一种基于分段折叠的基带信号快速捕获算法,即利用本地CB2I码前后两段折叠处理形成本地折叠CB2I码进行捕获运算。利用仿真的北斗B2信号源对本文提出的改进算法进行了验证,仿真结果表明,和传统的捕获算法相比,改进的快速捕获算法将捕获过程的总运算量以及单次FFT运算的点数降低了约一半,提高了北斗CB2I码的捕获速度。此外,可以根据信号强度的不同对捕获速度和捕获灵敏度进行权衡,保证北斗B2I信号捕获性能的最优。

When Beidou CB2 I code based on traditional parallel code phase search acquisition algorithm adopts a higher sampling frequency, there are much more operation points for each FFT, and the total calculation amount is also much larger. Aiming at the above problem, a fast acquisition algorithm based on dividing and folding is put forward, which realizes the acquisition based on the local folded CB2 I code formed by folding the two segments of local CB2 I code. The proposed algorithm is verified by simulated Beidou B2 signal source. Simulation results show that the total computation burden and the operation points of single FFT based on the suggested algorithm is approximately reduced by 50% compared with that of traditional acquisition algorithm, which improves the acquisition speed of Beidou CB2 I code. In addition, the acquisition performance of Beidou B2 I signal can be optimized by the trade-off between acquisition speed and acquisition sensitivity under different signal strengths.