调制信号的抗多径和无模糊跟踪是现代全球导航卫星系统接收机码环设计中需要解决的两个重要问题。提出了一种基于优化算法的码鉴相器设计方法,该方法使用多相关器结构,以组合权值为优化变量,根据无模糊跟踪要求给出了约束条件。以多径包络面积为目标函数建立了非线性最优化问题,提出了一种基于曲线赋形技术的优化初值设置方法。仿真结果表明,与传统的鉴相器相比,所设计的鉴相器具有更好的抗多径性能,且能实现对二进制偏移载波调制信号的无模糊跟踪。
The multipath mitigation and unambiguous tracking for modulated signals are two important re- quirements of the code tracking loop in modern global navigation satellite system (GNSS) receivers. A code dis- criminator design method based on optimization technique is proposed to meet these requirements. The proposed discriminator is based on multi-correlator structure and the combined weights are treated as optimization varia- ble. The mathematical constraints are given according to the unambiguous tracking requirement, and the enclose area of multipath error envelope is used as an objective function to establish the optimization problem. Then an initial value setting method based on curve shaping technique is proposed. The simulation results indicate that compared with the traditional discriminator the proposed discriminator performs better in multipath mitigation and it can track binary offset carrier modulated signals unambiguously.