卫星导航调制方式的非线性和兼容性分析

对比研究了最小频移键控（Minimum Shift Keying，MSK）和正交相移键控（Quadrature Phase Shift Keying，QPSK）调制信号的非线性和兼容性。首先建立MSK调制卫星导航信号的时域和频域模型，讨论了MSK调制对码片脉冲形状的影响，指出MSK调制作为卫星导航信号候选调制方式的可行性。然后建立非线性信道模型，仿真了MSK和QPSK调制卫星导航信号的带外功率损耗、相关损耗和码跟踪误差以及与同频段信号的谱分离系数。仿真结果表明，在保证信号跟踪性能的前提下，卫星导航信号采用MSK调制时的非线性和兼容性优于同参数下的QPSK调制。

Nonlinear and Compatibility Analysis on Satellite Navigation Modulation

The nonlinear characteristics and compatibility of minimum shift keying (MSK) and quadrature phase shift keying (QPSK) modulated signals were analyzed. Firstly, the time domain and frequency domain models of MSK modulated navigation signal were established and its impact on code pulse shape was discussed. It was suggested that MSK can be a candidate modulation for navigation signal. Secondly, nonlinear channel model was established, and the power loss, correlation loss, code tracking and spectrum separation coefficients of MSK and QPSK modulated navigation signals were simulated. Finally the simulation results show that the nonlinear performance and compatibility of MSK modulated navigation signals are better than QPSK modulated signals, ensuring the code tracking performance.