导航信号 IQ 正交性测试软件设计与实现

摘要

As the general commercial instruments cannot satisfy the testing requirements for IQ or-thogonality testing of modern navigation signal, a testing software for IQ orthogonality has been developed based on Matlab GUI. The software controls high-speed digital oscilloscope via the network interface and samples the PPS (Pulse Per second)and navigation signals of navigation signals source respectively in du-al-channel. The navigation signal data is extracted according to the starting point of the navigation signal determined by the PPS. After digital waveform-matching of navigation signal has been done with the local pseudo-random code modulation wave, the carrier initial phase of I and Q branch can be precisely esti-mated, then the test result of IQ orthogonality is obtained. The software has characteristics of friendly in-terface, easy operation, intuitive display. The simulation results show that random error of the test result is less than 0. 5 degrees in the case of typical carrier to noise ratio.%针对通用的商用仪器不能适用现代导航信号 IQ 正交性的测试要求，开发一种基于 Matlab GUI 环境的导航信号 IQ 正交性测试软件。该软件通过网络接口控制高速数字示波器，对导航信号源的秒脉冲信号和导航信号进行双通道高速数据采样，根据秒脉冲信号确定导航信号起始点，截取导航信号数据，采用本地数字波形对导航信号进行匹配滤波和伪随机码同步等数字信号处理，精密估计 I 和 Q 支路载波初始相位，从而得到 IQ 正交性测试结果。软件具有界面友好，操作简单，显示直观等特点。仿真测试结果表明，在典型载噪比情况下，测试软件所得到的测试结果随机误差小于0.5°。