GPS接收机中模拟一阶环路滤波器matlab实现过程推导

Posted 2022-01-02 者乎之类的

抄自：https://blog.csdn.net/weixin_43179259/article/details/121050837

GPS接收机跟踪环，使用模拟环形式，即参数为时间常数${\tau }_1,{\tau }_2$,而非c1和c2。

           % Implement carrier loop discriminator (phase detector)
            carrError = atan(Q_P / I_P) / (2.0 * pi);
            
            % Implement carrier loop filter and generate NCO command
            carrNco = oldCarrNco + (tau2carr/tau1carr) * ...
                (carrError - oldCarrError) + carrError * (PDIcarr/tau1carr);
            oldCarrNco   = carrNco;
            oldCarrError = carrError;

            % Modify carrier freq based on NCO command
            carrFreq = carrFreqBasis + carrNco;

为区分模拟环和数字环，我认为下图推导中n，n-1换为$t+\Delta t,t$更好些