基于VFD滤波器的导航信道模拟器动态时延模拟方法*

针对卫星导航信道模拟器信号仿真中,传统伪距多普勒模拟方法瞬时控制精度差、滤波器资源占用较大的不足,提出了基于拉格朗日插值延迟滤波器及Farrow结构实现的伪距多普勒模拟方法。在分析信道模拟器系统架构的基础上,建立了多普勒模拟方法的模型,包括延时计算模块和可变延迟滤波器两部分。与多速率采样数字延迟滤波器方法比较,该方法滤波器系数个数约为后者的0.2%,并且改变时延特性时,仅需更新1个参数。信道模拟器实测数据结果表明使用该方法伪码多普勒模拟精度可以达到0.1mHz。

Method of Pseudo-range Doppler Simulation in Navigation Channel Simulator Based on VFD Filter

A new method about pseudo-range Doppler simulation was proposed,which used Lagrange interpolation variable fraction delay filter and Farrow structure. Based on analyzing the system architecture of channel simulator, the model of Doppler simulation was established, including two parts: delay calculation module and variable delay filter. Comparing with the multi-rate sampling digital delay filter method, the new method is just about 0.2% of the former filter coefficients, and the only one parameter was update when the delay of filter was changed. Actual measured results with channel simulator indicate that the precise of pseudo-range Doppler simulation is 0.1 mHz in proposed method.