基于变频率动态采样的导航信号高精度多普勒频移中频模拟方法

High-Precision Doppler Shift Intermediate Frequency Simulation Method of Navigation Signal Based on Variable Frequency Dynamic Sampling

研究了中频模拟器中时变系统采样间隔的高动态多普勒频移模拟方法.基于卫星运动模型研究了信号高动态频移特性,提出基于变频率动态采样的伪码和载波多普勒频率偏移模拟方法;给出高精度码多普勒频移模拟设计方案,通过省略传统方法中必需的码数控振荡器模块来降低系统实现的硬件复杂度;通过对伪码频率模拟误差精度的分析,推导了算法主要参数取值的闭式解.仿真结果表明,在接收信号频率具有有限二阶变化率的高动态环境下,该方法可有效提升多普勒频移模拟精度,并给出具有高稳定度的结果.

A method of high dynamic Doppler shift simulation with time-varying sampling interval on in- termediate frequency simulator was presented. Based on satellite movement model, the high dynamic frequency shift characteristic of the signal was researched and a Pseudo-code and carrier Doppler shift simulated method was proposed as well based on variable frequency dynamic samplings. A design scheme of high-precision Doppler simulation was given, it reduces the system hardware complexity by omitting the code numerically controlled oscillator module in conventional methods. With analysis on error accuracy of pseudo-code frequency, the closed-form solution of the main parameters was derived. Simulation shows that the method can effectively improve the accuracy of the Doppler shift simulation, and provide high stability under high dynamic environment, with which, the frequency of the received signal will reach a fi- nite second-order change rate.