导航信号的射频直接采样与数字下变频方法

RF direct sampling and digital down conversion to navigation signals

摘要:

研究导航信号的射频直接采样与数字下变频方法，并对1.2 GHz和1.5 GHz 2个频点附近的导航信号进行了仿真验证。首先运用带通采样原理，选择合适的采样频率完成对导航信号的射频直接采样，然后结合积分梳状滤波器、半带滤波器，对采样后的信号进行抽取滤波，实现了降采样率的目的。最后，通过Matlab对5个频点的导航信号进行了仿真验证，完成了导航信号的射频直接采样并降低了采样率，恢复且分离了原始导航信号，从而验证了射频直接采样与数字下变频方法是可行的。

Abstract:

A method for navigation signals down sampling was presented in this study by combining RF direct sampling and digital down conversion. An analysis of navigation signals at frequencies that close to 1.2 GHz and 1.5 GHz was performed. Firstly, bandpass sampling principle was used to select appropriate sampling frequency for the completion of RF direct sampling to navigation signals. Then cascaded integrator comb filter and Half-Band(HB) filter were adopted to carry out decimation filter to the sampled signals, thus realizing the purpose of reducing sampling frequency. Finally, the navigation signals of 5 frequencies were simulated in Matlab, RF direct sampling of the navigation signals was accomplished and the sampling frequency was reduced. The original navigation signal was recovered and separated. It proves the methods of RF direct sampling and digital down conversion are feasible.