一种新型直接抽取算法的数字下变频设计

摘要

In order to simplify satel ite navigation receiver architceture,a down conversion method based on digital signal decimation is proposed.By using separating and accumulating method,direct down-conversion of a digitized carrier signal with relative high frequency is realized.This method has virtues of simpler structure,high speed and less calculation.Also it can wel preserve navigation message and Doppler information,whereas it may degrade th S/N of signal and sensitivity of receiver.Analysis and simulation results show that it has no effect on positioning precision of receiver.%为了简化卫星导航接收机框架，提出一种基于数字信号抽取的下变频方法。通过分离和累计法，人们发现了一种具有高频率数字载波信号的直接下变频方法。这种方法不仅具有结构简单、速度高和计算简单的特点，还能够很好的保持导航电文和多普勒信息，但这种方法有可能会使S/N信号和接收机的灵敏度降低：分析和仿真结果显示，它对接收机的定位灵敏度没有任何的影响。