双线性极化天线的CAPS信号合成捕获算法  

An Algorithm for Signal Synthesis and Acquisition of CAPS Based on Dual-Linear Polarization Antennas

作　　者：甘彤[1,2] 马冠一[1] 

机构地区：[1]中国科学院国家天文台,北京100012 [2]中国科学院研究生院,北京100049

出　　处：《天文研究与技术》2013年第1期36-41,共6页Astronomical Research & Technology

基　　金：国家重点基础研究计划"973"项目(2007CB815500)资助

摘　　要：针对中国区域定位系统(China Area Positioning System,CAPS)接收机采用圆极化天线接收线极化信号引入极化损失的问题,提出了一种基于双线性极化天线的信号合成捕获算法。算法首先对双线性极化天线接收的两路CAPS导航信号实现捕获,并根据捕获结果进行信号同步;进而利用最大比合并合成两路信号以提高接收信号的信噪比。应用于实测数据的分析表明,合成信号的信噪比相比单路信号信噪比有1.5 dB左右的改善。Aiming at solving polarization loss caused by a circular polarization antenna receiving linear polarization signals in the China Area Positioning System（CAPS）,this paper proposes a signal synthesis and acquisition algorithm of CAPS based on dual-linear polarization antennas.Because in CAPS commercial communication satellites serve as navigation satellites,a variety of antennas have to be used for transponders.These include horizontally polarized antennas and vertically polarized antennas.Since the signal polarization needs to fit the antenna polarization,CAPS navigation signals have two types of polarization—horizontal polarization and vertical polarization.Using a circular polarization antenna can receive these two types of signals,but will introduce a polarization loss of 3dB.Our new algorithm uses two linear polarization antennas to receive signals individually and carries out some signal processing to reduce the polarization loss.The algorithm first performs signal acquisition with the dual-linear polarization antennas.According to the acquisition result the algorithm then synchronizes the signals.After the synchronization,it sums the signals from the two channels using the maximal-SNR（signal-to-noise ratio） combining which reduces the energy loss caused by polarization mismatching.The algorithm has already been applied to an experimental receiving system.By analyzing the data acquired by the experimental system,we find the SNR of the synthesized signal increases 1.5dB over the one-channel signals.

关 键 词：CAPS系统 双线性极化天线 信号捕获 信号合成 信噪比 

分 类 号：TN927[电子电信—通信与信息系统]