GEOSTAR卫星无线电定位系统扩频接收机的实现

implementation of GEOSTAR RDSSspread spectrum receiver

GEOSTAR卫星无线电定位系统是为美国本土和世界各地妁地面移动用户以及航海、航空用户提供准确的位置信息和辅助双向信息。用户至Geostar中心线路由移动站的发射机、中继卫星和中心接收站组成并已经建成。来自用户终端的扩频和卷积编码的突发射频信号通过卫星被中继到GEOSTAR中心,由该中心进行信息包的捕获、解调和处理。在突发工作方式的扩频系统中,传输和数据误差率取决予线路特性、捕获概率、虚警概率和使用的解调器数量。本文比较了用户至GEOSTAR中心线路理论和实测传输特性和数据误差特性。

The GEOSTAR Radio Determination Satellite System is designed to provide accurate position information and ancillary two-way message passing capability to land mobile, marine, and aeronautical users in the United States and eventually worldwide. The user to GEOSTAR Central segment consisting of transmitters on mobile platforms, a satellite relay, and a central receive station has been construeted. The spread spectrum and convolutionally encoded radio freqaeney bursts from the user terminals are relayed via saiellite to GEOSTAR Central where packet acquisition, demodulation, and processing are performed. The passage and data error rates in a burst, spread spectrum system are depen- dent on the link characteristies, probability of acquisition, false alarm rate and the number of cemodualtors usec. This paper compares the thcoretical and mea-sured passage and data crror performance of the user to GEOSTAR Central link.