GPS民用导航电文CNAV的特点

Some Features of the GPS Civil Navigation Message

美国政府于2004年底公布了新的GPS接口文件,文件中除了对已使用多年的导航电文(在文件中记做NAV)内容及格式进行规定以外,还规定了一种新的民用导航电文CNAV的格式和内容。介绍了两种导航电文的主要不同之处,并从导航电文的内容构成、卫星位置用户算法和电文编排方式、效率等方面,采用与旧的导航电文NAV对比的方法,分析了新导航电文CNAV的特点和性能。

Except the old navigation message （NAV）, a new civil navigation message （CNAV） was specified in the new issued GPS IS document in 2004. The new civil navigation message will be broadcasted on L2 CM. In this paper, the main differences between NAV and CNAV are listed. Based on comparsion with NAV, the features of CNAV are introduced, including formation of the message, the user algorithm for the computation of the ECEF coordinates of position of the phase center of the SVs＇ antennas and the communication efficiency.