GPS CNAV电文构成与应用分析

Analysis of GPS CNAV Message Constitution and Application

CNAV电文是GPS现代化进程中的一个重要改进。介绍了CNAV电文的基本特征,包括编码方式、结构组成、电文数据类型以及电文的校验方法;结合原有的NAV电文,主要讨论了CNAV电文中新增的各类参数以及相关模型的优化,客观地分析了CNAV电文模型上的改进以及广播参数在计算精度上的提升对最终定位的影响;最后研究了CNAV电文灵活的广播体制以及其对用户导航解算的影响。通过对CNAV电文和NAV详细的比较,突出新型CNAV电文的特点和优势。

CNAV is an important improvement in GPS modernization. In this paper, the basic characters of CNAV message are presented, including encoding mode, message structure, frame types and the parity algorithm. The new-added parameters and modified calculation models applied in the CNAV message are compared with models involved in NAV messages. Because of the improved parameters precision, the effect of the last position is discussed. Finally, the flexible broadcasting mechanism and its influence on navigation solution are analyzed. The comparison of CNAV with NAV highlights the advantages and features.