全球定位系统信号模拟中导航电文生成与测试

Generation and test of navigation message in GPS signal simulation

为了模拟全球定位系统(GPS)中频信号,研究如何产生GPS卫星导航电文的方法。通过OEM-STAR接收机采集原始导航电文,在此基础上外推导航电文的时间参数和轨道参数等,根据GPS卫星导航电文结构生成任意时刻的导航电文。给出了导航电文参数外推的算法、原始导航电文转换的算法和生成导航电文的算法,基于Matlab分析了外推轨道参数的星座分布,开发了生成导航电文的图形用户界面。通过测试表明,该方法生成的导航电文有效、可靠,符合真实GPS卫星星座排列规律。

In order to simulate the Global Positioning System（GPS） intermediate frequency signal, how to generate GPS navigation messages is studied. The original navigation messages are collected by the OEM-STAR receiver, then the time parameters and orbit parameters of navigation messages are extrapolated, and the navigation messages at any time are generated according to the structures of GPS real navigation. The algorithms of navigation parameters extrapolation, of the original navigation messages conversion and of the navigation messages generation are put forward. The extrapolated orbit parameters constellation distribution is analyzed in Matlab, and the GUI of generating navigation messages is developed. The test indicates that the navigation messages generated with the proposed method are effective and reliable, consistent to the real GPS satellite constellation rule.