时间频率学报

随着卫星导航系统的应用推广，越来越多的低轨卫星配置了导航接收机来获取实时高精度位置和测速信息，伪距和多普勒测量值精度关系到导航接收机位置和测速精度；另外，随着低轨卫星对时间精度需求越来越高，低轨卫星对导航接收机的时间确定和维持精度同样提出了较高的要求。无论实时测速还是钟漂信息的解算精度，都与接收机在低轨运行场景下的实时多普勒测量精度紧密相关。基于多项式拟合公式得到高精度多普勒测量值，从而实现高精度实时测速，通过公式简化得到易于工程应用的系数和计算方法，最终实现导航接收机在低轨卫星高动态场景下的高精度测速。搭建了模拟器测试环境，在低轨场景下对不同计算方法进行对比验证，结果表明，采用多项式拟合进行实时多普勒估计的方法能够获得较高精度的测速结果。

Along with the application of Global Navigation Satellite System(GNSS), more and more low earth orbiting(LEO) satellites are equipped with navigation receiver to obtain real-time high-precision position and velocity measurement, and the accuracy of pseudorange and Doppler measurement values is related to the accuracy of position and velocity measurement. In addition, with the increasing demand for time accuracy of low-orbit satellites, low-orbit satellites also put forward higher requirements for the time determination and maintain the accuracy of navigation receiver. Both the real-time velocity measurement and the calculation accuracy of the clock drift information are closely related to the real-time Doppler measurement accuracy of the receiver in the low-orbit operation scenario. In this study, precise Doppler estimation is obtained based on the polynomial fitting, so as to achieve high-precision real-time velocity measurement, and the coefficients and calculation methods that are easy to apply in engineering are obtained, and finally realize the precise velocity estimation of the navigation receiver in the high-dynamic scenario of the LEO satellites. In this study, a simulator test environment is set up to compare and verify different calculation methods in low-orbit scenarios,and the results show that the method of real-time Doppler estimation by polynomial fitting can obtain highprecision velocity measurement results.