High-precision Global Navigation Satellite System Velocimetry Algorithm Considering Light Travel Time Correction

Abstract:

The velocimetry algorithm of the traditional global navigation satellite system（GNSS） considers the fact that the Doppler measurement value is the projection of the relative motion velocity of the receiver and GNSS satellites along the line of sight direction， without considering the influence of light travel time. As a result， there is a small systematic deviation， and the velocity estimation accuracy is not high， limiting its application in the field of precision velocity determination. In this paper， based on the velocimetry algorithm of the traditional GNSS， a first-order to third-order integral Doppler interpolation algorithm is proposed. The instantaneous Doppler is used to replace the average Doppler， and the accuracy of velocity determination using second-order interpolated integral Doppler is improved by three orders of magnitude compared with the accuracy of velocity determination using average Doppler. Besides， the influence of light travel time is considered， and the Doppler deviation caused by the inconsistency of receiving and transmitting time is corrected， and the correction algorithms in the earth inertial coordinate system （ECI） and in the earth fixed coordinate system （ECEF） are given respectively. The experimental results show that the systematic deviation is eliminated， and the root mean square （RMS） of three-dimensional velocity error is reduced to 3.3 mm·s^-1， which can meet the application requirements of high-precision velocity determination.