Development of three dimensional orbit determination by Doppler measurement between two satelites

我们试图达到最高的精度，在多普勒测量，通过调查可能的误差源有关的多普勒测量，并通过开发一个新的电离层和对流层模型。首先，通过对卫星发射的载波频率稳定度和相位噪声的测量，推导出卫星自旋对相位变化的影响。然后，利用多普勒和VLBI数据进行了定轨仿真，结果表明，利用多普勒和VLBI数据可以较好地恢复边缘附近的重力场，而单纯利用多普勒数据恢复边缘附近的重力场效果较差。接下来，我们运行了一个新的轨道确定方法的模拟，以了解重力场将如何恢复的情况下，SELENE使命。通过VLBI与双向和四向多普勒测量的结合，将提高模型中所有系数的精度。本文还讨论了VLBI数据对确定R星精密轨道的影响，它是四向多普勒测量的参考。通过添加VLBI数据，小于33度的系数将提高约2倍，其中2度系数的最佳提高为2.6倍。如果通过适当的力模型使R/Vstar的弧长大于1天，则SELENE重力场的最终精度将比LP 100 J在30度以下的精度提高一个数量级。

We try to attain the highest accuracy in Doppler measurements by investigating possible error sources related to the Doppler measurements and by developing a new model of the ionosphere and the troposphere. First of all we formulated the effect of spin of a satellite on phase change after we measured frequency stability and phase noise of carrier wave emitted from the satellite. Next, we did a simulation of orbit determination by using Doppler and VLBI data and showed that gravity field near the limb, which was poorly recovered only by Doppler measurements, would be better recovered by combining the Doppler and VLBI data. Next, we ran a simulation of a new method for orbit determination in order to know how the gravity field would be well recovered for the case of SELENE mission. Accuracies of all the coefficients included in the model will be improved by combining VLBI with 2-way and 4-way Doppler measurements. What is accounted for here includes the effect of VLBI data on determining the precise orbit of the Rstar which is a reference of 4-way Doppler measurement. By adding VLBI data, the coefficients of degrees less than 33rd will be improved by about a factor of 2, with the best improvement in the 2nd degree coefficient by a factor 2.6. If we could make R/Vstar arc length to be longer than 1 day by proper force modeling, the final accuracy of SELENE gravity field will be one order of magnitude better than that of LP100J below degree around 30.