利用交叉点不符值对GOCE卫星重力梯度数据进行精度评定
Accuracy Evaluation Method of GOCE SGG Data Based on Satellite Crossovers
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摘要: 研究了基于GOCE卫星轨迹交叉点不符值的SGG数据精度评定方法,针对经典评定公式评价精度偏低的不足,提出了修正的精度评定公式;分析了系统误差对上述评定方法的影响,针对尺度因子会同比例放大或缩小精度评定结果,建议利用现有的重力场模型对尺度因子进行预先标定。模拟计算结果表明,无系统误差情况下,经典评定公式评价出的数据精度比实际精度偏低,相对误差约13%,而利用本文提出的修正公式可较准确地估计数据精度,相对误差降至5%。有系统误差情况下,利用现有的重力场模型可较为准确地标定尺度因子,其标定相对误差最大值不超过2%,平均值在0.9%左右。在此基础上,利用修正公式进行数据精度评定,其结果与无系统误差情况下的结果相差无几,相对误差也在5%。Abstract: method of accuracy evaluation using crossover differences is studied.A revised formula for accuracy evaluation is proposed to overcome the shortcomings of the classic formula.The influence of the systematic errors on the accuracy evaluation is analyzed.The calibration of scale factor by using the existing gravity field model is proposed.A numerical example from the simulated Tzz of GOCE satellite is performed.The results show that the new method can reasonably evaluate the accuracy of data with the relative error of 5%,which is far better than the classic method with the relative error of 13%.The scale factor can efficiently calibrated using the existing gravity field model with no more than 2% of relative error,and the average of relative errors is about 0.9%.The result of accuracy evaluation is almost the same between the cases with and without systematic errors.
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