CHAMP卫星加速度计标校参数序列的谱分析

给出了利用能量守恒方法求定CHAMP卫星加速度计标校参数的基本原理和算法．对2001年8月-2003年12月共约两年半的CHAMP卫星加速度计数据进行了标校，导出了尺度、偏差和偏差漂移参数的时间序列，分别采用最小二乘谱分析和抗差谱分析对这些时间序列进行了分析．结果表明，尺度、偏差和偏差漂移参数都有明显的周期变化，但各主周期项略有差异．尺度的主周期是441d、220d、126d和13．4d的周期变化，其中220d和441d的周期变化的贡献相对较大．偏差中有明显的220d、126d和13．4d周期变化，各周期变化的贡献几乎相当；偏差漂移的主周期是220d、13．4d和9d的周期变化，其中13．4d的周期变化最为显著，几乎比其他周期项变化高出一个数量级．另外尺度和偏差参数还有明显的长期变化，而偏差漂移参数的长期变化不明显．

Spectral Analysis on Time Series of Calibration Parameters of CHAMP Accelerometer

The theory and algorithm of determining system errors of CHAMP accelerometer are presented based on energy conservation method. The time series of scale factor, bias and bias drift is analyzed using about two and a half years' accelerometer data of CHAMP from August 2001 to December 2003. The long-term and principal periods variations are obtained by using LS spectral analysis as well as the robust one. The results show that there are clear periodic variations in the time series of scale factor, bias and bias drift. For scale factor, the principal periods are 441 d, 220 d, 126 d and 13.4 d. 441 d and 220 d periods make great contributions to scale factor. For bias, the principal periods are 220 d, 126 d and 13.4 d, and they make almost the same contributions. For bias drift, the principal periods are 220 d, 13.4 d and 9d, and 13.4 d makes the greatest contribution. There are obvious long-term variations in the time series of scale factor and bias except bias drift. It is shown that the results of the robust spectral analysis are superior to that of LS one in the whole. Further investigations about why there are long-term and period variations in system errors of CHAMP accelerometer are necessary.