ROBUST SPECTRAL ANALYSIS OF TIME SERIES OF GEO
IONOSPHERIC CORRECTION
1）College of Navigation & Aerospace Engineering，Information Engineering University，Zhengzhou 450052
2）State Key Laboratory of Geographic Information Engineering，Xi’an 710054
3）Xi’an Research Institute of Surveying and Mapping，Xi’an 710054
Abstract Ionospheric delay was obtained with day’s observation data from Compass GEO satellite，based on dualfrequency ionospheric correction model.The robust spectral analysis method was applied to analize ionosphere delay data for detaching the long term，period terms and random errors and controlling the effects of error on the terms.In order to control the influences of colored noises，the residuals are fitted by using an AR model.The result shows that the ionospheric correction is effected by not only trend term and period term changes，but also by color noises.After being fitted by piecewise polynomial，period terms and color noise，the ionospheric correction residual terms turn out to be white noises.The result proves the method is seffective.
