SPECTRAL COMBINATION METHOD COMBINED GOCE AND GRACE GEOPOTENTIAL COEFFICIENTS
Lu Biao;Zhong Bo;Ni Wei;School of Geodesy and Geomatics,Wuhan University;Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University;
According to GOCE and GRACE are complementary in the spectrum of earth gravity field,spectral combination method combined GOCE and GRACE geopotential coefficients was studied. The spectral combination formulas are established based on the coefficients' error degree variance weighting,error variance weighting and block diagonal error covariance weighting. As a test,the GRACE gravity field model ITG-GRACE2010s and GOCE gravity field model GO_CONS_GCF_2_DIR_R1 are used for calculating and checking the spectral combination method. The results show that the accuracy of the combined gravity field models established by these three kinds of spectral combination methods is higher than the GRACE or GOCE's independent model,and their total accuracy is superior to GOCO01S model which is based on GOCE and GRACE. Spectral combination method based on the block diagonal error covariance weighting is relatively optimal in these three kinds of weighting schemes,because it considers the correlation among the coefficients of same order m.