?????似??????????????

????????????????????VLBI?????????????SLR???????λ????GPS??3????????????????????????????????????仯???????￡???????????????????????????仯?????????3?????????????仯???????????????????????????????????????????,3???????????????????μ?:VLBI??GPS??????????仯??????С????SLR??????????????10??;GPS ??SLR??????????仯??????3 mm/a?????????VLBI??SLR??????????仯???????в???1 mm/a??????

COMPARISON AMONG CRUSTAL MOVEMENTS MEASURED WITH THREE SPACE TECHNIQUES

It is dicussed whether the systematic errors exist or not in crustal movement monitoring by three space observation techniques i.e. VLBI,SLR and GPS.Taking account of vertical change rate,the baseline length changing rates of co-located sites are solved by use of velocity of geocentric coordinations, and these rates are fitted pair to pair,and then their correlativities are analyzed.The computed results show that the crustal movements measured by this three techniques are consistent with each others:the difference between the baseline length changing rates by VLBI and GPS is small, and about 10% larger than that by SLR,there is a constant difference of about 3 mm/a between those by GPS and SLR,but less than 1 mm/a between those by VLBI and SLR.