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????????????????????????????????????????????????????÷??????????????GPS????????е???????????????λ??????IGS????????????????????????????ν???????????????????????????????????仯??????????????????????????????????仯????????????????????????仯?????????????????????????????仯?,??????????????????????????????ó???????????????????????????????????У??????????????????????????t????????????????????ж???????????????????????λ????????峱???????????????????????????÷???????δ?????????????????????????????????????????????????????

AN IMPROVED SATELLITE CLOCK BIAS DETERMINATION METHOD OF HIGH SAMPLING RATE

As there are several shortcomings in current clock bias determination methods, an improved high sampling rate satellite clock bias determination method is proposed.At first, satellite epoch differenced satellite clock bias is estimated station by station using undifferenced iono free phase observations from a GPS network, IGS precise ephemeris and low rate satellite clock bias product and then averaged. After completing satellite epoch differenced satellite clock bias calculation, satellite differenced clock bias at each epoch is derived using summation method. Finally,satellite clock bias at each epoch is determined. During satellite clock bias determination, reference satellite change problem should be considered, precise troposphere zenith delay value is used to correct troposphere delay and other errors, e.g. phase windup, solid earth tide are also corrected. Theory analysis and experiment results show that the improved method has several advantages, such as less unknown parameters, simple algorithm, high computation efficiency and high accuracy, and could be used in high rate satellite clock bias determination.