卫星差分码偏差对北斗三号双频精密单点定位的影响OACSTPCD

To explore the influence of BDS-3(BeiDou navigation satellite system phase Ⅲ)different frequency combination satellite DCB(differential code bias)on PPP(precise point positioning),the BDS-3 different frequency ionospheric-free combined satellite DCB correction model was derived and performed DCB correction experiments by seven different dual-frequency combinations based on the observation data of four MGEX stations during seven consecutive days.The results show that the DCB correction has a significant improvement of the PPP accuracy in the initial epoch,which helped to converge the filtering and improve the RMS of the single-day solution,but weakly in the final positioning accuracy.Although the positioning accuracy of the B2a/B3I and B2b/B3I combinations'convergence speed are considerably thinner than other combinations,it still enhances after DCB correction.Otherwise,the positioning accuracy and convergence time of the other 5 combinations are equivalent after correction.The RMS of the static PPP single-day solution is about 5.50 cm,2.50 cm,and 6.25 cm in the E,N,and U directions,which are approximately 20%～65%higher than before.The average convergence time,an increase of about 6%,is 38 minutes.And the kinematic PPP,an increase of about 20%,is 59 minutes.The final positioning accuracy is better than 5 cm in the horizontal component and 7 cm in the elevation component.