中文摘要：

分析GPS时空参考点下卫星钟差参数改正原理，结合伪距观测方程推导BDS单频及双频消电离层组合在标准单点定位、精密单点定位下的差分码偏差（DCB）改正公式。采用MGEX发布的DCB文件，分别进行多个测站的定位解算。结果表明，BDS伪距B1B2及B1B3双频定位DCB改正前E、N方向精度较单频差，严重影响定位精度，改正后E方向精度提高在dm级，N、U方向提高在m级；精密定位下B1B3组合DCB改正后与B1B2组合定位结果非常吻合，静态及仿动态下精度都有提高。

英文摘要：

This paper analyses the satellite clock correction principle of parameters with respect to GPS space-time reference points and deduces the BDS differential code bias （DCB） correction formula of single-frequency and dual-frequency ionospheric free combination in standard point position （SPP） and precise point position （PPP）. With DCB files distributed by a multi-GNSS experiment （MGEX）, some observation stations are calculated both in SPP and PPP. The results of BDS B1 B3 and B1/32 du- al-frequency SPP show that E direction improvement accuracy is at the sub-meter level, while N, U direction improvement accuracy are at the meter level. Moreover, before correction the position accuracy is extremely poor, with poorer accuracy of dual-frequency positioning compared to single-frequency positioning in E, N direction. From the results in BDS precise positioning, solutions in B1B3, in combination with DCB corrections, are very consistent with the B1B2 combination, and accuracy is improved in static and kinematic modes.