Improving BDS integer ambiguity resolution using satellite-induced code bias correction for precise orbit determination

Successful resolution of integer ambiguity over long baselines is a key to improve the accuracy of precise orbit determination for global navigation satellite system satellites. The satellite-induced code bias (SCB) found in BDS signals severely prevents the BDS integer ambiguity resolution (AR) of long baselines. We present BDS AR using satellite-induced code bias correction for precise orbit determination. The impacts of the BDS SCB on double-difference AR for different baseline length and satellite type are first assessed. About one month of BDS tracking data collected from the MGEX and Fugro network are processed for precise orbit determination using independent single-system method. The results of orbit overlap comparison and satellite laser ranging (SLR) validation suggest that the SCB has no obvious impacts on BDS float solutions; however, it shows significant implications on ambiguity-fixed solutions, especially for MEO satellites and long baselines. When applying the SCB correction model to BDS AR, the 3D mean RMS of overlapping orbit are reduced from 14.02 to 10.46 cm for IGSO and from 10.97 to 6.89 cm for MEO satellite, with the improvement of 25.4 and 37.2%. The contribution of AR with SCB correction on orbit accuracy of BDS could reach the level close to that of GPS. SLR residuals also confirm the improvement.