An Overview of a Special Issue on Upcoming Positioning, Navigation, and Timing: GPS, GLONASS, Galileo and BeiDou.

References 1 Wang M., Shan T., Zhang W., Huan H. Analysis of BDS/GPS Signals' Characteristics and Navigation Accuracy for a Geostationary Satellite. The proposed algorithm mainly focuses on the absorption of orbit and clock offset errors in the line of sight (LOS) and is applied to the GPS/BDS measurements obtained from the FngYun-3C satellite. Ref. [[4]] presented an ISCB estimation algorithm and analyzed the clustering code bias characteristics of BDS-2 and BDS-3. BDS satellites can be categorized into three stages: demonstration systems (BDS-1), regional systems (BDS-2), and global systems (BDS-3). [Extracted from the article]