A Comparative Study of Static Pseudorange Single Point Positioning by Double Frequency between BDS and GPS

BeiDou Navigation Satellite System (BDS) was put into operation in Asian Pacific region in December 2012. To give a comprehensively comparative study of static pseudorange single point positioning between BDS and Global Positioning System (GPS), the double frequency data was sampled at 10s interval for 56h in Beijing in April 2014. The number of visible BDS satellites is larger than that of GPS. However, since BDS constellation is not finished yet, it has a positioning dilution of precision (PDOP) value of 2.49, which is a little larger than that of GPS:2.12. The standard error of unit weight is 2.28m and 2.50m for BDS and GPS, respectively. This indicates that BDS has a better psuedorange precision than GPS. The occurrence frequency of gross error is 0.57% for BDS and 1.02% for GPS, which shows that the usability of BDS is better than that of GPS. After removing the gross error, inner coincidence accuracy of BDS is better than that of GPS. It is 3.24m in horizontal direction and 4.40m in vertical direction for BDS. It is 3.90m horizontally and 5.47m vertically for GPS. But deviation between standard coordinate of BDS (8.50m, 3.73m, -0.80m) is less satisfying than that of GPS (4.50m, 2.25m, 0.56m), which means that BDS is better than GPS on stability but less accurate than GPS. It can be predicted that BDS will achieve better performance with the improvement and fulfillment of its constellation.