Abstract: In order to analyze the data quality and positioning performance of BDS-3 in the polar region, this paper evaluates the data quality based on the observation data of four stations near the north and south polar regions of MGEX during 7 consecutive days, and analyzes the positioning performance of different PPP combinations about dual-frequency and tri-frequency. The results show that the average number of visible satellites at the region of BDS-3 is about 10, the value of PDOP is 1.7, the data completeness is about 96.2% and 90.1% at the south and north polar regions, respectively. The value of SNR is a little difference between north and south region, both around 45 db-Hz, and the MP RMS is between 27~35 cm. In the polar region, the positioning accuracy of the BDS-3 PPP's dual-frequency and tri-frequency can reach 1~3 cm after convergence, and the positioning accuracy of the tri-frequency PPP is improved to a better extent compared with that of the dual-frequency PPP. The improvement accuracy of the IF combination in the direction of U is the largest, which is about 21.8%, and the average accuracy increase of UC combination is about 8.3%. The convergence time of dual-frequency and tri-frequency IF combination is 15.4 and 18.3 min respectively, which is better than 28.0 and 28.2 min of UC.

Key words: BDS-3, new frequency point, data quality, precise point positioning, tri-frequency