PWV Retrieval Performance Evaluation for the Fresh BDS‐3 With Multisource Data

Abstract The entire global operation of the newly launched BDS global navigation satellite system (BDS‐3) was completed in July 2020. After that, a series of performance tests were conducted, such as positioning, navigation, and signal experiments. However, the precipitable water vapor (PWV) retrieval performance evaluation of BDS‐3 has not yet been carried out, so in this paper, we thoroughly verified its accuracy with AIRS v7, ERA5, and radiosonde data to know the current performance of BDS‐3 PWV. From the tests applied with different satellite systems, we found that BDS‐3 has a comparable PWV retrieval performance as global positioning system (GPS), and a better outcome was achieved using the combined data from GPS and BDS‐3. Furthermore, BDS‐3 PWV accuracy calibrated by AIRS v7 showed a strong correlation with the spatial distribution. In addition, the PWV content decreased with the climbing of the latitude and elevation, and the relative root mean square error (ReRMSE) indicated better in the low‐latitude areas. Finally, the effect of different surface types on PWV performance was analyzed, showing the BDS‐3 PWV accuracy in the land type was the highest, the sea one was the lowest, and the coast type was in the middle. These findings will provide a good reference for the community to understand the PWV performance of BDS‐3 at the present stage.