Developing of Beidou Radiosonde System and Analysis on Its Wind Measuring Performance

As an important constituent of the integrated meteorological observation system, the upper air meteorological observations have extremely important effects on weather forecast, climate change research and other work, and it plays an irreplaceable benchmark function in atmospheric remote sensing observation authenticity verification and calibration of testing. The development of Beidou radiosonde and the ground receiving system is based on Beidou Satellite Navigation System with completely independent intellectual property rights, and the prototypes are assembled. By the end of 2012, Beidou Satellite Navigation System can provide preliminary service with 14 satellites in orbit, including 5 Geostationary Earth Orbit (GEO) satellites, 4 Medium Earth Orbit (MEO) satellites and 5 Inclined Geosynchronous Satellite Orbit (IGSO) satellites in 3 inclined orbits. On this basis, Beidou radiosonde is examined, and comparative analysis are carried out on its different patterns of wind measuring, i.e., single Beidou, single GPS and mixed mode. The results show that the wind measuring performance of Beidou and GPS radiosonde is quite close. The deviation of Beidou radiosonde compared to the GPS radiosonde is as follows: The standard deviation of the north velocity is 0.05 m·s^-1, the average deviation is-0.05 m·s^-1, the standard deviation of the east velocity is 0.03 m·s^-1, the average deviation is-0.01 m·s^-1, the height standard deviation is 6.88 m and the average deviation is 7.48 m. The PDOP value in single Beidou mode is large compared to GPS radiosonde and the accuracy of positioning is poor, because the current constellation is not fully deployed. Beidou radiosonde performance is relatively stable in the lower atmosphere, but a violent wave happens in the high level atmosphere, which means that the stability of the national dual-mode chip and module needs improving.