A New GNSS-R Interferometric Ocean Altimetry Using Beidou-3 Signal

GNSS-R interferometric altimetry can be used for meso-scale sea level observation with the advantages of high spatial resolution and high measurement accuracy. Compared with the traditional GNSS-R which uses local code tracking for altimetry, GNSS-R interferometric could effectively improve the altimetry accuracy. Although a lot of researches had been carried out in GNSS-R interferometric altimetry around the world, there are few researches in the application of interferometric altimetry using Beidou-3 signal. This article introduces the basic theory of GNSS-R interferometric altimetry technology and its advantages. Aiming at the application of Beidou-3 signal in interferometric altimetry, a GNSS interferometric altimetry instrument had been developed. The overall architecture and implementation of this new instrument is introduced in this paper. An open-field GNSS-R water surface altimetry experiments was conducted using this instrument. In the experiment, the interferometric waveforms generated from Beidou-3 B1 and B2 signal were obtained for the first time, and were compared with the traditional GPS L1 and Beidou-2 B1 local code tracking waveforms. Finally, the inversion results of the water surface height calculated by the two approaches are compared. The comparison results show that the precision of Beidou-3 system’s interferometric measurement is significantly better than that of GPS L1 and Beidou-2 B1 traditional local code altimetry.