Evaluation of spaceborne GNSS-R based sea surface altimetry using multiple constellation signals

Comparisons between different global navigation satellite system (GNSS) signals and GNSS-reflectometry (GNSS-R) systems can provide valuable suggestions for future development of the GNSS-R instrument signal processing method. This article evaluates ocean altimetry performance multiple GNSS constellation using raw intermediate frequency data collected by Cyclone (CYGNSS) TechDemoSat-1 (TDS-1) satellites. Data used evaluation include observations GPS L1, Galileo E1, BDS B1 band signal. The specular point position ground-truth bistatic delay are calculated through HALF After ionospheric, tropospheric, tide corrections, sea surface height be retrieved; then is compared with DTU18 mean model derived one. Based on satellite-collected observations, an optimal incoherent integral duration determined. By making use duration, CYGNSS-based ranging estimating accuracy reach up to 2.38 m, 1.98 1.91 m GPS, BDS, respectively; TDS-1 based one 5.46 3.84 Galileo, respectively. results suggestion strategies multi-constellation fusion improve accuracy.