Application Of Significant Wave Height Measurement Using GNSS-R Signals

The use of reflected GNSS signals as a source of opportunity for remote sensing applications, known as GNSS-R technique, has been a research area of increasing interest for the past years. There are several advantages of GNSS-R such as high temporal and spatial resolution, low cost, rich of GNSS resources, high flexibility in comparison with the other remote sensing tools, which can offset the lack of regional detection means.This paper introduced the observation equipment and the technical principle about the significant wave height sounding by GNSS reflected signals. And we had coastal experiments to study GNSS-R reflections in Scientific Experiment Base on Marine Meteorology at Bohe of Maoming, and Shanwei Guangdong province in South China Sea. By analyzing the data from Bohe experiment, we confirmed that the autocorrelation time of the interferometric complex field (ICF) can be used to infer the sea surface characteristics, since they change in dependence of the sea surface. And the significant wave height (SWH), as one of the important parameters in sea features, was related to the significant coherence time of the interferometric complex field (ICF).The results show that the higher SWH indicating the coarser sea surface and shorter autocorrelation time of the ICF. On the other side, the lower SWH indicating the smoother sea surface and the longer autocorrelation time. Through building a experiential retrievable model between the Significant Wave Height (SWH) and correlation time of the autocorrelation functions corrected for the bit-navigation effect, a fitting function is proposed. The retrieved result is consistent with the data of wave-measuring radar and buoy.The SWH is also compared with the wind speed and the difference is analyzed.