SNOW DEPTH ESTIMATION WITH GNSS-R DUAL-RECEIVER OBSERVATION

Snow is an important part of freshwater resources. Accurately measuring the snow depth is of great significance for studying the hydrological cycle and preventing flood hazards. In addition to the traditional ground-based direct measurement, snow depth can also be estimated by the space-borne or airborne remote sensing. Compared with the traditional method, the latter has advantages in resource optimization and data processing. GNSS Reflectometry (GNSS-R) as an emerging technology can be used to estimate snow depth. In this paper, we present a new method to estimate snow depth. The method combines the carrier phase observations of GPS dual-frequency (L1 and L2) obtained by the dual-receiver system. This phase combination is geometry free and is not affected by ionospheric delays. A theoretical model is established to describe the relationship between the snow depth and the spectral peak frequency of the combined phase. In the actual snow depth estimation process, the carrier phase observation data recorded by GNSS receivers are processed to obtain the spectral peak frequency which is then used to calculate the snow depth based on the developed model.