Snow Depth Detection and Error Analysis Derived from SNR of GPS and BDS

There are several significant advantages in snow depth inversion with GNSS reflected signals,such as all-time,all-weather,large amount of data and low cost.An experiment of GNSS-reflectometry was designed at Arctic Yellow River Station and dual-frequency signal to noise ratio (SNR) observations of GPS and BDS were collected.The effects on snow depth inversion,including satellite elevation,arc length,number of satellites,azimuth,time scale,constellation structure,signal frequency and SNR intensity,were discussed comprehensively.And then the inversion accuracy and reliability were improved by large sample statistics,quality control and error analysis.According to the error analysis,we recommend the following inversion strategy:to use L1 and B1I observations,with 5 to 25 degrees satellite elevation,from multi-satellites and four azimuths.In this way,we can finally achieve the accuracy of 5 cm in one day.In addition,arc length,constellation structure and signal frequency have small effects on the accuracy of the results