Preliminary Research On GNSS-MR For Snow Depth Monitoring

The environment around GNSS station will have a multipath effect on GNSS observations,and how to eliminate or reduce the impact of multipath effects has attracted attention of the majority of scholars.On the contrary,with the deepening research and application on the Global Navigation Satellite System,the subject that using signal-to-noise influenced by multipath to inverse the surrounding environment parameters around station has become a new research hotspot,which makes the GNSS active in the field of remote sensing.Based on the research of domestic and foreign scholars,this paper applies the GNSS-MR technology to snow depth measurement.Combined with the original GNSS observation data of American PBO and snow depth data of SNOTEL,the feasibility and precision of the algorithm are studied and analyzed.The main contents and achievements are as follows:1?The multipath and SNR characteristics are summarized,and the relationship between multipath and SNR is discussed emphatically.Low-elevation SNR data is greatly influenced by multipath effect.The method of polynomial fitting can realize the separation of direct signal and multipath reflected signal.And then using SNR influenced by the multipath to realize the extraction of surface environment parameters.2?The basic principle and calculation flow of GNSS-MR technology are given,and snow depth detection range and the trajectories of signal reflection point are discussed.GNSS-MR snow depth detection range is about 1000m2;GNSS signal reflection point trajectory on the one hand can achieve satellite choosing,on the other hand can get the spatial distribution information of snow.3?The frequency of SNR residual sequence has a negative correlation with the snowfall thickness.And the feasibility of GPS-MR snow depth monitoring algorithm is proved from single satellite,multi-satellite and long-term sequence.Its measurement accuracy can reach to 0.1m.4?The influence factors of GPS-MR snow depth measurement technology are analyzed.Reasonable setting of the elevation angle range,the SNR data with high received power or high sampling all can make a useful contribution to the inversion result.And the inversion accuracy is relatively high and more stable.5?New changes of Rinex3.X format are introduced in this paper.A GNSS-MR snow depth monitoring data processing system is designed by MATLAB language.Combined with the measured data,its correctness is verified.And corresponding chart or document can be output according to the data processing requirements.At present,multi-frequency and multi-mode satellite navigation systems is developing rapidly,and GNSS tracking stations around the world(such as IGS,PBO,Cmonoc,etc.)are also mushrooming.So that the GNSS-MR technology has abundant resource and development space.With the continuous improvement of research and technology,the application of GNSS-MR in real-time surface environmental monitoring(snow,soil moisture,sea level,etc.)is for people to look forward!...