Research On Snow Depth Inversion At Arctic Yellow River Station Based On GNSS-R Signal

Snow is an important freshwater resource and the detection of snow depth is of great significance in the fields of meteorology,environmental science and hydrology.With the continuous development of the theory and application of GNSS(Global Navigation Satellite System),the GNSS-R(Global Navigation Satellite System Reflectometry)technology has become a new type of snow depth acquisition method.The theory and model of the technology Traditional microwave remote sensing technology has many similarities.At the same time,it has outstanding advantages such as sufficient data,all-weather,all-day,and low-cost.This paper systematically introduces the basic theory and research status of GNSS-R.Based on the basic theory of electromagnetic waves,the characteristics of electromagnetic wave polarization and reflection are discussed.The relationship between GNSS multipath effect and signal to noise ratio is discussed with emphasis on the use of GNSS-.The R signal inversion snow depth provides a theoretical basis.Based on this,the snow depth inversion theory and method based on GNSS-R signal are studied,and the related research work is performed using the data collected by the Arctic Yellow River Station.The main research contents and innovations of the paper are as follows:(1)Analyze the working principle,observation mode and technical characteristics of GNSS-R,and study the polarization mode of GNSS reflection signal and reflection coefficient of reflection surface,and analyze the characteristics and influencing factors of SNR sequence of SNR.On this basis,the relationship between GNSS multipath effect and SNR SNR is analyzed in detail.(2)The inversion model of snow depth inversion based on GNSS-R signal is studied.The acquisition method of the SNR sequence to remove the long-term trend term is discussed,and the spectrum analysis of the sequences using low satellite elevation angles is discussed.The details of data processing were discussed and the snow depth inversion process based on GNSS?R signals was finally presented.In the strategy of data processing,an optimization strategy based on large sample and quality control was proposed.(3)Through the analysis accuracy and correlation coefficient and other indicators,the inversion results of various factors such as elevation angle range,period length,number of satellites,azimuth angle,time scale,constellation structure,signal frequency,and signal-to-noise ratio intensity were explored.Impact.Analyze the causes of each factor's impact on the results,and finally give a better inversion strategy,that is,select the L1 and B1 observations with higher signal-to-noise ratio intensity,the height angle range is 5-25,multiple satellites and four A large number of azimuth observations can eventually achieve a 5 cm inversion accuracy on a day time scale;(4)Using the given inversion strategy to complete the snow depth inversion at the Yellow River Station in 2014 and 2015,and comparing the measured data from the New Olsons weather station,verifying the snow depth inversion based on the GNSS-R signal.The effectiveness of technology.And based on this analysis of the scope of application of the method and the deficiencies.