基于GPS和北斗信噪比观测值的雪深反演及其误差分析

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

利用GNSS反射信号反演雪深具有全天时、全天候、数据量大、成本低等突出优点。本文围绕基于信噪比观测值的雪深反演方法,利用参加中国北极科学考察的机会在黄河站设计了GNSS-R试验,采集了GPS和北斗的双频信噪比观测数据,详细讨论了高度角范围、弧段长度、卫星数量、方位角、时间尺度、星座结构、信号频率、信噪比强度等多种因素对雪深反演结果的影响。通过大样本、质量控制、误差分析等手段,雪深反演精度和可靠性得到有效提高。根据误差分析的结果,本文推荐的反演策略如下:选择高度角范围为5°~25°、信噪比强度较高的L1和B1I观测值,充分利用多颗卫星和4个方位角的大量观测数据,在一天的时间尺度上,可以实现5cm的反演精度。另外,弧段长度、星座结构、信号频率等对反演结果的精度影响较小。

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-satellitesandfourazimuths.Inthis way,we can finally achieve the accuracy of 5 cm in one day.Inaddition,arc length,constellation structure and signal frequency have small effects on the accuracy of the results.