Inverse Modeling of GPS Multipath for Snow Depth Estimation - Part I: Formulation and Simulations
نویسندگان
چکیده
Snowpacks provide reservoirs of freshwater. The amount stored and how fast it is released by melting are vital information for both scientists and water supply managers. GPS multipath reflectometry (GPS-MR) is a new technique that can be used to measure snow depth. Signal-tonoise ratio (SNR) data collected by GPS inst uments exhibit peaks and troughs as coherent direct and reflected signals go in and out of phase. These interference fringes are used to retrieve the unknown land surface characteristics. In this two-part contribution a forward/inverse approach is offered for GPS-MR of snow depth. Part I starts with the physically-based forward model utilized to simulate the coupling of the surface and antenna responses. A statistically-rigorous inverse model is presented and employed to retrieve parameter corrections responsible for observation residuals. The unknown snow characteristics are parameterized; the observation/parameter sensitivity is illustrated; the inversion performance is assessed in terms of its precision and its accuracy; and the dependence of model results on the satellite direction are quantified. The latter serves to indicate the sensing footprint of the reflection. Page 13 of 44 Transactions on Geoscience and Remote Sensing 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
منابع مشابه
Inverse Modeling of GPS Multipath for Snow Depth Estimation - Part II: Application and Validation
GPS multipath reflectometry (GPS-MR) is a technique that uses geodetic quality GPS receivers to estimate snow depth. The accuracy and precision of GPS-MR retrievals are evaluated at three different sites: grasslands, alpine, and forested. The assessment yields a correlation of 0.98 and an rms error of 6–8 cm for observed snow depths of up to 2.5 m. GPS-MR underestimates in situ snow depth by 10...
متن کاملAssessment of modernized GPS L5 SNR for ground-based multipath reflectometry applications
Global Positioning System (GPS) signal-to-noise ratio (SNR) measurements can be employed to retrieve environmental variables in multipath reception conditions, whereby direct or line-of-sight transmission is received simultaneously with coherent reflections thereof. Previous GPS SNR multipath studies of soil moisture and snow depth have focused on the legacy GPS L1 and L2 bands. In the present ...
متن کاملGPS Snow Depth Meter with Geometry-free Linear Combinations of Carrier Phases
Multipath in Global Positioning System (GPS) is the interference of the microwave signals directly from satellites and those reflected before reaching the antenna, typically by the ground. Because reflected signals cause positioning errors, GPS antennas are designed to reduce such interference. Recent studies show that multipath could be utilized to infer the properties of the ground around the...
متن کاملSnow depth sensing using the GPS L2C signal with a dipole antenna
Prior research has shown that the currently deployed geodetic global positioning system (GPS) stations can be used to measure snow depth in an area around the antenna installation via GPS interferometric reflectometry (GPS-IR). Although such a technique provides the advantages of large spatial coverage and high temporal measurement sampling, there are also drawbacks in using geodetic equipment ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- IEEE Trans. Geoscience and Remote Sensing
دوره 52 شماره
صفحات -
تاریخ انتشار 2014