Characteristics and limitations of GPS L1 observations from submerged antennas

Observations from a submerged GNSS antenna underneath a snowpack need to be analyzed to investigate its potential for snowpack characterization. The magnitude of the main interaction processes involved in the GPS L1 signal propagation through different layers of snow, ice, or freshwater is examined theoretically in the present paper. For this purpose, the GPS signal penetration depth, attenuation, reflection, refraction as well as the excess path length are theoretically investigated. Liquid water exerts the largest influence on GPS signal propagation through a snowpack. An experiment is thus set up with a submerged geodetic GPS antenna to investigate the influence of liquid water on the GPS observations. The experimental results correspond well with theory and show that the GPS signal penetrates the liquid water up to three centimeters. The error in the height component due to the signal propagation delay in water can be corrected with a newly derived model. The water level above the submerged antenna could also be estimated.

[1]  Johan Löfgren,et al.  Local Sea Level Observations Using Reflected GNSS Signals , 2014 .

[2]  Kamal Sarabandi,et al.  Microwave Radar and Radiometric Remote Sensing , 2013 .

[3]  Christian Mätzler,et al.  Microwave Properties of Ice and Snow , 1998 .

[4]  Gérard Lachapelle,et al.  Tracking performance of a HSGPS receiver under avalanche deposited snow , 2008 .

[5]  F. Ares,et al.  SICRA: A GNSS cooperative system for avalanche rescue , 2012, 2012 6th ESA Workshop on Satellite Navigation Technologies (Navitec 2012) & European Workshop on GNSS Signals and Signal Processing.

[6]  Chris Rizos,et al.  The International GNSS Service in a changing landscape of Global Navigation Satellite Systems , 2009 .

[7]  R. Armstrong,et al.  The international classification for seasonal snow on the ground (UNESCO, IHP (International Hydrological Programme)–VII, Technical Documents in Hydrology, No 83; IACS (International Association of Cryospheric Sciences) contribution No 1) , 2009 .

[8]  F. Nievinski,et al.  Can we measure snow depth with GPS receivers? , 2009 .

[9]  C. Mätzler,et al.  ERRATUM: Dielectric properties of fresh-water ice at microwave frequencies , 1987 .

[10]  R. Schulin,et al.  Calibration of time domain reflectometry for water content measurement using a composite dielectric approach , 1990 .

[11]  U. Kaatze.  Complex Permittivity of Water as a Function of Frequency and Temperature , 1989 .

[12]  B. Hofmann-Wellenhof,et al.  Global Positioning System , 1992 .

[13]  Felipe G. Nievinski,et al.  Comparison of Snow Data Assimilation System with GPS reflectometry snow depth in the Western United States , 2015 .

[14]  Ari Sihvola,et al.  Snow Fork for Field Determination of the Density and Wetness Profiles of a Snow Pack , 1986, IEEE Transactions on Geoscience and Remote Sensing.

[15]  R. Dach,et al.  Bernese GNSS Software Version 5.2 , 2015 .

[16]  Ice.  The international classification for seasonal snow on the ground , 1990 .

[17]  I. Woodhouse.  Introduction to Microwave Remote Sensing , 2005 .

[18]  Wolfram Mauser,et al.  Measuring Snow Liquid Water Content with Low-Cost GPS Receivers , 2014, Sensors.

[19]  Craig F. Bohren,et al.  Absorption and Scattering by an Arbitrary Particle , 2007 .

[20]  E. Cardellach,et al.  Characterization of dry-snow sub-structure using GNSS reflected signals , 2012 .

[21]  K. Heki,et al.  GPS snow depth meter with geometry-free linear combinations of carrier phases , 2012, Journal of Geodesy.

[22]  G. Koh.  Complex dielectric constant of ice at 1.8 GHz , 1997 .