Multi-sensor Study of Lake Michigan’s Surface using GNSS-Reflectometry

Roohollah Parvizi, Houshine Sabbagh Zadeh, Li Pan, Boris Pervan,  Seebany Datta-Barua

Abstract:	In this paper, a summer data campaign is presented to study the freshwater surface using GNSS signals reflected from Lake Michigan. To analyze the scattered power in terms of surface conditions, verification sensors are collocated with the GNSS receiver. The ground-based mobile sensor suite we have developed consists of: a reflected-GNSS antenna and universal software radio peripheral (USRP) front end; a second (direct) GNSS reference antenna and USRP; lidar; camera; weather station and supporting power and electronics. The mobile sensor suite is set up on a dock on the Lake Michigan shore in Chicago, Illinois. Data are post-processed to acquire GPS L1 signals and to estimate the sensor suite location. The weather station and collocated camera data provide the reference surface temperature and wind speed conditions. Almanac information is used to compute the specular points’ (SP) positions in the east-north-up coordinate system (ENU). To determine specular point position on the surface, a LiDAR-SP map is computed. The SP-LiDAR map helps to find the location of the SP on the water. A delay-Doppler map (DDM) is a representation of the power scattered in time delay and Doppler shift, and depends on surface conditions. A DDM is computed for the satellite whose corresponding SP is located on the water and has a high elevation angle, to minimize direct GPS signal interference. We use an incoherent integration signal processing method to compute the DDM due to the signal noise level in this work. The DDMs for both direct and reflected GPS signals are examined. DDMs generated from the directly received signal correctly show the power concentrated at the code chip and Doppler frequency of the acquired satellite, indicating that the incoherent processing is sound. The sensor suite and processing will be used in future data campaigns for detecting seasonal freshwater and surface ice variations.
Published in:	Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018) September 24 - 28, 2018 Hyatt Regency Miami Miami, Florida
Pages:	2834 - 2847
Cite this article:	Parvizi, Roohollah, Zadeh, Houshine Sabbagh, Pan, Li, Pervan, Boris, Datta-Barua,  Seebany, "Multi-sensor Study of Lake Michigan’s Surface using GNSS-Reflectometry," Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018, pp. 2834-2847. https://doi.org/10.33012/2018.15860
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