Sodsar: A tower-based 1–10 ghz sar system for snow, soil and vegetation studies

We introduce SodSAR, a fully polarimetric tower-based wide frequency (1–10 GHz) range Synthetic Aperture Radar (SAR) aimed at snow, soil and vegetation studies. The instrument is located in the Arctic Space Centre of the Finnish Meteorological Institute in Sodankylä, Finland. The system is based on...

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Bibliographic Details
Published in:Sensors
Main Authors: Ruiz, Jorge Jorge, Vehmas, Risto, Lemmetyinen, Juha, Uusitalo, Josu, Lahtinen, Janne, Lehtinen, Kari, Kontu, Anna, Rautiainen, Kimmo, Tarvainen, Riku, Pulliainen, Jouni, Praks, Jaan
Other Authors: Department of Electronics and Nanoengineering, Jaan Praks Group, Fraunhofer Institute for High Frequency Physics and Radar Techniques, Finnish Meteorological Institute, Harp Technologies Ltd, Aalto-yliopisto, Aalto University
Format: Article in Journal/Newspaper
Language:English
Published: Multidisciplinary Digital Publishing Institute (MDPI) 2020
Subjects:
Boreal forest
Insar
Radiometric calibration
Scatterometer
SodSAR
Synthetic aperture radar
Temporal coherence
Vector network analyzer
Arctic
Sodankylä
Online Access:https://aaltodoc.aalto.fi/handle/123456789/101664
https://doi.org/10.3390/s20226702
Description
Summary:We introduce SodSAR, a fully polarimetric tower-based wide frequency (1–10 GHz) range Synthetic Aperture Radar (SAR) aimed at snow, soil and vegetation studies. The instrument is located in the Arctic Space Centre of the Finnish Meteorological Institute in Sodankylä, Finland. The system is based on a Vector Network Analyzer (VNA)-operated scatterometer mounted on a rail allowing the formation of SAR images, including interferometric pairs separated by a temporal baseline. We present the description of the radar, the applied SAR focusing technique, the radar calibration and measurement stability analysis. Measured stability of the backscattering intensity over a three-month period was observed to be better than 0.5 dB, when measuring a target with a known radar cross section. Deviations of the estimated target range were in the order of a few cm over the same period, indicating also good stability of the measured phase. Interforometric SAR (InSAR) capabilities are also discussed, and as a example, the coherence of subsequent SAR acquisitions over the observed boreal forest stand are analyzed over increasing temporal baselines. The analysis shows good conservation of coherence in particular at L-band, while higher frequencies are susceptible to loss of coherence in particular for dense vegetation. The potential of the instrument for satellite calibration and validation activities is also discussed. Peer reviewed

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