Bistatic real-aperture radar - development & applications

Enlarged view: KAPRI — KAPRI - a polarimetric Ku-Band advanced portable radar interferometer.

We are equipped with a ground based real aperture radar interferometer. It is a Ku band real aperture FMCW radar, which offers a range resolution of 0.75 m and an azimuth resolution of 0.4 degrees. With the addition of vertically and horizontally polarized antennas, this model allows to acquire a fully polarimetric, interferometric data set in a single pass. This is of interest for terrain mapping (generation of DEMs), deformation measurement and agricultural applications.

KAPRI is also capable of operating in the so-called "bistatic" mode, where two spatially-separated devices are employed, and one serves as a transmitter, while the other as a receiver. This provides an additional look at the observed scene, under a different scattering angle. Bistatic radar has not yet been thoroughly researched, and thus KAPRI is an excellent device for exploration of this parameter space owing to its portability and fast acquisition rates. We can thus experiment with different acquisition configurations, bistatic angles, time scales and observed scenes.

Enlarged view: Polarimetric image of area surrounding ETH Honggerberg campus. — Polarimetric radar images of area surrounding ETH Honggerberg campus at Ku-band in Pauli basis during a test acquisition. Individual RGB colours depict three different scattering mechanisms. Left: Monostatic, Right: Bistatic. Map data: OpenStreetMap

Publications:

M. Stefko, O. Frey, C. Werner and I. Hajnsek, "Calibration and Operation of a Bistatic Real-Aperture Polarimetric-Interferometric Ku-Band Radar," in IEEE Transactions on Geoscience and Remote Sensing, doi: external page 10.1109/TGRS.2021.3121466.

Selected conference submissions:

Stefko, M., Leinss, S., and Hajnsek, I.: Bistatic radar observations of the coherent backscatter opposition effect in dry snow, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4563, external page https://doi.org/10.5194/egusphere-egu21-4563, 2021.
M. Stefko, O. Frey, C. Werner and I. Hajnsek, "KAPRI: A Bistatic Full-Polarimetric Interferometric Real-Aperture Radar System for Monitoring of Natural Environments," 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021, pp. 1950-1953, doi: external page 10.1109/IGARSS47720.2021.9553427.
Woodwark, J. and Stefko, M. and the GRAVL development team: GRAVL: a new satellite mission concept aiming to detect earthquakes with a magnitude of 6.5 Mw and higher, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8304, external page https://doi.org/10.5194/egusphere-egu2020-8304, 2020
Stefko, M., Baffelli, S., & Hajnsek, I. (2019). First acquisition using a Ku-Band polarimetric bistatic terrestrial radar: KAPRI. In 9th International Workshop on Science and Applications of SAR Polarimetry and Polarimetric Interferometry (POLinSAR 2019) (p. 204) doi: external page 10.3929/ethz-b-000452171.