Flo SAR Forward Looking SAR David Felton EECS

Flo. SAR (Forward Looking SAR) David Felton EECS 826 April 20, 2021

Conventional SAR In conventional SAR, a linear array (aperture) is synthesized along the sensors motion vector and transmits energy perpendicular to the motion vector. To form a SAR image, measurements are collected along orthogonal axes: along track (azimuth) via movement of the sensor, and cross track (range) via time delays. This limits the number of coordinates of the imaged pixel. Determining the third coordinate (height) requires additional flight passages across the scene (In. SAR).

Motivation With conventional SAR, there is no way to approach the problem of an airplane landing in low visibility with obstacles located on or nearby the landing strip or flying in its vicinity. [2] The forward-looking geometry in SAR is typically never used due to ambiguity problems (grating lobes). Doppler shift techniques have been used to remove uncertainty in measurements, but there is a much simpler and more general ”array approach”. In order to perform a 2 -D scan (azimuth and elevation), a planar array can be used but is impractical on an aircraft. However, a linear array is. Multi-pass SAR effectively synthesizes a planar array in the bassline and azimuth dimensions so why not just use an actual array?

Flo. SAR

Processing

Resolutions z(km) 1 14 24. 5 10 5 32 55 50 10 45 77 100 140 245 1000

PRF Considerations

Flo. SAR Simulations

Flo. SAR Simulations

References [1] G. Franceschetti, A. Iodice and D. Riccio, "FLo. SAR: A new concept for Synthetic Aperture Radar, " 2008 IEEE Radar Conference, Rome, Italy, 2008, pp. 1 -4. [2] G. Franceschetti, A. Iodice and D. Riccio, "Forward-Looking Synthetic Aperture Radar (FLo. SAR): The Array Approach, " in IEEE Geoscience and Remote Sensing Letters, vol. 11, no. 1, pp. 303 -307, Jan. 2014. [3] Cumming, I. and F. Wong. “Digital Processing of Synthetic Aperture Radar Data: Algorithms and Implementation. ” (2005).