GPU Processing for UAS-Based LFM-CW Stripmap SAR

Abstract

Unmanned air systems (UAS) provide an excellent platform for synthetic aperture radar (SAR), enabling surveillance and research over areas too difficult, dangerous, or costly to reach using manned aircraft. However, the nimble nature of the small UAS makes them more susceptible to external forces, thus requiring significant motion compensation in order for SAR images to focus properly. SAR backprojection has been found to improve the focusing of low-altitude stripmap SAR images compared to frequency domain algorithms. In this paper we describe the development and implementation of SAR backprojection appropriate for UAS based stripmap SAR that utilizes the unique architecture of a GPU in order to produce high-quality imagery in real-time.

A Review of Synthetic-Aperture Radar Image Formation Algorithms and Implementations: A Computational Perspective

“…A real-time GPU implementation of the backprojection algorithm for Stripmap SAR is presented in [36]. The ability to execute the algorithm in real-time comes from the reduction of pulse contributions calculated for each pixel.…”

A Car-Borne SAR System for Interferometric Measurements: Development Status and System Enhancements

“…The SAR data is focused using a time-domain backprojection approach [5], [6] adapted to FMCW systems [7]- [9]. Also a graphics processing unit (GPU)-based parallelized implementation of a TDBP algorithm [5], [6] based on NVIDIA's Compute Unified Device Architecture (CUDA) application programming interface had been implemented; a brief performance analysis of a first implementation was given in [8].…”

Ground-Based 3D Radar Imaging of Trees Using a 2D Synthetic Aperture

“…The positions and separation distance between the transmit and the receive antennas are accounted for in the backprojection processing geometry. While graphics processing unit (GPU)-based processing algorithm to form images could have been used [17], for this study, the processing is done in Matlab (Mathworks, Sunnyvale, CA, USA, 2011) without attempting formal calibration of A or σ, i.e., the images are uncalibrated [16]. Unfortunately, radar calibration is hindered by the loss of critical calibration data due to a human error.…”