Distributed Real-Time Image Processing of Formation Flying SAR Based on Embedded GPUs

Abstract

Formation flying synthetic aperture radar (FF-SAR) systems, as an important development direction of multichannel SAR, can achieve high-resolution wide-swath imaging. Coherently combining data from satellite receivers puts a strain on the traditional real-time processing systems based on individual satellites. Characteristics, such as the power of real-time on-orbit processing platform, must be properly balanced with constrained memory and parallel computational resources. This article proposes a distributed SAR real-time imaging method based on the embedded graphics processing units (GPUs). The parallel computing method of the chirp scaling algorithm is designed based on the parallel programming model of compute unified device architecture, and the optimization methods of memory and performance are proposed for the hardware architecture of embedded GPUs. In particular, the unified memory management method is used to avoid data copying and communication delays between the CPU and GPU. A hardware verification system for distributed SAR real-time imaging processing based on multiple embedded GPUs is constructed. The proposed algorithm takes 5.86 s to process single-precision floating-point complex imaging with a data size of 8192 × 8192 on a single Jetson Nano platform. The actual power consumption is less than 5 W, and the performance-to-power ratio is greater than 1.7%. The experimental results show that the real-time processing method based on the embedded GPUs proposed in this article has high performance and low-power consumption.

Keywords

• Chirp scaling (CS) algorithm
• distributed architecture
• embedded graphics processing unit (GPU)
• on-orbit real-time processing
• synthetic aperture radar (SAR)