Spaceborne synthetic aperture radar signal processing using field-programmable gate arrays

摘要

Synthetic aperture radar (SAR) imagery requires image reproduction through the successive signal processing of received data before browsing images and extracting information. The received signal data records of ALOS-2/PALSAR-2 are stored in the onboard mission data storage and transmitted to the ground. To compensate for storage usage and transmission data capacity through the mission data communication network, the operation duty of PALSAR-2 is limited. This balance strongly relies on network availability. The observation operations of current spaceborne SAR systems are rigorously planned by simulating the mission data balance, given conflicting user demands. This problem should be solved so that we need not compromise the operations and potential of next-generation spaceborne SAR systems. One of the solutions is to compress the SAR data through onboard image reproduction and information extraction from the reproduced images. This is also beneficial for fast delivery of information products and event-driven observations by constellation. The Emergence Studio (Sohatsu kobo in Japanese) of the Japan Aerospace Exploration Agency has been developing evaluation models of the image processing system with the field-programmable gate array for onboard SAR image reproduction. The first model called the "Fast L1 Processor (FLIP)" can reproduce a 10-m resolution, single-look complex image (level 1.1) from ALOS/PALSAR raw signal data (level 1.0). FLIP processing speed at 200 MHz results in processing about five times faster than CPU-based computing at 3.7 GHz, corresponding to 50% real-time processing capability for ALOS/PALSAR. The FLIP'S image is almost identical to the image reproduced by 32-bit simulation in MATLAB. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)