FOPAIR: a focused array imaging radar for ocean remote sensing

FOPAIR, a FOcused Phased Array Imaging Radar, provides high-resolution X-band images of the ocean surface. The system is designed to provide high-speed imagery (up to 180 frames/s) for short range applications (50-400 m) from a fixed platform such as a pier or tower. FOPAIR employs a fast, sequentially sampled antenna array and uses a software-based beamforming technique to generate high resolution imagery without the need for multiple radar receivers or beamforming hardware typical of active phased arrays. A summary of the principles of operation and the design of the instrument is given, followed by examples of FOPAIR's imaging capability. To the authors' knowledge, these examples include the highest-resolution, highest-speed microwave images of the ocean surface produced to date. A brief comparison between FOPAIR and synthetic aperture radar techniques is also included