A digital beamforming processor for the joint DoD/NASA Space Based Radar mission
Mark A. Fischman - Jet Propulsion Laboratory, Charles Le - Jet Propulsion Laboratory, Paul A. Rosen - Jet Propulsion Laboratory
Tue, 27 April 2004, 10:20 AM - 12:00 PM
The Space Based Radar (SBR) program includes a joint technology demonstration between NASA and the Air Force to design a low-Earth orbiting, 2?50 m L-band (1.26 GHz) radar system for both Earth science and intelligence-related observations. A key subsystem aboard SBR is the electronically-steerable digital beamformer (DBF) network that interfaces between 32 smaller sub-antenna panels in the array and the on-board processing electronics for Synthetic Aperture Radar (SAR) and Moving Target Indication (MTI). In this paper, we describe the development of a field-programmable gate array (FPGA) based DBF processor for handling the algorithmically simple yet computationally intensive inner-product operations for wideband, coherent beamforming across the 50 m length of the array. The core functions of the DBF?-the CORDIC (Coordinate Rotation Digital Computer) phase shifters and combiners?-have been designed in the Verilog hardware description language and implemented onto a high-density Xilinx Virtex II FPGA. The design takes full advantage of the massively parallel architecture of the Virtex II logic slices to achieve real-time processing at an input data rate of 25.6 Gbit/s. Tests with an antenna array simulator demonstrate that the beamformer performance metrics (0.07 degree rms phase precision per channel, -39.0 dB peak sidelobe level) will meet the system-level requirements for SAR and MTI operating modes.
Dr. Mark A. Fischman - Jet Propulsion Laboratory
Mark A. Fischman (S?95?M?01) received the B.S. degree in electrical engineering from the California Institute of Technology, Pasadena, CA, in 1989, and the M.S. and Ph.D. degrees in electrical engineering from the University of Michigan, Ann Arbor, MI, in 1996 and 2001.
He worked at the Sony Corporation television development groups, Tokyo, Japan and Pittsburgh, PA, from 1989 to 1995. In 2001, he joined the Radar Science and Engineering Section at the Jet Propulsion Laboratory, Pasadena, CA, where he is currently developing the beamforming and on-board processing systems for the Next-Generation Precipitation Radar and the Space Based Radar satellite instruments. His research interests include the development of advanced phased-array and digital receiver electronics for Earth-observing radar.