METRATEK, Inc......................We innovate for you!

      WINSAR is a high-performance interferometric SAR developed by METRATEK, Inc. with the support of the Office of Naval Research. WINSAR brings unparalleled flexibility to the remote sensing community by combining:

• the METRATEK Model 200 Imaging radar, developed for radar cross section measurements of high-technology aircraft,
• a high-throughput digitizer to provide a new generation of high-performance SAR for sophisticated remote sensing  and surveillance applications, and
• the ability to operate on small aircraft.

      WINSAR is designed to fly on small aircraft with low flight-hour costs. Ultimately it will fly on Unmanned Aerial Vehicles (UAV's). It has already flown twice on Navy P-3 patrol aircraft, and has provided images at VHF, S, and X-Band. The expanded digitizer capability will be flown in spring, 1998, on a Piper Navajo light-twin aircraft, which will have 4-hour endurance and 50-100 m/second flight speeds.

      WINSAR exploits Model 200 radar architecture to achieve broad band (200 MHz-18 GHz) operation using plug-in RF Modules and wide band Traveling Wave Tube power amplifiers. Two racks contain all the radar electronics except for the laptop computer that controls the system and provides real-time outputs. The racks shown above contain two 200-W Traveling Wave Tube Amplifiers (2-8 and 8-18 GHz).  An L-Band TWT and solid state transmitters below 1 GHz are also available. 

      WINSAR is capable of switching between  up to 16 different antenna ports on a pulse-by-pulse basis, thereby allowing  full-matrix polarization data collection. The Piper Navajo installation uses four 2-18 GHz dual-polarized ridged horns in the quad configuration (shown above) to provide both AT-INSAR and CT-INSAR (discussed below). The horns are mounted in the aircraft cabin and view the surface through a dielectric door that replaces the standard metal door. In other applications, the antennas are matched to the specific requirements of the system

      The radar employs a digitally-generated FM chirp to provide 1.2 m of basic range resolution and wide band frequency agility to enhance cross-range resolution without reducing synthetic aperture size for speckle reduction.  All signal processing is digital, using two fast SHARC Digital Signal Processors for real-time pulse processing and a Pentium-II PC for real-time downrange display. The high-speed digitizer produces up to 4000 range cells per pulse from a digitally-generated FM chirp. The data collection system provides 60-80 Mbytes/second throughput to a 110-Gbyte RAID array. This supports 4096 range cells at a collection rate of 3 KHz. When data are not being collected, the disks are offloaded to tape at 6 Mbytes/second. Larger storage systems are available for larger aircraft.

      System options include a high-performance GPS-augmented Inertial Measurement System and a Real-time Kinetic Differential GPS system. The latter allows the SAR terrain maps to be placed accurately in proper geophysical location for high-quality cartographic applications.                               INSAR and SAR processing software, tailored to the customer application, is also available. These applications include:

      METRATEK offers full product hardware and software support of WINSAR, and can provide turnkey units complete with aircraft, or installation in the customer's aircraft. For further information and pricing, please E-mail METRATEK.