Dual use multi-frequency radar for current shear mapping and ship target classification

A new radar is in final stages of development and testing by Imaging Science Research (ISR), Inc., sponsored by the Office of Naval Research. The system is based on digital receiver technology incorporated into a PC operating environment. A digital receiver eliminates the need for many radio frequency analogue components, providing more robust temperature-insensitive operation and lowers hardware costs. The digital approach allows operation beyond the High Frequency (HF) band, which occupies 3-30 MHz, and our current plan is to cover 2-55 MHz with a single system. The system can be tied to our ISR Rubidium Clock option, allowing bistatic operation using a single receive array and processing station with multiple transmit sites, for vector measurements of velocity. Here we provide a description of our digital transceiver, our radar block diagram, and our transmit and receive antenna arrays. Measurements of the radar cross section (RCS) of small boats are presented, based on work done by the author in the mid-70's, suggesting that ships and small boats can be classified based on their RCS radar frequency spectral properties. Results from a pilot experiment are displayed, demonstrating multi-frequency operation using 32 radar frequencies over the HF band.