Multistatic Sea-Based Radar Concepts and Architectures

Propagation Research Associates, Inc., (PRA) proposes two time-alignment techniques that can be implemented using existing radar systems to achieve coherency among multiple sea-based radar platforms operating in a multistatic configuration. For the first technique, the baseline multistatic technique, a single ship-based radar is designated as the primary transmitter for a multistatic sea-based system. The baseline technique uses a waveform transmitted from the primary radar to a cooperative target that is then received, delayed and/or encoded, and re-transmitted by each distributed radar system to determine time-of-arrival from each radar to the cooperative target. A unique Coherent Trilateration technology is used to estimate random clock errors among radar systems for timing correction. The second technique, the enhanced multiplatform technique, uses multiple diverse waveforms transmitted from every platform simultaneously to determine the times-of-arrival from each radar to the cooperative target and back to every radar which imparts additional spatial smoothing for improved time-alignment convergence as compared to the baseline technique. PRA plans to integrate an inertial sensor and star tracker system to measure the position and orientation of each radar antenna in an inertial frame to reduce antenna position biases and will use its knowledge of refractive effects to estimate propagation biases.