Adaptive power-managed FMCW emitter detection performance against low-RCS ships

The design of a modern 9.3 GHz homodyne triangular-FMCW emitter for detection of low radar cross section (RCS) ships is described. Both searchand track-mode processing are described including a description of transmit and receive waveforms. Tradeoffs in emitter design are examined as a function of the modulation bandwidth. To predict target detection capability, clutter and target models are developed as the emitter is flown at 300 m/s in a scenario that starts at a range of 15 nmi from the target. To evaluate the feasibility of detecting low RCS ships at the horizon, a low-RCS ship design is examined. Each sea state (0-4) is characterized by using a second-order polynomial that describes the normalized mean sea backscatter coefficient as a function of the grazing angle. The emitter transmit power is adapted in time to measure the target characteristics. The emitter transmit power level is consistent with the RCS and range to the target while keeping a target-to-clutter power ratio at 20 dB. For detection analysis, 50, 100 and 500 m/sup 2/ RCS values are considered.