Optimum coherent integration time for a surface target with periodic acceleration

Abstract

In this paper we consider the effect of surface target dynamics on the detection performance of coherent radar. The echo from a surface target traveling with a constant velocity, that is not radial to the radar look direction or constant rate acceleration is represented in the form of chirp function. This is a simplistic model that must be extended to account for other periodic accelerations acting on the target. The dominant periodic acceleration is the radial surge component that may result in the smearing of the targets Doppler. This radial surge component is a result of the interaction of the target with the ocean wave. This effect must be taken into account when determining the optimum coherent integration time (CIT). In this paper we extend the model to accommodate an echo from a periodic accelerating target with a frequency-modulated signal that represents the surge component. The optimum CIT is derived based on maximizing the signal-to-noise ratio (SNR) at the matched filter output. The results are verified based on data collected from a high frequency surface wave radar (HFSWR) operating at 15 MHz.