RADAR CLUTTER RESEARCH

Abstract : The objective of this program was to prepare a clutter research plan for Army air defense weapons that encompasses the anticipated methods of employment of these weapons, as well as the problems associated with the introduction of new radar technology in these systems. Specifically, the investigations included studies of the physics of electromagnetic scattering from rough surfaces, a definition of clutter problems as related to innovations in radar technology such as electronic beam steering, signal processing and design, computer technology, study of clutter models and simulation techniques, and a study of clutter effects in a radar defense complex. Probability density functions, correlation functions and doppler spectra of clutter signals are derived for the configuration in which only a few major scatterers are present. Results are presented for both coherent and noncoherent detection. Methods of simulating clutter, using both analog and digital approaches, are described. Emphasis is placed on advanced forms of simulators such as would be required for evaluation of future multi-dimensional radar systems rather than on additive filtered noise for the simulation of clutter. The simulation techniques are based on two suggested generic forms of clutter models, called open-loop and closed loop. Because of the greater flexibility of closed-loop simulation, this is presented in greater detail. Techniques for performing radar clutter measurements are described and some of the significant problems, related primarily to terrain and cultural observables, are discussed. Clutter problems as related to radar systems and innovations in radar technology, such as electronically steered phased arrays, are also described.