E.E. Koltyshev, P.A. Makarov, V.V. Mukhin, D.Y. Suslyakov, A.Y. Frolov, V.T. Jankowski
Detection of moving objects (targets) on a background of intense clutter of different origin (reflection from the surface, clouds, chaff) is one of the most urgent tasks on-board radar systems for mapping the underlying surface. Selection of moving objects is based on differences in spatial-temporal signals reflected from targets and fixed reflectors by their spectral separation using spatial multi-channel systems. Optimization algorithms for operation processing systems with multiple spatial channels is an important problem in the practical design and is based on a simplified model of clutter in the form of taking into account some of the most important components of the spectrum of jamming reflections. This approach to the optimization algorithms implemented practically is one of the main factors limiting the effectiveness of systems moving target for the suppression of jamming reflections.
Are considered space-time model of the signals reflected from moving objects, and jamming reflections characteristic of airborne coherent radar of forward-side and forward view. The method of synthesis algorithm of space-time selection of signals reflected from moving objects on the background of reflections from the surface in multichannel radar.
The linear processing system (filter) maximizing a signal-to-interference ratio is defined by transfer function which shall be coordinated not only with a signal range, but also with an energy spectrum of noise. Thus its transfer characteristic is defined by coercion of the correlated noise operating on an input of system, to a white noise. The optimum filter represents a serial connection of the rehabilitating filter and the filter coordinated with the useful signal, passed through rehabilitating filter.
In determining the structure of the processing system used assumptions that allow one side to ensure the feasibility of the algorithms and the other – to take into account a priori properties of interfering reflections:
– Structure of the processing system is defined in a class of multi-channel systems, which can be represented by a parallel-consecutive connection of elementary spatially and frequency selective chains;
– The ratio of power interfering reflections to the power of the internal noise of the receiver is not a significant value, which allows the influence of the internal noise neglected.
The example of optimization of system of processing for monopulse radar is considered. The resulting algorithm can achieve high efficiency of suppression of clutter, which is especially important when using the MTI algorithms for mapping the underlying surface with radar contrast stationary objects. The potential benefit with respect to the well-known algorithm achieves more than 30 dB. The above optimization technique can be extended to systems with a large number of spatial and temporal channels.