Study On Clutter Characteristics Of Airborne Distributed Phased Radio Probing System

Airborne distributed coherent radio frequency detection system, as a new generation of radar systems, has significant military applications. Compared to airborne phased array radar, airborne distributed coherent radio frequency detection system has series of strengths, including wider beam, higher resolution, higher degree of freedom, higher anti-jamming capability, but more difficult to deal with clutter. The characteristics of the clutter were changed due to the orthogonal waveform and lineup structure, the demand for computation and sample were increased because of high degree of freedom. This paper, focuses on the clutter characteristics and clutter suppression ways of airborne distributed coherent radio frequency detection system.Firstly the clutter characteristics of airborne distributed coherent radio frequency detection system were studied. The clutter model was established with transmitter and receiver array elements equally spaced, and the quadrature signals in the frequency transmitted; The doppler characteristics, space-time characteristic and time-frequency features of the clutter were analyzed from the point of the doppler frequency dimension, angle-doppler frequency dimensional and doppler frequency- range dimensional, respectively. The clutter doppler frequency had nothing to do with the distance with the broadside array, but the doppler frequency had a quadratic curve relationship with angle, affected by range significantly for a non-broadside array; The eigenvalue spectrum and the power spectrum of the clutter were analyzed with the change of system parameters such as CNR, sample numbers and step frequency of carrier frequency, and errors including doppler ambiguity, yaw and clutter fluctuations. The clutter decorrelation due to the error made the clutter power spectral broadening and the clutter rank increasing.Secondly space-time multi-channel clutter suppression methods are proposed. The space-time multichannel approach was proposed, based on the existing clutter suppression method. This methods processed synthesis array firstly, changing the transmitter-receiver-time dimensional into synthetic-time dimensional, then selected a number of adjacent beam channels and doppler channels to get space-time adaptive weights. Simulation results showed that this method obtained the same performance as EFA and 3DJDL methods, and had the lower computational demand and sample demand in a low cnr environment. Finally, the performance of the various clutter processing methods were compared, including to the clutter improvement factors curve, the residual clutter power curve, the compares of demand for computation and samples.