Research On Polarization Space Time Adaptive Processing Method For Airborne Conformal Array

The conformal array is usually mounted on the surface of the aircraft without changing the aerodynamic performance design of the carrier’s shape,which can achieve more beam scanning coverage and improve the stealth capability and combat performance.In addition,the conformal array is sensitive to polarization and has the ability to process polarization information.The integration of space,time and polarization domain information can improve the clutter suppression and moving target detection capability.Due to the curved surface of the carrier,the antennas of each array element has different installation directions,and the polarization patterns are also inconsistent.To deal with these problems,the structural characteristics and polarization characteristics of the conformal array are considered.A polarization-space-time joint clutter model is established.The clutter rank of the conformal array is analyzed.The polarization-space-time adaptive processing method for airborne conformal array is studied.The main contents of this thesis are summarized as follows:1.The airborne conformal array model is established according to the surface characteristics.The polarization pattern difference of the subarrays due to the inconsistency of the antenna installation position and the curvature of the carrier is analyzed via simulation experiments.Based on the established array model,the range history of clutter is derived.Aiming at the polarization covariance matrix in consistence of different subarrays,a joint polarization-space-time clutter model of the airborne conformal array is established.2.The clutter rank estimation method based on the regular array is studied and the applicable condition is discussed.Based on the analysis of clutter space-time coupling relationship,an arbitrary array clutter rank estimation method that ignores polarization is established,and the clutter rank estimation of regular planar arrays is extended to three-dimensional stereo array by using the theory of multi-dimensional aperture-bandwidth product.The method is verified by comparing the simulation and numerical calculation results.In addition,considering the inconsistency of the polarization response of the conformal subarrays,the vertical baseline,and the attitude change of the carrier,the influence of clutter rank and processing performance is qualitatively and quantitatively analyzed.3.According to the structural characteristics and clutter characteristics of the conformal array,the applicability of the classical polarization-space-time adaptive processing method is analyzed and verified by simulation experiments.Aiming at the inconsistency of the polarization response of each subarray of the conformal array,a polarization-space-time adaptive processing method based on polarization compensation is proposed.According to the prior information of the antenna position and the antenna installation direction,the compensation of the polarization pattern of each subarray is carried out to improve the polarization correlation of the clutter.Simulation validates that the algorithm can reduce the performance loss caused by the inconsistent polarization response,and improve the clutter suppression performance of the conformal array.