Enhancing GMTI Performance in Non-Stationary Clutter Using 3D STAP

In side-looking ground moving target indication (GMTI) radar, the 2-dimensional (2D) space time (azimuth-Doppler) domain can adequately define a clutter spectrum which is accurate for all range gates. However, in applications where the array boresight is not perpendicular to the velocity vector (e.g. forward-looking radar), the azimuth-Doppler clutter spectrum exhibits a dependence on elevation angle-of-arrival, creating range-varying (but elevation-dependent) clutter statistics, or non-stationary clutter. Classical space time adaptive processing (STAP) algorithms suffer substantial performance losses in non-stationary clutter since classical STAP assumes clutter stationary along the range (training) dimension. Planar arrays are inherently able to observe the azimuth-Doppler clutter spectrum as a function of the elevation angle, a capability which linear arrays lack. The incorporation of the planar array's vertical dimension into the joint azimuth-Doppler (2D) STAP domain has previously resulted in 3D STAP. This paper demonstrates the ability of 3D STAP to solve the non-stationary clutter problem by accounting for the elevation-dependent clutter statistics in a 3D covariance matrix. A forward-looking array is used to provide non-stationary clutter, and the performance of 2D and 3D versions of the adaptive matched filter (AMF) and joint domain localized (JDL) are used in a close-in sensing paradigm. The results show a >55 dB improvement in output SINR near the clutter null using 3D STAP algorithms in lieu of 2D STAP algorithms applied to the same (subarrayed) data.

[1]  I. Reed,et al.  Rapid Convergence Rate in Adaptive Arrays , 1974, IEEE Transactions on Aerospace and Electronic Systems.

[2]  W.L. Melvin,et al.  Comparison of bistatic clutter mitigation algorithms for varying geometries , 2005, IEEE International Radar Conference, 2005..

[3]  F.D. Lapierre,et al.  Estimation of geometric radar configuration parameters for range-dependent compensation in STAP in the presence of targets, jammers, and decorrelation effects , 2004, Processing Workshop Proceedings, 2004 Sensor Array and Multichannel Signal.

[4]  L. E. Brennan,et al.  Adaptive arrays in airborne MTI radar , 1976 .

[5]  J. R. Guerci,et al.  Optimal reduced-rank 3D STAP for joint hot and cold clutter mitigation , 1999, Proceedings of the 1999 IEEE Radar Conference. Radar into the Next Millennium (Cat. No.99CH36249).

[6]  F. Pearson,et al.  Simulation and Analysis of Adaptive Interference Suppression for Bistatic Surveillance Radars , 2001 .

[7]  B. Himed,et al.  Estimation of range-dependent clutter covariance by configuration system parameter estimation , 2005, IEEE International Radar Conference, 2005..

[8]  Peter G. Richardson.  Space-time adaptive processing for manoeuvring airborne radar , 1998 .

[9]  R. Klemm,et al.  Doppler compensation in forward-looking STAP radar , 2001 .

[10]  Joseph R. Guerci,et al.  Optimal and adaptive reduced-rank STAP , 2000, IEEE Trans. Aerosp. Electron. Syst..

[11]  F.D. Lapierre,et al.  Computationally-efficient range-dependence compensation method for bistatic radar STAP , 2005, IEEE International Radar Conference, 2005..

[12]  Braham Himed,et al.  STAP with angle-Doppler compensation for bistatic airborne radars , 2002, Proceedings of the 2002 IEEE Radar Conference (IEEE Cat. No.02CH37322).

[13]  S. D. Hayward,et al.  Effects of motion on adaptive arrays , 1997 .

[14]  William L. Melvin,et al.  Space-time adaptive radar performance in heterogeneous clutter , 2000, IEEE Trans. Aerosp. Electron. Syst..

[15]  Mark E. Oxley,et al.  Localized three-dimensional adaptive spatial-temporal processing for airborne radar , 2002, RADAR 2002.

[16]  Joseph R. Guerci,et al.  Space-Time Adaptive Processing for Radar , 2003 .

[17]  T.B. Hale,et al.  Space-time adaptive processing for forward looking arrays , 2004, Proceedings of the 2004 IEEE Radar Conference (IEEE Cat. No.04CH37509).

[18]  G. K. Borsari,et al.  Mitigating effects on STAP processing caused by an inclined array , 1998, Proceedings of the 1998 IEEE Radar Conference, RADARCON'98. Challenges in Radar Systems and Solutions (Cat. No.98CH36197).

[19]  James Ward,et al.  Space-time adaptive processing for airborne radar , 1998 .

[20]  P.M. Corbell,et al.  Forward-Looking Planar Array 3D-STAP using Space Time Illumination Patterns (STIP) , 2006, Fourth IEEE Workshop on Sensor Array and Multichannel Processing, 2006..

[21]  S. D. Hayward,et al.  Adaptive space time processing for forward looking radar , 1995, Proceedings International Radar Conference.