In Chapter 14, we have seen high-resolution images of the ground scene produced by a radar flying on an elevated platform and thereby forming a long synthetic aperture. This long aperture resulted in a very fine azimuth or cross-range resolution. For ground-based radar systems it is often also highly desirable to get images of detected targets, e.g. of the observed aircraft. This could be a valuable contribution to a classification of flying targets.

Chapter Contents:

• 15.1 Introduction: basic principle
• 15.2 Synthetic aperture and beam forming by target motion
• 15.3 Target cross-range image
• 15.4 Focusing
• 15.4.1 Range focusing and range walk
• 15.4.2 Focusing with straight-line assumption
• 15.4.3 Focusing for arbitrary flight paths
• 15.4.3.1 Iteration with Fourier transform and Kalman filter
• 15.4.3.2 Doppler shift of a target and its scatterers
• 15.4.3.3 Focusing with Wigner-Ville distribution
• 15.5 High-range resolution
• 15.6 Alternative image planes
• 15.7 Conclusions
• References