SOME ISSUES IN INVERSE SYNTHETIC-APERTURE RADAR IMAGE-RECONSTRUCTION

One-dimensional radar target recognition schemes are based upon so-cal led 'range profiles' and contain little or no cross-range target infor mation. This limitation often restricts the usefulness of range-only m ethods in problems of target identification and target detection-in-cl utter. Consequently, cross-range algorithms are usually required for t hese more demanding tasks. Because the ratio of wavelength to physical aperture is so much greater than it is for optical instruments of com parable dimensions, radar 'imaging' methods usually attempt to artific ially increase the effective aperture of the data acquisition system b y employing SAR or ISAR techniques. Unfortunately, there are a host of problems associated with practical implementations of these SAR/ISAR techniques and the quality of the reconstructed image-as well as our a bility to interpret it-can be seriously compromised. We present a brie f overview of the ISAR techniques relevant to the problem of target re cognition and pay special attention to scattering model limitations, s ources of reconstruction error, and some current efforts to address th ese problems.