Three dimensional fully polarimetric W-band ISAR imagery of scale-model tactical targets using a 1.56THz compact range

摘要

Using the high-frequency terahertz compact range developed recently for measurement of polarimetric return of scale models of tactical targets, we have developed several techniques to produce three-dimensional data sets. Fully polarimetric three-dimensional ISAR data has been collected on several 1/16th scale model tactical targets in free space at individual look angles. The three-dimensional scattering coordinates are calculated by viewing the target through a two-dimensional angular aperture in both azimuth and elevation while simultaneously performing a linear frequency chirp to measure the down-range coordinate. Due to the high frequency of W-band radar, this technique produces high-resolution cross-range images from relatively small (approximately 1 degree) angular integrations. Several techniques for calculation of the three-dimensional coordinates have been developed. In addition to the technique described above, a new method utilizing the phase change of the scattering centers due to differentially small changes in angle will be described. Data collected using this technique can be processed to produce three-dimensional scattering information similar to that obtained by monopulse systems. Results from this analysis will be shown.