Bistatic radar is the superset of monostatic radar system. Hence bistatic system might give certain advantages over the monostatic system in the present usages of monostatic radar system. Bistatic technology, if implemented successfully, can give rise to a wide spectrum of novel and innovative usages, which would have been impossible using the simpler monostatic system. Automatic target classification and recognition has been an area of active research for monostatic radars. This is also a major usage of an airborne radar system. Hence it is pertinent at the current stage to look at different aspects of automatic target recognition (ATR) using the synthetic aperture radar (SAR) image as collected by a bistatic radar system. This as applied to classification of ground targets has been the aim of the present project. Simulating a database of bistatic SAR images of ground targets using a generic electro magnetic (EM) computational tool is the first contribution of the present project. Major challenges in this approach consisted of selecting a usable and available EM simulator, modelling a selection of ground targets, finding a simple and effective algorithm to generate SAR images using the output from the EM simulator, developing a simple and efficient image formation algorithm for bistatic SAR image generation, and managing the database to be used efficiently in a classification task. All these challenges have been successfully tackled in the present project. The second contribution is an analysis of different aspects of bistatic SAR ATR. This consists of developing an efficient and fast ATR algorithm, studying the effect of clutter noise, bistatic angle, polarisation, k space support on bistatic ATR, comparison of monostatic and bistatic ATR, and suggestion of ways to improve bistatic ATR performance. In this it has been shown that contrary to popular expectations, bistatic ATR is not significantly worse than monostatic ATR. Given a proper ATR algorithm, the bistatic ATR performance could be made as good as if not better than the monostatic ATR performance. Lastly, the loss of ATR performance in the bistatic domain is more due to loss of image resolution as to any loss of image information. The last contribution of the project is the study of the usage of multipolar data in an ATR exercise. A group of different algorithms were developed to use the multipolar information for a better ATR performance. It was shown that, using multipolar data significantly improves the ATR performance, for some of the multipolar ATR algorithms the ATR performance was shown to be much more stable than the monopolar counterpart, and a new algorithm was proposed to use multipolar data so that the ATR performance becomes independent of the polarisation of the radar antenna in the test phase. It was also shown that bistatic multipolar data does hold information about the targets which could easily be exploited, as contrary to reservations held by experts in the past.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:657847 |
| Date | January 2006 |
| Creators | Mishra, Amit Kumar |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/15404 |
Page generated in 0.0024 seconds