11-02-2013, 12:45 PM
ROLE OF IMAGING PROCESSING RADAR IN COUNTER TERRORISM
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ABSTRACT:
Recent years, practical interests arising from rescue missions, behind the wall target detection, surveillance and reconnaissance etal, claim for high capability of imaging in complicated environment. Through-wall radar attracts great attention in these areas. The ability to image targets through building walls, to detect and classify personnel and objects within rooms, is of significant importance in counterterrorism operations. Conventional narrow band systems, such as Doppler radar and Interferometric radar are no longer applicable here due to their insufficient down range resolution.
Ultra-wide band (uwb) waveform can provide unambiguous high resolution imaging at any distance. The purpose of this paper is to elucidate an UWB radar which has been investigated for THROUGH WALL IMAGING (TWI) in recent years is the most promising candidate due to its high resolution and high power efficiency. This paper details a novel aperture taking form as a variable length scanner or MOBILE ROBOT. Here the method adopted is called MIGRATION, which generates high resolution images using ‘vector network analyser (VNA)’.
In the aftermath of a terrorist attack, people inside the buildings can be detected and differentiated from terrorists using UWB-TWI radar. Thus, it is an ideal candidate sensor for covert imaging of obscured ranges in hostile environment.
INTRODUCTION
The ability to image targets through building walls, to detect and classify personnel and objects within rooms, is of significant importance in counter terrorism operations. Borrowing from success in geological and medical imaging environments, researches have attempted to apply Radio frequency(RF) and other sensing modes to penetrate wall materials and optimally estimate the content and structure of rooms and buildings. Terrorist activities and law enforcement situations often involve hostage situations underscore the need for effective clandestine TWI.
UWB RADAR
A radar image of the objects in an environment can be generated by transmitting a signal and measuring the round-trip time of its arrivals reflected off the objects and returned to the receiver. UWB transmitter send pulses sufficiently narrow in time to allow for path resolution at the receiver, avoiding overlap of the pulses which may otherwise combine in a destructive manner and render poor results.
CONCLUSION
This paper proposed a novel UWB radar system with synthetic aperture realised through a variable-length scanner or Mobile Robot. The wide dynamic range of the system coupled with its unrestricted aperture length allows us to generate high resolution Through the wall images upto a range of 8 mts. These parameters were fit through an extensive measurement campaign using a VNA coupled to a monostatic antenna array. The novelty of the model captures the dependence on the range, frequency sample interval and cross range sample interval. This work significantly improves the position of objects and focussed image quality over conventional migrations with constant velocity model, especially when the wall thickness and relative permittivity is not neglectable.