TARGET IMAGING FOR SFCW BASED TWI SYSTEM

Abstract

This work deals with the use of Stepped Frequency Continuous Wave (SFCW) radar in the frequency range of 1 GHz- 3GHz for Through Wall Imaging (TWI) applications. There are many challenges associated with Through Wall Imaging. Since the through wall applications are such that the capability of the system to perform in real time is important, PC is interfaced with the Vector Network Analyzer (VNA) and data acquisition and processing is carried out in real time. Detection of oriented targets is a big challenge for through wall imaging applications as oriented targets (especially metallic) reflects a major part of incident radiation away from transmitter antenna. So this detection has to be performed by using antenna in bistatic mode. Real time moving target detection is one of the prime areas in the field of through wall imaging as identifying moving objects and humans is the topmost priority. In this project detection of target with surface parallel to wall and moving perpendicular to wall is carried out. A metallic target was designed which acted as a human mock up and good results have been obtained- by this mock target, but detection of a human target behind the wall is still a great challenge due to its complex dielectric properties and irregular shape resulting in uneven scattering. However with the help of ICA algorithm the detection of low dielectric substance is possible. The micro-Doppler characteristic of human body can be detected by SFCW radar at much lower sampling rates and power. With the help ofhigh bandwidth of our present TWI system the moving activity like heart beat detection is possible. By technique named Range Doppler Processing the heart beat of a human at different standoff distances ranging 30 cm to I m was measured with small error.