An Experimental Study on an Accurate UWB Radar Imaging Method for a Target with Unknown Motion using a Small Number of Antennas

Developing a cost-effective security system has been an important issue in crime prevention. Although cameras have been known as an effective candidate for this purpose, they have some downside, such as difficulty in accurately estimating the three-dimensional shape of a target, and the exact distance to a target [1], [2]. Ultra-wideband (UWB) pulse radar is an alternative for resolving these problems of camera-based conventional systems. Although UWB radar imaging methods such as SAR (synthetic aperture radar) or other migration methods estimate target shape using simple and stable processes, the methods are not suitable for surveillance systems because the accuracy of shape estimation is of a wavelength order and is time-consuming for estimation [3], [4]. SEABED (Shape Estimation Algorithm based on BST and Extraction of Directly scattered waves) is known as a fast and highly accurate imaging algorithm for UWB pulse radar [5], [6]. SEABED assumes a system with a scanning antenna or with array antennas and fixed targets. This costly type of system is, however, unrealistic for commercial applications such as surveillance systems. To overcome this problem, we proposed a new UWB radar imaging algorithm using the motion of targets instead of a scanning antenna [7-9]. This method has been improved to produce an accurate image of a target with arbitrary motion using three fixed antennas [10]. Numerical simulation showed the accuracy of estimating target shape using the proposed method is dependent on target shape and antenna interval between each antenna, and clarified that the proposed method is effective for accurately estimating target shape to the order of mm under noisy environment [11]. However, an experiment in an actual situation has not been performed yet. This study applies the proposed UWB radar imaging method to experimental data and clarifies that the method accurately estimates shape of a target moving arbitrary even in a real environment.