Development of an Ir-Uwb Radar System for High-Resolution Through-Wall Imaging

Abstract

Through-Wall-Imaging (TWI) radar offers considerable advantages for applications that require safety and security, such as disaster survivor rescue and tracking terrorist activities. In such situations, the use of an impulse UWB radar system is constantly increasing due to its ability to provide precise images of hidden targets in a short period of time. This paper presents a new radar system for through-wall imaging using an impulse-radio ultra-wideband (IR-UWB) signal. The radar system is built using a field-programmable gate array (FPGA) board, an oscilloscope, and Vivaldi antennas. The radar system transmits impulse signals, which have a monocycle shape with a 400-picosecond duration and a 4.6 GHz bandwidth. The FPGA board is used to produce impulse signals that have a short time duration in the sub-nanosecond range in order to expand the bandwidth of the generated signal and make the developed radar capable of providing high-resolution images. The FPGA-based implementation of the IR-UWB generator offers the flexibility to modify the spectrum characteristics of the generated signal. The receiver side of the radar system collects the echoes using the principle of synthetic aperture radar (SAR), and then the time-domain back-projection algorithm is applied to the radar echo to form 2D images. An indoor imaging experiment was carried out with two human targets to investigate the imaging capability of the designed IR-UWB radar. The obtained experimental results demonstrate that this radar has the potential to deliver high-resolution images of multiple human targets and identify their locations.

Ultra‐wideband imaging with an improved backward projection algorithm for far‐field applications

“…[10][11][12] Considering the required portable property of our application, a stepper radar is used to achieve the desired imaging performance. [13][14][15] The antenna plays an important role in transmitting and receiving signals in an imaging system. The Vivaldi antenna, also known as the tapered slot antenna (TSA), consists of solid sheet metal and a printed circuit board.…”

“…UWB through‐wall SAR systems based on a vector network analyzer (VNA) are a type of step frequency continuous waveform (SFCW) radar to provide high‐resolution detection and imaging of multiple objects behind a wall 10–12 . Considering the required portable property of our application, a stepper radar is used to achieve the desired imaging performance 13–15 …”

Research on Perspective Imaging Method of Building Structure Based on Multipath Information

“…W ith the development of electronic information technology, electromagnetic perspective has been a relatively active and novel topic since it was proposed to determine the environmental structure information of buildings and green belts in the area by the propagation law of electromagnetic waves in different areas, which has a large demand not only in anti-terrorism and rescue, but also increasingly in the civil field and disaster relief [1]. In counter-terrorism operations and urban combat, if we can obtain the location of terrorists and the internal structure information of buildings in advance, it will help our combatants in their actions; in the case of sudden disasters, obtaining the location of victims and the damage of buildings can reasonably arrange rescuers for rescue, thus maximizing the safety of people's lives.…”

An efficient FPGA‐based implementation of UWB radar system for through‐wall imaging

“…The structure of these experiments requires adequate components to enable the radar to perform UWB transmission and reception operations, such as RF components and UWB antennas. Additionally, to process the UWB signal, the radar needs heavy and costly equipment such as a high-sampling oscilloscope, 11,12 or a vector network analyzer (VNA). 10 These experimental setups can successfully deliver the images of objects behind a wall under different scenarios.…”

“…However, they are unable to satisfy the demands of current through‐wall imaging radars in terms of autonomy, portability, and low cost, and more importantly, they cannot support real‐time processing. In the context of UWB through‐wall imaging, the most commonly used radar structures in the literature employ frequency‐domain signals such as step frequency continuous wave (SFCW), 10 frequency modulated continuous wave (FMCW), 13 or employ time‐domain signals like impulse‐radio ultra‐wideband (IR‐UWB), 9,11,12,14 and noise signals 15 . Typically, the CW radar system has a simple structure and good target detection capability 2,16 .…”