Conference Paper

See-Through-Wall Imaging using Ultra Wideband Pulse Systems.

Dept. of Mech., Aerosp., & Biomed. Eng., Tennessee Univ., Knoxville, TN, USA
DOI: 10.1109/AIPR.2005.40 Conference: 34th Applied Image Pattern Recognition Workshop (AIPR 2005), 19-21 October 2005, Washington, DC, USA, Proceedings
Source: DBLP


Surveillance/navigation systems presently used make extensive use of television, infrared, and other line-of-sight-surveillance hardware. However, these systems cannot tell what is happening or locate persons/assets on the other side of a wall, behind bushes, in the dark, in a tunnel or a cave, or through a dense fog. It is our objective here to develop a new sensor, based on UWB technology. A small, lightweight, low power transceiver or multiples that are based upon the fact that microwave frequencies can be optimized to penetrate nonmetallic materials, and providing very precise ranging information. This new surveillance/navigation capability can help provide information about what is in a wall or on the other side of a door, and can be extended to provide precise global position in areas where these services are denied such as in tunnels or caves. This paper presents our efforts along these lines including image enhancements.

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Available from: Ahmed Badawi
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    • "assets tracking [4], [5]. Its feature of high resolution can be utilized in UWB radars to achieve high accuracy in ranging and precise 3-D positioning [6], [2]. These UWB systems use very narrow pulses, rendering the pulse's retrieval in receivers as one of the system operation's bottlenecks. "
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    ABSTRACT: Step recovery diode (SRD)-based ultra-wide band (UWB) pulse generators (PGs) suffer from jitter caused by AM-to-PM conversion, SRD shot noise, and clock jitter. These noise sources significantly impact the accuracy of UWB systems if very high precision ranging/positioning is required. Jitter behavior caused by the transmitter and receiver is mostly detrimental in the equivalent time-sampling receiver. Thus, a mathematical model for simulation of the jitter and amplitude variation effect in the equivalent time-sampling technique has been developed and used in SystemVue simulations. A criterion as an estimate of system accuracy is defined as signal-to-distortion ratio (SDR) and used. Similarly, a model for AM and PM noise analysis for an SRD-based UWB PG is developed that was validated experimentally. In addition, SRD shot-noise contribution on output jitter was evaluated using the proposed model. Based on these models, methods to reduce the output jitter of the system have been recommended. Simulation showed that clock jitter and SRD shot noise led to pronounced output jitter, with shot noise the primary cause. For a typical SRD-based UWB PG, an output jitter of around 3 ps has been achieved using improvement techniques based on the proposed method, compared to a 15-ps jitter before improvement. These measured results are in good agreement with our predictions.
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    • "High-resolution imaging through obstacles such as walls, doors, and other visually opaque materials using microwave signals is considered a powerful tool in both military and commercial applications including the rapid detection of human maneuvering, rescue missions in avalanches or collapsed buildings, target feature extraction, and surveillance and reconnaissance . While narrowband Doppler radar in the millimeterwave or infrared spectrum has been shown to provide good resolution through clothing and packaging [1], penetration through denser materials like fiberglass, wood, sheetrock, plaster, brick, and concrete blocks requires operation below 10 GHz [2], [3]; this band however yields poor resolution, limiting application. Ultra-Wideband (UWB) signals are characterized by a bandwidth greater than 500 MHz or one exceeding 20% the center frequency of radiation [4]. "
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    ABSTRACT: High-resolution imaging through walls and other materials using microwave signals serves amongst other applications in the rapid detection of human maneuvering, rescue missions in collapsed buildings, and target feature extraction. While narrowband Doppler radar in the millimeter-wave or infrared spectrum can provide good resolution through clothing and packaging, penetration through denser sheetrock, plaster, and brick requires operation below 10 GHz; this band however yields poor resolution. As an alternative, Ultra-Wideband radar operating in this band boosts the bandwidth which translates into fine range resolution; still it requires an aperture length of several meters for comparable cross-range resolution. The associated cost and portability in realizing such an aperture through antenna arrays or fixed-length scanners have limited their lengths to the order of 1 meter in prototype systems to date. In this work, we propose a novel aperture taking form as a variable-length scanner or mobile robot. The wide dynamic range of our system coupled with its unrestricted aperture length allows us to generate high-resolution images up to a range of 8 meters or more.
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