In this paper we describe the use of a horizontally polarised Ultra-Wideband imaging radar to detect metal tripwires. A limited set of experimental measurements was processed using a wire detection algorithm designed to discriminate wires from clutter. A common threshold applied to the algorithm output successfully discriminated wires deployed at four orientations. Three independently measured cases rendered consistent results when processed using the same algorithm. These results suggest that further development is warranted to establish the performance on a statistical basis.
QinetiQ is developing a hand held Multi-sensor mine detector prototype for humanitarian applications. The sensor consists of a GPR, a metal detector and ancillary sensors. This paper describes how data produced by ancillary sensors can be exploited in order to assist the GPR processing. The GPR consists of a 3x3 array of antennas, and focused images of the volume beneath the sensor are formed by post reception synthetic aperture processing. The mine detector is intended to detect sub surface targets, and an accurate knowledge of the ground surface position relative to the sensor is required. Also the high frequency dielectric constant of the ground medium is required in order to produce focused images. This paper analyses the requirements for good post reception synthetic aperture processing. The accuracy of the ground surface position data and the dielectric constant estimation are determined. A model for soil dielectric constant is used to derive the sensitivity of post reception synthetic aperture processing to unknown soil texture. It is show that for the GPR configuration considered, a wide range of texture variations is tolerable provided the soil moisture can be accurately estimated. Variations in soil composition are also tolerable.
At present the most effective mechanical aids for the post conflict hand clearance of anti-personnel mines are metal detectors and probes. These are effective against the majority of current mine threats but clearance rates are limited because of the high incidence of false targets in post conflict areas. Such false targets must be exposed and removed with the same care required for handling genuine ordnance. Clearance rates would be substantially improved if false targets detected by metal detectors could be distinguished from mine threats and thus left in place. One possible approach to the problem of differentiating between metal fragments and anti-personnel land mines is the use of multiple sensors. In this paper we discuss the design of a GPR for such a multi-sensor detector head. One of the challenges for combined metal detectors and GPR is the design of the GPR antenna so that it can operate effectively in the presence of metal detector coils. For a practicable device the GPR antennas must operate with the metal detector coils in their near field and coupling between sensors is of primary importance. The antennas must also be designed so that their influence on the metal detector's sensitivity is minimized. In this paper we present one solution for this problem and present experimental results showing the how the proposed GPR design operates in the presence of metal detector coils and in the presence of a resistive transducer located below the antenna array. The GPR concerned uses a 3x3 antenna array and post reception synthetic aperture processing to provide a 3d image of the ground underneath the sensor. Focussed images of various targets are presented, and images to demonstrate the effects of the other sensors on the GPR are shown.
This paper presents the current program of activities of the Defence Evaluation and Research Agency in the area of Airborne Minefield Detection. An overview of the program status is given along with result obtained from sensor trials.
The Technical Cooperation Program subgroup K Action Group 23 is engaged in collaborative ultra-wideband (UWB) radar land mien detection experiments using instruments located in Australia, Canada, the UK and the US. In order to compare results, it is essential to develop standard characterization techniques to provide an improved basis for comparison of data and radar techniques. This paper discusses some suggested standard soil characterization techniques and standardized targets for UWB GPR mine detection experiments. For land mine detection using ground penetrating radar, it is the electrical characterization of soil over the relevant frequency range that is important. Some results of analysis of soil from test sites are given and discussed. Standardized targets are needed to allow reliable comparison of independently conducted experiments. Surrogate targets for this purpose need to be safely handled and deployed, sufficiently realistic to allow estimation of mine detection performance, and easily transported across national boundaries. It is desirable to have simple targets to allow comparison of numerical models with experiment. The design of a limited target set is discussed and sample signature measurements are presented in this and companion papers.
This paper describes the cumulative status-to-date, and current developments in the British Aerospace IR scene projector system technology in early 1997. The systems have been developed for Hardware-in-the-loop simulation in missile test and evaluation facilities. Historically, the technology has been called `Thermal Picture Synthesis' an early equivalent of what is now known as Infra-red Scene Projection. Earlier generations of system were based on a monolithic resistor-substrate construction, a modification of which is still used for ground target simulations (TPS3), whereas the more recent systems for air target simulations are based on fully suspended resistor designs (TPS4). These projector systems incorporating full scale arrays have been fabricated at up to 256 X 256 complexity. Research work is being carried out on high temperature arrays for air-to- air countermeasure simulations, and the first TPS5 full system at 512 X 512 complexity has completed its design stage and has recently moved into fabrication. Research testbed arrays of 768 X 768 have just been made, and 1024 X 1024 arrays are presently being fabricated. The paper includes an initial introduction to the basics of the technology, and is followed by a section on certain specialized features to combat inherent issues in the technology. Specifications and the current status of each category of device is then given.
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