Article

Multisensor vehicle-mounted teleoperated mine detector with data fusion

Authors:
  • McFysics Consulting
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

The Improved Landmine Detector Project (ILDP) was initiated in Autumn 1994 to develop a prototype teleoperated vehicle mounted mine detector for low metal content and nonmetallic mines to meet the Canadian requirements for rear area mine clearance in combat situations and peacekeeping on roads and tracks. The relatively relaxed requirements, such as low speed and reduced detectability of completely nonmetallic mines, greatly increase the likelihood of success. The ILDP system consists of a unique teleoperated vehicle carrying a forward looking infrared imager, a 3 m wide down-looking highly sensitive electromagnetic induction detector and a 3 m wide down-looking ground probing radar, which all scan the ground in front of the vehicle. Scanning sensor information is combined using a suite of navigation sensors and custom designed navigation, spatial correspondence and data fusion algorithms. Suspect targets are then confirmed by a thermal neutron analysis detector. A key element to the success of the system is the combination of sensor information. This requires coordinated communication between the sensors and navigation system and well designed sensor co-registration, spatial correspondence and data fusion methodologies. These complex tasks are discussed in detail. The advanced development model was completed in October 1997 and testing and improvements are ongoing. Results of system performance during extensive field trials are presented. A follow-on project has been initiated to build four to six production units for the Canadian Forces by the year 2000.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Active systems of various designs (e.g., impulse, continuous wave (CW), frequency modulated continuous wave (FM-CW), step frequency, separated aperture or waveguide beyond cutoff, balanced bridge and so on) have been developed over more than three decades for the detection of buried landmines. Although these systems can detect buried antitank nonmetallic landmines under certain conditions and form a part of some multisensor military systems [12], the detection of antipersonnel landmines under realistic conditions continues to be one of the most difficult problems for this technology and no operationally satisfactory system exists. Soil inhomogeneity, low target contrast, uneven soil surface, vegetation and nuisance targets, such as rocks, are some of the basic problems. ...
... The cause of the radiation change is the alteration of the heat flow by the landmine and disturbed soil and the change in surface emissivity of the disturbed soil. Infrared imagers of sufficient temperature resolution (∼ 0.1 @BULLET C) and spatial resolution to detect the anomalies due to a landmine are commercially available and are used in some multisensor military systems [12]. Soil parameters relevant to the operation of IR systems include thermal resistivity, thermal diffusivity and specific heat capacity, all of which are expected to depend on soil moisture content. ...
... Thermal Neutron Activation (TNA) is based on detecting γ-rays characteristic of 14 N . While X-ray Backscatter and Neutron Moderation techniques are at a research stage, a vehicle-mounted TNA device is already a part of a fielded military system [12]. Soil properties of relevance to X-ray Backscatter will include effective atomic number, weight, and mass density. ...
Article
Full-text available
Landmines are buried typically in the top 30 cm of soil. A number of physical, chemical and electromagnetic properties of this near-surface layer of ground will potentially affect the wide range of technologies under development worldwide for landmine detection and neutralization. Although standard soil survey information, as related to conventional soil classification, is directed toward agricultural and environmental applications, little or no information seems to exist in a form that is directly useful to humanitarian demining and the related R&D community. Thus, there is a general need for an information database devoted specifically to relevant soil properties, their geographic distribution and climate-driven variability. A brief description of the various detection technologies is used to introduce the full range of related soil properties. Following a general description of the need to establish a comprehensive soil property database, the discussion is then narrowed to soil properties affecting electromagnetic induction metal detectors - a problem of much restricted scope but of immediate and direct relevance to humanitarian demining. In particular, the complex magnetic susceptibility and, to a lesser degree, electrical conductivity of the host soil influence the performance of these widely used tools, and in the extreme instance, can render detectors unusable. A database comprising these properties for soils of landmine-affected countries would assist in predicting local detector performance, planning demining operations, designing and developing improved detectors and establishing realistic and representative test-evaluation facilities. The status of efforts made towards developing a database involving soil electromagnetic properties is reported.
... ILDS was a teleoperated, vehicle-mounted, multi-sensor anti-tank (AT) landmine detector manufactured by General Dynamics Canada (GDC), based on DRDC's original design and prototype. It was designed to meet the Canadian Forces requirement for rear area landmine clearance in combat situations and peacekeeping on roads and tracks [3,4]. The system consists of three different rapid sensors, which scan the ground in front of the vehicle. ...
... Data acquisition system schematic used to acquire time spectra at selectable energy windows.3 Saint Gobain, France.4 Photonis, France. ...
Article
A commercialized thermal neutron analysis (TNA) sensor has been developed to confirm the presence of buried bulk explosives as part of a multi-sensor anti-tank landmine detection system. Continuing improvements to the TNA system have included the use of an electronic pulsed neutron generator that offers the possibility of applying fast neutron analysis (FNA) methods to improve the system's detection capability. This paper describes an investigation into the use of FNA as a complementary component in such a TNA system. The results of a modeling study using simple geometries and a full model of the TNA sensor head are presented, as well as preliminary results from an experimental associated particle imaging (API) system that supports the modeling study results. The investigation has concluded that the pulsed beam FNA approach would not improve the detection performance of a TNA system for landmine or buried IED detection in a confirmation role, and could not be made into a practical stand-alone detection system for buried anti-tank landmines. Detection of buried landmines and IEDs by FNA remains a possibility, however, through the use of the API technique.
... The chief reason for the delay is that since the July 1997 experiment, there has been a substantial diversion of e ort toward the high priority development of a teleoperated, vehicle mounted, multisensor landmine detector under the Improved Landmine Detector Project ILDP. 10 at studying its role in ILDP, and additional e ort at DRES was expended in subsequent competitive trialing of ILDP in the U.S. Ground-based Stando Mine Detector System GSTAMIDS trials of Summer 1998. Most of the preliminary analysis has been done on the 15 cm resolution spectral mode imagery. ...
... For the long term, investigations continue on determining the feasibility of employing a casi as a forward looking imager in ILDP or its associated protection vehicle. 10 As a part of this, a mirror stabilization system is being developed and real-time processing of the data is being implemented. Spatial spectral algorithms which pro t from the large number of pixels subtended by a mine are also under development. ...
Article
Full-text available
The feasibility of detecting surface-laid and, in some circumstances, buried mines by analysis of visible to near-infrared VNIR hyperspectral imagery has been demonstrated by the authors in previous studies. An important factor in the practical success of such technology is being able to achieve the necessary spatial and spectral resolution to allow discrimination of mines from background. With some restrictions, both can be improved by increasing the instrument data output rate or decreasing the platform speed and both can be traded oo against one another. The optimum trade-oo must be determined for a given problem, including the choice of algorithm. Airborne VNIR hyperspectral data were collected over several controlled surface-laid mine elds using a casi hyperspectral imager and a helicopter. The combination of the imager's high speed data recording coupled with the low airspeed of the helicopter enabled the collection of hyperspectral data ranging from four 136 nm wide spectral bands at 10 cm resolution to nine 60 nm wide spectral bands at 20 cm resolution. Each mine eld contained a variety of mines ranging from small anti-personnel mines to large anti-vehicle mines. An assessment of the feasibility and practicality of using airborne hyperspectral data to detect various surface-laid mines and mine elds was conducted. In addition, the trade-oos between spectral and spatial resolution for the detectability of surface-laid mines and mine elds are discussed.
... Lateral migration X-ray backscatter imaging [5] and thermal neutron activation (TNA) are among the most promising for vehicle mounted applications and are still being actively investigated. The only known nuclear-based land mine detector that is commercially available is a production version of a Californium-based thermal neutron activation detector [6,7] developed as a confirmation sensor for the Canadian Improved Landmine Detection System (ILDS), a vehiclemounted , multisensor, land mine detector system [8]. A prototype neutron generator-based version is now undergoing testing [9]. ...
... At a workshop in 1985 to identify nuclear techniques suitable for land mine detection [3], experts placed neutron moderation among the top three techniques, after X-ray backscatter imaging and thermal neutron capture gamma rays (TNA). In spite of this, neutron moderation has not been very successful to date, while TNA is now a fielded confirmation detection technology for a vehicle-mounted system [6,7,8]. The reason for this is that natural variations in hydrogen content in the soil, chiefly due to water, and surface irregularities and detector height variations all effect the albedo contrast . ...
Article
Full-text available
Neutron moderation land mine detection involves irradiating the ground with fast neutrons and subsequently detecting the thermalized neutrons which return. This technique has been studied since the 1950s, but only using non-imaging detectors. Without imaging, natural variations in moisture content, surface irregularities, and sensor height variations produce sufficient false alarms to render the method impractical in all but the driest conditions. This paper describes research to design and build a prototype land mine detector based on neutron moderation imaging. After reviewing various neutron detector technologies, a design concept was developed. It consists of a novel thermal neutron imaging system, a unique neutron source to uniformly irradiate the underlying ground, and hardware and software for image generation and enhancement. A proof-of-principle imager has been built, but with a point source offset from the detector to roughly approximate a very weak uniform source at the detector plane. Imagery from the detector of mine surrogates is presented. Realistic Monte Carlo simulations were performed using the same two dimensional neutron imaging geometry as the detector in order to assess its performance. The target-to-background contrast was calculated for various soil types and moisture contents, explosive types and sizes, burial depths, detector standoffs, and ground height variations. The simulations showed that the neutron moderation imager is feasible as a land mine detector in a slow scanning or confirmation role and that image quality should be sufficient to significantly improve detector performance and reduce false alarm rates compared to non-imaging albedo detection, particularly in moist soils, where surface irregularities exist and when the sensor height is uncertain. Performance capability, including spatial resolution and detection times, was estimated.
... The vehicle has a constant velocity and relatively stable sensor to ground orientation so that the mine signatures from the EMI and GPR sensors are fairly consistent. As a result, feature-based techniques are useful in the vehicle-based mine detection system [7], [25]- [29]. ...
... In order to reduce the number of false alarms, several groups have investigated target identification, or discrimination, using EMI sensors [8]- [24], GPR sensors [2]- [7], [25], or other commonly-used sensors [1]- [7], [30]- [32]. Other research efforts include the development of novel sensor modalities [33]- [38] or sensor fusion [25]- [29]. In contrast to the vehicle-based systems, hand-held systems can operate in two distinct modes. ...
Article
Full-text available
Signal processing algorithms for hand-held mine detection sensors are described. The goals of the algorithms are to provide alarms to a human operator indicating the likelihood of the presence of a buried mine. Two modes of operations are considered: search mode and discrimination mode. Search mode generates an initial detection at a suspected location and discrimination mode confirms that the suspected location contains a land mine. Search mode requires that the signal processing algorithm generate a detection confidence value immediately at the current sample location and no delay in producing an alarm confidence is tolerable. Search mode detection has a high false-alarm rate. Discrimination mode allows the operator to interrogate the entire suspected location to eliminate false alarms. It does not require that the signal processing algorithm produce an alarm confidence immediately for the current sample location, but rather allows the system to process all the data acquired over the region before producing an alarm. This paper proposes discrimination mode processing algorithms for metal detectors (MDs), or electromagnetic induction sensors (EMIs), ground-penetrating radars (GPRs), and their fusion. The MD discrimination mode algorithm employs a model-based approach and uses the target model parameters to discriminate between mines and clutter objects. The GPR discrimination mode algorithm uses the consistency of detection as well as the shape of the detection peaks over several sweeps to improve the discrimination accuracy. The performances of the proposed algorithms were examined on a dataset collected at a government test site, and performance was compared with baseline techniques. Experimental results showed that the proposed method can reduce the probability of false alarm by as much as 70% at a 100% correct detection rate and performed comparable to the best human operator on a blind test with data collected at approximately 1000 locations.
... Wichmann/NIITEK GPR data after pre-processing[34] ...
... A single unit was constructed to be part of the original DRDC-designed POC vehicle-mounted mine detector system, then called ILDP. 2 The requirements imposed by the application had a significant impact on the design. Beyond the obvious constraints of size, mass and power consumption, the two most significant requirements were interrogation time and field of view (FOV). ...
Conference Paper
Defence R&D Canada - Suffield and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives since 1994. First generation sensors, employing an isotopic source and NaI(Tl) gamma ray detectors, were deployed by Canadian Forces in 2002 as confirmation sensors on the ILDS teleoperated, vehicle-mounted, multi-sensor anti-tank landmine detection systems. The first generation TNA could detect anti-tank mines buried 10 cm or less in no more than a minute, but deeper mines and those significantly displaced horizontally required considerably longer times. Mines as deep as 30 cm could be detected with long counting times (1000 s). The second generation TNA detector is being developed with a number of improvements aimed at increasing sensitivity and facilitating ease of operation. Among these are an electronic neutron generator to increase sensitivity for deeper and horizontally displaced explosives; LaBr3(Ce) scintillators, to improve time response and energy resolution; improved thermal and electronic stability; improved sensor head geometry to minimize spatial response nonuniformity; and more robust data processing. This improved sensitivity can translate to either decreased counting times, decreased minimum detectable explosive quantities, increased maximum sensor-to-target displacement, or a trade off among all three. Experiments to characterize the performance of the latest generation TNA in detecting buried landmines and IEDs hidden in culverts were conducted during 2011. This paper describes the second generation system. The experimental setup and methodology are detailed and preliminary comparisons between the performance of first and second generation systems are presented.
... A number of recent technology publications [e.g., McFee et al., 1998;Rotondo et al., 1998;Collins et al., 2000;MacDonald et al., 2003] have cited the limitations of individual sensors, and the fact that advances in mine and IED detection capability -specifically false alarm reduction -are most likely to occur through the development of multi-sensor systems. While the multi-sensor approach has shown promising results, our experience in the development and testing of the U.S. Army NEMESIS multisensor system highlights that the ultimate effectiveness of a multi-sensor system is determined, in large part, by the treatment of the individual sensor data. ...
Conference Paper
To safely and efficiently return foreign landmine or domestic UXO range areas to public use, ordnance clearance technology must reliably detect a wide variety of ordnance while minimizing the number of false alarms resulting from non‐ordnance items. Large variability in mines and other munitions of concern, target placement and orientation, as well as environmental and subsurface conditions challenge the development of robust target recognition software. While our multi‐sensor approach has shown promising results, we find that the ultimate effectiveness of the multi‐sensor system is determined, primarily, by the treatment of the individual sensor data. We present the analysis of stepped‐frequency ground penetrating radar and electromagnetic induction array data simultaneously acquired at government ordnance test facilities with the NEMESIS unmanned vehicle platform. Although our primary focus is on improved detection and discrimination of landmines, we also report the potential for NEMESIS to detect unexploded ordnance and other explosive remnants of war. We describe the application of a variety of and signal processing techniques to data acquired during field demonstrations in 2007. Emphasis is placed on the new environmental calibration and “on‐the‐fly” discrimination methods.
... These detectors are mainly based on the eddy-current principle. Mine detectors are usually hand-held devices, but detectors mounted on vehicles or Unmanned Vehicle Systems (UVS) can also be encountered [1]. Simple hand-held detectors for localization of small metal objects in small depths, such as AP (antipersonnel) mines, usually have audio outputs. ...
Article
Full-text available
Distinguishing of mines from scrap metal is a difficult task that provides challenge when seeking an ultimate solution. An eddy-current imaging feature added to standard handheld metal detector is an option for such discrimination. Our metal detector was enhanced by an inertial measurement unit aided by velocity information, measured by optic flow sensor. It lead to further improvement of the proposed procedure by means of position and orientation tracking. The achieved accuracy of mine signal localization is 1 cm in 1×1 m scanning area.
... This would require a minimum of modifications to the casi itself, but would lead to a choice of some design elements that would not be extendable to further increase speed later on. Such an instrument could still be very useful as an additional or replacement sensor on a teleoperated vehicle- mounted multi-sensor mine detector system such as ILDP ( McFee et al, 1998) or on the protection vehicle that precedes it. ...
Article
A ground vehicle-based, real-time, surface mine detection system, utilizing a Compact Airborne Spectrographic Image (casi), efficient mine detection algorithms, and real-time processing systems, was designed and tested. The combined real-time system was capable of 'learning' the in-situ spectra of various mines, thus providing a spectral library for the detection algorithms. The real-time processing of the casi data involved three steps. The first step was the radiometric correction of the raw data. The second step involved the application of the mine detection algorithms to the corrected data, referencing the spectral library. In the final step, the results of the real-time processes were stored and displayed, usually within a few frame times of the data acquisition. To the authors knowledge, this system represents the first hyperspectral imager to detect mines in real-time. This paper describes the generation of the in-situ mine spectral library, the collection of the scene data, the real-time processing of the scene data and the subsequent display and recording of the detection data. The limitation and expansion capabilities of the real-time system are discussed as well as various techniques that were implemented to achieve the goals. Planned future improvements that have been identified to create a more robust and higher performance, yet simpler processing systems are also discussed.
... This multimode or multisensor approach, when combined with appropriate data fusion, is widely recognized as having a much higher likelihood of success for mine or mine eld detection than single sensors alone. 2 For example, passive and active illumination can be accommodated by pulsing the source and polarizers can be inserted or removed. Illumination wavelengths should be chosen to maximize the contrast between tripwires and backgrounds. ...
Article
Full-text available
Research to assess the feasibility of developing a standoo active or passive optical tripwire detector is discussed. Reeectivities of typical tripwires and background materials were measured for UV, VNIR and SWIR wavelengths. A breadboard testbed was developed to obtain images of tripwires against various backgrounds for various geometries and a wide range of UV and VNIR wavelengths. Sample images of simulated and real tripwires in uncluttered environments and against typical cluttered backgrounds were acquired and analyzed. Line detection algorithms were applied to the images to detect tripwires. Although detection was not attempted in real-time, analysis showed that available, cost-eeective DSPs could potentially execute those algorithms on the images in real-time. The algorithms successfully detected tripwires in a heavily cluttered background and even have the capability to detect partially obscured wires. To complement the measurements, a spreadsheet model was developed to evaluate the merits of diierent detectors, sources of illumination, wavebands and geometries for diierent scenarios. Acceptable signal-to-clutter ratios were found for a number of reasonable passive and active illumination scenarios. The study demonstrated that an optical tripwire detector is feasible in principle.
... There are few commercial TNA sensors designed for landmine detection. One is a part of the Improved Landmine Detector System (ILDS), a teleoperated, vehicle-mounted, multisensor landmine detector [4], [5] ( Fig. 1). Four are in service with the Canadian Forces for rear area landmine clearance in combat situations and peacekeeping on roads and tracks. ...
Article
Full-text available
The Improved Landmine Detector System, a militarily fielded, teleoperated vehicle-mounted multi-sensor landmine detector, uses a thermal neutron analysis (TNA) detector to confirm the presence of a mine by detecting the bulk nitrogen in its explosives. To improve the nitrogen sensitivity or measurement times of the TNA detector, higher gamma ray rates will be required. The chief bottleneck to achieving the maximum possible performance from the present TNA or future versions is the relatively slow fluorescent decay time of the NaI(Tl) scintillators which are currently used. An experimental investigation was undertaken to compare a number of modern, fast inorganic scintillators to NaI(Tl) with respect to parameters relevant to TNA landmine detection, including efficiency, energy resolution, linearity, available size and cost. This paper presents results in the context of the high-rate, high-gamma-energy environments expected in such a TNA application. Large (7.62 cm times 7.62 cm) LaBr3:Ce scintillators, and to a lesser degree LaCl3:Ce, were found to stand-out as as the principal candidates for the detector upgrade to the TNA confirmation system. Their properties also make them ideal candidates for fast neutron analysis and associated particle imaging bulk explosives detectors.
... Moreover, the low detection limits obtained by nuclear-based methods are generally well within the requirements of the present application. Thermal neutron and fast neutron analysis have been proposed for landmine detection Lunardon et al., 2004;McFee et al., 1998;Cousins et al., 1998;Kuznetsov et al., 2004;Vourvopoulos and Womble, 2001) looking at the characteristic gamma-rays produced by neutrons. However, one of the major limitations in the use of such sensors is represented by their weight and size that makes them usable only in vehiclemounted systems, with a specific limited impact on the humanitarian de-mining operations (Viesti et al., 2006). ...
Article
Experiments were carried out to optimize the performance of the neutron back-scattering (NBS) technique in landmine detection using an assembly consisting of three different layers placed above a (252)Cf neuron source, producing about 10(4)s(-1), in conjunction with a (3)He detector. The assembly was optimized experimentally. The selected assembly configuration was then examined against different (252)Cf stand-off distances and mine burial depths using dummy landmines. Furthermore, Monte Carlo simulations were performed to study the effect of the shield when a (252)Cf source in the range 10(4)-10(7)s(-1) was employed, and to optimize the geometry for future prototypes.
... The Improved Landmine Detector System (ILDS) is a teleoperated, vehicle-mounted, multisensor landmine detector. It is based on Defence R&D Canada's (DRDC) concept, original design and prototype [1]. Four are in service with the Canadian Forces for rear area mine clearance in combat situations and peacekeeping on roads and tracks. ...
Conference Paper
Full-text available
The improved landmine detector system is a vehicle-mounted multi-sensor landmine detector which uses a thermal neutron activation (TNA) detector to confirm the presence of a mine by detecting the bulk nitrogen in its explosives. The input count rate to the TNA is very high and count rates of future systems could be an order of magnitude higher, allowing correspondingly higher sensitivity or shorter detection times for land mines. The chief bottleneck to achieving the maximum possible performance from the present TNA or a future system is the relatively slow fluorescent decay time of the NaI(Tl) scintillators which are currently used. This paper presents preliminary results from an experimental study into various fast scintillators as potential detector upgrades to the TNA confirmation detector, A number of fast, inorganic scintillators are compared with NaI(Tl) with respect to efficiency, energy resolution, available size and cost in the present application.
... While surface emplaced antitank mines and mines with significant metal content were easily detected, buried plastic mines were found to be challenging. Development and testing of a vehicle-mounted multisensor demining platform that uses EMI, GPR, and IR for detection and a TNA sensor for target confirmation is underway at the Canadian Defence Research Establishment [10]. Gunatilaka and Baertlein [11] compared predetection (feature-level) and postdetection (hard and soft decision-level) fusion of EMI, GPR, and IR data. ...
Article
We present and compare methods for feature-level (predetection) and decision-level (postdetection) fusion of multisensor data. This study emphasizes fusion techniques that are suitable for noncommensurate data sampled at noncoincident points. Decision-level fusion is most convenient for such data, but it is suboptimal in principle, since targets not detected by all sensors will not obtain the full benefits of fusion. A novel algorithm for feature-level fusion of noncommensurate, noncoincidently sampled data is described, in which a model is fitted to the sensor data and the model parameters are used as features. Formulations for both feature-level and decision-level fusion are described, along with some practical simplifications. A closed-form expression is available for feature-level fusion of normally distributed data and this expression is used with simulated data to study requirements for sample position accuracy in multisensor data. The performance of feature-level and decision-level fusion algorithms are compared for experimental data acquired by a metal detector, a ground-penetrating radar, and an infrared camera at a challenging test site containing surrogate mines. It is found that fusion of binary decisions does not perform significantly better than the best available sensor. The performance of feature-level fusion is significantly better than the individual sensors, as is decision-level fusion when detection confidence information is also available (“soft-decision” fusion)
Article
Starting in 1990, the Defence Research Establishment Suffield began to investigate combining key landmine detection capabilities with robotics technologies to effect a landmine detection system which would remove soldiers from the danger and tedium of landmine detection. The resulting solution was a tele-operated (strict master/slave) robotic vehicle combined with a multi-sensor detection array of sensors specifically chosen for their ability to detect the properties of low metal content and non-metallic anti-tank landmines on roads and tracks. The focus of this paper is to 1) describe how telematics have been applied in this tele-operated landmine detection system, 2) provide a functional description of the robotic tele-operation control system and 3) speculate on the addition of complementary control technologies to make such systems more autonomous.
Chapter
The mine warfare in the 20th century has a history of near hundred years, related with countless military conflicts all over the world. As it is documented, the first systematic and large-scale application of mines took place during the siege of the Russian Army by Japanese at Port Arthur and Mukden in 1904. There the protection of Russian trenched positions by minefields with electric ignition was responsible for the major part of the near 120,000 casualties from the Japanese side [48].
Chapter
If a plant has a model in the form of a Takagi-Sugeno (T-S) fuzzy system that interpolates linear dynamic systems, which we call the plant fuzzy system, one approach to stabilizing it is called parallel distributed control (PDC). The rules of the plant fuzzy system have consequents that are dynamic linear systems in continuous- or discrete- time normal state space form, or linear input-output difference equation form. If the plant fuzzy system consists of plants described by normal form state equations, the controller fuzzy system's consequents are linear state feedback laws. This type of PDC results in nonlinear state regulation. Regulation is guaranteed if the feedback law satisfies a series of linear matrix inequalities (LMI). If the plant fuzzy system consists of plants described by input-output difference equations, the controller fuzzy system consequents can be either tracking control laws or model reference control laws. continuous time systems; discrete time systems; fuzzy systems
Conference Paper
Bulk explosives hidden in culverts pose a serious threat to the Canadian and allied armies. Culverts provide an opportunity to conceal insurgent activity, avoid the need for detectable surface disturbances, and limit the applicability of conventional sub-surface sensing techniques. Further, in spite of the large masses of explosives that can be employed, the large sensor{target separation makes detection of the bulk explosive content challeng- ing. Defence R&D Canada { Sueld and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives for over 15 years. The next generation TNA sensor, known as TNA2, incorporates a number of improvements that allow for increased sensor-to-target dis- tances, making it potentially feasible to detect large improvised explosive devices (IEDs) in culverts using TNA. Experiments to determine the ability of TNA2 to detect improvised explosive devices in culverts are described, and the resulting signal levels observed for relevant quantities of explosives are presented. Observations conrm that bulk explosives detection using TNA against a culvert-IED is possible, with large charges posing a detection challenge at least as dicult as that of a deeply buried anti-tank landmine. Because of the prototype nature of the TNA sensor used, it is not yet possible to make denitive statements about the absolute sensitivity or detection time. Further investigation is warranted.
Article
While the United Nations UN) agencies work to restrict the manufacture, sale, and use of land-mines worldwide, a massive clean-up effort is needed to find and destroy the estimated 100 million land-mines still buried around the world. Land-mines left behind from wars worldwide are one of the past century's main unsolved problems of war and remain the focus of humanitarian land-mine detection and removal primarily in Europe, Africa, Asia and Central and South America. For example, approximately 1 million anti-personnel mines and other various kinds which have been buried in the 249.4 km (155 miles) demilitarized zone (DMZ) of the Korean peninsular should be completely removed in historical process of the peaceful unification between South and North Korea. In this regard, the current trends of technologies linked to land-mine detection systems are surveyed.
Article
There are currently no fielded technologies for noncontact detection of tripwires. Itres Research Ltd. and DRDC Suffield have been conducting research on optical detection of tripwires since 1996, both for hand-held and vehicle-mounted roles. A proof-of-concept brassboard imager, initially for a vehicle-mounted role, has been constructed. The imager uses a high spatial resolution, panchromatic focal plane array whose high degree of integration includes on-board digitization and flexible addressing capabilities for windowing and subimaging. Command, control and signal processing are accomplished by a computer, based on dual 1GHz Pentium III processors. Using a high level, rapid prototyping language, 1 image frame can be processed in 3 seconds. Straightforward improvements should allow true real-time operation to be achieved. Preliminary testing of the imager was conducted in the outdoor DRDC Suffield Mine Pen in January 2003. Taut, sagging and undulating tripwires of various materials were partially hidden, often nearly invisible to the naked eye, in a number of types of local vegetation. Preliminary, quasi-real-time results showed that many of the wires were detected, although a significant number of false alarms occurred. As expected with the present algorithm, sagging, undulating and highly obscured wires were often difficult to detect. The instrument, results of the trial, planned improvements and future research will be discussed.
Article
The Improved Landmine Detector System is a vehicle-mounted multi-sensor landmine detector, conceived and developed by Defence R&D Canada (DRDC). Suspicious targets are identified by fusing data from scanning sensors. A Thermal Neutron Activation (TNA) detector, developed by DRDC and Bubble Technology Industries (BTI), then confirms the presence of a mine by detecting the bulk nitrogen in its explosives. While the first generation TNA detector has been fielded by the Canadian Forces, DRDC and BTI have continued development and optimization of a second generation TNA sensor based around an electronic neutron generator source. By implementing faster detectors, faster electronics and more intense neutron sources, it is possible that this system could achieve 10 to 15 times higher rates, allowing correspondingly higher sensitivity or shorter detection times for landmines. The chief bottleneck to achieving the maximum possible performance from the present TNA or a future system is the relatively slow fluorescent decay time of the NaI(Tl) scintillators which are currently used. An experimental investigation was undertaken to compare a number of modern, fast inorganic scintillators to NaI(Tl) with respect to parameters relevant to TNA, including efficiency, energy resolution, linearity, available size and cost. This paper presents results in the context of the high-rate, high-gamma-energy environments expected in a TNA application. Large (7.62 cm × 7.62 cm) LaBr3:Ce scintillators, and to a lesser degree LaCl3:Ce, were found to stand-out as as the principal candidates for the detector upgrade to the TNA confirmation system. Their properties also make them ideal candidates for fast neutron activation and associated particle imaging bulk explosives detectors.
Article
Full-text available
Compact, cost-efficient and high-resolution imaging sensors are especially desirable in the field of short-range observation and surveillance. Such sensors are of great value in fields of security, rescue and medical applications. Systems can be formed for various practical purposes, such as detecting concealed weapons in public places, locating people inside buildings or beneath rubbles during emergency rescue, detecting landmine with small vehicle-based systems, and finding early-stage lesions inside human bodies. The advantage of such systems is that imaging can be achieved in real-time, which allows for safer and more effective operation as well as intelligence gathering. In order to observe moving targets, the system must operate quickly enough to generate a focused real-time 3-D image. Cost efficiency is another factor to consider for market reasons. Existing systems based on synthetic aperture radar (SAR) technology or array with sequential operation of identical transceiver pairs are costly, thus commercially difficult to be widely deployed. Their drawbacks are obvious when compared with compact, lightweight and high-resolution imaging systems which can provide real-time perception of the target. The combination of ultra-wideband (UWB) technology and real-aperture multiple-input multiple-output (MIMO) array offers a novel and practical solution for safe, reliable and cost-efficient imaging sensors with high resolution capability. UWB impulse with high fractional bandwidth controls the appearance of grating lobes caused by the sparsity of the array; while asymmetric transmit and receive arrays further reduce the number of required antenna elements within the array aperture. Compared to the conventional SAR systems, the combined advantages of UWB technology and MIMO technique can drastically reduce element density, data-acquisition time and the system costs. The development of UWB-MIMO array and related imaging algorithms is an important and novel research subject. The International Research Centre for Telecommunications and Radar (IRCTR) of Delft University of Technology has initiated several projects with the purpose to develop high performance array-based UWB imaging systems for different short-range applications. Under this framework, my research has achieved the following novelties and main results which are elaborated in the thesis: Properties of UWB focusing. A novel theory of ultra-wideband focusing is proposed, which has corrected the previous misunderstanding of the impact of bandwidth on imaging. The proposed theory shows that sparsity only ensures the existence of a grating lobe free region within the image space rather than the complete absence of grating lobes. Instead, the bandwidth relative to the center frequency, or fractional bandwidth, has deterministic impact on the formation of grating lobes. Specifically, the bandwidth of an imaging system must exceed its central frequency in order to benefit from the merit of wideband impulse properties, allowing high-resolution imaging with significantly reduced number of antenna elements. The proposed theory helps to resolve the dilemma between angular resolution and grating lobe level for a sparse aperture/array. MIMO array topology design. Novel design approaches for one-dimensional and two-dimensional MIMO arrays have been proposed. They allow direct formation of array topologies without the need of numerical optimization. The designed arrays following the proposed strategies are able to provide three-dimensional imaging capabilities and low grating/side lobe level with large element spacing and minimum number of antenna elements. Combination of UWB technology and MIMO array technique. It is demonstrated that the combination of UWB and MIMO array is a beneficial concept for microwave imaging systems. The MIMO array-based UWB imaging system is able to provide high down- and cross-range resolution, low side/grating lobe level, simplified RF scheme and significantly increased data acquisition speed. A procedure for designing UWB-MIMO array for short-range imaging has been formulated. The process translates requirements from the application into specific array specifications, such as operational frequency band, number of elements needed, aperture dimension, and array topology. Modified Kirchhoff migration for MIMO configuration. Modified Kirchhoff migration has been developed for both free-space and subsurface imaging. The modifications allow for extension of the classical Kirchhoff algorithm, which is based on the exploding reflector concept and is formulated for co-located transmit-receive antennas, to multistatic imaging with arbitrary positions of transmit and receive antennas. The algorithm combines the high quality imaging performance with acceptable computational costs, thus can be applied to demanding applications in practice. Range migration algorithm for MIMO configuration. Range migration algorithm is formulated for multistatic array configuration in the frequency-wavenumber domain for near-field imaging. By taking advantage of the computation efficiency of the fast Fourier transform (FFT), imaging speed of MIMO array-based system are significantly increased while maintaining high-quality imaging capabilities. Demonstration of UWB-MIMO system in different applications. Within the framework of several European projects, prototypes of MIMO array-based UWB imaging systems were designed and implemented for through-wall imaging (PROBANT), ground penetrating radar (Cadmium), and concealed weapon detection (RADIOTECT, ATOM). The feasibility of operational systems under various practical circumstances has been demonstrated. Thanks to the combination of UWB focusing, MIMO array and advanced digital beamforming algorithms, high resolution 3-D images were obtained using sparse aperture array with simplified front-end and low-cost equipments.
Article
Full-text available
En el presente artículo se realiza una revisión general sobre los sistemas robóticos teleoperados, su estructura, componentes principales, clasificación, tipos de sensores, sistemas de locomoción y aplicaciones; como ejemplo se mencionan algunos trabajos realizados en Colombia y en el mundo.
Article
A thermal neutron sensor prototype for Humanitarian Demining has been developed, trying to minimize cost and complexity of the system as required in such application. A (252)Cf source or a sealed-tube neutron generator is employed to produce primary fast neutrons that are thermalized in a moderator designed to optimize the neutron capture reaction yield in buried samples. A description of the sensor, including the performances of the acquisition system based on a Flash ADC card and final tests with explosive simulants are reported. A comparison of the sensor performance when using a radioactive source to that when employing a sealed-tube neutron generator is presented. Limitations and possible applications of this technique are discussed.
Article
Neutron backscattering (NB) sensors have been proposed for Humanitarian De-mining applications. Recently, a prototype hand-held system integrating a NB sensor in a metal detector has been developed within the EU-funded DIAMINE Project. The results obtained in terms of performance of the NB systems and limitations in its use are presented in this work. It is found that the performance of NB sensors is strongly limited by the presence of the soil moisture and by its small-scale variations. The use of the neutron hit distribution to reduce false alarms is explored.
Conference Paper
This paper presents an experimental evaluation procedure for a landmine detection GPR with a single transmit antenna and a receive antenna array. The procedure includes calibration of the ultra-wideband array, estimation of its footprint and cross-range resolution for different size of the aperture, checking the capability to image landmines buried within the array aperture. For the evaluation, the authors developed an imaging algorithm combining a synthetic aperture focusing in the mechanical scan direction with a focusing of the array in the cross-scan direction.
Conference Paper
This paper presents the investigation of antenna step and aperture size for an ultra-wideband (UWB) ground penetrating radar (GPR) with a linear array. The procedure includes the optimization of receiving array, verification of optimization results by EM simulation and experimental measurement for both surface and subsurface imaging. The imaging algorithm used for the evaluation combines the focusing of the array and the synthetic aperture radar technique in the mechanical scan direction.
Article
In this paper, the development of an ultra-wideband (UWB) array-based time-domain radar sensor for near-field imaging is described. The radar sensor is designed to be used within a vehicle-mounted multisensor system for humanitarian demining. The main novelty of the radar lies in the system design with a single transmitter and multichannel receiver. Design of the UWB antenna array is also novel. The radar produces 3D images of subsurface by 1D mechanical scanning. The imaging capability of the radar is realized via electronic steering of the receive antenna footprint in a cross-scan direction and synthetic aperture processing in an along-scan direction. Imaging via footprint steering allows for a drastic increase in the scanning speed.
ResearchGate has not been able to resolve any references for this publication.