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This paper presents a new approach for automatic vehicle model recognition and simultaneous estimation of lateral transit position, based on magnetic sensor technology. A set of magnetic sensors is deployed on the road surface and, upon transit of a target vehicle on the equipment, the system records six magnetic signatures relative to different vehicle sections. The recorded signatures are then compared with the Dynamic Time Warping algorithm to previously recorded ones, which are relative to known vehicles that have transited at known lateral position; the system then assesses whether the target vehicle’s model matches one of the models already in the database, and estimates its lateral transit position. With the considered experimental set-up, the system is able to discriminate between many different vehicle models and six lateral positions, with a resolution of about $20\,cm$ : the performance of the system is presented by comparing a set of different classifiers. In terms of vehicle model recognition, 1-Nearest Neighbor classifier obtains 0% of misclassification rate, while for lateral position estimation, if an error of one position is tolerated (precision of $\pm \,20\,cm$ ), the system is shown to reach 2.4% of misclassification rate.

We demonstrate a new type of haptic actuator, which we call MagnetIO, that is comprised of two parts: one battery-powered voice-coil worn on the user's fingernail and any number of interactive soft patches that can be attached onto any surface (everyday objects, user's body, appliances, etc.). When the user's finger wearing our voice-coil contacts any of the interactive patches it detects its magnetic signature via magnetometer and vibrates the patch, adding haptic feedback to otherwise input-only interactions. To allow these passive patches to vibrate, we make them from silicone with regions doped with polarized neodymium powder, resulting in soft and stretchable magnets. This stretchable form-factor allows them to be wrapped to the user's body or everyday objects of various shapes. We demonstrate how these add haptic output to many situations, such as adding haptic buttons to the walls of one's home.

We demonstrate a new type of haptic actuator, which we call MagnetIO, that is comprised of two parts: one battery-powered voice-coil worn on the user's fingernail and any number of interactive soft patches that can be attached onto any surface (everyday objects, user's body, appliances, etc.). When the user's finger wearing our voice-coil contacts any of the interactive patches it detects its magnetic signature via magnetometer and vibrates the patch, adding haptic feedback to otherwise input-only interactions. To allow these passive patches to vibrate, we make them from silicone with regions doped with polarized neodymium powder, resulting in soft and stretchable magnets. This stretchable form-factor allows them to be wrapped to the user's body or everyday objects of various shapes. We demonstrate how these add haptic output to many situations, such as adding haptic buttons to the walls of one's home.

In this paper, a software-based stochastic approach for calibration purposes in measuring facilities is introduced. The algorithm of the calibration procedure is tested with simulation analysis and evaluated with real measurements in a facility with two magnetometers. The results validate that the algorithm can accurately predict the actual positions of the magnetometers, making the multiple dipole model prediction more accurate and enabling the precise extrapolation of the magnetic field. This study illustrates the importance of the calibration process verification tests for equipment having magnetic cleanliness requirements in space missions.

In order to avoid detection by sea mines, the magnetic signature of merchant and naval vessels can be reduced by running a current through a set of on-board copper coils. This process is called degaussing. Studies have shown that the volume, weight and energy losses of a degaussing system can be reduced by replacing the copper coils with high temperature superconductive (HTS) coils. Moreover, since the technology and production of HTS has matured and the material is highly available, the use of HTS for degaussing coils is a serious option. As a preliminary study towards an HTS degaussing test setup, this paper presents the design of a table-top demonstration with copper degaussing coils. The goal of the demonstration is to measure the magnetic signature and the magnetic signature reduction of a cylindrical object. The design choices of the test setup and the measuring system are discussed. The magnetic signature of the table-top model is calculated as well as the optimal placement of the degaussing coils and the optimal degaussing currents. These results are compared with measurements of the magnetic flux density around the demonstrator.

Scientific goals in magnetometry require extremely high resolution magnetometers, a very good program of magnetic cleanliness and a powerful processing methodology. When magnetic cleanliness reaches its limits the exhaustive characterisation of the magnetic signature of the different subsystems together with compensation systems (HW) and algorithms (SW) may be the only way to achieve the performance demanded by the scientific objectives. Furthermore, exploration horizons, only within the limits of our Solar System, present scientific challenges in harsh conditions which comprise, among others, extreme swings of temperature. The magnetic properties of materials depend on temperature and the electrical resistance of wires and coils too. Therefore in wide temperature ranges the behaviour of the magnetic signature with temperature needs to be analysed, minimized when possible, and introduced in the retrieval algorithms for an optimal response. The requirements for the subsystems are present in their testing route documentation. However there are not standards or norms with the established procedures to develop these tests. In this work the INTA Space Magnetism Laboratory will overview different methodologies implemented for standard tests, will introduce some of the upcoming and challenging requirements and will present some of the solutions implemented.

We present preliminary results of a multidisciplinary geophysical investigation applied to the subsoil imaging of the archaeological site of Cocciano, near Rome. We acquired capacitive coupled resistivity data along two parallel profiles and we performed a magnetic survey over a small subset of the survey area. The recovered resistivity models suggest the presence of a shallow, sub-horizontal, resistive layer ( r > 350 Ωm), of slightly variable thickness (2 – 3 m), which we interpret as the response of ancient substructions overlying a relatively low-resistive layer, which we ascribe to the geological substratum. Processed magnetic data show a clear magnetic signature aligned to form a curve-shaped anomaly right at the prosecution of a nearby, partially exposed, ancient wall.

Passive magnetic sensors measure the magnetic field density in three axes and are often integrated on a single chip. These low-cost sensors are widely used in car navigation as well as in battery powered navigation equipment such as smartphones as part of an electronic compass. We focus on a train localization application with multiple, exclusively onboard sensors and a track map. This approach is considered as a base technology for future railway applications such as collision avoidance systems or autonomous train driving. In this paper, we address the following question: how beneficial are passive magnetic measurements for train localization? We present and analyze measurements of two different magnetometers recorded on a regional train at regular passenger service. We show promising correlations of the measurements with the track positions and the traveled switch way. The processed data reveals that the railway environment has repeatable, location-dependent magnetic signatures. This is considered as a novel approach to train localization, as the use of these magnetic signals at first view is not obvious. The proposed methods based on passive magnetic measurements show a high potential to be integrated in new and existing train localization approaches.

Magnetic fields of naval vessels are widely used all over the world for detection and localization of naval vessel. Magnetic Anomaly Detectors (MADs) installed on air borne vehicles are used to detect submarine operating in shallow waters. Underwater mines fitted with magnetic sensor are used for detection and destruction of naval vessels in the times of conflict. Reduction of magnetic signature of naval vessels is carried out by deperming and installation of degaussing system onboard the vessel. Present paper elaborates details of studies carried out at Magnetics Division of Naval Science and Technological Laboratory (NSTL) for minimizing the magnetic signature of naval vessels by designing a degaussing system. Magnetic fields of a small ship model are predicted and a degaussing system is designed for reducing magnetic detection. The details of the model, methodology used for estimation of magnetic signature of the vessel and design of degaussing system is brought out in this paper with details of experimental setup and results.

Micro-magnetic nondestructive evaluation and testing techniques are particularly efficient for the evaluation of plastic strain in steel components. A new method derived from the magnetic incremental permeability experimental setup and called Eddy Current Magnetic Signature (EC-MS) seems to be the particularly adapted for such evaluation. Numerical simulation of EC-MS has never been done before. In this article, the EC-MS method is described first, then a lump scalar phenomenological model based on a modified Jiles-Atherton model and extended to dynamic behavior is proposed for its simulation. All the simulation details are exposed and justified with physical observations.Micro-magnetic nondestructive evaluation and testing techniques are particularly efficient for the evaluation of plastic strain in steel components. A new method derived from the magnetic incremental permeability experimental setup and called Eddy Current Magnetic Signature (EC-MS) seems to be the particularly adapted for such evaluation. Numerical simulation of EC-MS has never been done before. In this article, the EC-MS method is described first, then a lump scalar phenomenological model based on a modified Jiles-Atherton model and extended to dynamic behavior is proposed for its simulation. All the simulation details are exposed and justified with physical observations.

Introduction/purpose In vivo detection of cerebral microbleeds (CMBs) from T2* gradient recalled echo (GRE) magnitude image suffers from low specificity, modest inter-rater reproducibility and is biased by its sensitivity to acquisition parameters. New methods were proposed for improving this identification, but they mostly rely on 3D acquisitions, not always feasible in clinical practice. A fast 2D phase processing technique for computing internal field maps (IFM) has been shown to make it possible to characterize CMBs through their magnetic signature in routine clinical setting, based on 2D multi-slice acquisitions. However, its clinical interest for CMBs identification with respect to more common images remained to be assessed. To do so, systematic experiments were undertaken to compare the ratings obtained by trained observers with several image types, T2* magnitude, Susceptibility Weighted Imaging reconstructions (SWI) and IFM built from the same T2*-weighted acquisition. Materials/methods 15 participants from the MEMENTO multi-center cohort were selected: six subjects with numerous CMBs (20 ± 6 CMBs), five subjects with a few CMBs (2 ± 1 CMBs) and four subjects without CMB. 2D multi-slice T2* GRE sequences were acquired on Philips and Siemens 3T systems. After pilot experiments, T2* magnitude, Susceptibility Weighted Imaging (SWI) minimum intensity projection (mIP) on three slices and IFM were considered for the rating experiments. A graphical user interface (GUI) was designed in order to consistently display images in random order. Six raters of various background and expertise independently selected “definite” or “possible” CMBs. Rating results were compared with respect to a specific consensus reference, on both lesion and subject type points of view. Results IFM yielded increased sensitivity and decreased false positives rate (FPR) for CMBs identification compared to T2* magnitude and SWI-mIP images. Inter-rater variability was decreased with IFM when identifying subjects with numerous lesions, with only a limited increase in rating time. IFM thus appears as an interesting candidate to improve CMBs identification in clinical setting., Highlights • We introduce an evaluation of phase-contrast for CMBs detection in clinical setting. • Comparison included T2* magnitude, SWI-mIP and IFM images using a specific GUI. • Rating results showed an improved sensitivity of IFM compared to T2*and SWI-mIP. • A decreased false positive rate with IFM with respect to T2*and SWI-mIP was proved. • We demonstrate a decreased inter-rater variability with IFM.

The La Gila Encantada Site is located on an isolated ridge top north of Silver City, New Mexico in an area defined culturally as the Mimbres Mogollon region. The 180 m × 80 m (14400 m2) sized site was originally recorded as a dense scatter of ceramics, lithics, and ground stone along with a number of surface depressions that appear to represent pithouses. Cesium magnetometer surveys were conducted to identify hearths, pithouse boundaries, and activity areas outside of pithouses in support of archaeological investigations, and to test this instrument's ability to image these features. This paper presents a characterization of the magnetic signature of a pithouse as a magnetic high in the center caused by the central hearth, low magnetic variability along the floor of the house, and then increased magnetic variability at the pithouse boundary. This characterization was successfully confirmed for three pithouses using cesium magnetometery and archaeological excavation.

This paper concerns a special type of eddy-current sensor in the form of inductive loops. Such sensors are applied in the measuring systems classifying road vehicles. They usually have a rectangular shape with dimensions of 1 × 2 m, and are installed under the surface of the traffic lane. The wide Point Spread Function (PSF) of such sensors causes the information on chassis geometry, contained in the measurement signal, to be strongly averaged. This significantly limits the effectiveness of the vehicle classification. Restoration of the chassis shape, by solving the inverse problem (deconvolution), is also difficult due to the fact that it is ill-conditioned. An original approach to solving this problem is presented in this paper. It is a hardware-based solution and involves the use of inductive loops with an asymmetrical PSF. Laboratory experiments and simulation tests, conducted with models of an inductive loop, confirmed the effectiveness of the proposed solution. In this case, the principle applies that the higher the level of sensor spatial asymmetry, the greater the effectiveness of the deconvolution algorithm.

This paper describes an effort to adapt a fleet of autonomous underwater vehicles (AUVs) for the measurement of the magnetic signature of surface ships. Currently, two such vehicles have been upgraded with the necessary navigation and measurement hardware to perform magnetic measurements. Initial testing has been performed at the Naval Acoustic Research Detachment at Lake Pend Oreille, Idaho. Two vehicles have leveraged formation control algorithms originally developed for mine countermeasure missions to operate collaboratively. In the testing area, changes in ambient field were measured to be ∼1,000–2,000 nT. Over one square meter area segments, the standard deviation of total field measurements was below 25 nT. When a steel barge was located in the testing area, localized fields of ∼50,000 nT to ∼62,000 nT were observed.

[1] Using observations made by the Finnish chain of pulsation magnetometers, we select typical properties of the ULF response to sprite-associated lightning events taken from the EuroSprite 2003 summer campaign. We concentrate on frequencies below the Schumann resonance and compare the obtained results with properties obtained from positive cloud-to-ground lightning discharges which are not associated with sprites. The latter we take from listings of the Meteorage Lightning Detection Network, which correlate with strong impulsive events seen in the Finnish chain. The evidence shows no unique and identifiable ULF signature relating to the sprite causative discharges.

This paper presents a new theoretical approach able to understand the contribution of the motor laminated stator core for high frequency electromagnetic emissions. The proposed analytical model is based on skin effect in laminations, it shows that HF current loops in magnetic sheets have a major effect on high frequency magnetic field existing in the vicinity of a standard machine fed by a PWM inverter.

The Improved Landmine Detection System (ILDS) is intended to meet Canadian military mine clearance requirements in rear area combat situations and peacekeeping on roads and tracks. The system consists of two teleoperated vehicles and a command vehicle. The teleoperated protection vehicle precedes, clearing antipersonnel mines and magnetic and tilt rod-fuzed antitank mines. It consists of an armoured personnel carrier with a forward looking infrared imager, a finger plow or roller and a magnetic signature duplicator. The teleoperated detection vehicle follows to detect antitank mines. The purpose-built vehicle carries forward looking infrared and visible imagers, a 3 m wide, down-looking sensitive electromagnetic induction detector array and a 3 m wide down-looking ground probing radar, which scan the ground in front of the vehicle. Sensor information is combined using navigation sensors and custom navigation, registration, spatial correspondence and data fusion algorithms. Suspicious targets are then confirmed by a thermal neutron activation detector. The prototype, designed and built by Defence R&D Canada, was completed in October 1997. General Dynamics Canada delivered four production units, based on the prototype concept and technologies, to the Canadian Forces (CF) in 2002. ILDS was deployed in Afghanistan in 2003, making the system the first militarily fielded, teleoperated, multi-sensor vehicle-mounted mine detector and the first with a fielded confirmation sensor. Performance of the prototype in Canadian and independent US trials is summarized and recent results from the production version of the confirmation sensor are discussed. CF operations with ILDS in Afghanistan are described.

A ship's classification by its magnetic signatures is of great importance in the development of magnetic mines. This work concerns the use of a neural network classification system combined with the relevant features method to solve this problem.

Arrays of vector magnetometers employing matched field processing have demonstrated the ability to accurately detect, track, and characterize the magnetic signature of vehicles traveling within range of the sensor field, regardless of weather conditions. This processing works on all types of vehicles, including passenger cars, light trucks, tractor-trailers, tanks, armored personnel carriers, etc. Consistency among the magnetic dipole estimates from similar vehicles has led to investigations of the ability to classify using magnetic information obtained from this process. Preliminary results suggest that separation of the permanent and induced portions of a vehicle's magnetic moment can provide the basis for an accurate, all-weather vehicle classifier.

Ferrofluids are stable colloidal suspensions of magnetic particles in various carrier liquids with high saturation magnetizations, which can be manipulated in virtually any fashion, defying gravitational or viscous forces in response to external magnetic fields. In this report, the authors review the results of their investigation of the potential of ferrofluids (1) to accurately and effectively guide reactants (for in-situ treatment) or barrier liquids (low-viscosity permeation grouts) to contaminated target zones in the subsurface using electromagnetic forces, and (2) to trace the movement and position of liquids injected in the subsurface using geophysical methods. They investigate the use of ferrofluids to enhance the efficiency of in-situ treatment and waste containment through (a) accurate guidance and delivery of reagent liquids to the desired subsurface contamination targets and/or (b) effective sweeping of the contaminated zone as ferrofluids move from the application point to an attracting magnet/collection point. They also investigate exploiting the strong magnetic signature of ferrofluids to develop a method for monitoring of liquid movement and position during injection using electromagnetic methods. The authors demonstrated the ability to induce ferrofluid movement in response to a magnetic field, and measured the corresponding magnetopressure. They demonstrated the feasibility of using conventional magnetometry for detecting subsurface zones of various shapes containing ferrofluids for tracing liquids injected for remediation or barrier formation. Experiments involving spherical, cylindrical and horizontal slabs showed a very good agreement between predictions and measurements.

This report covers a continuation of work described in PSR Report 2474. In the earlier study it became apparent that a great portion of the variability of the magnetic anomaly signatures stemmed not from the submarine-centered anomaly itself but rather from the path of the airborne magnetometer through the anomaly. Accordingly, this study focused on the anomaly in target-fixed coordinates, revealing the lobe structure of the anomaly, which, in turn, enabled a clearer understanding of the signatures produced by an airborne magnetometer. Additionally, temporal and spatial dependencies of magnetic anomalies from modulated galvanic currents were determined in both target-fixed and sensor-fixed coordinates.

The relationship between the measured time fluctuations of the ambient magnetic field due to the passage of a ship or submarine and the characteristic magnetization properties of this vessel are derived. This relationship would be useful in identifying or classifying ships and submarines according to their magnetization properties.

The use of magnetic anomaly detection (MAD) systems to search for and track submarines is a subject of renewed interest to the Canadian Forces with the recent acquisition of the new Aurora maritime patrol aircraft with its highly sensitive ASQ-502 magnetometer. To enhance the performance of the new magnetometer, to develop signal detection algorithms and to evaluate and refine existing MAD search tactics, the Defence Research Establishment Pacific (DREP) has developed an interactive minicomputer-based MAD search simulator— the MADSIM program, report summarizes the basic MAD search problem, describes the magnetic signature, outlines the simulation procedure of the program, presents several examples of computer output and concludes with a look at the utility and applications of the search simulator.