An overpass solution for antitank pressure-fused mines was developed and demonstrated for a teleoperated, four-wheeled experimental unmanned ground vehicle hosting a mine detection system using a downlooking ground-penetrating radar. The capability to overpass pressure-activated antitank mines is one way to protect the vehicle. The requirement was to make the vehicle overpass capable by giving it an average footprint pressure of no more than 5 psi using commercially available equipment and without requiring any vehicle modification. An overpass solution was developed and demonstrated using low-pressure, minimal casing rigidity tires that produce a uniformly low ground pressure and enable the vehicle to exert less than the minimum force required to activate the large majority of pressure-fused antitank mines. Overpass requirements are discussed in terms of antitank mine threats, pressure plate size, activation forces, and ground pressure distribution uniformity. A variable-load tire footprint pressure measurement system and laboratory were developed and laboratory evaluation of a number of tire candidates was completed. Laboratory results were demonstrated through field performance demos of the selected low-pressure tire. Results present the successful overpass of various threat representative antitank mines with the pressure plate elevations/exposures at various positions relative to local grade.
An empirical performance model for the Mine Hunter/Killer (MH/K) Ground Penetrating Radar (GPR) was developed and used to analyze the performance of this GPR as a function of soil type, soil moisture, mine casing and mine depth. The empirical modeling approach used can be modified to evaluate the performance of other GPRs if adequate data are collected. All of the data were reprocessed with the final MH/K automatic target recognition (ATR) algorithm so that performance variations due to environmental conditions could be characterized independently of ATR changes. The model estimates Probability of Detection (Pd) and False Alarm Rate (FAR) for buried mines as a function of ATR confidence, estimated soil moisture content (dry, moist or wet), mine casing (metal or plastic), burial depth (shallow or deep) and soil type (dirt or gravel). Time Domain Reflectometry (TDR) moisture probe measurements at one location augmented with qualitative observations of the soil conditions characterized the soil moisture content. The performance model was created from 52 alarm files collected at a temperate US Army test site over a total of 4 weeks during a 13-month period. The results show that for the MH/K GPR performance against plastic mines in dirt improves as soil moisture increases and performance in gravel is better overall than in dirt.
This report presents a summary of signal strength testing conducted with the metal detector (MD) subsystem of the Mine H/K (hunter/killer) vehicular mine detection system. An overview of the operational characteristics of the MD subsystem, the VMV16, is provided. Tests are described that assess the variation in sensitivity across the MD coil array. Absolute sensitivity measurements of the MD array are also presented. Results presented show that the array has sufficient sensitivity to detect low metal (LM) mines provided the mines are not located further than 3.5 inches from the plane of array. Laboratory experiments indicate that saturation and a limited temporal sampling window severely restrict any opportunity for discrimination based on eddy current decay predictions/comparisions.
The Close-In Detector (CID) is the vehicle-mounted multi-sensor anti-tank landmine detection technology for the Army CECOM Night Vision Electronic Sensors Directorate (NVESD) Mine Hunter-Killer (MH/K) Program. The CID includes two down-looking sensor arrays: a 20-antenna ground-penetrating radar (GPR) and a 16-coil metal detector (MD). These arrays span 3-meters in front of a high mobility, multipurpose wheeled vehicle (HMMWV). The CID also includes a roof-mounted, forward looking infrared (FLIR) camera that images a trapezoidal area of the road ahead of the vehicle. Signals from each of the three sensors are processed separately to detect and localize objects of interest. Features of candidate objects are integrated in a processor that uses them to discriminates between anti-tank (AT) mines and clutter and produces a list of suspected mine locations which are passed to the neutralization subsystem of MH/K. This paper reviews the current design and performance of the CID based on field test results on dirt and gravel mine test lanes. Improvements in CID performance for probability of detection, false alarm rate, target positional accuracy and system rate of advance over the past year and a half that meet most of the program goals are described. Sensor performances are compared, and the effectiveness of six different sensor fusion approaches are measured and compared.
The Close-in Detection (CID) System is the vehicle-mounted multisensor landmine detection system for the Army CECOM Night Vision Electronic Sensors Directorate (NVESD) Mine Hunter/Killer (MH/K) Program. The CID System is being developed by BAE Systems in San Diego, CA. TRW Systems and Information Technology Group in Arlington, VA and a team of specialists for ERIM, E-OIR, SNL, and APL/JHU support NVESD in the development, analysis and testing of the CID and associated signal and data processing. The CID System includes tow down-looking sensor arrays: a ground- penetrating radar (GPR) array, and a set of Electro-Magnetic Induction (EMI) coils for metal detection. These arrays span a 3-meter wide swath in front of a high mobility, multipurpose wheeled vehicle. The system also includes a forward looking IR imaging system mounted on the roof of the vehicle and covering a swath of the road ahead of the vehicle. Signals from each sensor are processed separately to detect and localize objects of interest. Features of candidate objects are integrated in a processor that uses them to discriminates between anti-tank miens and clutter. Mine locations are passed to the neutralization subsystem of MH/K. This paper reviews the design of the sensors and signal processing of the CID system and gives examples and analysis of recent test results at the NVESD mine lanes. The strengths and weaknesses of each sensor are discussed, and the application of multisensor fusion is illustrated.