The original NVESD Mine Lanes Facility was built in 1959 to support testing of early metal detectors. Recently, it has undergone extensive renovation.
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Picture 1: Renovated NVESD Mine Lanes Facility
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It now consists of an indoor, dry lane portion, a greenhouse portion with moisture-controlled lanes, a new, expanded control room, and two outdoor lanes. The facility bridges the gap between laboratory measurements and field data collections by controlling environmental, soil and sensor parameters that effect overall-sensor performance.
Test lanes
The indoor, dry lane portion is a (mostly) non-metal structure. Picture 2 shows an interior view of the dry lane portion. It is not heated or cooled, but it is equipped with several roof mounted exhaust fans to control summertime temperatures. The building contains six mine lanes, each approximately 2.4m (width) x 1.2m (depth) x 33m (length). These lanes contain six different soil types: a magnetite/sand mixture (the McIntire mixture), silt, crusher run gravel (bluestone), bank run gravel, Virginia red clay, and fine white sand. The lanes are separated by nonmetallic barriers.
The center two lanes (lanes 3 and 4) have a trolley system, fabricated predominately out of aluminum, for mounting the various mine detection systems and sensors under test. Eventually, all six lanes will be serviced by a total of three overhead trolley systems (1 trolley per each 2 adjacent lanes).
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| Picture 2: Interior view of the indoor dry lane portion |
A greenhouse structure was added to the facility to provide a transition area for testing sensor capabilities in an area where the introduction of environmental parameters can occur in a controlled laboratory setting. A large, gable mounted exhaust fan controls summertime heat build-up. Double hung windows surrounding the three walls of the greenhouse end of the mine lanes facility can be opened or closed. An elevated cat walk provides look down capability across all lanes for various sensors. The greenhouse lanes are each 2.4m (width) x 1.8m (depth) x 18m (length) with identical soil types to those in the indoor part of the facility. A built in sprinkler system delivers precise amounts of water to each lane. In-ground detectors allow for precise measurement of the soil moisture content in the lanes. The sliding roof panels of the greenhouse are motorized, and can be rolled back to open 40% of the roof area.
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| Picture 3: Sliding roof panels of the greenhouse lanes |
Additionally, two outdoor lanes have been added to the facility, one on each side of the building. Each lane is 2.5m wide x 1.8m deep x 25m long. One of these lanes contains crusher run gravel, and the other one contains bank run gravel. No sensor positioning system is foreseen in the outdoor lanes.
Sensor platform
The overhead trolley system in the dry indoor lanes provides 3-axis linear motion control and can be operated from the trolley with a manual joystick cabled to the trolley, or by a remote computer running graphical user interface (GUI) software. The entire platform can be raised and lowered on two jackscrews at diagonal corners of the trolley platform. Data acquisition and data logging is fully automated. The system also includes activation of a laser cross hair used to measure positions of mines for ground truth and to permit researchers to make use of the high resolution position encoders for utility measurements.
The greenhouse contains a single, overhead trolley system (similar to an industrial warehouse crane) that is to be used for mounting of the mine detection systems and sensors under test. The sensor positioning system in the greenhouse lanes is still under construction. Because of the requirement for natural illumination through the open roof, the trolley support structures available in the dry indoor lanes have not been extended. To avoid significant obscuration to incoming solar illumination and exposure of the trolley control electronics and mechanical interfaces to rain, a gantry type overhead crane is being installed. This installation will provide the capability to position, under computer control, a sensor anywhere within the area covered by the greenhouse lanes from ground level to an elevation of up to 5 meters. The positioning and motion control will be accomplished under the same graphical user interface developed for the trolleys in the dry indoor lanes. The weight of the sensor package and associated support and control equipment mounted on the cross-beam trolley is limited to 225Kg. An inverted gimbaled mount will be attached to the bottom of the sensor mounting bracket to provide the ability to change the view angle of a sensor in elevation and azimuth.
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| Picture 4: Greenhouse, catwalk and overhead crane |
Test targets
TABLE 1 summarising the available targets:
| Type |
Mine Target |
Quantity |
| ? |
Adom |
1 |
| AT |
Bar Mine |
3 |
| AP |
PFM1 (Butterfly) |
27 |
| AT |
FFV028 |
11 |
| AT |
HPDF1 |
1 |
| AT |
M/47-1 |
2 |
| AP |
M12 |
3 |
| AP |
M14 |
36 |
| AT |
M15 |
10 |
| AP |
M16 (bouncing betty) |
11 |
| AP |
M-18 (Claymore) |
1 |
| AT |
M19 |
13 |
| AT |
M-20 |
3 |
| AT |
M21 |
2 |
| AT |
M6-A2 |
1 |
| AP |
MON1 |
1 |
| AP |
OZM3 |
8 |
| AP |
OZM |
1 |
| ? |
PM60 |
14 |
| AP |
PMA-3 |
3 |
| AP |
PMD6 (wooden box) |
5 |
| AP |
PMN-6 |
12 |
| AP |
PPM-2 |
1 |
| ? |
RAM |
22 |
| AT |
TM46 |
5 |
| AT |
TM57 |
1 |
| AT |
TM-62M |
1 |
| AT |
TM-62P |
2 |
| AT |
TMA-1A |
1 |
| AT |
TMA-2 |
1 |
| AT |
TMA-3 |
1 |
| AT |
TMA-4 |
1 |
| AT |
TMP1 |
1 |
| AP |
TS50 |
5 |
| AP |
Valmara 69 |
1 |
| AT |
VS 2.2 |
2 |
| AT |
VS-1.6 |
11 |
| AP |
VS50 |
5 |
| AT |
VS-HCT2 |
5 |
| ? |
VSMK-2 |
19 |
| AT |
TMD-B (wooden box) |
6 |
|
? |
4 |
| AP |
Gator |
5 |
| AT |
PGMDM |
1 |
| AP |
PMA2 |
1 |
| AP |
PMA-1A |
1 |
| AT |
TMRP-6 |
1 |
A set of of inert mines and simulant targets are available (Table 1). No targets are permanently buried in the ground.
Supporting equipment
All six lanes in the greenhouse are equipped with an automated sprinkler system. Each lane is considered a separate "zone" by the sprinkler system. Flow meters precisely measure the amount of water delivered to each zone. A data logger system collects and stores sprinkler history. The sprinkler computer can be programmed to command "rain events" at specified times and durations.
Several of the lanes in the greenhouse are monitored with capacitance moisture probes. Two main classes of probes have been used. One class is used for single point measurements of water content, temperature, and frequency dependent dielectric constant. The second class of sensor consists of a long probe column containing rings of sensors along its length. By recording the moisture for each of the depths one obtains a time profile of the moisture flow in the soil from the surface down.
Possibilities for research
Effects of various soils, soil moisture content, and mine types on sensor performance, both at the component level and across an entire system, can be evaluated. Various environmental conditions can be simulated. Furthermore, characterization of the migration of water applied at the surface through the region where mines would be emplaced is also possible. Using automation, measurements can be repeated over time to measure technical progress in mine detection sensors and to correlate with earlier data.
Several data collections have recently been organised in the test lanes, e.g. Acoustic/Laser Doppler Vibrometer landmine signatures and IR tripwire imagery.
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