| | |  | HOPE mine detector locates mines with little metal content until now difficult to find | |
ESA projects help to develop new improved land mine detector
25 May 2001
The ground penetration radar (GPR) sensor used in the HOPE project has been developed by the Swiss company, RST Radar Systemtechnik AG, using technology first designed for two ESA-funded projects: GINGER and PIRA.
GINGER (Guidance and INto the Ground Exploration Radar) is a radar sensor designed for use on a planetary rover. It enables the detection of obstacles at medium range, can measure speed in forward and lateral directions, and identifies soil traversability and ground-penetration. The GINGER technology has been successfully tested at the CNES Moon and Mars test site.
| | GINGER on a rover mockup | |
PIRA (Planetary Into the ground Radar and Altimeter) includes a GPR and a radar altimeter for surface height measurements from a planetary orbiter platform. Although it requires only a few watts of power, the GPR can pierce planetary soil by applying advanced antenna beam sharpening and clutter suppression techniques for more than 1 km from an orbit height of 300 km. The PIRA concept has been successfully demonstrated in helicopter radar trials over glaciers in Norway.
RST has adapted the GPR technology developed for these two projects to develop a GPR sensor for the HOPE land mine detector. It is well known that longer wavelengths penetrate deeper into the ground while large bandwidths provide adequate depth resolution. The sensor developed by RST for HOPE operates at 4 GHz with 100% bandwidth, this gives a depth resolution of more than 3 cm in typical soils and an adequate penetration depth even in high attentuative soils.
| | PMN-type mine located by GPR | |
The GPR operates in two basic modes, the finger-print mode and the imaging mode.
In the finger-print mode the radar is able to investigate the spectral properties of the radar targets under the antennas, thus helping to distinguish between mines and rocks, one of the big problems faced in mine detection.
When ‘suspicious’ data is detected by the metal detector and the GPR in the finger-print mode then the imaging mode is used. This provides radar images with high lateral resolutions, which together with other data, provides an improved radar resolution of more than 3 cm. The data processing system used is similar to the synthetic aperture radar techniques well-known in satellite remote sensing.
Work on integrating the two radar sensors for GPR and the metal detector is close to completion and is ongoing for the microwave radiometer and the ‘intelligent data fusion’ of the three contributing sensors. A first prototype should be available later this year and if all goes well, production could start three years from now.
| | Horizontal slices of mine located by GPR | |
Testing planned in Bosnia
As the first basic testing has to be carried out in a controlled environment, a sandbox has been installed at RST to test for various mines buried at different angles and at different depths. Tests have also been carried out at a special test facility at the University of Karlsruhe, Germany.
To date, the results have been excellent; the prototype has successfully detected mines in various soil conditions and in different positions and depths. The next step is to test the prototype in a minefield established by the Belgian Military containing different soils and targets. Tests are also planned with the German military.
To gather statistical information on the detection and false-alarm rate, a final evaluation of the HOPE system will be carried out in Bosnia in June and July. Trials in Mostar and Sarajevo will allow testing under realistic soil and operational outdoor conditions and will be carried out with the help of Non-governmental Organisations, such as Norwegian Peoples Aid.
Companies participating in HOPE project
The main companies involved in producing the HOPE sensor system are:
- Vallon GmbH (Germany): metal detector
- DLR (Germany): microwave radiometer
- RST Radar Systemtechnik AG (Switzerland): ground penetration radar
Other companies and institutions involved in the HOPE project include: the Royal Military Academy (Belgium), BATS (Belgium), Spacebel (Belgium), University of Karlsruhe (Germany), Onera (France), ISL (France), University of Milan (Italy) and the University of Bochum (Germany).
| |
