23-06-2012, 12:15 PM
LANDMINE DETECTION USING RADAR
27689281-Landmine-Detection-Using-Radars.pdf (Size: 621.76 KB / Downloads: 164)
INTRODUCTION
Landmines and unexploded ordnance
(UXO) are a legacy of war, insurrection, and guerilla
activity. Landmines kill and maim approximately
26,000 people annually. In Cambodia, whole areas of
arable land cannot be farmed due to the threat of
landmines. United Nations relief operations are made
more difficult and dangerous due to the mining of
roads. Current demining techniques are heavily
reliant on metal detectors and prodders.
Ground Penetrating Radar
Due to the difficulty in detecting the tiny amounts of
metal in a plastic landmine with a metal detector,
technology development has been funded in other
areas. Ground penetrating radar (GPR) has been used
for nearly 70 years for a variety of geophysical
subsurface imaging applications including utility
mapping and hazardous waste container location and
has been actively applied to the problem of landmine
detection for nearly 20 years. When parameters such
as frequency range, antenna size, antenna separation,
and system timing are optimized for detection of
mine-sized objects in the near subsurface, GPR is
quite effective in detecting both metal and plastic
landmines in a variety of soils.
OVERVIEW OF THE SYSTEM
A series of measurements has been taken
using a set of targets buried in the various types of
soil. An FR-127-MSCB impulse ground penetrating
radar (ImGPR) system developed by the
Commonwealth Scientific and Industrial Research
Organization (CSIRO), Australia, has been used for
these measurements. The system collects 127 returns,
or surroundings, per second, each composed of 512
samples with 12 bit accuracy. The sounding range
may vary from 4 ns to 32ns. The GPR system uses
bi-static bow-tie antennas which transmit wideband,
ultra short duration pulses.
SIGNAL CLUTTER
The sources of clutter particularly includes
multiple reflections between the rough surface of the
soil and antenna, reflections internal to antenna and
reflections from the soil due to radiation from the
open ends of the antenna. Fortunately, the frequency
components and magnitude distributions of most
clutter can be assumed as wide-sense stationary
processes and they have slowly varying values along
a B-scan frame.
DEPLOYMENT PLATFORM
US army hand held standoff mine detection
system that is a self propelled cart with GPR system.
As technological development for land mine
detection tends to be a vehicular based system. This
vehicular based system is shown in figure 10. This
vehicle is self propelled so it can use in war places.
This is a vehicular based system because vehicle can
carry the weight and supply the power.
ADVANTAGES
i. GPR has accurate measurements.
ii. GPR locates even small targets.
iii. It has been well founded by the defense.
iv. GPR operates by detecting the dielectric
soils which allows it to locate even no
metallic mines.
DISADVANTAGES
i. The sensor such as GPR is larger and
heavier.
ii. It is plagued with the problem of excessive
signal clutter.
iii. GPR is more power hungry.
iv. GPR can suffer falls alarm rates as high as
metal detectors.
SUMMARY
Impulse GPR system is using for detecting
anti-tank and antipersonnel mines. Anti-tank mines
are using for destroying the vehicles and antipersonal
mines, which are designed to kill and maim
people. Currently, very little technology is used in
real-world demining activities. Active programs by
the U.S Army in both land mine detection sensor
development and systems integration are evaluating
new technologies, incrementally improving existing
technologies, increasing the probability of detection,
reducing the false alarm rate, and planning out
useable deployment scenarios.