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HSTAMIDS is a combined metal-detector and Ground
Penetrating Radar produced for US Army CECOM NVESD with encouragement
from some field demining groups. However, (in 2004) it is a classified
technology designed primarily for military use.
The
first HSTAMID accident (I know of) occurred in Afghanistan in 2003, when
a serving soldier with an HSTAMID in his hand lost his foot.
Despite several requests for more information about how the
accident occurred, I have received no details. I have received
an assurance that the HSTAMID was not at fault. There may have
already been other accidents with serving soldiers.
HSTAMIDS
Following
my skepticism about the HSTAMID system, I was invited to Newcastle,
UK, for an informal viewing in 2003 - this new detector is still
"restricted" and may not be available to the public for a couple
of years. (Field trials with HALO Trust are reported to be starting
in 2005.) While it is sort of "classified", the guys did not
put any restraints on my freedom to comment.
HSTAMID
combines a hand-held GPR and a metal-detector - an approach
that is also being worked on elsewhere (two programmes in UK,
for example). What makes it "different" is that it is already
(2003) being used by US soldiers in Afghanistan - so is considered
to be already field-deployable.
I
took some targets and hoped to be able to place a few on the
riverbank outside the Pearson factory where the brief meeting
took place. Pearson have a "nice" lawn, but I was only going
to use the mowed dandelions on the riverbank strip. The Pearson
people would not let me dig there even when I promised to lift
"turf" carefully and return it so that no one would know. So
the targets had to be placed above ground.
Surprisingly,
I could still learn some useful stuff from that. The system
is heavy, but lighter than anticipated with a small search-head
- that means an advance in small increments. It has a sexy foldable
design - far more robust than the mini-Schiebel but with a few
design bugs (wimpy looking head-hinge, exposed wire to the head,
low-volume - but nothing that could not be addressed). Also,
thickness of the head-plastic may need to be increased to prevent
it wearing through. It is designed to work below water (as a
metal-detector only) so is presumably well sealed against moisture.
Early
models had the metal-detector and GPR separately operated -
but on this model you could not turn-on the GPR on its own.
When the MineLab F3 metal detector signals, the volume of the
GPR signal instantly kicks in unless you have turned the GPR
off (which can be done if you want to use it as a stand-alone
and rather cumbersome metal-detector). If the GPR "finds" an
object under the ground and around/under above the metal reading,
the GPR gives an audio-signal that is very different from the
metal-detector indication. So the user-interface is by interpreting
varying sounds only. The difference in sound is easy to hear.
In its current configuration, it cannot be used to find mines
with no metal content - but they are more myth than reality
in any case.
It
is power-hungry - and the battery is worn on your belt. All
MineLabs are battery guzzlers and I guess the GPR is also a
bit of a glutton. The manufacturers assure me that battery types
can be varied (a US military battery is used currently).
The
operator said that, with experience, you can begin to tell (very
crudely) the size and shape of the GPR detection - partly from
the speed of the signal and partly by moving the search-head
towards it from all sides as you would with a metal-detector.
There was a different GPR audio-signal when passing over a [surrogate
filled] PMN and a GYATA-64, reflecting the different cavities
inside these mines (both have a very similar outward appearance).
However, he said that normal use would be that any GPR signal
accompanying a metal-detection should always be investigated.
Ground
compensation and set-up are computerised, with a female voice
announcing when the detector is ready to use. Cute, but a trifle
toe-curling.
Above
surface, the metal-detector and GPR combination worked well
- with the GPR kicking in on everything with bulk that the metal-detector
"found". It even kicked in on an MUV fuze - with cavities inside
the metal - while staying silent when the metal was a solid
lump of frag, etc.
Sounds
very simple - and it is. I was thrown a little by the 40hrs
training time recommended, but that is apparently to break existing
habits and reinforce new ones. Still seems a little excessive.
The
questions over reliability in real contexts could not begin
to be addressed. With an hour to play under Pearson restrictions,
I could not begin to assess how reliable it was when the object
was buried in soil, among stones, roots, on dry, 30-50% wet
ground, flush with surface or at varying depths - all of which
are critical questions and should be assessed with a range of
targets. I could not begin to assess how deep the metal-detector
was capable of searching - or how similar its performance was
to the stand alone model of the Minelab F3.
If
the GPR element is reliable - or if it is easy to tell in what
conditions is may not be reliable (this may be what takes so
long in training) I can think of places where it would be useful.
I can also think of many where it would never be any more useful
than a metal-detector on its own - such as a typical Afghan
hillside of stones (stones would make the GPR signal). The ability to turn off the GPR would allow
the detector to still be used there (if nothing smaller was
available).
If
the GPR and operator are less than 100% reliable at either identifying
a mine-like object or indicating that they cannot determine
whether a mine-like object is there - the system reduces "safety"
over the use of the MineLab on its own (when all metal indications
would be investigated as potential mines). ["Safety" in Humanitarian
demining refers to the "safety" of the operator/deminer and
(crucially) the "safety" of the eventual end-users of the cleared
land.]
In
all detection systems there are three typical false-alarms:
1)
False indication - where nothing is present.
2) False-positive - where the article present is not an ERW
item.
3) False-negative - where an item of ERW is present but the
detection system fails to indicate this.
Of
these, the False-indication and False-positive result in extra
work, but do not have a direct impact on safety. If they make
the operator "careless", they may have an indirect impact on
safety but this can be controlled by adequate procedures and supervision.
A False-negative is a major safety issue, with missed items
resulting in deminer and civilian injury. This already happens
(rarely) and any new technology should not be allowed to risk increasing
the number of these incidents.
Because
safety is supposed to be the prime concern in HD, concerns to
limit "False-positives" must start with a requirement that "False-negatives"
be reduced to zero (or as close to zero as is possible). With
existing equipment, this often comes down to devising and enforcing
safe operating procedures - and that would be the same for HSTAMIDS.
I
should stress that, even assuming that the HSTAMIDS system (with
operator) could ever be 100% effective (no False-negatives),
the addition of the GPR to the MineLab F3 does not increase
the thoroughness of current methods of mine detection using
metal-detectors. In other words, it does not increase "safety"
by finding more than a metal-detector would on its own. It is
not intended to. It is intended to add increased speed - but
if that is achieved at the expense of thoroughness (safety),
it is not an appropriate tool outside a military context (where
speed may be more important than occasional False-negatives
and missed devices).
Before
putting this on the market in HD, I recommend that the following
should be field evaluated using genuinely experienced actual
deminers under the supervision of suitably skeptical independent
assessors:
a)
The level of operator training, base intelligence and experience
that is realistically required for the user to confidently discriminate
signals.
b)
The ability of the GPR to give meaningful signals on irregular
dry or wet ground with mixed soils, and ways for the user to
assess the parameters where its use may be unsafe in the field.
c)
Realistic assessment of detection depth - and how to do this
in-and-for each area of use.
d)
Realistic assessment of the likelihood of false-negative indications.
e)
Field durability and reliability.
f)
Cost-benefit analysis over current methods.
The
eventual unit cost of this system has been variously estimated
to be at 12 -50 thousand US dollars. Those sources closest to
the actual programme have expressed the lowest figure. At a price that may be around six times the cost of existing metal-detectors
with good GC capabilities, the system would have to have real
speed advantages over solo metal-detectors to be cost-effective.
If what I have been told about it proved to be true, it could
achieve this in some mined areas - so we may see it being added
to the toolbox when it is made available in a couple of years.
Sexy?
Yes. Potential? Perhaps. As NVESD put it - "the best thing
since sliced bread"? Well no, I cannot agree with that.
I prefer to slice my own bread. However, if well-organised and
real field-testing proved its ability while addressing the safety
concerns, the technology could replace the solo metal-detector
in some areas. It would never increase the thoroughness of clearance over that achieved using existing procedures and metal detectors, so whether it will ever be useful enough to justify the cost of developing
it is doubtful (at best).
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