Leader Scan - 5.7 Define the search distances; 5.8 Defining the sensor sensitivity

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5.7 Define the search distances
Modify the search distances based on the debris composition in the field and depending on
the depth to be analysed.
Real time search mode: A closer search zone (Mini-Maxi) helps provide higher sensitivity in
the selected zone and less “noise” from the outside.
If the user selects 2-5m (6-15ft), the noise at a distance under 2m (6ft) and a distance over 5m will
be lower. If the user selects the 0-10m (0-30ft) zone, they will keep all noise in the 0-10m (0-30ft)
distance.
Automatic search mode: A larger zone means a longer search time as each 3m (9ft) section
requires 1 minute of search. If the user selects zone 0-9m (0-27ft), it will take up to 3 minutes to
complete the search.
The user must first locate the possible locations to find living people and then define the relevant
detection zone. In general, a minimum height of 30cm is required to allow the survival of a person
lying between 2 concrete slabs.
It is possible to detect the position of “pockets of life” to direct the search. If a victim is potentially
present from 3 to 4m (9 to 12ft) from the UWB sensor, the emergency worker will define a 2-5m
(6-10ft) search zone.
Main rules for defining a zone:
1. Narrower zone: Higher sensitivity and less noise (Real time mode) and a faster search
(Automatic mode).
2. It is preferable to start the search from 0.5m (1.5ft) or higher. In the majority of cases, the
emergency worker on the surface of the debris sees the initial layers where to place the UWB
sensor and knows what is under the first centimetres/metres (a wall with an empty space behind,
a concrete slab which is 50cm (1.5ft) thick, etc.). They can therefore define the Mini (minimum
distance on the top of the cone) at 0.5m, 1m or 1.5m (1.5ft, 3ft or 4.5ft) to optimise sensitivity from
this distance and therefore avoiding scanning a known zone.
5.8 Defining the sensor sensitivity
Sensitivity is a threshold for the device algorithm which allows it to make a decision if a “weak
movement” or “strong movement” icon is displayed in the determined search zone (cone).
High sensitivity allows detection of a small movement, therefore the possibility of detecting a large
number of movements in the same zone (Movement of fabric or vibrating cord, etc...) which means
that it is more likely to detect a false victim.
Advice: In a free field, reduce the sensitivity to the average level (2) or even lower (0 or 1). However
when dealing with a concrete slab (or other dense material), sensitivity must be defined higher
(3 or 4).