FLIR Ranger HRC MS, Руководство оператора

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Ranger HRC™ operator´s manual – System description
Publ. No. TM 614 006 699 Rev B – ENGLISH (EN) – Oct 30. 2008
three signals are needed to provide a position or “GPS fix” (­latitude and
longitude) for vehicle navigation systems.
The GPS unit is an advanced device for GPS based geomapping, which is
used to determine the exact position of the system.
The GPS unit consists of two parts, the external antenna and the internal
electronics. In order to allow the GPS antenna to receive the GPS signals,
the antenna must be outdoors with an unobstructed view of the sky. The
GPS unit can operate in all weather types, except for heavy snowfall.
3.1.5 Digital Magnetic Compass
The Digital Magnetic Compass (DMC) unit is an optional system compo -
nent.
The DMC unit is a high sensitivity precision instrument, which measures
magnetic fields in three dimensions. The intention is to measure the geo-
magnetic field, in order to find magnetic north. However, also other mag-
netic fields near the DMC unit will be included in the result and have
effect on the readings. For that reason, it is important that the system is
placed away from any sources of magnetic interference; such as transfor
-
mers, motors, radars, power lines and steel vehicles.
The geomagnetic field also has a declination (­also referred to as variation
or deviation) between magnetic north and true north. Each geographical
location has its own fixed declination, in the order of a few to several de-
grees. A common situation is that there also is a variable declination over
24 hours in the order of tenths of degrees. In order to find true north, the
local magnetic declination between magnetic north and true north must
be entered into the system when the DMC unit is calibrated. A negative
number corrects toward west and a positive number towards east.
For more information about DMC calibration, see section 10.3.1.