Geometrics MagArrow, User Manual

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APPENDIX C: Terminology Used with MFAM Based Magnetometers
Absolute:
An absolute magnetometer is one where the measured value is equal to the strength of the magnetic
field and does not depend on other things such as time and temperature and orientation. The MFAM is
an absolute magnetometer.
Cell:
The area within the sensor where the field measurement occurs. For the MFAM sensor, this area is a
5mm diameter volume at the center of the sensor assembly.
GPS HDOP, VDOP, PDOP:
Acronyms used when speaking of the loss of GPS position accuracy. Commonly, you will see the
following acronyms used to describe the type of position accuracy in question.

HDOP – horizontal dilution of precision

VDOP – vertical dilution of precision

PDOP – position (3D) dilution of precision

TDOP – time dilution of precision

GDOP – geometric dilution of precision
DOP
Value
Rating Description
<1 Ideal This is the highest possible confidence level.
1-2 Excellent
At this confidence level, the position measurements are accurate enough
to meet all but the most demanding applications.
2-5 Good
This represents a level that marks the minimum appropriate for making
accurate surveys.
5-10 Moderate
The position measurements could be used for some cases, but the fix
quality should be improved. A more open view of the sky is
recommended.