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LIBERTY MANUAL
‘H’ – Hemisphere of Operation
Description:
This command allows the user to set or change the “hemisphere of operation” vector.
Since the sensor(s) can only operate in one hemisphere at a time relative to the source, it
is necessary to tell LIBERTY which side of the source they will be on, for each station.
LIBERTY also provides hemisphere tracking, a feature whereby LIBERTY can
continuously modify its operating hemisphere, given that it is started in a known, valid
hemisphere.
Because of the symmetry of the magnetic fields generated by the source, there are two
mathematical solutions to each set of sensor data processed. Therefore, only half of the
total spatial sphere surrounding the source is practically used at any one time without
experiencing an ambiguity (usually sign flips) in the X, Y, Z measurements. This half
sphere is referred to as the current hemisphere. The chosen hemisphere is defined by an
LOS vector from the source through a point at the zenith of the hemisphere, and is
specified by the LOS direction cosines.
Syntax:
Hstation[ ,[p1],[p2],[p3] ]<>
Part
Description
station
1 to 16, which specifies the relevant source/sensor pair
p1
The initial x-component of a vector pointing in the direction of the
operational hemisphere’s zenith.
p2
The initial y-component of a vector pointing in the direction of the
operational hemisphere’s zenith.
p3
The initial z-component of a vector pointing in the direction of the
operational hemisphere’s zenith.
Remarks:
The arguments p1-p3 above are the vector components of the operational hemisphere’s
zenith. The default hemisphere values are: 1,0,0 which is positive X or “forward”
hemisphere.
Hemisphere Tracking is enabled by sending Hstation,0,0,0<>. It is not enabled by
default. LIBERTY modifies the operating hemisphere automatically.
When turning on Hemisphere Tracking, the sensor of the specified station must be
initially located in the currently set hemisphere.
REV. H
33
AUGUST 2012