Guralp Systems CMG-DM24 - Manual (Page 56)

CMG-DM24
LEAPSECOND
Syntax: yyyy mm dd LEAPSECOND
Manually notify the digitizer of an upcoming leap second. This
command is not normally necessary, since GPS already has support for
leap seconds. However, some older GPS receivers did not properly
implement this feature. See SQPATCH, below.
The leap second is taken to be at the end of the day yyyy-mm-dd.
SQPATCH
Syntax: SQPATCH ENABLE or SQPATCH DISABLE
Enables or disables the internal patch for older GPS receivers – those
based on Trimble Lassen SQ units. These units misinterpret the GPS
system's advance notification of a leap second and, consequently, run
one second slow until the leap second occurs.
With SQPATCH enabled, the time reported by the digitizer is offset by 1
second to counteract this problem. If you have set LEAPSECOND,
above, SQPATCH will automatically be disabled when the leap second
occurs and the digitizer will then run normally.
GPS receivers with the latest firmware do not suffer from this problem.
To find out whether SQPATCH is currently enabled, issue the
command
.SQPATCH
AZIMUTH
Syntax: instrument angle AZIMUTH
Some borehole digitizers can rotate incoming signals algorithmically
as they are digitized. This feature allows you to compensate for an
instrument being out of alignment with the North/South axis. To use
it, first measure the orientation of the sensor, then connect to the
digitizer and issue an AZIMUTH command, giving the angle you have
measured.
instrument tells the digitizer which instrument to apply the rotation
to; 0 for sensor A or 1 for sensor B.
56 Issue N