Guralp Systems CMG-3TB - Manual (Page 53)

Operator's guide
Our sample instrument is thus aligned at –90.35 ± 0.07 °.
16.The error given is only a rough estimate.
You should repeat the orientation experiment several times
using different data sets.
The true error in the computed orientation can be determined
by observing the spread of the results.
The Blacknest orientation method generally provides a reliable
indication of the sensor's orientation. In most cases, the greatest source
of error is in the installation of the reference sensor.
Applying automatic rotation
You can configure a DM24 mk3 digitizer to apply an automatic
rotation to the digitized data and output streams representing ground
motion on true North/South and East/West axes.
This is done within the DSP to minimize the reduction in data quality.
To set up the rotation:
1. Open a terminal session with the digitizer. You can do this with
a program such as minicom (for Linux) or hypertrm (for
Microsoft Windows). Alternatively, you can access the digitizer's
console through Scream! by right-clicking on its icon and
selecting Terminal....
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