Spectra Precision Survey Pro v4.5 Ranger User Manual - Manual (Page 263)

GPS Module
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Origin: is the coordinate on the intermediate mapping plane of the
centroid of the control points. It is calculated by average of the
mapping plane (y,x) coordinates of all control points.
Translation: is the shift from the Origin to the centroid of the
control points in the local coordinate system.
Mapping Plane Mode:
Scale: is the scale difference between the intermediate mapping
plane using the autonomous GPS position and the actual mapping
plane control coordinates. Scale should be very close to 1.0. A value of
1.0 corresponds to grid distances on the selected conformal mapping
plane.
A scale value significantly greater or smaller than 1.0 may indicate
problems with the control point accuracy and/or the control
measurement precision. It might also indicate a scale bias in the
control point plane coordinates, which you may want to correct by
solving a fixed scale transformation.
Rotation: is the rotation between intermediate mapping plane using
the autonomous GPS position and the actual mapping plane. The
rotation should be very close to 0.0. A rotation value significantly
greater or smaller than 0.0 may indicate problems with the control
point accuracy and/or control measurement precision. It might also be
an orientation bias of the mapping plane control system that you wish
to solve for.
Origin: is the coordinate on the intermediate mapping plane of the
centroid of the control points. It is calculated by average of the
mapping plane (y,x) coordinates of all control points.
Translation: is the shift from the Origin to the centroid of the
control points in the local coordinate system. This value represents
the shift introduced by the inaccurate autonomous GPS starting
position, and is usually less than 10m, the accuracy of an autonomous
GPS position.