Specifications

66 Z-Family Technical Reference Manual
Internally, the receiver implements the transformation from WGS-84 to WGS-72.
Figure 5.1 demonstrates the change in the coordinate systems.
At this time, the receiver is computing geodetic coordinates in the system defined. All
coordinates output by the receiver will now be in this new system.
Do not forget to issue the $PASHS,DTM,UDD command after defining the transformation
parameters with the $PASHS,UDD command. Otherwise, the newly entered parameters are not
used.
After issuing the $PASHS,DTM,UDD command, the receiver internally transforms positions from
the reference datum (WGS-84) to the user-defined datum. In standard text books, however, the
datum transformations are given from local datums to WGS-84. To simplify entering the
transformation parameters, the translation, rotation, and scale parameters are defined from the local
datum to WGS-84.
Figure 5.1: Rotation and Translation Between Coordinate Systems