Specifications

64 Z-Family Technical Reference Manual
The remainder of this chapter describes in more detail the coordinate transformation
features of your receiver.
Interpretation
Datum to Datum
The receiver normally computes and outputs positions in the WGS-84 coordinate
reference frame. However, it is possible to output positions in NMEA messages in a
number of different pre-defined datums, as well as in a user defined datum.
To set the receiver to output positions in a different datum, use the $PASHS,DTM
command. Once set to a different datum, then all position outputs in NMEA messages
such as GGA and GLL and the position displayed on the LED screen will be
referenced to the chosen datum. For a list of Datums, refer to Appendix A, Reference
Datums and Ellipsoids.
If the list of datums does not include a datum of interest to the user, a user defined
datum may be created and supplied to the receiver. This is done using the
$PASHS,UDD command along with the $PASHS,DTM command. Prior to using
these commands, the user must first define the required parameters including the
length of the semi-major axis and amount of flattening in the reference ellipsoid, and
the translation, rotation, and scale between the user defined system and WGS-84.
The rotation and scale parameters are only available in version UC00 or later.
Datum to Grid Data projected from a geodetic system, associated with WGS-84 or a user
defined datum and a specified grid system.
Map Projections Supported
• Mercator (EMER)
• Transverse Mercator (TM83)
• Oblique Mercator (OM83)
• Sterographic (Polar and Oblique) (STER)
• Lambert Conformal Conic (2 standard parallels) (LC83)
Special Map Projections Specific to NAD27
• Transverse Mercator 27 (TM27 and TMA7)
• Oblique Mercator 27 (OM83)
• Lambert Conformal Conic 27 (LC27)
Elevation Modeling Interpolation of geoidal undulations
Table 5.1: User Coordinate Transformation Functionalities (continued)
Transformation Description