Spectra Precision Survey Pro v4.5 Recon and Nomad User Manual - Manual (Page 219)

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GPS Overview
This portion of the User's Manual includes basic fundamentals of
GPS coordinate systems and measurements. The following section
discusses how GPS coordinates are used in Survey Pro. Both of these
sections contain general information that applies to both the GPS
module and Basic GPS module.
Following these general sections are two sections that are specific for
the GPS module and the Basic GPS module. Each of these sections
provide instructions that guide you through how to set up GPS
equipment and use Survey Pro for GPS data collection and stake out,
including tutorial jobs.
There are two methods to collect GPS measurements with Survey
Pro: Real Time Kinematic (RTK), and data logging for post
processing. Both methods calculate geodetic positions with a
differential GPS solution using carrier phase pseudo range
positioning. When doing RTK GPS, you will need to solve a coordinate
system in the data collector to transform the real time geodetic
coordinates into local coordinates for your survey. When doing post
processing, you may solve a coordinate system in the PC software.
This section describes some basic concepts and terminology
associated with RTK and post processing data collection. In this
section, you will learn:
¾ Some basic terminology and theory required to understand
GPS measurements.
¾ A description of the different GPS solution types, and the
expected precision of each one.
¾ A description of the WGS84 datum and how to use different
horizontal datum transformations in Survey Pro.
¾ A description of different vertical datums in North America.
¾ A description of geodetic and mapping plane coordinate
systems.
¾ A description of scale corrections for the mapping plane, scale
correction for height, and how to apply the combined scale
factor to convert ground to grid distances.