Spectra Precision Survey Pro v4.6 Recon and Nomad User Manual - Manual (Page 281)

GPS Module
271
Start GPS Survey - Choose
Projection Mode
The Start GPS Survey Choose Projection mode screen is used to
choose the horizontal projection mode. There are two choices:
Choose to Use Ground – TDS Localization when your
survey is a ground level site with no projection and no
datum to relate the local coordinates to geodetic. When
you choose Ground – TDS Localization, the next step will
be base and rover setup, and solving the localization
adjustment.
Choose to Select a Mapping Plane Zone when your survey
coordinate system is a conformal mapping plane defined
in the coordinate system database. When you choose
Mapping Plane
mode, your next step will be to select a
coordinate system from the database (Page 250). Then,
you will proceed with base and rover setup. If you set
the base on a known point, you do not need a
localization adjustment and you will be ready to collect
data after rover setup. If you start from an autonomous
base, you must solve a localization adjustment.