Trimble Outdoors AgGPS 252 - Manual (Page 18)

2 Overview
1 2 AgGPS 252 Receiver User Guide
instrument was turned on. This process is called convergence.
Convergence to where the error is estimated to be below 30 cm
(approximate 12 inches) typically takes around 20 minutes. Factors that
influence the time to convergence include the environment, the
geographical location, and the distance to the closest OmniSTAR
corrections base station. OmniSTAR is continually improving the
service.
For more information about OmniSTAR, go to the OmniSTAR website
at www.omnistar.com. For information about activating an OmniSTAR
subscription, see OmniSTAR, page 29.
25.3
Autonomous GPS positioning
Autonomous GPS positioning uses no corrections. The rover receiver
calculates its position using only the GPS signals it receives. This
method does not have high absolute accuracy, but the relative accuracy
is comparable to the other methods.
Ag252_100B_UserGuide_ENG.book Page 12 Thursday, July 28, 2005 4:06 PM