Product Manual

45
DGPS Tab
Differential GPS (DGPS) positioning involves subtracting a combination of
ranges measured to various satellites from two or more receivers measuring
the same satellites simultaneously. When the signals are subtracted, the major
error sources cancel each other out.
The GPS receiver used with SatViewer can provide DGPS through the
Satellite Based Augmentation System (SBAS), which uses multiple ground
stations and then broadcasts corrections to the end users via SBAS satellites.
Usage: configures the DGPS requirements as follows:
 Auto: will use DGPS when available, but
continue to provide autonomous
(uncorrected) positions when DGPS is not
available.
 DGPS Required: will only provide positions
when DGPS is available. Autonomous
positions will not be available. When DGPS
data is available, it can be applied to your
GPS position to increase the accuracy of
your position reading.
 Ignored: will not provide DGPS positions
even when available.
NOTE: Due to the limited number and
availability of SBAS satellites in the sky, DGPS
coverage from SBAS satellites may not always be available. Therefore, it is
recommended that you use the Auto setting where the GPS will use and apply
DGPS data when available, but will continue providing positions even when
DGPS is not available.
Type: allows you to select SBAS ON or SBAS OFF. (Currently SBAS is the
only DGPS service available, but other DGPS systems may be available in the
future.)
SBAS Sat. PRN: configures which SBAS satellite to use. Selecting Auto
instructs the GPS receiver to automatically make the selection.
Return to Default Settings: If connected to your Nomad GPS receiver, the
following settings are changed and applied to your Nomad GPS receiver:
 Restores DGPS settings back to default state:
o Usage: Auto
o Type: SBAS ON
o SBAS Sat PRN: Auto