Outback S3 - Overview of Differential Correction Types

S3 User Guide 56 PN 875-0196-000 Rev C1
Chapter 5: Differential Correction Types
Overview
This chapter provides an overview of the differential correction types used by the S3.
The S3 supports several differential correction types including SBAS (Space Based
Augmentation System), e-Dif, LOCRTK, and L-Band.
• For North American distribution SBAS (WAAS) and LOCRTK are the factory
installed options. WAAS is free and is available throughout most of North
America. To use LOCRTK, you must have an Outback BaseLineX or Outback
A220/A221 system.
• For European distribution SBAS (EGNOS) and LOCRTK are the factory
installed options. EGNOS, like WAAS, is also free and is available
throughout most of Europe. Again, to use LOCRTK, you must have a
BaseLineX or A220/A221 system.
If you are in a location that does not have access to SBAS corrections like WAAS or
EGNOS, then e-Dif and LOCRTK are the factory installed options. You will not need any
additional hardware to use e-Dif. However, to use LOCRTK, you will need a BaseLineX
or A220/A221.
Review the following information regarding correction types:
•LOCRTK
LOCRTK, as factory installed, is not pre-activated. To use LOCRTK, you will
need a BaseLineX rover unit or A220 smart antenna, a base station, and a
one-time subscription code. For more information on using the LOCRTK
correction type refer to the BaseLineX, A220, or A221 User Guide (all
available from the Outback Guidance website at
www.outbackguidance.com).
•e-Dif
S3’s e-Dif application comes with a pre-activated one-time primary
subscription that you can use anywhere in the world. e-Dif should be used
only for relative guidance applications and is not recommended for data
recording and subsequent comparative analysis. Relative positional
accuracy will typically drift at a rate of 1-2 m (3-6.5 ft) per hour making pass
to pass accuracy for broad-acre applications acceptable. However, absolute
positional accuracy errors may approach ±10 m (±33 ft).
• RTK/BaseLineX
Real Time Kinematic (RTK) technology provides high levels of positional
accuracy. RTK technology uses a base receiver on a site of known
coordinates and broadcasts corrections to a rover unit.
BaseLineX and A221 offer Differential GPS (DGPS) that uses RTK technology.
Both use a base station (stationary) to broadcast corrections over a wireless
link to a rover radio (mobile) or multiple rover radios. The localized
corrections from the base station are processed in the rover GPS system to
achieve accuracy and repeatability that is not possible with SBAS, beacon,
e-Dif or most other differential correction methods.
One of the advantages of using BaseLineX or A221 is that one base station
can be used with multiple rover radios.
For more information on BaseLineX or A221 refer to the BaseLineX or A221
User Guide (both available from the Outback Guidance website at
www.outbackguidance.com).