This guide will summarise what differential corrections are, their uses and how to use them on OxTS units.
What are differential corrections and why they are needed
The atmosphere contains a partially ionised medium, as result of the X and UV rays of Solar Radiation and the incidence of charged particles. As a result, the signals from satellites are compressed by varying amounts in different places and at different times due to these changes. This is why position accuracy without corrections (position mode SPS) can only give 1.5m accuracy, using corrections can improve this to 1-2 cm when receiving Integer level corrections.
To counter this there are several methods to apply differential corrections for correct these errors (select the links below for further information):
- SBAS (Satellite Based Augmentation Systems)
- Serial port based corrections: base station and external NTRIP (Networked Transport of RTCM via Internet Protocol) client
- Internal NTRIP client
- Network DGPS corrections
It is good practice to only enable ONE correction type at a given time to avoid conflicting messages.