GPS / GNSS Corrections
A club member operates an NTRIP correction service and makes the data stream available to ZL2KS members free of charge.
If you are working with high-accuracy GNSS/GPS equipment and need positioning accuracy at approximately the centimetre level, access to this service may be useful.
If you would like access to the service, please email the Secretary. They will arrange for you to receive the connection details and credentials.
What is NTRIP?
A normal GPS/GNSS receiver can determine its position to several metres. For applications where much greater accuracy is required, a receiver can use additional correction data from a precisely surveyed reference station.
NTRIP stands for Networked Transport of RTCM via Internet Protocol. It is a standard method for delivering GNSS correction data over the Internet.
In simple terms, an NTRIP system works like this:
- A fixed GNSS reference station knows its own position very accurately and receives signals from the satellites.
- The reference station generates correction information based on the difference between its known position and the position calculated from the satellite signals.
- The correction data is sent over the Internet to an NTRIP caster.
- A user’s GNSS receiver, or suitable software connected to it, acts as an NTRIP client and receives the correction data.
- The receiver uses this information together with the satellite signals it is receiving to calculate a much more accurate position.
An NTRIP caster is essentially a central distribution point: it receives GNSS data streams from reference stations and makes those streams available to multiple users.
Why use it?
With suitable GNSS hardware, correction data can improve positioning from ordinary metre-level accuracy to centimetre-level accuracy under suitable conditions. High-precision positioning is commonly used for surveying, mapping, machine control and other applications where knowing an exact position is important.
The actual accuracy achieved depends on the GNSS receiver and antenna, the correction service, satellite reception, atmospheric conditions, distance from the reference station or network, and how the equipment is configured. Centimetre-level accuracy should therefore not be assumed simply because an NTRIP connection is being used.
For ZL2KS members
The ZL2KS member-operated service is available free of charge to members.
If you have suitable GNSS equipment and would like to use the service, please contact the Secretary to request access details and credentials.