The FINPOS service of the National Land Survey of Finland provides to users real-time DGNSS corrections free of charge from the station closest to the user. Using DGNSS corrections, the positioning accuracy is at best about half a metre. Positioning solutions achieved with DGNSS can be used, for example, for navigation or for various measurement tasks.
Description of the service
DGNSS correction data is transmitted in two versions of the RTCM standard, RTCM 2.2 and RTCM 3.2 (MSM). Version 2.2 can only send corrections for GPS and Glonass systems. Corrections in version 3.2 (MSM1) are not supported by at least older devices, and for new ones this may be rare. Check the documentation of your device or ask from the device manufacturer which of the RTCM messages are supported. The corrections are accompanied by the EUREF-FIN coordinates for the reference stations.
The message types to be sent for version 2.2 are:
| Message Type | Transmission interval | Content |
|---|---|---|
| 1 | 1 sec | GPS differential correction |
| 3 | 10 sec | Reference Station Information |
| 31 | 1 sec | GLONASS Differential Correction |
And for version 3.2 (MSM1):
| Message Type | Transmission interval | Content |
|---|---|---|
| 1006 | 10 sec | Reference Station Information |
| 1071 | 1 sec | GPS code observations and differential correction |
| 1081 | 1 sec | GLONASS code observations and differential correction |
| 1091 | 1 sec | Galileo Code Observations and Differential Correction |
| 1121 | 1 sec | BeiDou code observations and differential correction |
Using the service
The data from the service is sent to the user via the internet in accordance with the NTRIP protocol. Enter the information below into the NTRIP client on your device/software to access the service. To receive the data, the user's device must send an approximate location to the service as an NMEA message.
| URL | opencaster.nls.fi |
| Port |
2102 (unencrypted) or 2105 (TLS encrypted) Not all devices may support TLS encrypted traffic, use port 2102 |
| Username and password |
In addition to this information, also select the desired correction data mountpoint from the following:
| Mountpoint | Description |
|---|---|
| DGNSS | The service automatically links the user to the corrections of the nearest reference station (RTCM 2.2) |
| DGNSS-12SAT | Same as DGNSS, but sending up to 12 satellite corrections. Works with old 12-channel receivers. |
|
DGNSS-MSM1 |
The service automatically links the user to the corrections of the nearest reference station (RTCM 3.2) |
All available mountpoints can be found in the sourcetable of the service.