1. SWEPOS™ – a Multi-purpose National Network of Reference Stations
Lantmäteriet National Land Survey of Sweden
Christina Kempe, Bo Jonsson, Gunnar Hedling and Peter Wiklund

2. How it started 1991: SWEPOS was established as a collaboration project
1992: Establishment of some experi-mental permanent reference stations
1994: A network of 21 stations in test operation
: SWEPOS was designed and financed by a number of governmental agencies
2000-: Lantmäteriet is responsible for operation and development of SWEPOS

3. The Purpose of SWEPOS The purposes of SWEPOS are
Provide L1 and L2 raw data for post-processing
Provide DGPS and RTK corrections
Act as high-precision control points
Scientific studies of crustal motion
Monitor the integrity of the GPS system

4. The SWEPOS™ Network 21 complete stations 40 simplified stations
5 IGS stations: Kiruna, Mårtsbo, Borås, Onsala, Visby
7 EPN stations: Kiruna, Mårtsbo, Borås, Onsala, Visby, Skellefteå, Vilhelmina

5. Complete SWEPOS Station
Mounted on bedrock
Power backup for 48 hours
64 kb leased lines for data communication and 19.2 kb lines for back-up
Redundant GPS receivers, back-up computers and communication equipment
Temperature and power monitoring
Burglar alarm

6. Simplified SWEPOS Station
Antenna mounted on building
Battery back-up for 30 minutes
64 kb data connection, no back-up line
One GPS receiver, no back-up computer or communi-cation equipment
Monitored by the 21 complete SWEPOS stations (daily)

7. Monitoring of SWEPOS Data In-door temperature Power supply
Data connections
Visitors
SWEPOS Control Centre

8. SWEPOS Data Post-processing data
Single-frequency RINEX – metre accuracy
Dual-frequency RINEX – centimetre accuracy
Real-time data
L1/L2 data in receiver format
DGPS data RTCM ver. 2.2 – metre accuracy
Network RTK data (regionally) – centimetre accuracy

9. SWEPOS Real-time Services
EPOS™ (metre accuracy)
DGPS service operated by Cartesia
RDS channel on the FM radio band
Omnistar (metre accuracy)
WADGPS service operated by Fugro
Satellite distribution
Network RTK service (centimetre accuracy)
Cellular phone (VRS mode)

10. Post-processing Service
Observation data (RINEX file)
Computed position
Quality parameters
Post-processing
Service  

11. Network RTK in Sweden
Network RTK for navigation and positioning with centimetre accuracy
Pre-study projects
Prototype Production Projects,
National Positioning Service + Establishment Projects, 1 Jan 2004
Design
Densification of the existing SWEPOS infrastructure
Collaboration projects between Lantmäteriet and GPS users

12. Prototype Production Networks (2002-2003)
Pos. Stockholm- Mälaren 2
Väst-RTK
SKAN-RTK 2
Experiences from the users
Network RTK is efficient and easy to use
The “GPS maturity” of the users is varying
A high availability of the Network RTK service is required
The coverage of suitable distribution channels is a bottleneck in some areas
Standards for data format and GPS receivers are welcome

13. 1 January 2004 Network RTK service 180 subscribers 1 Feb 2004
User fees for operation costs
Starting fee: € 550/connection
Unlimited data amount: € 1600 /year and connection
Down-loaded data: € 550 /year and connection + € 0.5 /min
180 subscribers 1 Feb 2004
The cost for distribution of data via GSM is not included.

14. The Future Proposal on a National Network RTK service of 112 stations
2005
2006
2004
Proposal on a National Network RTK service of 112 stations
Estimated investment cost of 4 million € and a yearly operation cost of 2.5 million €
The investment is covered by governmental funds and the operation costs mainly by user fees
The proposal is approved by the Director General

15. Applications today and in the future
2005
2006
2004

16. Conclusions
A multi-purpose network of permanent stations is bene-ficial both for users and for the providers of national infra-structure for positioning and non-safety-of-life navigation.
Further developments in standardisation, reliability and precision are desirable