LantmäterietNational Land Survey of Sweden

Christina Kempe, Bo Jonsson, Gunnar Hedling and Peter Wiklund

christina.kempe@lm.se

www.swepos.com

SWEPOS™ –a Multi-purpose National

Network of Reference

Stations

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

1995-1999: SWEPOS was designed and financed by a number of governmental agencies

2000-: Lantmäteriet is responsible for operation and development of SWEPOS

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

The SWEPOS™ Network

5 IGS stations: Kiruna, Mårtsbo, Borås, Onsala, Visby7 EPN stations: Kiruna, Mårtsbo, Borås, Onsala, Visby, Skellefteå, Vilhelmina

21 complete stations 40 simplified stations

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

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)

Monitoring of SWEPOS

• Data• In-door temperature• Power supply• Data connections• Visitors

SWEPOS Control Centre

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

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)

Post-processing Service

Post-processingService

Post-processingService

Observation data(RINEX file)

Observation data(RINEX file)

Computed positionQuality parameters

Computed positionQuality parameters

Network RTK in Sweden

• Network RTK for navigation and positioning with centimetre accuracy

– Pre-study projects 1999-2001

– Prototype Production Projects, 2002-2003

– National Positioning Service + Establishment Projects, 1 Jan 2004

• Design– Densification of the existing

SWEPOS infrastructure

– Collaboration projects between Lantmäteriet and GPS users

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

Prototype ProductionNetworks (2002-2003)

Pos. Stockholm-Mälaren 2

Väst-RTK

SKAN-RTK 2

1 January 2004

• Network RTK service – 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.

The Future

• 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

2005

2006

2004

2005

Applications today and in the future

2005

2006

2004

2005

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