Lantmteriet National Land Survey of Sweden

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SWEPOS a Multi-purpose National Network of
Reference Stations

• LantmäterietNational Land Survey of Sweden
• Christina Kempe, Bo Jonsson, Gunnar Hedling and
  Peter Wiklund
• christina.kempe_at_lm.se
• www.swepos.com

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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
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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

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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
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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

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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)

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Monitoring of SWEPOS

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

SWEPOS Control Centre
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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

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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)

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Post-processing Service
Observation data(RINEX file)
Computed position Quality parameters
Post-processing Service
?
?
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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

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Prototype ProductionNetworks (2002-2003)

• 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

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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.
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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

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Applications today and in the future
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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