2 September 2016
Changes to Ordnance Survey GNSS Control Networks and Geoid Models in Britain, Ireland and Northern Ireland and the implications for users of Leica SmartNet and GNSS
Changes to SmartNet services on 4th September 2016
On the evening of Sunday 4th September 2016 Leica Geosystems will update the reference station coordinates for the default SmartNet services. Customers wishing to carry out surveys in OSGB36 coordinates on new sites after that date where consistency with previous work is not essential are recommended to install and use the new OSGB36(15) coordinates system files and not to use OSGB36(02).
Users who need to work with the "old" reference station positions should configure their kit to receive those corrections.
It is recommended not to use the new OSGB36(15) coordinates system in combination with the "old" reference station coordinates.
Continued support of old active station coordinates for users of Leica SmartNet real time and post processing services
Leica Geosystems will continue to support the use of the "old" active station coordinates in both real-time correction services and post processing until at least the end of 2016.
Brief summary of required actions for users of Leica SmartNet real time and post processing services
• Users wishing to adopt OSGB36(15) or Irish coordinate systems with the new geoid model on field kit and office software must download and install the coordinate system parameter files:
• SmartNet NRTK users who need their work to be consistent with previous work on a particular site, whether that be in OSGB36(02), ITM, Irish Grid, SnakeGrid, Highways Agency grids, or any local site grids will have to make changes to the settings on field kit after the 4th September 2016:
• Users wishing to create new locally determined coordinate systems onboard field kit can continue as normal, but be aware that the active station coordinates will have changed on the 4th September 2016.
• Users wishing to post process GNSS baselines in Leica Geo Office or Infinity using the old active station coordinates should follow these instructions
• Users wishing to post process GNSS baselines in Leica Geo Office or Infinity using the new active station coordinates can continue as normal.
Background to the coordinate system changes in Britain, Ireland and Northern Ireland
Ordnance Survey of Great Britain, Ordnance Survey Ireland and Land & Property Services Northern Ireland have jointly developed a new zero order control network based on the 2009 realisation of ETRS89 which has been ratified by EUREF as an improved and homogeneous realisation of ETRS89 for the entire region.
Further information on this can be found in the article published in both the July/August 2016 edition of the ICES Civil Engineering Surveyor magazine and the July/August 2016 edition of the RICS Geomatics World magazine:
New coordinate systems for Britain and Ireland
There are new geoid models for Britain, Ireland and Northern Ireland.
Britain gets a new horizontal transformation network, OSTN15, which minimises the effects of the active station movement on East/North coordinates computed from GNSS measurements. In Ireland and Northern Ireland the existing ITM polynomial remains the official horizontal coordinate system.
More information on this is available in the webinar recording: https://leica-geosystems.webex.com/leica-geosystems/ldr.php?RCID=f3964def3950d9ce9e1689aa1fc04131