GNSS Survey Orientation & Map Integration

Survey Orientation - using GNSS RTK, we routinely orientate our surveys to Ordnance Survey grid and Newlyn datum. We can also orientate existing 3rd party surveys and measure the position of 3rd party survey markers such as UAV ground markers.

What is GNSS RTK? - GNSS (Global Navigation Satellite System); receivers such as GPS in your car can triangulate your position to within metres. GNSS RTK (Real-Time Kinematic) ups the ante, with potential accuracy in the order of a centimetre. The device triangulates using up to 21 satellites & utilises a remote RTK network service to fine-tune accuracy in real-time.

Investment - We made the high capital investment in GNSS RTK in 2009, when we saw this technology's potential.

Survey Orientation - We can capture the absolute positions of our land survey control points and then orientate the whole survey to Ordnance Survey (OS) grid and Newlyn datum (mean sea level).

Datum - Ordnance Survey guidance highlights limitations in the traditional Benchmark system. GNSS RTK is generally quicker & safer than traversing to the nearest surviving OSBM, which could be kilometres away. GNSS RTK datum acquisition does not impact on the high relative accuracy of the local survey levelling; we use a single datum (as per RICS 'Virtually Level' guidelines).

Plan Orientation - Given the widespread use of the Ordnance Survey grid space by the Land Registry, Environment Agency, DEFRA and Local Planning Authorities, it often makes sense to orientate land survey plans into this space for consistency.

Our survey plans are oriented to the GNSS controls using a specialised software process with quality controls. It employs a least-squares best-fit approach with no relative deformation, so there is no loss in the high relative accuracy of our Total Station survey. The local survey can be scaled to OS local scale factor, if required.

Post-Orientation - We can orientate existing surveys too. We attend site and use GNSS RTK to acquire the absolute positions of existing survey control markers. Given the co-ordinates in the existing survey, we can geo-reference the original survey. We also have an in-house software utility to bulk-update all spot level text annotation to a revised datum.

Map Integration - We have experience and capability integrating different map data. We routinely overlay and combine OS data, Defra habitat maps, Local Plan spatial models, deed plans and 3rd party plans such as proposed highway improvements.