GNSS vs Total Station — Which Is Right for Your Construction Project?
GNSS (GPS) is best for establishing primary control over large areas and open sites where satellite signal is clear. A total station is best for precise setting out, detail survey, and work in areas where GNSS signal is obstructed — inside structures, near tall buildings, or under tree cover. On most UK construction projects, both are used at different stages and for different tasks.
GNSS rover and total station set up on an active construction site — two of the core tools AKN Engineering uses to deliver precise survey control and setting out across infrastructure and highways projects in the South East, (Hertfordshire, Essex, Cambridgeshire, Northamptonshire).
What Each Instrument Actually Does
Both GNSS and total stations are used to measure position accurately on a construction site — but they work in fundamentally different ways and suit different tasks.
GNSS — Global Navigation Satellite System, commonly called GPS — determines position by receiving signals from satellites. Modern construction-grade GNSS receivers use Real Time Kinematic (RTK) corrections to achieve centimetre-level accuracy in good conditions. They work best in open environments with a clear view of the sky.
A total station is an optical instrument that measures angles and distances from a fixed setup point to a target prism. It works by line of sight — the instrument and the target need to be visible to each other. It is highly accurate over both short and long distances and is not affected by satellite signal conditions.
When GNSS Is the Right Choice
✔ Establishing primary control networks across large open sites
✔ Topographic surveys of open ground — fields, greenfield sites, large earthworks areas
✔ Setting out long linear features — roads, pipelines, boundary lines — across open terrain
✔ Machine control and grading on large earthworks where continuous positioning is needed
✔ Rapid data collection across a wide area where total station setups would be time-consuming
GNSS becomes unreliable where satellite signals are obstructed — inside or near buildings, under dense tree cover, in deep cuttings, or in urban environments with tall structures on multiple sides.
When a Total Station Is the Right Choice
✔ Precise setting out of structural elements — columns, pile positions, slab edges
✔ Work inside buildings or structures where the GNSS signal cannot penetrate
✔ Urban sites where the satellite signal is degraded by surrounding buildings
✔ Detailed survey of existing structures, facades, or complex geometry
✔ Monitoring and as-built checking where millimetre-level accuracy is required
✔ Verification of control points established by GNSS
A total station requires line of sight and a prism target, which means it can be slower on large open sites where many setups would be needed. It also requires a verified control network to set up from.
How They Work Together on a Typical Project
On most UK construction and infrastructure projects, both instruments are used — at different stages and for different tasks. A typical approach:
GNSS is used to establish the primary control network at the start of the project — fixing a small number of high-accuracy reference points tied to Ordnance Survey National Grid coordinates
The primary control is verified independently before any works begin
Total station is used for all precision setting out derived from that control — pile positions, columns, drainage, road centrelines
GNSS may be used again for topographic survey during and after earthworks
Total station is used for as-built checking and verification at handover
The control network established by GNSS at the start of the project is what makes total station setting out reliable throughout the programme. The two instruments are complementary, not competing.
Common Mistakes When Choosing Between Them
Assuming GNSS is always accurate enough for setting out — it isn't in obstructed environments or for precision structural work
Relying on GNSS inside buildings or in urban canyons where signal quality is poor and positions are unreliable
Using a total station without a verified control network — accuracy is only as good as the point it's set up from
Not checking which instrument was used for which task in the setting out register — important when a question arises later
Not Sure Which You Need?
If you're planning a project and aren't sure which approach is right for your site conditions, we're happy to advise. In most cases a short conversation about the site, the scope, and the programme is enough to confirm the right approach.
The Institution of Civil Engineers (ICE) publishes guidance on survey methods and professional standards for construction engineering practice in the UK.
Not sure which survey method your project needs?