GNSS (Global Navigation Satellite Systems) is the technology that determines position from signals coming from satellite constellations such as GPS, GLONASS, Galileo and BeiDou. Because it offers fast, consistent measurement over wide, open areas, it is one of the fundamental tools of surveying.
When is GNSS the right tool?
There is no single “best” instrument for every measurement; the right choice depends on the site. GNSS stands out especially in these conditions:
- Wide, open areas — terrain, surface mining, large sites.
- Points with a clear view of the sky — places where the satellite signal is not blocked.
- Jobs that need speed — collecting a large number of points in a short time.
By contrast, GNSS weakens in enclosed volumes, dense building interiors and environments where the view of the satellites is blocked. In these cases the total station or laser scanning takes over.
Working methods
GNSS measurement is done in different forms depending on the accuracy required:
- RTK (real-time kinematic): with corrections from a reference (base) station, position at centimetre accuracy within seconds. Common in setting out and fast field survey.
- Static measurement: high accuracy obtained by collecting data at points over a longer period. Used in control networks and precise geodetic work.
- Post-processing: accuracy increased by processing the collected raw data in the office.
GNSS and the total station together
A professional survey team uses GNSS and the total station not as alternatives but as complements. GNSS builds a fast control network over a wide area; the total station, relying on that network, measures enclosed and precise points. Using the two together preserves both speed and accuracy.
Where is it used?
- Production of the topographic base map
- Surface mining and volume-calculation surveys
- Wide-area setting out and control work
- Control-network establishment within industrial surveying
Used in the right conditions, GNSS is the most practical way to measure wide sites quickly and reliably.