Differential GNSS
Also known as: DGNSS, Differential GPS, DGPS
Definition
A correction technique that improves GNSS positioning accuracy by comparing a fixed reference station's known, surveyed position against its GNSS-derived position, then broadcasting the resulting correction to nearby receivers to apply to their own position fix.
Key Points
- Relies on a reference station at a precisely known, surveyed location, which continuously compares its GNSS-derived position against its actual known position to calculate the current error
- Broadcasts the calculated correction to nearby receivers, which apply it to their own GNSS fix on the assumption that the same atmospheric and satellite-related error sources affect both the reference station and nearby receivers similarly
- Correction accuracy degrades with distance from the reference station, since the assumption that both the reference station and the receiver experience the same error sources becomes less reliable as the receiver moves farther away
- Improves accuracy specifically by correcting for shared error sources — atmospheric delay, satellite clock and ephemeris error — rather than addressing receiver-specific error sources that a shared correction can't account for
- A foundational accuracy-improvement technique underlying applications requiring positioning precision beyond what standalone GNSS reliably provides, including dynamic positioning and other precision navigation applications
Concept
A DGNSS reference station, because its true position is already precisely known through survey, can calculate exactly how much error its own GNSS receiver is currently experiencing — atmospheric delay, satellite clock drift, ephemeris inaccuracy — and broadcast that error value to any nearby receiver. Those receivers apply the broadcast correction to their own GNSS fix, improving their accuracy under the assumption that they're experiencing largely the same error sources the reference station just measured.
Explainer
The distance-dependent accuracy of DGNSS correction is a direct consequence of the technique's core assumption — that a receiver experiences essentially the same atmospheric and satellite error the reference station does — which holds well for a receiver near the reference station but progressively breaks down as distance increases and the receiver's actual atmospheric path and satellite geometry diverge from the reference station's own. This is precisely why DGNSS deployment planning accounts for reference station coverage radius as a practical design constraint, rather than assuming a single reference station provides uniformly reliable correction across an arbitrarily large area. For CE verticals, DGNSS-level accuracy is a direct prerequisite for applications where standalone GNSS's typical accuracy isn't sufficient — dynamic positioning for offshore vessels holding station near fixed infrastructure, precision agriculture, and survey-grade positioning all depend on DGNSS or comparable correction techniques to achieve the accuracy their specific operational requirement demands.
Cite this entry
Differential GNSS. ConnectedEarth Knowledge Base. https://connectedearth.space/knowledge-base/differential-gnss/ (updated 13 September 2026).