Definition

Differential GPS (DGPS) is an enhancement of the standard Global Positioning System (GPS) that improves location accuracy by using a network of fixed ground-based reference stations. These stations broadcast correction signals to GPS receivers, reducing positional errors caused by atmospheric interference, signal delay, or satellite drift.

Usage

In drone operations, Differential GPS provides highly accurate positioning for surveying, mapping, and precision agriculture. By applying correction data from a nearby reference station, drones can achieve centimeter-level accuracy instead of the typical 2–5 meters offered by standalone GPS.

Relevance to the Industry

Differential GPS is vital in missions where accuracy is critical—such as topographic mapping, infrastructure inspections, and land surveying. It ensures that collected geospatial data aligns precisely with ground coordinates. This reliability supports safe autonomous flight paths, consistent flight planning, and improved data quality for post-processing.

How Does DGPS (Differential GPS) Work?

Differential GPS functions by comparing satellite signals received at a known reference station with those from a drone or mobile receiver. The system calculates the positional error and transmits correction data to the drone.
Key steps include:

• Reference Station Setup: A fixed station at a known location receives satellite signals.

• Error Calculation: The station calculates differences between its actual position and satellite-based GPS readings.

• Correction Transmission: These corrections are sent to nearby drones in real time via radio or internet link.

• Accurate Positioning: The drone applies the correction to improve its positional accuracy.

Example in Use

A drone conducting a land survey uses DGPS to map a construction site with high precision. The system corrects positional data in real time, ensuring the 3D model aligns perfectly with surveyed ground control points.

Frequently Asked Questions About DGPS (Differential GPS)

How accurate is DGPS compared to GPS?
DGPS improves positional accuracy from several meters to within a few centimeters.

Does DGPS require an internet connection?
Not always. DGPS can transmit correction signals via radio frequency, though some systems use online correction services.

Is DGPS still used with modern drones?
Yes. Although RTK and PPK have become more common, DGPS remains a reliable and widely used positioning enhancement system.