The key difference between GPS and DGPS lies in their accuracy and how they achieve it; GPS (Global Positioning System) provides standard location information, while DGPS (Differential Global Positioning System) enhances accuracy by using a network of ground-based reference stations that correct GPS signals.
Here's a breakdown of the key differences:
Accuracy
- GPS: Provides accuracy that can range from a few meters to tens of meters, depending on factors such as atmospheric conditions and satellite geometry.
- DGPS: Offers significantly improved accuracy, often down to sub-meter levels. This enhanced accuracy makes it suitable for applications requiring precise positioning.
Correction Method
- GPS: Relies solely on signals received from GPS satellites to determine location. It doesn't use external correction signals in its standard form.
- DGPS: Uses a network of fixed, known location reference stations. These stations receive GPS signals, calculate the errors, and then broadcast correction signals to DGPS-enabled receivers. This real-time correction minimizes errors caused by atmospheric interference, satellite clock errors, and other factors.
Components
- GPS: Consists primarily of GPS satellites orbiting the Earth and GPS receivers that calculate their position based on these satellite signals.
- DGPS: Includes all the components of GPS, plus a network of reference stations, data links to transmit correction signals, and DGPS-enabled receivers capable of processing these corrections.
Applications
- GPS: Used for a wide range of applications, including navigation (in cars, smartphones, and airplanes), mapping, recreation, and location tracking.
- DGPS: Deployed in applications that demand high precision, such as surveying, precision agriculture (e.g., automated tractor guidance), construction, marine navigation (e.g., harbor navigation, dredging), and scientific research.
Cost
- GPS: Standard GPS receivers are relatively inexpensive and widely available.
- DGPS: DGPS-enabled receivers are typically more expensive than standard GPS receivers due to the added complexity of processing correction signals. Also, using DGPS often involves subscription fees for accessing correction services.
Summary Table
| Feature | GPS | DGPS |
|---|---|---|
| Accuracy | Meters to tens of meters | Sub-meter |
| Correction | None (in standard form) | Uses ground-based reference stations to correct signal errors |
| Components | Satellites, GPS receivers | Satellites, GPS receivers, reference stations, data links |
| Applications | Navigation, mapping, general tracking | Surveying, precision agriculture, construction, marine navigation |
| Cost | Lower | Higher (receivers and often subscription fees for correction data streams) |
In essence, DGPS is an enhanced version of GPS that leverages ground-based reference stations to significantly improve positional accuracy by mitigating errors present in standard GPS signals.
