What is DGPS?

Differential GPS (DGPS) is a refinement of the Global Positioning System (GPS) that reduces errors caused by atmospheric conditions, satellite clock drift, and signal delays. It works by comparing signals received by a stationary base station (with a known location) and a mobile rover unit. Corrections calculated by the base station are sent in real-time to the rover, significantly increasing positional accuracy.

Key Components

• Base Station – A fixed GPS receiver at a known location that calculates correction data.

• Rover – A mobile GPS receiver that moves around the survey area and applies the corrections.

• Radio Link or GSM Modem – Transmits correction signals from the base to the rover.

• Controller/Data Collector – Logs coordinates and stores data.

• Software – Used for post-processing and mapping.

Surveying Procedure

1. Setup Base Station – Install the base station over a known control point.

2. Initialize Rover – Connect and configure the rover to receive real-time corrections.

3. Data Collection – Move the rover to different survey points and record accurate coordinates.

4. Post-Processing (if required) – Apply corrections in software to further refine accuracy.

5. Data Export – Extract and format data for use in CAD, GIS, or other mapping systems.

Applications

• Topographic and cadastral mapping

• Road and railway alignment

• Utility mapping and infrastructure surveys

• Coastal and marine navigation

• Precision agriculture

• Mining and quarrying

Advantages

• High positional accuracy (sub-meter to centimeter level)

• Real-time corrections for immediate results

• Works in remote or open areas where traditional methods are difficult

• Efficient data collection over large areas

• Compatible with GIS and CAD software for seamless integration

Conclusion

DGPS Surveying is a powerful and precise technique for capturing geospatial data with high accuracy. Its ability to provide real-time corrected positioning makes it a go-to method for many modern surveying tasks, especially where accuracy and efficiency are critical.