What are the types of GPS used in surveying?

Short Answer:

There are several types of GPS used in surveying based on the level of accuracy and application. The main types include Handheld GPS, Mapping GPS, Survey-grade GPS, Differential GPS (DGPS), and Real-Time Kinematic (RTK) GPS. Each type serves a different purpose, from basic navigation to high-precision land surveying.

Survey-grade and RTK GPS systems are used for precise engineering work, while handheld and mapping GPS units are used for general location tasks, route marking, and basic measurements in field mapping and planning activities.

Detailed Explanation:

Types of GPS used in surveying

GPS (Global Positioning System) is widely used in civil engineering for measuring land positions, mapping, and construction layouts. Depending on the accuracy and function required, different types of GPS systems are available for various surveying needs. The main types used in surveying are explained below:

1. Handheld GPS

  • These are small, portable units mainly used for basic navigation and low-accuracy tasks.
  • Commonly used in environmental studies, hiking, and route marking.
  • Accuracy: Usually 3 to 10 meters.
  • Not suitable for precise engineering or boundary surveying.

Use Case: General location tracking and non-critical data collection.

2. Mapping GPS

  • These provide slightly better accuracy than handheld GPS and are used in GIS mapping and land records work.
  • They can map features like roads, water bodies, and land boundaries for planning purposes.
  • Accuracy: 1 to 3 meters.

Use Case: Town planning, forestry surveys, and utility mapping.

3. Survey-grade GPS

  • This is the most accurate type, used for engineering, construction, and cadastral surveys.
  • It consists of base and rover units with very precise timing and signal correction features.
  • Uses static or RTK methods.
  • Accuracy: Up to millimeters (in RTK) or centimeters (in static).

Use Case: High-precision work such as road alignment, boundary surveys, and building layout.

4. Differential GPS (DGPS)

  • DGPS uses a reference station at a known location to correct the GPS signals received by the surveyor’s mobile unit.
  • It improves the accuracy significantly by correcting signal errors.
  • Accuracy: Less than 1 meter.

Use Case: Marine navigation, agriculture, and moderate-accuracy land surveys.

5. Real-Time Kinematic (RTK) GPS

  • RTK is a method used with survey-grade GPS systems to give real-time correction while measuring.
  • A fixed base station sends correction data to a mobile receiver (rover).
  • Results are displayed instantly with high accuracy.
  • Accuracy: 1 to 2 centimeters.

Use Case: Precision construction, roadworks, and large infrastructure projects.

Conclusion

The types of GPS used in surveying vary based on the level of accuracy and purpose. From basic handheld GPS units to highly accurate survey-grade and RTK systems, each serves different tasks in civil engineering. Choosing the right GPS depends on the project requirement, budget, and the level of detail needed for the survey.