Hoe does GPS work? GPS trilateration and uses of gps

How does GPS work?

GPS stands for Global Positioning System.

It is a radio navigation system used on land, sea, and air to determine exact location, time, and velocity irrespective of weather conditions. The military first used it in the year 1960.

Components of GPS system

GPS system is made up of 3 components:

1. Satellites
2. Ground stations and
3. Receiver

There are at least four satellites in the line of sight of the receiver on Earth. GPS satellites send radio signals. Many satellites are orbiting Earth. Each satellite continuously broadcasts its exact position, the exact time according to its very accurate atomic clocks, and a coded radio signal. The receiver receives the satellite's radio signals and also can estimate the distance to the satellite :

Distance = Speed * travel time

The receiver calculates the time difference. The main role of the ground station is to monitor the GPS satellite system. Using the trilateration process, the receiver locates its position as the signals are obtained from at least 3 satellites.

• For a GPS to calculate 2D position, a minimum of 3 satellites are required.
• For 3D position, a minimum of 4 satellites are needed.

Use of GPS in Forest Inventory:

• It helps in Mapping and Navigation of forest area.
• Plot location and boundary determination.
• Data collection
• Integration with GIS: GPS data can be integrated with GIS to analyse and visualise forest inventory data spatially.
• Forest fire management: GPS is used to record the location of fire incidents, fire lines, burned areas, fire control points, and hotspots.
• Wildlife management: GPS helps locate wildlife, monitor animal movements, and map habitats and corridors when GPS collars are used.
• Illegal activities and encroachment monitoring: Location of illegal logging, forest encroachment, poaching sites, and other disturbances can be recorded.

Thus, GPS is an essential geospatial technology in modern forestry that enables accurate field data collection and mapping, monitoring and navigation, thereby supporting evidence-based, efficient and sustainable management of forest resources.