Meaning
GPS is a satellite-based navigation system that provides information about location, velocity, and time to users anywhere on or near the Earth, as long as they have a compatible receiver.
It was developed by the United States and is one of the most widely used global navigation systems in the world.
Nature of the system
GPS is a global navigation satellite system. It works through a constellation of satellites orbiting the Earth and transmitting signals to ground-based receivers such as phones, vehicles, ships, aircraft, and navigation devices.
A GPS receiver calculates its position by measuring signals from multiple satellites.
Main segments of GPS
GPS has three major segments:
• Space segment
The satellites orbiting the Earth
• Control segment
Ground stations that monitor and manage the satellites
• User segment
Receivers used by civilians, military forces, transport systems, and other users
How it works
GPS works on the principle of trilateration.
A receiver determines its position by calculating its distance from multiple satellites using the time taken by the signals to reach it.
To determine an accurate position, the receiver generally needs signals from at least:
• 4 satellites
This helps it calculate:
• latitude
• longitude
• altitude
• time correction
Main functions
GPS provides:
• positioning
• navigation
• timing
That is why it is often called a PNT system — Positioning, Navigation, and Timing.
Uses of GPS
GPS is used in many sectors:
• road navigation
• aviation
• maritime transport
• military operations
• disaster management
• agriculture
• surveying and mapping
• mobile phones and location-based services
• telecommunications and timing synchronization
