Trilateration
Topic: Remote Sensing, GIS and GNSS · NCERT: Beyond NCERT
Meaning
Trilateration is how a GNSS (satellite navigation) receiver finds where it is. Each satellite sends a signal that carries the time it was sent. The receiver works out its distance to the satellite from how long the signal took to arrive. It needs distances to at least four satellites. Three distances fix the position. The fourth corrects the error in the receiver's own clock. This is why very precise atomic clocks on the satellites are so important.
Example
A delivery rider in Chennai opens a map app. The phone picks up signals from four or more navigation satellites, measures its distance to each, and marks the rider's position on the street map.
Don't confuse with
- Triangulation: triangulation is an old ground survey method that fixes positions by measuring angles. Trilateration fixes position by measuring distances.
Related concepts
- Global navigation satellite system
- Global Positioning System
- NavIC
- NVS series satellites
- GAGAN
- Continuously Operating Reference Stations