14.42 GNSS Instruments

14.42.2 Describe the basic principles and operation of a GNSS (Global Navigation Satellite System).

GNSS is a satellite-based navigation system that provides position, velocity, and time (PVT) information

Principle:

• Based on time and distance measurement
• Satellites transmit signals with precise time and position data
• The receiver measures the time delay of each signal
• Distance = speed of light × time taken

Operation:

• The receiver requires signals from at least 4 satellites
• By calculating distances to multiple satellites, it determines its position using trilateration
• Provides:
  • Latitude, longitude, altitude
  • Groundspeed and track
  • Accurate time