GNSS

GNSS (Global Navigation Satellite System) is the generic term for satellite navigation systems providing global coverage. It includes:

• GPS (USA) — 31 satellites
• GLONASS (Russia) — 24 satellites
• Galileo (EU) — 30 satellites
• BeiDou (China) — 35 satellites

Modern aviation receivers can use multiple constellations simultaneously for improved accuracy and reliability. GNSS forms the basis for RNAV/RNP navigation and is supplemented by augmentation systems like SBAS (WAAS, EGNOS) and GBAS for approach operations.