Global Navigation Satellite System (GNSS): Meaning, Working, NavIC & Uses

In today’s digital world, navigation apps, ride-hailing services, and even banking systems rely heavily on satellite-based positioning. This is made possible through the Global Navigation Satellite System (GNSS) — a powerful space-based navigation system that provides accurate location, timing, and navigation services worldwide.

Read on if you are wondering what is Global Navigation Satellite System or what is GNSS.

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About Global Navigation Satellite System

The GNSS full form stands for Global Navigation Satellite System. It is an umbrella term that describes any satellite navigation system with global coverage. While many people use the term “GPS” generically, GPS is actually just one component of the broader GNSS ecosystem.

GNSS relies on constellations of satellites, ground control networks, and special receivers. This technology offers positioning, navigation, and timing (PNT) services and is essential across many sectors, impacting our daily lives.

Types of Global Navigation Satellite Systems

Several countries have developed their own satellite navigation systems. These systems differ in their satellite numbers and orbital paths. Together, they form the broader Global Navigation Satellite System.

• GPS (Global Positioning System): This is the United States’ system. It has 24 satellites orbiting at 20,200 km. Six satellites are almost always visible from any point on Earth.
• GLONASS (Russian Federation): Russia’s system uses 24 operational satellites. They orbit at 19,140 km in circular paths. GLONASS offers reliable navigation, similar to GPS.
• Galileo (European System): Europe’s system started in 2016. It plans to have 30 satellites, including spares, at 23,222 km. This system provides precise positioning.
• BeiDou Navigation System China (BDS): China’s system includes 35 satellites. It uses different orbits (GEO, IGSO, MEO). BeiDou provides enhanced global positioning capabilities.
• NavIC (India Navigation System): India’s IRNSS, or NavIC, is a regional system. It uses geosynchronous satellites at 20,650 km. NavIC provides accurate real-time positioning in India and nearby areas.
• QZSS (Japan): Japan’s Quasi-Zenith Satellite System is a regional system. It has four satellites. QZSS improves GPS accuracy in Asia-Oceania.

Global Navigation Satellite System Features

Global Navigation Satellite System components work together to provide accurate services. These systems rely on space-based and ground-based infrastructure. They ensure reliable positioning, navigation, and timing.

• Satellite Constellations: GNSS includes many satellites orbiting Earth. These satellites continuously broadcast their location and time signals. Receivers use these signals to find precise geographic positions.
• Trilateration Technique GNSS: Receivers calculate their position by measuring distances to multiple satellites. This process, known as trilateration, ensures high accuracy. Signal quality and receiver capabilities affect precision.
• Multi-System Interoperability: Modern receivers can use signals from various GNSS. This includes GPS, GLONASS, Galileo, and BeiDou. This improves accuracy, especially in difficult areas.
• GNSS Ground Control Stations: A global network of control stations supports GNSS. These stations process satellite data. This maintains system accuracy and reliability.
• Signal Transmission: Satellites send out ranging codes on two radio frequencies. Receivers decode these signals. They then compute positions with different levels of precision.
• International GNSS Service (IGS): IGS provides global data from hundreds of stations. This data supports scientific research. It also helps improve GNSS accuracy.

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How Does it Work? The Trilateration Technique GNSS

The core of geospatial positioning technology lies in the trilateration technique of GNSS. To determine a 2D location (latitude and longitude), a receiver needs signals from at least three satellites. For 3D positioning (including altitude), a fourth satellite is required.

This satellite positioning system relies on high-precision atomic clocks to ensure GNSS accuracy and signals remain consistent. Even a microsecond of error could lead to a position displacement of several kilometers.

Real-World GNSS Applications in India

The importance of GNSS in modern technology cannot be overstated, especially within the Indian landscape:

• GNSS-based Electronic Toll Collection India: The government is transitioning from traditional RFID to a FASTag GNSS system in India, where tolls are deducted based on the actual distance traveled on highways via satellite orbit navigation system tracking.
• GNSS in Transportation Systems: Beyond tolls, it manages fleet tracking, aviation safety, and maritime navigation.
• GNSS in Agriculture and Surveying: Farmers use global positioning technology for precision farming, while surveyors use it for land mapping and urban planning.
• Satellite-Based Timing System: Banks and power grids use GNSS to synchronize timing across vast distances.

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Whether it is for personal navigation or national security, GNSS determines the efficiency of tomorrow. As India integrates the NavIC system into more consumer devices and implements GNSS-based tolling, our reliance on this satellite based timing system and positioning tech will only grow.

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