A Brief History of Satellite Navigation System, and the difference between GPS and GNSS
Updated: Jun 5, 2022
The first artificial satellite to orbit the Earth, Sputnik, was launched by the Soviets on Oct. 4, 1957, and scientists could determine its orbit from its radio transmission. This paved the way for satellite navigation.
We can see the benefits of satellite navigation everywhere. It is a reliable tool for businesses and organizations across a multitude of sectors. Satellite positioning helps to enhance traffic flow and vehicle efficiency; provides user guidance, and tracks products and shipments, and even family members or lost pets. It supports rescue missions and emergency operations, especially in hazardous situations like mines and war zones. Satellite navigation is a useful tool in time-stamping financial transactions and conducting meteorological and earth science studies. It provides accurate time and location data, which is critical in an IoT network. Because of the extensive usage of navigation devices, such as cellphones, tablets, and vehicles, we can no longer imagine a life without satellite navigation.
What is GNSS and how is it different from GPS?
The words GNSS and GPS are often used when discussing Satellite Navigation. The Global Navigation Satellite System (GNSS) is a constellation of satellites that deliver timing and location information to receivers on the ground. However, GPS is currently the most widely used GNSS on the planet and it is usually taken for granted. Most individuals are unaware that they are using GNSS when they use their phones or Google Maps to navigate.
So, what exactly is GNSS, and how does it differ from GPS?
What is GPS?
Let's talk about what GPS is first. The Global Positioning System (GPS) is one component of the Global Navigation Satellite System. GPS is now the most widely used GNSS in the world, and provides continuous positioning and timing information globally, under any weather conditions.
The Global Positioning System (GPS) is a satellite constellation that has revolutionized how humans travel and navigate. The satellite system consists of 24 satellites in six orbits, each with four satellites. The US Military created it to transmit coordinates to soldiers to avoid the use of charts or landmarks. Citizens first had access to GPS in the 1990s.
We only need three satellites to produce a location on the earth's surface via trilateration. We do, however, use a fourth satellite to confirm the data from the other three. The third dimension, altitude, is also provided by the fourth satellite.
What is the GNSS (Global Navigation Satellite System) and how does it function?
GNSS refers to all global satellite positioning systems. This is a constellation of satellites that give position and timing data from orbit to ground-based GNSS receivers.
How can we find out the location from satellites?
The satellites send out signals that are picked up by a receiver and used to calculate the satellites' positions. Each satellite transmits to the earth a sequence of data, including the time, location, and speed. The time difference between signal reception and broadcast is used to calculate the distance between the receiver and the satellite. The receiver transforms its precise position about each satellite into a coordinates system: i.e. latitude, longitude, and altitude.
What is the difference between GNSS and GPS?
The "GPS" is a subset of the GNSS system. A GPS receiver can only read information from satellites in the GPS satellite network, whereas a standard GNSS device can receive data from both GPS and GLONASS, as well as any other system.
The European Union partnered with China, India, Japan, and Russia to establish the GNSS network. There are 60 satellites accessible for viewing on a GNSS receiver. While only three satellites are required to detect a device's location, accuracy improves as the number of satellites increases. A GNSS device can read more satellites, which improves accuracy.
Other GNSS constellations
For many years, GPS and its Russian-owned equivalent GLONASS were the only GNSS systems accessible. However, the world today benefits from the European Union's Galileo, China's BeiDou, India's NaviC, and Japan's Quasi-Zenith Satellite System or QZSS. Each one effectively performs the same function: sending timing and locational data that may be used to calculate local time and location on the ground or in the air. They are different from each other by the number of satellites, their orbit, and operating frequencies.
GALILEO (EU) Europe’s own GNSS program
The Galileo satellite navigation system is Europe's global navigation satellite system. Galileo deserves special attention since, unlike other systems, it is controlled by civil law. Millions of individuals use satellite navigation daily, including truck and taxi drivers, ship and aviation crews, financial transactions, and telecommunication broadcasts, as well as utility services, security and humanitarian missions, and emergency services. Depending solely on military-controlled American Global Positioning System (GPS) or Russian GLONASS signals would be suicidal. Therefore, Galileo is now a reliable choice, and users may now know their exact position under any circumstances, with greater precision, thanks to Galileo's multi-constellations.
GPS is the first global navigation satellite system to be developed; therefore, the term "GPS" is commonly used to apply to all satellite navigation systems. However, the GNSS is a collection of satellite-based navigation systems, and GPS is just one component in the GNSS, that is employed all over the world. Other GNSS systems include Russia's GLONASS, the European Union's Galileo, China's BeiDou, India's NaviC, and Japan's QZSS.