GNSS and GPS are both used to pinpoint the location of a specific location. However, GPS uses United States satellites, and signals can sometimes be blocked by bad weather or geographic obstacles. GNSS technology uses signals from any navigation satellite to increase accuracy and reliability. These two technologies were developed in different parts of the world and are used for various purposes. Here is a brief comparison of their respective strengths and weaknesses.
GPS is the Most Common GNSS System, Though Other Nations Have Fielded Systems of Their Own
The first thing to understand about GNSS and GPS is how they work. GNSS and GPS are global navigation satellite systems. GPS is a United States-owned system, and all of its components were developed for military use. It is the most widely used satellite navigation system globally and uses a constellation of satellites orbiting the earth at an altitude of approximately 11000 nautical miles. While GPS has the advantage of being more precise, other GNSS systems, like GLONASS, are still in their early stages and need some time to be widely adopted.
GPS is the World’s Most Widely Used Geospatial Satellite System
If you are confused about the differences between GPS and GNSS, here is a brief primer. GPS is the world’s most widely used geospatial satellite system. Initially developed for military purposes, GPS is now available for civilian use. GPS receivers use synchronized radio signals from a constellation of four or more geosynchronous satellites to determine their location in real-time. Because GPS operates independently of wireless or internet connectivity, it requires no user-supplied data to determine its location. However, wireless or internet connections enhance the value of the information provided by GPS.
While civilians widely use GPS, aviators use GNSS for navigation. They work together to provide the most accurate location, and GNSS systems work with satellites other than GPS. Unlike GPS, GNSS receivers do not rely on satellites not located in the same orbit.
GPS uses GPS satellites to provide location data. Gnss devices use signals from other satellite systems to calculate the location
While the GPS uses GPS satellites to provide location data, GNSS devices use signals from other satellite systems to calculate location. It makes GNSS devices much more accurate than GPS based on one system. It also provides a fourth dimension – time. In addition to the traditional three dimensions of time, GNSS receivers also use atomic clocks to synchronize with their location.
Global positioning systems were first developed in the 1960s. The United States was the first to use the Global Positioning System, and this technology was eventually joined by Russia’s GLONASS and China’s BeiDou. Until recently, GPS users relied on signals from the Russian GLONASS and American GPS constellations. But now, these two systems have a civil alternative. In addition to GPS, GNSS also uses geostationary satellites for positioning. In addition, the European Union has launched the global Galileo system, and China’s BeiDou satellite constellation has 35 satellites.
A GNSS receiver should be purchased as a first step toward precision agriculture. The type of GNSS receiver to buy depends on the needs and budget of the farm. A low-cost receiver may be sufficient for soil tillage and crop operations. However, for high-accuracy tractor operations, a survey-grade RTK-capable GNSS receiver is required. You can check this link for more information.
GNSS is Used for Landing and Takeoff Phases
While GPS and GNSS are widely used for in-flight navigation, GNSS is used for landing and takeoff phases. Future air navigation systems could benefit from using GNSS geolocation to facilitate continuous descent, reduced separation, and route network optimization.
GNSS satellite constellations comprise multiple groups of satellites orbiting earth. Each constellation broadcasts signals to master control stations and GNSS users across the globe.
While GPS satellites orbit between 20,000 and 37,000 kilometers above Earth, GNSS constellations operate on different continents, and various countries manage the satellites. The constellations of each system are unique, but they all share the same basic technology.
Satellites in GNSS constellations must constantly monitor their orbits and position. Each satellite receives frequent corrections of its estimated position and incorporates them into the navigation message to provide accurate information. Since a wave travels close to the speed of light, it is essential to measure the signal’s propagation time accurately. It is critical because slight measurement errors can result in large uncertainties in the distance between a satellite and its receiver. One microsecond error can equate to up to 300 meters error.
