What’s the difference between GNSS and GPS?
Satellite navigation is a system of satellites that provide autonomous geo-spatial positioning everywhere in the world and allow small electronic receivers to determine their position, including longitude, latitude, altitude, and elevation, using time signals transmitted from satellites. The terms GNSS and GPS are used interchangeably but there are fundamental differences between them. Here we analyse GPS vs GNSS:
GNSS stands for Global Navigation Satellite System and is the term used worldwide for different types of satellite-based positioning, navigation, and timing (PNT) constellations used globally. These systems are nation-owned and operated but available to all potential users. The benefit to having access to multiple constellations is the ability to see more satellites in your sky view. This ensures greater availability of signals to your receiver which increases the accuracy and resilience of your position data even if a satellite system fails, signals are blocked, or line of sight is obstructed.
GPS (Global Positioning System) was launched in the late 1970’s by the United States Department of Defence and was the first ever GNSS system. It is currently the world’s most utilised satellite navigation system and, consequently, GPS is commonly used to describe GNSS technology. GPS uses a constellation of 31 satellites in six different orbital planes, the exact number can vary due to older satellites being retired and replaced.
Other GNSS constellations
GLONASS (Global’naya Navigatsionnaya Sputnikovaya Sistema) is a Russian constellation of 24 satellites operating on three orbital planes which are especially useful for high latitudes (north and south).
Galileo was created by the European Union and European Space Agency, going live in 2016. One of the aims of Galileo is to provide an independent high-precision positioning system so European political and military authorities do not have to rely on the GPS or GLONASS systems. Galileo has 24 active satellites.
BeiDou is a Chinese system comprising of 35 satellites. It uses the name given by ancient Chinese astronomers to the seven brightest stars of the Ursa Major constellation, known in English as the “Big Dipper”.
There are two additional constellations; QZSS is a 5 satellite Japanese constellation providing coverage over the Asia-Oceania regions and IRNSS (Indian Regional Navigation System), also known as NavIC, uses 9 satellites to cover the Indian subcontinent
GNSS vs GPS vs GNSS?
The main difference between GPS and GNSS is that GNSS-compatible equipment can use satellites from other networks beyond the GPS system, this flexibility makes it more accurate and reliable than GPS technology alone. In summary, all GNSS receivers are compatible with GPS, but GPS receivers are not always compatible with GNSS.