April 18, 2021

The Difference between GPS & GNSS

2 min read

Source: EduCBA

Over the past weeks we have heard lots and lots of debates in groups between professionals and juniors over technological terms. Most companies and individuals end up buying the wrong products due to lack of insight into these technical terms.

Today, right now and in this post we’re going to outline the differences between the two terms so that you know what they really mean and what they are capable of doing within the job space.

Lets get into a bit of background for now.

What is a Satellite Navigation

A satellite navigation or “satnav” system is a system of satellites that provide autonomous geo-spatial positioning with global coverage and allow small electronic receivers to determine location (longitude, latitude, and altitude/elevation) using time signals transmitted along a line of sight by radio from satellites.

GPS

The United States’ Global Positioning System (GPS) consists of up to 32 medium Earth orbit satellites in six different orbital planes, with the exact number of satellites varying as older satellites are retired and replaced. Operational since 1978 and globally available since 1994, GPS is currently the world’s most utilized satellite navigation system.

We’ve outlined some of the key characteristics of GPS technology below:

  • 32 satellites
  • 6 orbits
  • 4 satellites per orbit
  • orbit period = approx 12hrs
  • orbit radius = 26600 Km (approx)
  • satellites altitude = 20,200 Km
  • inclination with Earth = 55 degrees
  • angle between orbital planes = 60 degrees
  • satellites do not rotate with respect to earth but with respect to distant stars
  • 6 to 11 satellites are always in sight from earth surface
  • 4 satellites are sufficient for GPS receiver

More characteristics also exist for GPS but however we chose only to display the main ones in this post.

GNSS

GNSS stands for Global Navigation Satellite System, and is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage. This term includes e.g. the GPS, GLONASS, Galileo, Beidou and other regional systems. GNSS is a term used worldwide The advantage to having access to multiple satellites is accuracy, redundancy and availability at all times.  Though satellite systems don’t often fail, if one fails GNSS receivers can pick up signals from other systems.  Also if line of sight is obstructed, having access to multiple satellites is also a benefit.

 Common GNSS Systems are GPS, GLONASS, Galileo, Beidou and other regional systems.

A lot of people, well lets just say the majority has a tendency of calling on all the satellite systems and generalizing the term to GPS. After reading this post we hope you now have an insight on what GNSS and GPS really mean.

Stay tuned as we will be publishing another article explaining the other satellite systems which are:

  • GLONASS
  • Galileo
  • Beidou
  • IRNSS
  • QZSS

Wow! We could go on and on forever trying to list them. Stay tuned.

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