Navigation technology has come a long way over the years, and today it’s available on our mobile phones and devices – which certainly makes getting from A to B a lot easier. But, beyond helping you plan your road trip, the technology plays a central role in supporting the operations of a myriad of industries, such as agriculture, aviation, the military and more.
GNSS is the umbrella term for all global satellite positioning systems, including GPS, Russia’s GLONASS, Europe’s Galileo, and China’s BeiDou, while GPS refers only to the single constellation operated by the United States. The terms are often used interchangeably, but there are important differences in coverage, accuracy, and reliability that affect which is the right fit for a given project.
This article introduces the key differences between GNSS and GPS, and how to choose between them for your project. It is the first in KOREC’s GNSS guides series. The other articles in the series cover how GNSS is used in land surveying and mapping, choosing the right Trimble GNSS receiver, the benefits of GPS in construction setting out, GNSS receiver setup, low cost GNSS receiver applications, IMU-based tilt compensation, and integrating GNSS with total stations and laser scanners.
GPS was one of the first GNSS technologies to become available to the layperson, which is why it’s more recognisable as a term. The two are often used interchangeably, but there are a number of important differences. We’ll discuss these below as well as offer up some tips for deciding which of the two technologies is right for you and your project.
As briefly outlined above, GNSS – which stands for Global Navigation Satellite System – refers to any and all global satellite positioning systems, including GPS. It originally came into existence to assist in military developments, but is now accessible to everyone.
GPS is the U.S. global positioning system, but GPS isn’t the only GNSS, there are a number of other satellite navigation systems. These include:
When you use GNSS technology, you have access to all of the satellite navigation systems.
This means it can provide detailed positioning across the globe and, if one satellite is impaired, it can switch to receiving information from another.
While GNSS offers access to numerous satellites and can provide accurate positioning data, it does come with some drawbacks. Below we discuss the main pros and cons of the technology.
For help choosing the right Trimble GNSS receiver for your project goals, see our Quick Guide and once your chosen a receiver you can view our GNSS Receiver Setup guide for further advice.
GNSS is used in a variety of industries, including:
GPS – an acronym for Global Positioning System – is an example of GNSS and originates in the United States. It comprises 31 Earth orbit satellites across six orbital planes. The exact number of satellites is changeable as some expire and, occasionally, new ones are added.
It’s existed since 1978 as a tool for the U.S Department of Defence, and only became available to civilians in 1994. It’s currently the world’s most used GNSS, but only provides positioning informed by US satellites.
Again, GPS does have some weaknesses as well as some benefits, which we delve into below:
GPS is employed for a number of activities, both professional and recreational, including:
The essential difference between GNSS and GPS is that the former refers to all satellite navigation systems, while GPS refers only to the American offering of the technology.
However, they also have the following differences when used in practice:
GNSS and GPS are certainly not equal in terms of their coverage. GPS only covers specific areas of the globe, while the wider GNSS system covers over two-thirds of the world, including remote and obscure locations.
Notable, as GPS only receives signals from US satellites, it fails to cover a number of areas. Additionally, mountains and skyscrapers can actually block the satellites it does interact with.
GNSS, however, employs several satellite systems from a variety of countries making its coverage far superior.
GPS receivers typically provide accuracy within 10 metres with survey grade GPS often achieving centimetre accuracy. GNSS receivers on the other hand, can typically provide accuracy within 1 metre, with some surveying products offering millimetre accuracy, such as the Trimble R780. This is because GNSS systems use multiple satellite constellations to determine location.
So as to the question ‘which is more accurate: GNSS or GPS?’ The answer is clear: GNSS. However both can experience decreased accuracy due to bad weather conditions and electromagnetic interference.
At the time of writing, GPS uses 31 satellites and GNSS systems use a total of 35. This effectively means GNSS systems can offer more accurate information simply because they have access to more satellites within their constellation.
While in urban dwellings this doesn’t make a huge difference, in more remote locations, GPS coverage tends to be significantly weaker than GNSS.
Both GPS and GNSS systems are widely used in surveying, but GNSS constellations can provide more accuracy than GPS alone.
Note here that, while accuracy and precision both measure observational error, accuracy refers specifically to how close a measurement is to the true value. Precision, meanwhile, is how close different measurements of the same reading are to each other.
So, with GNSS, its accuracy refers to how closely it determines your location to be vs where you actually are. Precision, on the other hand, is how often it determines your location to be accurate.
Choosing whether to opt for a GNSS system or GPS depends on how you intend to use the technology. If surveying is your goal, you may prefer to opt for GNSS given its superior accuracy.
However, if you are simply a hobbyist or wish to use location positioning for recreational activities such as geocaching, GPS will likely meet all of your needs while still providing sufficient accuracy. Discover more about affordable GNSS receiver for less demanding applications in our guide, Low Cost GNSS Receiver Applications.
GPS is also widely available and fairly reliable. However, it is reliant on clear signals and can be affected by signal jamming and interference.
GNSS doesn’t tend to suffer from this as badly as it taps into multiple satellite systems. Therefore, if one becomes unavailable, it can still access satellite navigation from a different system.
GNSS and GPS are both satellite navigation technologies that provide positioning information. GPS is the more well known term and is typically widely available as it’s used in a wider range of navigation products. GNSS, however, due to the fact it utilises all satellites across different countries, provides more robust coverage and a greater degree of accuracy.
When it comes to deciding which mapping technology is right for your project, the standard advice is that if you require superior accuracy and reliability, GNSS is the better system to opt for.
However, both technologies are always evolving, with new advancements and innovations occurring on a frequent basis. So it may well be that GPS’ accuracy rivals GNSS before long, or that GNSS becomes more affordable for the layperson.
KOREC supplies the full range of Trimble GNSS systems and as the authorised Trimble dealer for the UK and Ireland, KOREC provides in-person training along with technical support.
No. GPS is one specific system, the US-operated constellation, while GNSS is the umbrella term covering GPS plus other systems like Galileo, GLONASS, BeiDou, IRNSS, and QZSS. All GPS is GNSS, but not all GNSS is GPS.
GNSS is generally more accurate. Standard GPS receivers typically achieve accuracy within about 10 metres, while GNSS receivers can typically reach within 1 metre, and specialist survey equipment can get down to millimetre level.
Yes, generally. Because GNSS pulls from multiple satellite constellations, it can maintain a connection even when some signals are blocked or unavailable, useful in dense forests, mountainous terrain, or urban areas with tall buildings. GPS, relying on a single constellation, is more vulnerable to gaps in these conditions.
Both can be affected. Spoofing is when a false signal is fed to a receiver to mislead it about its true position, while jamming disrupts signal reception altogether. GNSS’s use of multiple systems gives it more resilience, since it can fall back on another constellation if one is compromised.
GNSS is usually the better choice for surveying, land mapping, construction setting-out, and other work requiring high precision, thanks to its superior accuracy and reliability. GPS is generally sufficient for recreational uses like geocaching or everyday navigation.
Yes, both are susceptible to reduced accuracy from poor weather conditions and electromagnetic interference, though GNSS’s access to multiple constellations helps offset some of this vulnerability.
GNSS is widely used across surveying, land mapping, agriculture, aviation, and maritime/naval navigation, where high accuracy and reliable global coverage matter most.
KOREC can advise you on the right GNSS system for your project. Speak to our friendly experts today to get the right technology to solve your business challenges.
