What is GLONASS? GPS vs GLONASS – which is best. Used by Garmin, Apple, Suunto, Samsung and others

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What is GLONASS – Used on sports watches and many other devices

What is GLONASS? GLONASS is Russia’s version of America’s GPS. It is used to enable electronic devices to tell you where you are.

“GPS” specifically refers to the American system of navigational satellites rather than generic satellite navigation. We all use the term ‘GPS’ incorrectly in that sense. The correct term that we should all use is GNSS rather than GPS. GNSS stands for Global Navigation Satellite System. GLONASS is a GNSS and GPS is a GNSS.

GLONASS capability is increasingly used in high-end SMART devices in cars, phones and sports watches, including the new Garmin Fenix 5 and Suunto SPARTAN.

GLONASS Accuracy

GLONASS is neither particularly better nor worse than GPS.

HOWEVER, when they are used TOGETHER the likelihood of accuracy IS increased. Simply because there are more satellites available in both ‘constellations’ and hence a higher chance that your watch will be able to see enough of them for a good positional fix.

It is said that using GPS+GLONASS can give accuracy down to 4.5/5m and can also improve accuracy in built-up areas; especially in the Northern Hemisphere. That is THE SAME level of accuracy as standalone GPS. It’s just that the LIKLIHOOD of achieving it MAY be increased.

GLONASS Downsides?

None really. Might use more battery power though depending on how well the watch manufacturer has optimised the navigational chip inside the device. Well…I say “none really” but, in my experience, turning on GLONASS does take a hit on battery that in many cases seem to reduce battery life to between 80 & 90% of ‘normal’.

Do I really need it? It will help with tree cover and nearby tall buildings. It may also help in mountainous areas or areas of high latitude (nearer to Arctic circle). I would say “It shouldn’t hurt” but, from my experience, often it does NOT SEEM to improve positional tracking

Don’t be fooled: Just because a device is advertised to have GLONASS doesn’t mean that much for the ACTUAL level of accuracy you will receive. There are VERY MANY OTHER factors that will affect this such as: quality of GPS/GLONASS chip; position of antennae; electromagnetic shielding within the device; algorithm used by the manufacturer of the end device. Indeed my anecdotal evidence is that sometimes GLONASS might lower accuracy.

Q: Why?

A: One of the factors is the quality of the manufacturer’s algorithm might be sub-par.

Don’t think it will make the running PACE shown on your watch more accurate. If you want accurate, instant running pace/speed then you MUST buy a footpod. The most super-accurate is STRYD  and the cheapest, ‘sensible’ option is the MILESTONE pod. And yes this advice STILL applies even if you’ve just spend £600/$700 on a top-end Garmin Fenix 5X…eesh.

ESSENTIAL READING: (Here) are my GPS/GLONASS tests on sports watches – as of 11Feb 2017 best performer so far are: Suunto SPARTAN Sport (not ULTRA); and Polar’s V800.


  • GLONASS is Globalnaya Navigazionnaya Sputnikovaya Sistema or Global Navigation Satellite System.
  • Versions: GLONASS (1982); GLONASS-M (2003); GLONASS-K (2011, sub-versions K1, K2, KM)
    • GLONASS-K (2011)
    • GLONASS K2 (2015-)
    • GLONASS-KM (2025)
  • A-GLONASS is assisted-GLONASS. There is also assisted-GPS or A-GPS. This feature gives you a quick satellite lock when you first start your device. The ‘assisted’ feature involves caching future satellite positions for 7 days or so, so your device knows where to find them. The exact positions vary unpredictably all the time and so an initial lock without A-GLONASS or A-GPS might take many 10’s of seconds. A-GLONASS does NOT increase or decrease accuracy. It just lowers the time-to-readiness.
  • GLONASS was first commercially used in the car navigator “Glospace SGK-70” and Apple first used it in the iPhone 4S
  • Turn-by-turn (TBT) – GLONASS has nothing to do with turn-by-turn navigation. GPS and GLONASS just find the current position. Your smart phone, sports watch or other navigation device can then use your position, route and destination coupled with some knowledge of a map to give you TBT. ie TBT comes from the intelligence on the navigational device NOT from GPS and GLONASS
  • SPEED and PACE – Your navigational device can use GLONASS and GPS to work out the difference in distance at two points of recorded time. As it knows the time taken to get between those points and the distance then it can easily calculate SPEED/PACE and derive other navigation data such as acceleration and direction. However due to the inherent inaccuracy in determining your precise location the derived speed/pace will be inaccurate over short periods of time eg less than 2 minutes. Over longer distances and longer periods of time the accuracy of speed and distance will improve as the various measuring errors cancel each other out. You should hope for 99% accuracy over such extended periods eg if 5000m comes out as 5050m then that is acceptable, in my opinion.
  • RUNNING PACE/SPEED – Suunto and others combine wrist movements (to derive cadence/footfall) with an estimated or known stride-length to further refine pace/speed from GPS/GLONASS. Suunto call this Fused-Speed. Speed/Pace only from a quality footpod like STRYD will, however, be more accurate than GPS/GLONASS derived pace.
  • GLONASS ALTIMETER – GPS and GLONASS can also be used to determine your altitude by measuring precise timing that a signal takes to come from a satellite at a known altitude. This is still somewhat inaccurate and greater accuracy can be obtained from an onboard BAROMETRIC ALTIMETER. Combining a barometric altimeter and GPS altimeter could give even better accuracy (or not!). Suunto do this with their Fused-Alti algorithm.
  • GLONASS COMPASS – GPS and GLONASS can be used to give you an indication of your direction of travel. Providing you are moving the difference in GPS/GLONASS co-ordinates over a period of a few seconds will indicate your direction of travel. This is NOT as accurate as a magnetic compass.
  • IRNSS or Indian Regional Navigation Satellite System. As the name suggested this is like GPS and GLONASS but operates regionally rather than globally
  • BeiDou Navigation Satellite System is China’s system. It is close to full operational capacity. As of 2018 it is operational regionally in Asia.
  • Galileo is Europe’s system. It is close to full operational capacity (stated as 2020 but I understand that a sufficient constellation of satellites is already in orbit).

Garmin Fenix 5X 5 5S Forerunner 935 Review


Europe’s Galileo system will come into action around 2020. Many chips currently enabled with GPS and GLONASS also support Galileo. GREATLY increased accuracy is hopefully going to happen then with 1m accuracy. HOWEVER my suspicion is that there will be an increased USER-cost associated with obtaining the 1m accuracy of Galileo and hence the extra accuracy may not be passed on to you or, if it is, you may well be charged more for it. Thus, for most of us, Galileo may well make no difference other than, like GLONASS, giving more satellites for us to see and get a higher chance of achieving the 4.5/5m accuracy that we should have had all along!

September 2017 Saw the announcement of Broadcomm’s BCM47755 chip. Using a combination of old and new frequencies from new satellites it supposedly can deliver 30cm accuracy and is slated for release onto smart watches in 2018.

FWIW I have changed my usage of GLONASS in 2017 and indeed now I tend to turn it OFF. From my testing of several devices it seems that OFF is OFTEN more accurate. Plus turning GLONASS to ‘OFF’ better enables a like-for-like comparison with the accuracy of other devices. Having said that I would have it ON when navigating with a bike computer. and I would certainly turn it off on occasions where I am doing a long exercise that might be battery dependent.


It’s a “nice-to-have” for most people. It will make little difference.

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2 thoughts on “What is GLONASS? GPS vs GLONASS – which is best. Used by Garmin, Apple, Suunto, Samsung and others

    1. yes.
      but the device needs to be optimised for them eg with sports watches I get better results from 5 year old Polar V800 devices which only work with GPS rather than £1000 Garmin Fenix 6 devices that works with GPS and either GLONASS or GALILEO. ie aerial/antennae construction is important also

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