GPS Accuracy : Sony : Suunto, Polar & COROS

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Test Route

The results of some recent GPS tests were worthy of a post of their own for once. For those of you with Polar and Suunto devices here are some important and provisional findings.

It’s been a busy week for things to test. As well, I had some old data to go through. Busy. Busy.

What’s New

  • COROS APEX – who? Read on and see. But they interestingly use the same Sony GNSS chip that both Polar (Vantage) and Suunto (9) have opted for. It’s mostly due to the low power consumption of the chip.
  • Yesterday Suunto enabled GLONASS with a new firmware release for the Suunto 9.

For once there is positive stuff to report. But perhaps not from where you expected it.

I’ve only done one run with the COROS APEX. But it equalled the best-ever score which the AMBIT3 RUN turned in for me in 2017. It could be a fluke of course but the course is sufficiently hard for me to say that the COROS APEX obviously has at least a reasonably accurate GNSS device here. I used GPS+GLONASS for the COROS.

I had a similar experience with the COROS Pace earlier in the year but downgraded my opinion of its accuracy slightly with more usage.

  • Q: How can a newcomer do so well at this? With two devices each using different chips?
  • A: If I knew I would be offering consulting services in this field.

A massive sigh of relief at Suunto HQ. I was looking at  results from a week or so ago with GPS and comparing to the new firmware using GPS+GLONASS. So two things have changed – firmware and GNSS mode. Well three. Accuracy, being the third. It is NOTABLY improved. With GLONASS enabled, the Suunto 9 put in a 79% score, which is the same as with the best-ever Garmin result I had recently for the Fenix 5S Plus in GPS-only mode (Galileo?…nah). It’s still not quite good enough for Suunto but this is a big move in the right direction (hopefully).

For some bizarre reason Suunto have hidden away the option to turn GLONASS on in the menu navigation. No doubt it will be a battery-eater…who cares?!?! The Suunto 9 has a bigger battery than my car.

Polar? Nothing to report with the Polar test. Nothing has changed at any rate.

The good news for Suunto and Polar is that the Sony chip obviously CAN BE GOOD. COROS proved it.

Lots of caveats here of course but generally happy, smiling faces in London tonight.

Special thanks to @RiphRaph for nagging me into doing this. It was worth it !!


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Is the coros apex can track sleeping?


Any updates on this? My Suunto Traverse just suffered a cracked screen. I’m thinking that I’ll buy a new watch instead of replacing the screen. Curious about the 24/7 HR tracking in today’s watches. I’m not a triathlete but my job keeps me out in remote Canadian mountains for weeks on end. Helicopter in, pitch a tent, and go. Tons and tons of hiking through dense bush. Durability is important. Would love to have something that gives me decent 24/7 HR tracking… and I’m intrigued by sleep tracking as well. Decent battery life would be nice. Don’t want to have to run generator every night to charge the thing. Considering the Apex, Vantage M, Suunto 9, or Garmin Tactix. Don’t need the smart options – a phone is enough for me. GPS is good but I’ve got Garmin handhelds for all my back country use so 100% accuracy is a non-issue. I actually prefer larger watches (big wrists) so size doesn’t matter. Budget doesn’t matter either. Been working my way through your site. Phenomenal work. Keep it up. I was super close to going with the Suunto 9 until I discovered the5k. Now, after seeing everything else out there, I’m… Read more »


And thanks right back for allowing yourself to be nagged! This is indeed very interesting news, and it looks as though the Suunto 9 is now on my shortlist again.


The only remaining variable between corros and the rest would be antenna design.


I guess is the metallic bezel. That may explain the differences between Vantage V and M also…


Titanium is not a ferromagnetic metal, so, at least in theory, it may not interfere the signal. Question is, what’s the material used on the Suunto and the VV?


Suunto’s bezel is made of iron. If it is the same for the VV, my hipothesis may be still valid hehe

Running Otaku

Can you share with us how you compute the test score. I couldn’t figure out what “79%” indicated. Thanks!


There is a post with all the results. In the excel chart, it is explained how the global score is calculated


I’ve seen the AW2 is among the tested devices, but there’s no AW3 or AW4 data. May I ask if you have in mind testing also the apple device? DC has mixed results (good accuracy, specially on OWS, but lots of corners cutted…


fair enough 🙁 Not a cheap device, that’s also true… I thought some of the watches you reviewed were offered by the brands for testing purposes (although I know they don’t give you the GPS for free).


Huami’s Amazfit watches also share the same GNSS chip, the latest Sony: Bip, Pace, Stratos (and maybe the Verge too). The latter two have ceramic bezel and the Bip has full plastic shell.
Moreover, it is funny that the screen of the Suunto Spartan Sport/Ultra/9 and the Amazfit Stratos is the same.


Please look at the date of the article and the dates on the photos.
Verge was announced this year and in 2016 the Chinese version of Pace (A1602) was their only GPS watch on the market.
Some additional information to your “Sports Watch Update” article ( Model / Name(s) ):
A1608 Amazfit Bip, Amazfit Bip Lite, Amazfit Youth Edition (firmware update turns it into a multi-language version)
A1602 Amazfit Smartwatch (Chinese version of Pace)
A1612 Amazfit Pace (International version)
A1609 Amazfit Smartwatch 2 / Pace 2 (Chinese version of Stratos; 2S is the sapphire version)
A1619 Amazfit Stratos (International version) (Stratos + is the sapphire version)
A1811 Amazfit Verge

More information:


According to this URL, CXD5603GF also supports Galileo and Beidu.
Perhaps in the near future Sony will make it available in a firmware update.

Could you please repeat the test run sometime on your Stratos with the latest firmware ( Thanks!


Thank you for the testing. The latest measurement shows an upward trend in accuracy.


Hello, a bit time has passed since las time. : ) I’m following with interest the Coros Apex and in general the future of Coros in this area of sport watches. I opened a thread too in our forum and contacted them with some suggestion trying to help them to improve in the future and be success from a professional point of view. Surprisingly for me, their CEO (L.W.) wrote me about it. He commented me about the development plans they have with partners like Stryd, etc. And “if” they acomplish to get enough big customer base, they have an open mind about one of my suggestions of release a future sdk for their watches ; ) For that reason I ask you about to add to your review the storage capacity of the Apex or if you can add it to your review, although, i imagine that this model still could have a small one and a bigger in future models. And add what is the state of the Apex compatibility with accesories like bands, power meters, etc. He also said me that they have finished the navigation feature in their webpage. Is that feature already available? If you… Read more »


I forgot mention that i already told them about add detailed manuals for the Coros Apex and Pace in their web page and reported a bug, they have crossed links between Pace and OMNI quick start guides. And that they should add the navigation feature for the Coros Apex page with image and descriptions. Remember it to them too ; )


One last thing … I also mentioned you as a good possible reviewer for their Apex. It was around November 3rd. I’m glad you received one for your review. Very happy with that. I will read your review very carefully.


That’s a pretty stout score for a newbie. Interest is certainly peaked…


They should use the Broadcom BCM47755.

The BCM47755 from Broadcom is a single-chip device that combines location awareness capabilities with the typical functions of a sensor hub. The combination provides synergistic benefits that cannot be achieved with multiple ICs, such as low power consumption, higher accuracy, reduced footprint and a smaller BOM.

It is capable of centimeter accuracy with minimal power consumption and has a small footprint, enabling an entirely new suite of high-precision Location Based Service applications including lane-level vehicle navigation and mobile augmented reality (AR). The device built on a 28 nm process has an integrated multi-frequency GNSS baseband and RF front end for simultaneous reception of GPS, GLONASS, BeiDou (BDS), Galileo (GAL), and SBAS satellite signals.

tfk, the5krunner

yes it uses L1+L5 so could increase accuracy.
however i cant see the power consumption stats for it and that’s why its maybe not used so much in werables – it was announced in 2018, so might not be advertised for a reason!


I don’t see power consumption numbers either. Seems like it uses a combination of sensors to achieve accuracy. One of them being a gyroscope, so I wonder if it would work well in a watch when you are jogging or cycling off-road where the device is subject to a lot of movement.

tfk, the5krunner

i think it could work when running. eg a la Suunto FusedTrack