What’s up with GPS?

A few years back when I gave multi-sport events a whirl I used a Garmin Forerunner 910xt during my training.  It was not only able to track me when I ran or biked but also when I swam, so really it was perfect for a budding triathlete.

Even after giving up triathlons (because I wasn’t that keen on drowning or being hit by a car) the Garmin was still used when I (or more often James) ran.

Since I started running regularly again, I’ve only used the Garmin a couple of times although I’ve worn it more than a couple of times but ran without it recording as I couldn’t be arsed waiting for it to connect to a satellite – honestly one morning I ran just over 1.5k (according to the running app on my phone) before my Garmin connected.

I’m not saying that my running app is perfect either – in fact I’ve had my fair share of problems with that too, so I guess it’s lucky that on those occasions I’ve had both tracking devices going and have ended up with at least one record.

Today’s Forerunners have come along way and Santa may have dropped a little something at my house slightly early (probably because I’ve been so super good) and today I went out for my first distance run with my new Garmin Forerunner 620.

It’s cute enough to wear daily as a regular watch, then with the push of a button it “transforms” seamlessly into a GPS tracking device, which connects almost immediately to a satellite when you want to go out for a run and then when you’ve finished it wirelessly sends the data to Garmin Connect and any other additional accounts you have set up.

This morning I continued to use my running app in conjunction with my new toy (just to be safe) and the thing I noticed almost immediately was the distance and therefore pace didn’t match, it started out being a small difference in distance 30m in the first 250m but over the course of an hour the difference was nearly half a kilometre!

Confused as to why I did some research and I found out that the Garmin is more accurate (so lucky I ran until my watch said I hit 10k even though the Nike lady had told me I’d reached my goal as I’d feel really ripped off now if I hadn’t) 😉

In short a Garmin uses the satellites that orbit the earth and your phone uses cell phone towers.  Additionally a GPS watch is continually getting data from the satellites, whereas your phone only gets periodic position updates which are then averaged out. That averaging isn’t quite as accurate but is done in order to conserve battery life in your phone.

Pity it doesn’t mean I can run without my phone though ..

How would I uber back if I get lost (or tired) if I don’t have my phone with me! 😉

Till next time



If your interested in the accuracy of your running app, you can read this article that explains it more in depth that I have.



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