GPS vs Phone

[danp]

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I have the cheapest Garmin Zumo 396-LMT-S which I used to hate using because of how hard it was to program a route into it, but I've discovered a new method that works very well:

I use my phone to create a route on onthegomap.com then save it as a gpx file. It's the easiest and fastest way I've found to create a custom route. I then use the garmin link app to transfer that gpx file to the garmin over bluetooth.

The problem with using a phone (in addition to the risks to the phone itself) is that you have to turn it on and load the gps app each time you get on the bike. With a Garmin it automatically turns on when I turn on the bike and starts showing my route, no need to waste time pressing anything. It's just more convenient. It also receives power through the mount, so no cables hanging all over the place (just the one neatly connected to hte mount).

 

[adri]

Just wanted to say, as I've gone through a ton of tunnels this past week, that even when I have no signal, my phone, and by extension my android auto unit, does a pretty good job of approximating my location, even inside of mountains where I would also not have GPS signal.

 

[Lightcycle]

Just wanted to say, as I've gone through a ton of tunnels this past week, that even when I have no signal, my phone, and by extension my android auto unit, does a pretty good job of approximating my location, even inside of mountains where I would also not have GPS signal.

Yep, most basic GPSs use a technology called "dead reckoning", which uses last known position, speed and direction, along with map information to extrapolate your current position when there's loss of signal.

More advanced systems have an internal IMU (or can tie into the vehicle's IMU or speedometer) for detecting acceleration/deceleration and lateral movement to gain additional telemetry for more accurate estimates. I believe Google Maps utilizes info from your phone's IMU, if available. Interestingly, Garmin Zumo only uses dead reckoning and has no internal IMU (at least I haven't found evidence of one), so score +1 for phones/Google Maps.

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