Originally Posted by
Steve B.
This is a common issue with GPS unit’s, car models included. The unit just cannot generate a location fast enough for the nav part to keep up with what’s happening real time. I’ve encountered this with car units and recall a bike touring post of some folks using a Garmin 1000 in Switzerland where the unit just couldn’t keep up in narrow streets with a maze of turns.
Possibly in a few years as processor speed gets better at this level.
Originally Posted by
Marcus_Ti
Processor speed isn't the limiter. It really isn't. As far as narrow street navigation, it will always be a problem. You have minimal line-of-sight to the sky therefore estimated-probable-error is high due to lack of satellites....and in narrow medieval alley-way environs the error in position is larger than the distance between "streets"...making position routing/tracking problematic. It isn't a computing power limit problem, it is a geometry problem.
Bike GPS units are held back due to needing to maximize battery life....maximizing battery life means minimizing power draw which means using as low-a-power CPU as can do the job. I ranted on my Edge1000 because even after the battery-saving measures its battery life sucked and was never even half-of-rated-sticker life IRL. They can make today a wizzo-fast CPU and put it in an Edge--but you'll only get an hour of battery life.
It needs noted that most of the measures that have drastically improved smartphone battery life over the last decade didn't directly come from hardware like new amazing batteries....it came from software measures to minimize usage and throttle things down. Having more computationally powerful CPUs did help, to be fair, because a 2.5gHZ maximum-clock 8-core CPU phone can spend 99% of its time either in Deep Sleep on in 1-core mode clocked down to 1/10 of rated maximum. As opposed to older chips that needed to spend 100% of CPU time at 100% power to do anything.
I've been using GPS based bike computers, generally at the state of the art when they came out, since about the Garmin 305 and non GPS bike computers for decades before that. Every single one, and even to this day, I wind up turning off the turn by turn navigation instructions and rerouting.
In almost any ride I do, I wind up deviating from a ride for a bit at some point, and it just gets plain annoying while the little bike computer goes nuts recalculating or warning me that I'm off the route. I much prefer having the route shown on the map and I can find my way to it and how to stay on it. Having a field that one can have on a screen that says "distance to next turn" (or equivalent) is more useful. Then when I get close to that point, I start watching the map.
So, for me, and I realize that YMMV, but I just don't find TbT to be all that useful in actual practice.
J.