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Re: GPS Driven Speedometer

PostPosted: Wed Nov 18, 2020 4:52 pm
by 1owner69Elan
I will compare the speedos with the `Head Up Display` App on the phone.
Next I will check if it works in the carpark under Tesco`s supermarket.
How do these cars cope with tunnels and forests where there is no GPS signal ?.

Not sure if my comments apply to all GPS speedos:

If you compare a phone app with one of the GPS speedos, the GPS speedos (at least the Classic Speed (NLA)) have a sampling rate 5x that of the phone GPS. So, the phone apps don't update as fast.

As far as no GPS signal, the Classic Speed uses an algorithm to extrapolate the reading, at least for a while. More for cosmetic reasons and keeping the needle from jumping around. Obviously not a true indicator of speed at such moments.

I haven't driven in a long tunnel - but would expect it to drop out at some point. Also, if returning to an underground carpark, there would be no reading until the signal is reacquired.

At each startup the Classic Speed runs a calibration check. Indicates a 30 mph if calibrated properly, while at rest. This also runs the odometer briefly.

So, the GPS speedos are not without some issues but the trade-off in accuracy is worth it IMHO. Especially in automatically accommodating changes in tire sizes, diffs, etc.

Re: GPS Driven Speedometer

PostPosted: Thu Nov 19, 2020 5:58 pm
by Mr.Gale
Please don't confuse me with anyone that knows what they are talking about. :-)