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Re: GPS Based Speedometers

From The Natural Philosopher <tnp@invalid.invalid>
Newsgroups comp.os.linux.misc, alt.comp.os.windows-11
Subject Re: GPS Based Speedometers
Date 2025-12-10 10:37 +0000
Organization A little, after lunch
Message-ID <10hbiho$1di3b$13@dont-email.me> (permalink)
References (17 earlier) <SkednTQAHeyrQqr0nZ2dnZfqn_sAAAAA@giganews.com> <slrn10jg6j3.iacq.lars@cleo.beagle-ears.com> <10h97bp$r51r$1@dont-email.me> <10h9apt$s0tc$4@dont-email.me> <wwvy0nbtlnt.fsf@LkoBDZeT.terraraq.uk>

Cross-posted to 2 groups.

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On 09/12/2025 21:01, Richard Kettlewell wrote:
> The Natural Philosopher <tnp@invalid.invalid> writes:
>> In the UK we have little 'this is your speed!' displays in green or
>> red depending on whether you are exceeding the limit or not.
>> These agree EXACTLY with my Tomtom Go  speeds, derived from GPS and
>> are always around 7% lower then the speedometer reads.
>>
>> On every car I have tried it on.
> 
> Last time I checked my car speedo read 68mph when GPS reads 70mph, so a
> little under 3% off. I’ve not checked the error at lower (or higher l-)
> speeds, nor often enough to say how it varies with time and conditions.
> 
You can calculate the effect of tyre wear quite easily.

I am sure your maths is up to that :-) :-)

Without a car tyre fitting place less easy to measure the change in 
circumference between inflated,  deflated and overinflated.


> Previous cars had less accurate speedos.
> 
Yes.

I think mostly they are counting sensor pulses on a wheel or final drive 
somewhere, but IIRC its possible to build a Doppler shift radar unit .

Measuring wheel/final drive RPM is inherently inaccurate.


-- 
The lifetime of any political organisation is about three years before 
its been subverted by the people it tried to warn you about.

Anon.

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Thread

Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-01 11:33 +0000
  Re: The "Standards" Game rbowman <bowman@montana.com> - 2025-12-01 21:25 +0000
    Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-01 21:48 +0000
      Re: The "Standards" Game Lars Poulsen <lars@beagle-ears.com> - 2025-12-02 02:51 +0000
      Re: The "Standards" Game rbowman <bowman@montana.com> - 2025-12-02 06:05 +0000
        Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-02 04:57 -0500
          Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-03 16:09 +0000
            Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-03 23:03 -0500
              Re: The "Standards" Game rbowman <bowman@montana.com> - 2025-12-04 07:00 +0000
    Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-01 23:21 -0500
  Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-01 22:49 -0500
    Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-02 11:12 +0000
      Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-02 21:14 -0500
        Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-03 11:24 +0000
          Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-03 22:13 -0500
            Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-04 12:32 +0000
            Re: The "Standards" Game Daniel70 <daniel47@nomail.afraid.org> - 2025-12-05 23:14 +1100
              Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-05 21:36 -0500
                Re: The "Standards" Game Daniel70 <daniel47@nomail.afraid.org> - 2025-12-06 22:52 +1100
                Re: The "Standards" Game Daniel70 <daniel47@nomail.afraid.org> - 2025-12-07 00:07 +1100
                Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-06 23:41 -0500
                Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-07 19:25 +0100
                Re: Double booting Rich <rich@example.invalid> - 2025-12-07 19:00 +0000
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-07 20:33 +0000
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-07 22:32 +0100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-08 08:56 +0000
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-08 14:53 +0100
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-07 22:31 +0100
                Re: Double booting Rich <rich@example.invalid> - 2025-12-07 22:24 +0000
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-08 14:53 +0100
                Re: Double booting Rich <rich@example.invalid> - 2025-12-08 22:43 +0000
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 10:11 +0000
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-09 15:48 +0100
                Re: Double booting Rich <rich@example.invalid> - 2025-12-09 16:18 +0000
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-07 19:33 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-09 00:20 +1100
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-08 14:59 +0100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-08 18:02 +0000
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-08 22:41 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-09 03:35 -0500
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 10:09 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-09 22:53 +1100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 14:08 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-11 22:18 +1100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-11 12:36 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-12 22:11 +1100
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-09 20:50 -0500
                Re: Double booting Rich <rich@example.invalid> - 2025-12-10 03:05 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-09 22:17 -0500
                Re: Double booting Rich <rich@example.invalid> - 2025-12-10 03:25 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-10 00:18 -0500
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:52 +0000
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-11 02:16 +0000
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-11 08:58 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-14 22:38 +1100
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-14 13:42 +0100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:49 +0000
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:45 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-09 20:28 -0500
                GPS Based Speedometers Lars Poulsen <lars@beagle-ears.com> - 2025-12-09 12:47 +0000
                Re: GPS Based Speedometers knuttle <keith_nuttle@yahoo.com> - 2025-12-09 08:14 -0500
                Re: GPS Based Speedometers The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 14:13 +0000
                Re: GPS Based Speedometers Rich <rich@example.invalid> - 2025-12-09 18:35 +0000
                Re: GPS Based Speedometers rbowman <bowman@montana.com> - 2025-12-09 20:30 +0000
                Re: GPS Based Speedometers Paul <nospam@needed.invalid> - 2025-12-09 16:52 -0500
                Re: GPS Based Speedometers Richard Kettlewell <invalid@invalid.invalid> - 2025-12-09 21:01 +0000
                Re: GPS Based Speedometers The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:37 +0000
                Re: GPS Based Speedometers Herbert Kleebauer <klee@unibwm.de> - 2025-12-09 16:24 +0100
                Re: GPS Based Speedometers Rich <rich@example.invalid> - 2025-12-09 18:39 +0000
                Re: GPS Based Speedometers Daniel70 <daniel47@nomail.afraid.org> - 2025-12-14 23:06 +1100
                Re: GPS Based Speedometers "Carlos E.R." <robin_listas@es.invalid> - 2025-12-14 13:43 +0100
                Re: GPS Based Speedometers rbowman <bowman@montana.com> - 2025-12-14 19:09 +0000
                Re: GPS Based Speedometers c186282 <c186282@nnada.net> - 2025-12-15 00:12 -0500
                Re: GPS Based Speedometers rbowman <bowman@montana.com> - 2025-12-09 20:46 +0000
                Re: GPS Based Speedometers c186282 <c186282@nnada.net> - 2025-12-09 21:31 -0500
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-09 20:23 +0000
                Re: Double booting Char Jackson <none@none.invalid> - 2025-12-09 17:01 -0600
                Re: Double booting Rich <rich@example.invalid> - 2025-12-10 03:15 +0000
                Cars, motors "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 11:16 +0100
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-10 03:18 +0000
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:30 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-10 05:59 -0500
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 11:46 +0000
                Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 11:11 +0100
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-11 21:28 +0000
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 03:42 +0100
                Re: Cars, engines... Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2025-12-11 21:49 -0800
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-12 07:09 +0000
                Re: Cars, engines... Daniel70 <daniel47@nomail.afraid.org> - 2025-12-15 23:19 +1100
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 14:19 +0100
                Re: Cars, engines... The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 15:27 +0000
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-12 17:49 +0000
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 20:48 +0100
                Re: Cars, engines... Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2025-12-13 15:40 -0800
                Re: Cars, engines... CrudeSausage <crude@sausa.ge> - 2025-12-13 19:32 -0500
                Re: Cars, engines... Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2025-12-13 21:08 -0800
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-14 01:32 +0000
                Re: Cars, engines... Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2025-12-13 21:14 -0800
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-14 01:33 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-14 08:45 +0000
                Re: Cars, engines... Daniel70 <daniel47@nomail.afraid.org> - 2025-12-15 23:45 +1100
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 14:32 +0100
                Re: Cars, engines... The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 15:39 +0000
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 20:59 +0100
                Re: Cars, engines... Lars Poulsen <lars@beagle-ears.com> - 2025-12-13 02:52 +0000
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-13 06:11 +0000
                Re: Cars, engines... Lars Poulsen <lars@beagle-ears.com> - 2025-12-14 03:48 +0000
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-14 08:50 +0000
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-14 13:51 +0100
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-13 04:06 -0500
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 21:03 +0100
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-14 00:03 -0500
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-14 13:59 +0100
                Re: Cars, engines... Graham J <nobody@nowhere.co.uk> - 2025-12-14 13:17 +0000
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-14 20:27 +0100
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-15 01:33 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-12 06:58 +0000
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-12 02:23 -0500
                Re: Cars, engines... The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:29 +0000
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-12 17:31 +0000
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-13 00:13 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-13 06:18 +0000
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-13 02:08 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-13 19:44 +0000
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-13 23:46 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-14 09:12 +0000
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-14 20:29 +0100
                Re: Cars, engines... Daniel70 <daniel47@nomail.afraid.org> - 2025-12-15 23:01 +1100
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-11 23:02 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-12 06:52 +0000
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-12 02:19 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-12 08:14 +0000
                Re: Cars, engines... c186282 <c186282@nnada.net> - 2025-12-12 22:35 -0500
                Re: Cars, engines... rbowman <bowman@montana.com> - 2025-12-13 06:03 +0000
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 14:25 +0100
                Re: Cars, engines... "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 14:23 +0100
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-09 22:50 +1100
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-09 14:48 +0100
                Re: Double booting Rich <rich@example.invalid> - 2025-12-09 18:50 +0000
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-09 21:28 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-11 22:21 +1100
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 12:56 +0100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-11 12:32 +0000
                Re: Double booting Rich <rich@example.invalid> - 2025-12-09 18:46 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-09 20:47 -0500
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-08 22:39 +0000
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 10:08 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-09 22:57 +1100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 14:09 +0000
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-09 15:50 +0100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 19:11 +0000
                Re: Double booting rbowman <bowman@montana.com> - 2025-12-09 20:20 +0000
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:27 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-10 05:57 -0500
                Wheels "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 11:20 +0100
                Re: Wheels Lars Poulsen <lars@beagle-ears.com> - 2025-12-11 18:51 +0000
                Re: Wheels "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 20:21 +0100
                Re: Wheels Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-12-11 19:40 +0000
                Re: Wheels "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 22:29 +0100
                Re: Wheels rbowman <bowman@montana.com> - 2025-12-11 21:23 +0000
                Re: Wheels "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 14:44 +0100
                Re: Wheels rbowman <bowman@montana.com> - 2025-12-12 19:12 +0000
                Re: Wheels "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 23:55 +0100
                Re: Wheels rbowman <bowman@montana.com> - 2025-12-14 01:36 +0000
                Re: Wheels c186282 <c186282@nnada.net> - 2025-12-11 23:15 -0500
                Re: Wheels "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 14:50 +0100
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-10 03:20 +0100
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-10 00:22 -0500
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 11:22 +0100
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-11 23:20 -0500
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:42 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-13 01:48 -0500
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 14:54 +0100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:54 +0000
                Re: Double booting Daniel70 <daniel47@nomail.afraid.org> - 2025-12-11 22:23 +1100
                Re: Double booting "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 12:57 +0100
                Re: Double booting The Natural Philosopher <tnp@invalid.invalid> - 2025-12-11 12:39 +0000
                Re: Double booting Rich <rich@example.invalid> - 2025-12-09 19:02 +0000
                Re: Double booting Rich <rich@example.invalid> - 2025-12-08 22:51 +0000
                Re: Double booting c186282 <c186282@nnada.net> - 2025-12-07 22:04 -0500
                Re: Double booting John Ames <commodorejohn@gmail.com> - 2025-12-08 09:16 -0800
                Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-06 12:17 +0000
              Re: The "Standards" Game Paul <nospam@needed.invalid> - 2025-12-05 22:19 -0500
                Re: The "Standards" Game Daniel70 <daniel47@nomail.afraid.org> - 2025-12-06 23:02 +1100
                Re: The "Standards" Game Paul <nospam@needed.invalid> - 2025-12-06 07:59 -0500
                Re: The "Standards" Game Daniel70 <daniel47@nomail.afraid.org> - 2025-12-07 00:20 +1100
      Re: The "Standards" Game Daniel70 <daniel47@nomail.afraid.org> - 2025-12-05 22:54 +1100
        Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-05 21:34 -0500
          Re: The "Standards" Game Paul <nospam@needed.invalid> - 2025-12-05 22:22 -0500
            Re: The "Standards" Game c186282 <c186282@nnada.net> - 2025-12-05 23:26 -0500
            Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-06 12:16 +0000
          Re: The "Standards" Game The Natural Philosopher <tnp@invalid.invalid> - 2025-12-06 12:13 +0000

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