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Re: GPS Based Speedometers

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On 2025-12-14 13:06, Daniel70 wrote:
> On 10/12/2025 12:14 am, knuttle wrote:
> 
> <Snip>
> 
>> GPS accuracy is 10 to 16 feet.   So the slower the vehicle is going 
>> the more imprecise that speed, as it is dependent on the accuracy of 
>> the starting position and the ending position. The time interval is 
>> also a factor in the accuracy of the speed by GPS. ie at 60MPH, the 
>> car travels 520 feet per minute, so 10 feet on the starting and ending 
>> positions has more affect than if the speed was at 30MPH or 1040 
>> feet.  These number could be higher depending on the interference in 
>> the area of the position.  It is best to put the numbers in a 
>> spreadsheet to understand the effect.
>>
>> The speed detecting radar is accurate to 1 to 2 miles per hour in 
>> ideal conditions.  In practice I suspect that if you stay within 10% 
>> of the speed, it is questionable if the radar detector can definitely 
>> say you are over the speed limit. (10% Based on actual experience with 
>> many electronic instruments)  Again there are many variables that 
>> affect the measurement of the speed detecting device.
> 
> And your GPS Speed is only indicating what you were doing, what, 0.5 
> Secs ago .... cause the signal has to go up to the Satellite and come 
> back down, doesn't it??

No, it does not go up. Just down. The GPS devices are receive only.

-- 
Cheers, Carlos.
ES🇪🇸, EU🇪🇺;

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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> - 2025-12-15 19:55 +0000

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