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speed variables

 
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Bas



Joined: 05 May 2009
Posts: 344
Location: Lodz, PL

PostPosted: Sat Oct 03, 2009 4:01 pm    Post subject: speed variables Reply with quote

1) Speed variables are calculated in two different ways I think, so we've got such values:



Moving speed is smaller than average speed...



2) When we start TB during drive we can see:


(data from car driving, not flight; speed range 110-120 km/h)

It would be better to reset speed values after a few seconds of getting stable fix because gps data aren't reliable and TB calculates wrong values.
What do you think?
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billy06



Joined: 01 Oct 2008
Posts: 434
Location: Lowestoft U.K

PostPosted: Sat Oct 03, 2009 7:52 pm    Post subject: Reply with quote

yes good idear Very Happy
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vincent



Joined: 11 Feb 2008
Posts: 196

PostPosted: Tue Oct 13, 2009 9:25 pm    Post subject: Reply with quote

I don't understand what you need ?

the speed that get TB is a doppler speed (if your gps support it) and this speed is very realable.

so the pb is the avg value ?

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Bas



Joined: 05 May 2009
Posts: 344
Location: Lodz, PL

PostPosted: Tue Oct 13, 2009 10:09 pm    Post subject: Reply with quote

vincent wrote:
this speed is very realable


really?



Is it normal car speed?

Average moving speed looks great but it is not acceptable. These variables should be real, not from the Guinness Book of Records. Program should correct false data from gps.

So... could you explain: average speed is higher than moving speed?
Even after 15 minutes driving? Is it really possible?



You can see these values very often when you start TB during driving. It isn't Doppler efect only because TB starts total time from the first GPS contact and moving speed/time from stable fix. You can count them (speed/time/distance). Maybe these variables should be counted the same way - from the same starting point?

Another "problem" is moving speed (spd-avg-auto variable) and moving time because TB counts every single second when you stop. It looks quite normal BUT when you drive on Friday afternoon and there is a lot of traffic your moving speed (from TB of course) is really high and absolutely false.

Example:
distance: 8 km (no coffee breaks, heavy traffic)
time: 40 minutes
real moving speed: 12 km/h
but TB shows: 20 or higher.

In this situation you can look at average speed but when your route is longer and more differentiated your moving speed variable is useless, average speed means "average" so... what is your moving speed in such situation? TB is very optimistic in this case.
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vincent



Joined: 11 Feb 2008
Posts: 196

PostPosted: Wed Oct 14, 2009 7:43 am    Post subject: Reply with quote

Quote:
Program should correct false data from gps.


hehehe from my point of view your gps is not really a good gps .. that's all ...
if your gps support doppler speed capability the speed is very realable.

have you configured your gps to give gprmc nmea ?

what gps do you use ?

but okay for the average speed .. there is a pb.

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Bas



Joined: 05 May 2009
Posts: 344
Location: Lodz, PL

PostPosted: Wed Oct 14, 2009 6:25 pm    Post subject: Reply with quote

vincent wrote:
hehehe from my point of view your gps is not really a good gps .. that's all ...
if your gps support doppler speed capability...


hehehe from my point of view spd-avg-auto variable comes from TB calculations, not from gps doppler speed capability... You can calculate it from simple formula speed=distance/time; time is total time of your "moving time" and distance is your total distance - do you see doppler speed capability here?
... and Spd variable is always good .. that's all ...

When you start every gps model your position is approximate. It is better after a few seconds. If you drive "fast" and you start TB program can calculate moving speed wrong and this values can be crazy, don't you think?

The problem is even if my speed is fixed/constant.
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