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peterc10 Frequent Visitor
Joined: Aug 21, 2005 Posts: 1761 Location: Kent, England
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Posted: Sat Oct 20, 2012 10:53 pm Post subject: |
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Earlier I tried an experiment. At home with a satellite fix I switched on CamerAlert and stood still for a minute. The spot speed showed 0mph throughout. The average speed started at zero then started to creep up to 19mph, before falling down to about 6mph.
How exactly is the average speed calculated? From within CamerAlert? Or by another app or system? Does CamerAlert calculate it from the static positions or one-off instant speeds it is fed by the sat nav chip, or does the chip calculate it all, both single point and average and feed it to CamerAlert. _________________ Peter
HTC Sensation
Sygic GPS for Europe (No more TT "support"!)
Copilot for USA
Bury CC9060 bluetooth car kit & Brodit mount |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Sat Oct 20, 2012 11:32 pm Post subject: |
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I just tried the standing still trick with a good sat lock and mine also started at 0 then jumped to 31 after about 10-15 secs, then jumped to 21 after another 10-15 secs (instantaneous speed remained at 0 throughout) |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Tue Oct 23, 2012 4:22 pm Post subject: |
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Have just done another run. Seemed OK at first, but jumped to 820 when stationery. Took a gps log of the trip (2 sec intervals), and there were no anomolies in either speed or position. |
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smar Occasional Visitor
Joined: May 22, 2009 Posts: 7
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Posted: Wed Oct 24, 2012 7:44 am Post subject: Improve averaging algorithm |
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Thanks everyone for all your help in testing this - I'm glad I'm not the only one!
Having been a developer in a past life, I would have thought that it would be reasonably straightforward to add some sort of validation and smoothing in the average speed calculations to avoid this? Even IF (and that's still a big if) the instantaneous speed reported internally by the GPS jumps for a split second, we should be able to recheck a second later and confirm reasonableness of the value etc.
Anyway, would really appreciate a fix to both this and the other tiling/zooming issue. I note that other nav related (non Google) apps don't have the tiling/zooming issue - e.g. CoPilot or Radaroid etc. This used to be one of my must have apps on an iPhone and really look forward to the Android version working fully.
Thanks again. |
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golf747 Occasional Visitor
Joined: Aug 14, 2005 Posts: 33
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Posted: Wed Oct 24, 2012 11:51 am Post subject: |
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Well interesting reading as I have had this issue as well. Running Ca on HTC Desire S. As others have said application regularly zooms out and back in again. Also find the movement on the screen a bit 'jerky'. Put that down to slow processor? The zooming in and out happens whether google maps is running or not. I often drive with no data/3g on so just relying on PGPWS app to warn. Which it does Ok but would be good to stop the zooming in and out. |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Wed Oct 24, 2012 1:46 pm Post subject: |
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golf747 wrote: | Which it does Ok but would be good to stop the zooming in and out. | Do you also get the average speed jumping up to some silly speed. This display can be started by tapping the speed readout and you get your average speed to the right. Tap the speed readout again to switch it off and again to re-start it. |
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AliOnHols Pocket GPS Verifier
Joined: Oct 15, 2008 Posts: 1936
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Posted: Wed Oct 24, 2012 1:54 pm Post subject: |
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peterc10 wrote: | .....And now we are 4!
Anymore for anymore.... |
Me = 5
Edit - and the cropped voice alerts. _________________ Garmin Nuvi 2599
Android with CamerAlert, OsmAnd+, Waze & TT Europe.
TomTom GO 730, GO 930, GO 940 & Rider2.
SatMap Active 10 & 20. |
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adamwolfe Lifetime Member
Joined: Apr 26, 2007 Posts: 101 Location: Scottish Borders
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Posted: Thu Oct 25, 2012 1:32 pm Post subject: |
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AliOnHols wrote: | peterc10 wrote: | .....And now we are 4!
Anymore for anymore.... |
Me = 5
Edit - and the cropped voice alerts. |
6 now. Exactly same issues. Samsung Galaxy S2. Excellent app apart from these (minor) issues. _________________ Adam |
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253 Lifetime Member
Joined: Mar 05, 2007 Posts: 1058 Location: The green bit between the M40, M4 and M25.
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Posted: Thu Oct 25, 2012 10:18 pm Post subject: |
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Well, going to add my two pence worth, but don't think it is going to add to the debate much.
Bottom line is, I can't replicate what you folks are getting.
Have a GS3 at the moment, have tried CA whilst sat in the launderette for 45 mins, good GPS, with and without Maps active.
The best I could do was for the speed to flicker between 0 and 1 for less than a second on three separate occasions. If I hadn't actually been looking at the phone I probably wouldn't have seen it.
Just driven 160 miles this afternoon, with CA running, no maps and no navigation stuff running, and it didn't give a false reading at any time that I could see.
Bit of a peculiar glitch this.
Wonder if it's anything to do with the version of Android and/or any of the chips for the GPS. _________________ Triumph Tbird 1700. And now a Bonnie T100. |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Thu Oct 25, 2012 10:44 pm Post subject: |
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Are you talking about the speed readout or the average speed readout? I am sure that the speed readout is ok for everyone? |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Thu Oct 25, 2012 10:46 pm Post subject: |
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Are you talking about the speed readout or the average speed readout? I am sure that the speed readout is ok for everyone? |
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peterc10 Frequent Visitor
Joined: Aug 21, 2005 Posts: 1761 Location: Kent, England
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Posted: Thu Oct 25, 2012 11:44 pm Post subject: |
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M8TJT wrote: | Are you talking about the speed readout or the average speed readout? I am sure that the speed readout is ok for everyone? |
A good point. In fact so good you made it twice. This problem ONLY occurs on average speed, which CamerAlert only shows when in Specs zones, unless you induce it to show average speed by hitting the speed readout button.
OK here are the results of another experiment I did today. Using GPS Essentials app's Dashboard (free from Play Store). Stood in exactly the same place as I did with CA running. Locked on to 5 satelites. Stood still for the same period of time. "Instant" speed recorded as zero. Average speed recorded at zero. So same info from same chip. One app gives the correct average speed the other (CamerAlert) does not.
Conclusion. It is much more likely that there is a problem with CamerAlert than my sat nav chip.
Can others try this too please so we can make the results a bit more reliable and covering more than one brand of phone. I hope it does not cost you as much as it cost me to do it though. When I first tried it a few days ago my Sensation slipped out of my hand and the fall smashed the screen. £80 later and I tried it again much more carefully! _________________ Peter
HTC Sensation
Sygic GPS for Europe (No more TT "support"!)
Copilot for USA
Bury CC9060 bluetooth car kit & Brodit mount |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Fri Oct 26, 2012 12:18 am Post subject: |
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Sent fom the stupid little on screen keyboard on my GA2. Don't quite know why it double posted though. I'll try again. |
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253 Lifetime Member
Joined: Mar 05, 2007 Posts: 1058 Location: The green bit between the M40, M4 and M25.
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Posted: Fri Oct 26, 2012 8:54 am Post subject: |
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M8TJT wrote: | Are you talking about the speed readout or the average speed readout? I am sure that the speed readout is ok for everyone? |
Got you, I was looking at the actual speed readout. So my little experiment doesn't count I guess.
However, during my 160 mile trip, I did go through the specs on the M4 outside Bristol onto the Severn bridges and didn't notice anything untoward.
The traffic was moving quite freely through them most of the time.
I didn't activate the average speed at anytime on the trip though.
I will check again when I go through them again next week _________________ Triumph Tbird 1700. And now a Bonnie T100. |
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M8TJT The Other Tired Old Man
Joined: Apr 04, 2006 Posts: 10118 Location: Bexhill, South Sussex, UK
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Posted: Fri Oct 26, 2012 9:37 am Post subject: |
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Start the av spd display any time by tapping the speed readout. You don't have to be going through specs to start it. |
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