TTN2 problems when walking

[matt_e]

Wow. Talk about dedication to the cause! You get my vote for post of the year :o)



I can understand now why I get such late instructions at some junctions. When I stop some distance before the junction and creep along very slowly it doesn't update my position until i have picked up speed and am actually already into the turn.



Matt

[Lost Cause]

Blimey. I don't belieeeeeeeve it ! Some people actually read it all ! And Mike B too. I've gone all dewy eyed - thought I might be talking to myself - given the length of the post.



Fabulous. Thanks for the comments, and will be interested to hear how you get on Aero. Dare say you have no 'moving too slow' problems in your car either (!)

[clivers]

i have the same problem using navman smart st and a sleeve, it usually does not keep up with what your doing. so if you turn down another street it takes 30 secs or so to catch up with me.

[MikeB]

Well done Lost Cause. I read the whole lot as well.



I think your theory may well be correct. If you have an application such as Memory-Map, OziExplorer or Fugawi, you will see the GPS trace jumping around somewhat. If you leave it for long enough your track will create a large blot where the position has wandered when in reality it is stationary.



As none of these programs have knowledge or roads the GPS pointer cannot snap to the road so roams freely.



Maybe TomTom only starts movement when you exceed a certain speed.
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Mike Barrett

[aero]

I have actually read all of that , but I don't have a 2210 .



Nevertheless congratulations on a remarkable post



In all seriousness though, I will try it with my 3970 & Emtac, it may aid in determining if the problem is isolated to the 2210. However, I will be doing this in the dark for I wish to maintain some credibility in these parts



Regards, aero

[Lost Cause]

OK, I've done a few more experiments and I'm now CONVINCED (!!!) that TTN2 on a 2210 has a 'speed' problem when used out walking i.e. it will not work at a walking pace !!! Completely convinced.



Why ? Well ......here's what I did yesterday.



I found a group of roads that formed a near perfect square, about 300yds down each side. And did the following:-



1. Drove my car around the square. No speed problems there, in a Porsche 944 Turbo SE TTN2 worked perfectly, showing my correct current position all the way round the square - with a 7-9 satellite fix. In Navigator or Map view.



2. I then walked around the square, while viewing the TTN2 'GPS' screen only - to check satellite reception. (Not in Map or Navigator view). I walked in the middle of the road holding the EMTAC over my head. (Lots of strange glances from on-lookers). All the way round the square the GPS screen showed a 7-9 satellite fix and continuously updated my lat/long, my speed, and continuously correctly updated my course/bearing as I rounded each corner. Hence, I now know that GPS and bluetooth are working perfectly around the square.



3. I then walked around the square, in the middle of the road, EMTAC above head, but looking in both Navigator and Map view. Despite still holding 7-9 sat fixes, TTN2 would NOT update my position on the square. It would continously show me at my starting point. Sometimes it would follow me to a corner, but then after rounding the corner it would not update my position. The blue pointer stayed stuck on the corner - even if I walked the complete length of the next side. On the rare occasion that it would follow me down one side, it would remain confused as to my bearing, with the blue arrow maybe at 90 degrees to the road, as it preceeeded. Tried all that for 30 mins walking around the square - it wouldn't work once. At best, it always got stuck on the first corner. Every time I switched back to GPS view, it confirmed correct reception/calculation of long/lat/speed/course.



4. Did the same as the above - but ran around the square !!! (More strange looks) TTN2 then worked PERFECTLY !! Aaaarghhh ! Running around the square, it always updated my postition, and the blue pointer always pointing correctly down the road, not only showing my correct position in Map view, but my correct direction of travel also. Just like when I drove around the square. It didn't fail once, when I was running.



5. Walked and ran around the square. Started walking down one side. Blue pointer doesn't move. Round the corner - pointer still stuck at start. Round the second corner - pointer still stuck. Then ran for 20 yards (even more strange looks from local offices !) and hey presto, the blue pointer jumps correctly to the other side of the square. Walk around the next corner, pointer still stuck in middle of the previous side. But run for ten yards and the pointer goes to my current position on the square. I walk - it doesn't know where I am. I run - it immediately updates my position.





Therefore, I present it to you (!), that if you are in Map or Navigator view, then TTN2 on a 2210 with EMTAC cannot be used for walking navigation - unless you're running. This must be a bug in the main piece of TTN2 software, because TTN2 GPS screen always reports my correct long/lat/course/speed.



My hypothesis is that due to the inaccuracies in GPS, then TTN2 have some kind of buffer to stop the pointer jumping about on the road - if you are actually stationery (say at a road junction). And that if you continuously move position slowly, then due to a poor programming algorithm, it will never actually register, ever, on the road map that you have moved at all. It will only update your postion on the road if it sees a large jump in a very short time period. Otherwise, it says continuously to itself 'GPS +/- error, don't move pointer' and will keep on doing that until it sees a movement too great to be an error. Even, if the sum of those small distances is a long way from where the pointer currently is. i.e. walking pace. If you rate of movement per second is less than the accuracy of GPS, then it will NEVER update your position.   I can find no other possible reason, bearing in mind the correct reporting of position in the GPS screen.





If anyone has actually read all of this (!) and if they have a 2210 EMTAC, then how about giving it a try and reporting here ?? I can't beleieve I'm the only one experiencing this

[TonyP]

It could be that you are not getting an accurate fix because the buildings on the pavement shield the sats. A car in the road gets a better view.



If you carry the GPS in your pocket, that will degrade the signal as well. It might be picking up reflections instead of direct signals.



Best to velcro the GPS to your cap and walk down the white line!



If TTN gets a position that doesnt properly correspond to a road it tends to ignore it, at least until the GPS position is some distance from any road, or the last known position.

[JimC]

I used mine while walking around towns and villages in France a few weeks back and had no trouble with the positioning (ipaq 5540, emtac BT, french maps on SD card).



I just tried a walk outside with the UK map and that works fine too.




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Jim

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