TTN5 200yds East of position.

rtj70 · Regular Visitor Joined: Jun 18, 2005 Posts: 144

I've experienced this a few times (UK and Italy) but I think roads have changed since the map data was collected. On all occasions when I looked around you could see an "old road" alongside or evidence of one. Another example of out of date mapping?

treborvfr · Occasional Visitor Joined: Aug 25, 2004 Posts: 34

mikealder · Posted: Sun Aug 28, 2005 12:47 pm Post subject:

Other than the atmospheric related stuff (where loads of people are affected over a large area) - a couple of other theories, vehicles / houses transmitting on CB radio (the illegal high power stuff), not as prevailant these days but still in use. Another possible is electrical interferance generated by a vehicle close by, could be from the ignition system or alternator this could upset the GPS while following the "faulty" vehicle, Mike

treborvfr · Occasional Visitor Joined: Aug 25, 2004 Posts: 34

dunos · Regular Visitor Joined: Feb 22, 2005 Posts: 75

I have had this a few times now. The last time it did it was on a trip from Oxford to Stafford via M6 Toll. I had to reset the gps receiver (TT bluetooth mk 1) and turn off/on the tomtom software before it would behave. I had wondered if it had had something to do with me not turning off the tt receiver before starting a new journey since tt 5.0 does that funny thing where it never botheres to tell the receiver that it has disconnected and turned off bluetooth and therefore the receiver just has to timeout.

dan
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julians · Occasional Visitor Joined: May 03, 2004 Posts: 7

I get exactly the same thing, never used to happen on TT3, but now happens a lot on TT5.

Dont know what they are doing different, but it is a big problem for me now.

gekko · Occasional Visitor Joined: Sep 01, 2005 Posts: 25

Does it happen at the same physical location everytime you pass there, i.e is it repeatable?
If it is repeatable is could be some error in the map or a combination of map error and TomTom bug. If it is not repeatable, who knows...?

I have encountered the same phenomenon twice, but I have not driven there again so I have not been able to check if the problem is repeatable in those locations. Both times I encountered it I was driving relatively close to mountains. Could it be GPS signal reflection?

chaddow · Occasional Visitor Joined: Jun 07, 2005 Posts: 25

Don't know if this is relevent or not, but as I'm a pilot when doing flight planning I need to read the current NOTAMs (Notices to Airmen) which details navigations hazards, temporary airspace etc. Sometimes in these there are entries such as;

EGTT
COM : FROM 05/08/30 08:00 TO 05/09/15 16:00 U1006/05
D)0800-1600
E)GPS SIGNALS WILL BE JAMMED, GROUND BASED JAMMERS PSN WI 5KM OF
5201N 00336W (SENNYBRIDGE TRAINING AREA, WALES) AFFECTING ACFT WI
189NM. GPS RECEIVERS MAY SUFFER INTERMITTENT OR TOTAL FAILURE, OR
GIVE INCORRECT PSN INFO. PILOTS SHOULD BE AWARE AND USE ALT MEANS OF
NAV.
EMERGENCY CEASE JAM POINT TEL:
SENNYBRIDGE OPS DESK 01874 635461
OR 07776134520 / 07813 592626
AIC 93/02 (PINK 41) ALSO REFERS.

about GPS signals being jammed. The above example states that aircraft within 189 nautical miles of the jamming site may be affected. I would guess that the range on the ground would be considerably less but there would probably still have an effect. Don't know exactly what form the jamming takes but one of the possible consequences described is incorrect position information. Maybe this could have something to do with some of the position inaccuracies reported ?

Cheers for now
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GrahamCresswell · Occasional Visitor Joined: Sep 09, 2005 Posts: 5

I have this problem all the time. TT5 shows my position about 200 yds NNE of the true position. When I'm driving N or S, it generally puts me on the correct road but, when I'm driving E or W, it puts me on all the side roads to the north and constantly recalculates a route back to the main road. It is virtually unuseable. As far as I am aware the GPS is sending the position in WGS84 but I have tried OSGB36 as well and it produces the same results although I understand that, with NMEA, the GPS always sends the position in WGS84 and the nav software is meant to adjust it for the datum of the map in use.

I'd be glad to hear of any solutions or about any alternative to TT5 that allows you to correct the position with an offset.

mikealder · Posted: Mon Sep 19, 2005 8:02 pm Post subject:

Graham, Where abouts in the country is this happening, local to you or all the time, if local do you live near a mil training base or mil fly training location? if not the it looks like the GPS unit could be at fault, have you tried another one? - also what kit are you using BT reciever or wired etc? Mike

flyguy26e · Posted: Tue Sep 20, 2005 3:12 am Post subject:

NickDavy · Occasional Visitor Joined: Aug 16, 2005 Posts: 6

I have been having similar problems with TT5 and Mio168, when I reported the problem, the 168 & TT5 was replaced but the new one showed the same problem. Normally rather than running parallel to my position the map jumps around sometimes showing my position ahead of where I am and then waiting for me to catch up with it.

I notice that TomTom support does not support the Mio so I guess that they would not be very interested in this problem

Robin2 · Posted: Fri Sep 30, 2005 12:33 am Post subject:

I don't think the problem is with TomTom. As I mentioned earlier in this thread, I got it with TT3 but the same thing was happening when I switched to CoPilot. I'm interested in the notice to aviators though, because I was in South Wales when it happened, about 40 miles from Sennybridge. I have since driven along the same road using TT5 with no problems.
Robin
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bunnyman69 · Regular Visitor Joined: Apr 25, 2005 Posts: 73

easy solution to the problem, avoid hanger lane. If ya know hanger lane lane like the back of ya hand why you tomtom anyway. I emailed tomtom today about it and they say the Hanger Lane problem is PLANE to see
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