GPS Satellite Reception Time Out

[drsec]

Your device should not stop navigate. At least it doesn't stop in mine.

My experience was, whenever satellite reception lost, it will re-calculate as soon as the signal is fixed again.

I agree with you. My experience with GMXT (on HTC HD) and Nuvi is that they never abort navigation unless you instruct it to stop navigating or you have arrived at the destination. In fact for both GMXT and Nuvi it will re continue from where it left off when the unit/software is switched on/reactivated after being switched off/terminated whilst navigating.

When satellite signal is lost, it gives a warning that satellite signal is weak or lost, but it is still in navigation mode. It will recalculate the route as soon as satellite lock is reestablished and it can establish your positioning. Throughout the entire time that there was no satellite signal, GMXT and the Nuvi are still in navigation mode except that it is unable to establish positioning, however long this time may be.

I have just tested my GMXT in my office with loss of satellite signal and GMXT continues to be in navigation mode and when I take it to the window to re-establish satellite lock, GMXT come out with a navigation alert.

Maybe Bro LLCC can explain what he means by "GMXT ending the navigation" and "Navigation aborts".

[Zeus73]

Bro LLCC did mention something about "not able to recalculate".

Need to check on the map to see what is stopping the recalculation around that area.

[Zeus73]

PIC00003.jpg

I think I have found the problem.

The highlighed section of KPE is a one way road not connected to anywhere.

If the GPS mis-detect and thinks that you are travelling on that section of the road, you will get that unable to recalculate error message.

You can feedback this issue to OngCC (mapper for Singapore) for further verification.

Moderators, I think you can move this topic to "Singapore Map Feedback".

[drsec]

Wow, this is quite an eye opener. So it is the specific location and map condition that causes the unit to fail to navigate.

Thanks for enlightening.

But what I've seen is that if I am in a place where there is "no road", as soon as the unit can establish its position, it will give an advise to get on the nearest recommended road. Its strange and Bro LLCC did say that it is Ok with his Garmin 76CSx. Is he using a different map for GMXT?

[Zeus73]

Its strange and Bro LLCC did say that it is Ok with his Garmin 76CSx. Is he using a different map for GMXT?

Now is where the accuracy of the GPS comes in.

Maybe the Garmin 76CSx is able to pick up the location correctly.

[colalite]

.... it locks on immediately but not before reconfirming if one is indoors or outdoors and then the usual location being the country and date query posed. No time out or reset mode came into place.

I do not use GMXT but a Nuvi.
However, I did get what bro Cruiser mentioned above. Just to proceed further on the topic; I wonder if bro LLCC accidentally press the wrong "button" (touch screen) and cancelled off the route. This happened to me before while driving and trying to clear the questions and then suddenly I am in the map mode without the route. Just a thought.
Cheers.

[LLCC]

You guys made some very good observations. Testimony of the quality of our forum's postings. Bravo.

1) Yes, my GMXT will continue to navigate when power is restored, even if it is powered off midway through its navigation. It won't stop navigating unless I manually key the stop navigation button or when it arrives at destination.

2) When GMXT arrives at the destination, it changes to map mode. However, Only in this peculiar case at the Tg Rhu exit of KPE, a screen pops up to say something about unable to continue navigation, instead of recalculating the route as expected. I'm unable to see clearly what the screen says because I need to concentrate on driving, and the message stays only a moment before the map screen takes over.

3) I've turned AGPS off for my last few tests. However, I remember it was running with AGPS initially with the same outcome. But I can try it again just to be sure if running AGPS fixes the problem. However, I doubt AGPS will help simply because the set already is "hot" starting if you know what I mean. (AGPS assists for cold starting IIRC). I have no problem getting an almost instant fix when I exit the tunnel.

4) It's a good observation of yours Zeus73. However, it doesn't explain why I can navigate through when using Garmin 76CSx but not with GMXT. All are using MFM map, albeit 76CSx is added with SLA postcode layer. Maybe I chose Show location on roads for GMXT while 76CSx (which is my boat unit), shows location at GPS location. I'll change it for the GMXT just to see on Monday.

5) My phone has no touch screen, and it lays on the dash untouched while I drive. So no chance of accidentally stopping navigation, every trip through (which is every workday).

Do keep your thoughts coming guys.

LL

PS: lastly about tracks. Sigh. I learned by the hard way, that I must not plug the set into power just when it is starting up (MFM splash screen). Doing so wipes off all my tracks, waypoints and routes, and resets the unit back to factory default

[Zeus73]

4) It's a good observation of yours Zeus73. However, it doesn't explain why I can navigate through when using Garmin 76CSx but not with GMXT. All are using MFM map, albeit 76CSx is added with SLA postcode layer. Maybe I chose Show location on roads for GMXT while 76CSx (which is my boat unit), shows location at GPS location. I'll change it for the GMXT just to see on Monday.

PS: lastly about tracks. Sigh. I learned by the hard way, that I must not plug the set into power just when it is starting up (MFM splash screen). Doing so wipes off all my tracks, waypoints and routes, and resets the unit back to factory default

The tracks for both N95 and N96 all gone?

Cos the answer to the problem is in there.

[vash_h]

when i pass the smart tunnel, i loose my satelite reception (for obvious reasons)..

gmxt jst says 'lost satelite reception' at the top part.

a few seconds after i exit the tunnel, the phone immediately recalculates and starts navigating again.

[Zeus73]

Let me show you the kind of errors we will get if we try to acquire satellites on the move.

PIC00005.jpg

The track highlighted in blue is the roads I'm travelling on.
The red one is what recorded by my nuvi 205W.
I was having lots of “Recalculating…” during that period. Luckily there wasn’t any funny tracks/roads around that area that would terminate the routing.