GPS Satellite Reception Time Out

[LLCC]

Just got GMXT ver 5.00.50s60.9 for N96. Finally, I can see the beautiful graphics that you guys had worked so hard to put up and hear a voice telling me to keep right and turn left. Bravo! chaps, and thanks for the map.

I noticed however, that when I navigate through the KPE tunnel en route from Tampines to Lower Delta Road, navigation will stop after satellite reception is re-established at the Shears Bridge. No route recalculation, the unit just goes into map mode.

However, when returning from the opposite direction, ie, from Lower Delta Road to Tampines via KPE tunnel, I find that the software will recalculate route and resume with navigation when satellite reception is re-established at the opposite side of the tunnel at Tampines exit.

This had been happening for many occasions already. Which leads me to suspect that the software will "time out" and abort navigation after a certain time had lapsed without satellite connection. I say this because I spend a longer time without satellite reception en route to Lower Delta Road due to morning traffic, than the other way around.

Does anyone who is more familiar with GMXT comment if it is indeed abort after time out?

LL

[winwintoto1234]

The device will stop functioning as soon as there is no satellite signal. In other word, immediately.

If you want to avoid this problem, you may want to activate you Assisted-GPS.
With A-GPS, the satellite signal is strengthen by GPRS. It will be more stable and faster in recalculating.
With A-GPS, (sometime) you can even use you device indoor but not sure if you are in the tunnel.
The drawback is, you need to pay for 1 block of GPRS usage (I think at each time the device announces something, eg. right turn, roundabout...etc).
In Malaysia, it costs 10 sen per block (10kb).

[LLCC]

I'm not talking about navigating in the tunnel. The GPSr certainly will not work in the tunnel (even with A-GPS enabled) as it doesn't have the other 3-4 points to fix a position. Maybe our town planners may one day install a few D-GPS beacon for tunnels so we can all navigate even underground, but I digress.

I'm talking about GMXT ending the navigation after a time spent without satellite coverage in the tunnel.

Today, I tried the same route using 76CSx. After coming out from the other side of the tunnel, the unit re-logs itself, does a recalculation and continues with navigation. No problem at all. However, as there was no traffic in the tunnel this morning, it may be the reason why it does not stop navigation - not long enough to time out.

Any others with similar experience?

LL

[cruiser]

Understood yr predicament at every similar occasion you drive thru under those circumstances.

Was indeed involved in a similar case at the short Dartford Tunnel in UK and after coming through (some 15-mins later) which normally takes less than a minute at avg 70kph permitted speed limit, 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.

[veloblur]

If Garmin updates their GMXT to take advantage of those phones with accelerometers, they can estimate your speed and direction in the KPE tunnel. Nokia Maps 2.0.something does this until you exit when it locks onto GPS again. Alternatively, it may only be using the last known speed to predict your journey to through the tunnel and assumes no change in speed while inside the tunnel.

[winwintoto1234]

I'm not talking about navigating in the tunnel. The GPSr certainly will not work in the tunnel (even with A-GPS enabled) as it doesn't have the other 3-4 points to fix a position. Maybe our town planners may one day install a few D-GPS beacon for tunnels so we can all navigate even underground, but I digress.

I'm talking about GMXT ending the navigation after a time spent without satellite coverage in the tunnel.

Today, I tried the same route using 76CSx. After coming out from the other side of the tunnel, the unit re-logs itself, does a recalculation and continues with navigation. No problem at all. However, as there was no traffic in the tunnel this morning, it may be the reason why it does not stop navigation - not long enough to time out.

Any others with similar experience?

LL

Sorry for misunderstood your question.

Your device should not stop navigate. At least it doesn't stop in mine.
Your previous experience was probably due to the satellite signal was not "relocked" in time.
My experience was, whenever satellite reception lost, it will re-calculate as soon as the signal is fixed again.
Of course it is only based on my own experience on my own device and I will stand corrected...

[LLCC]

Sorry for misunderstood your question.

Your device should not stop navigate. At least it doesn't stop in mine.
Your previous experience was probably due to the satellite signal was not "relocked" in time.
My experience was, whenever satellite reception lost, it will re-calculate as soon as the signal is fixed again.
Of course it is only based on my own experience on my own device and I will stand corrected...

Noworries, bro.

Today, I tried again using my wife's GMXT on N95 together with mine on N96. Results the same. However travelling the opposite direction last night, there's no problem recalculating once satellite log-on is re-established.

This morning when coming out of the KPE tunnel at Tg Rhu, both sets displayed a short message about "not able to recalculate" after satellite log on is established, and reverted to map mode. I can't see the full message as I was driving, and my wife's instinctive reaction to any window that pops up is to get rid of it, without knowing what is that window warning about

Anyone else who drive KPE encounter this? So far in my tests, Garmin 76CSx managed to go through the tunnel, come out, log on recalculate and continue navigation. GMXT on N95 and N96 stops navigation after satellite log on resumes on exiting the tunnel.

LL

[LLCC]

Doesn't any one on this forum encounter such an occurrence anywhere?

Anyway, on with my observations:

7 Jul 09, 19:55 hrs, enter KPE tunnel at Tg Rhu, travel towards Tampines. 20:02 hrs exit at Tampines exit, (total time without satellite coverage: 7mins 05 secs, timed by stopwatch). GMXT reconnected to satellite immediately upon exit of tunnel and resumed navigation to final destination. No problem with this side of the expressway on all journeys so far.

8 Jul 09, 08:05 hrs, enter KPE tunnel at Tampines, travel towards Tg Rhu. 08:12 hrs, exit at Tg Rhu exit, (total time without satellite coverage: 7mins 07 secs, timed by stopwatch). GMXT reconnected to satellite immediately upon exit of tunnel. I know it had reconnected immediately upon exit because I hear the navigation voice say "Wot the H*ll do you think you are doing? This is not the route that I planned for you..." But after that, silence, because GMXT was unable to recalculate the route for some reason, and navigation aborted.

That means my guess that navigation aborts after a long period without satellite log is wrong, as both trips took seven minutes, the difference is only 2 seconds delay)

From my observation so far, here are the condensed findings:
Navigation aborts when
1) Navigation aborts on the City going direction of the KPE.
2) Navigation aborts using GMXT (Map: MFM v1.63)

Navigation proceeds upon satellite reconnection when
1) Navigation on the KPE away from City using GMXT.
2) Navigation on both directions of KPE when using Garmin 76CSx (Map: MFM-Eastgear-SLA map v1.62)

So what could be the cause of GMXT to abort? Anyone encountered tis anywhere else?

LL

[LLCC]

That means my guess that navigation aborts after a long period without satellite log is wrong, as both trips took seven minutes, the difference is only 2 seconds delay)

From my observation so far, here are the condensed findings:
Navigation aborts when
1) Navigation aborts on the City going direction of the KPE.
2) Navigation aborts using GMXT (Map: MFM v1.63)

Navigation proceeds upon satellite reconnection when
1) Navigation on the KPE away from City using GMXT.
2) Navigation on both directions of KPE when using Garmin 76CSx (Map: MFM-Eastgear-SLA map v1.62)

So what could be the cause of GMXT to abort? Anyone encountered tis anywhere else?

Today's observation:

I chose to drive via the CTE tunnel this morning, entering the tunnel from Kg Java entrance and exiting at Outram. 3 mins 4 secs total time spent underground without satellite view, save for a short (few secs) reconnection at Kramat lane exit.

GMXT on N95 and N96 worked well, recalculating once I exit the tunnel and continued with navigation.

So what gives? Is it a problem with GMXT since it only affects at one way of KPE tunnel on GMXT?

Guess my next test is to standardise all maps for GMXT and 76CSx and test again.

Till then, I hope someone else can chip in your experience too,

LL

[Zeus73]

For your GMXT, do you have AGPS on?

Currently I don't have MapSource with me. Will help you check out this issue tonight.

GMXT has track recording function. Can you enable this option? This can speed up the investigation job too.