Can't see any satellites

[vibesg]

I have Comand 2.0 in a 2003 SL.
Driving down the M6 from Penrith southwards this afternoon I suddenly noticed that there was just the arrow on the screen with no maps or roads. It was showing no satellites being received.
This I have never experienced. I tried to input a fresh destination but it kept showing "Off road".
The wierd thing is that it then showed maps from elsewhere in the country and was trying to send me there with voice directions. Still showed no satellites though.

I have switched off the engine and removed the key twice to try to reboot. I have removed the navigation cd twice but no change.

Does this sound familiar to anyone? Any suggestions please.

 

[Gridlock]

Is the car the right way up?

(I got nothing..)

 

[vibesg]

I hope so. Plod sped past and left me well alone. Crept up on me though so I reduced speed using cruise control. He thought "too smart for me" and sped off.
Anyway back to the topic..someone bail me out of my Nav worries please.

 

[speedybiker]

Sounds like an Antenna problem

 

[Gridlock]

Indeed, unless a hard reboot exists the next step would be to verify that the antennae are properly connected to the head unit at the back (did you hit any large bumps? Any rattles behind the dash?) and that they are functioning as required - the former you could do yourself but the latter is a Pro job, I'd guess.

 

[wemorgan]

I'm possibly way off with my information, but I'll share in rare chance it helps:

In my TomTom if I turn it off, then travel a long distance, then turn in on again it takes a very long time to find the satellites. Could this be the case?

Also, I download updates each week, some of which are satellite locations, that are meant to speed up satellites locking. Another possibility?

 

[crammy69]

Could possibly be the Gyro, sounds similar to a problem I had, where it was saying I was off-road. However in the end Alfie opened it up and it wasnt the gyro but another little chip (sorry cant be more specific). Anyway the aeriel is probably the easiest and cheapest thing to fix first Id assume.

Hopefully Alfie will be along to comment ( hes 'The Man' when it come to Comand!)

 

[Alfie]

Almost certainly the antenna. Its soooo common.

I would try a different antenna plugged in and rested on the roof of the car. It will pick up some satellites in about 15 minutes. If it does then all you need to do is install the new antenna.

 

[vibesg]

Thanks Alfie.

How expensive are replacement antennas (antennae?) As you say its so common (I must have been lucky with my W209..5 years and not a whisker of a problem) whats the shelf life, how long can I expect to keep them for before the problem re-occurs?
Should I look for particular types or an MB Original.

 

[Diesel Benz]

Is the car the right way up?

(I got nothing..)

In the snow this could have been likely.

 

[Diesel Benz]

I'm possibly way off with my information, but I'll share in rare chance it helps:

In my TomTom if I turn it off, then travel a long distance, then turn in on again it takes a very long time to find the satellites. Could this be the case?

Also, I download updates each week, some of which are satellite locations, that are meant to speed up satellites locking. Another possibility?

The OEM navi finds and updated GPS fix every time ignition is turned on. You can only "move to a new, unknown place" by transporting the car on a flat bed or similar. The network assistance for almanac and ephemeris data like for TOM TOM and my Nokia Maps is useful when the device is switched on at a completely "unknown to the device place" like you say.

 

[vibesg]

I'm possibly way off with my information, but I'll share in rare chance it helps:

In my TomTom if I turn it off, then travel a long distance, then turn in on again it takes a very long time to find the satellites. Could this be the case?

Also, I download updates each week, some of which are satellite locations, that are meant to speed up satellites locking. Another possibility?

Thanks, though I dare say in this regard Tomtom may work differently from Comand.

 

[Baron_Samedi]

Conversely, I know that Comand works in exactly the same way.

I installed a Lithuanian unit in my W209 and until the almanac was compiled (ie the 15 minute wait), Comand thought it was still in Scandinavia or wherever

What Comand can do, is to carry on navigating for a period using 'dead reckoning'.

 

[markmifsud]

D

What Comand can do, is to carry on navigating for a period using 'dead reckoning'.

This feature is about the only one that I miss since changing from comand2 to kenwood. Even in a tunnel it knew what bend you was at and kept you on the road. Not that I often get lost in tunnels

 

[st13phil]

There are a limited number of chip suppliers for automotive GPSR's (GPS Receivers) and they all work in the same way in that they maintain a record of satellite almanac and ephemeris data so that they know where to "look" for satellites when they are first switched on rather than having to scan the skies looking for signals. This data is only valid for a relatively short period - a handful of days - and becomes invalid if the internal unit clock drifts (which it will until it re-synch's with a satellite signal). The latest "hotfix" technology where you hook a portable GPSR up to the web works by seeding the device's almanac with current data from the satellites so that it can get a quicker fix when you turn it on.

I can guarantee that Comand interacts with the satellite constellation in exactly the same way as any other automotive GPSR.

 

[Diesel Benz]

There are a limited number of chip suppliers for automotive GPSR's (GPS Receivers) and they all work in the same way in that they maintain a record of satellite almanac and ephemeris data so that they know where to "look" for satellites when they are first switched on rather than having to scan the skies looking for signals. This data is only valid for a relatively short period - a handful of days - and becomes invalid if the internal unit clock drifts (which it will until it re-synch's with a satellite signal). The latest "hotfix" technology where you hook a portable GPSR up to the web works by seeding the device's almanac with current data from the satellites so that it can get a quicker fix when you turn it on.

I can guarantee that Comand interacts with the satellite constellation in exactly the same way as any other automotive GPSR.

I'm not sure about TOM TOM but I assume it has the same capability as my phone that is using network assistance data to find its first position even without using the GPS receiver at all. This certainly is different from Comand. At least TOM TOM has the capability to request almanac and ephemeris info via internet connectivity (must be from the TOM TOM/Teleatlas servers while my phone does it from supl.nokia.com server). Comand cannot do it in any other way than reading from the satellites.

This makes the two GPS receivers different in details but Comand hardly ever needs this info that others may read over internet, I don't see Comand worse in this respect, just a bit different.