GPS reception on a Mio P550

PH68 · Occasional Visitor Joined: Jul 04, 2007 Posts: 9

Have bought a Mio P550 and everything seems sort of OK.
I have TomTom N6 installed and Google Maps.

After a bit of meesing with COM ports, I got a good GPS signal on TT (about 4 bars) and got a spot-on fix with Google Maps... I was in the house at the time.

Decided to see if TT could get me to work this morning.
It took ages to get a GPS signal. Sad

So I drove down the road for a mile or so (still no signal)... :x
So, I stopped the car, waited, and then got a 1 bar signal.
After a few miles it was up to 4-5 bars.
Everything then fine and never lost reception.

is this a Mio issue, or not, as I got a signal indoors at home ast night.

philpugh · Posted: Thu Jul 05, 2007 10:49 am Post subject:

What car are you driving? Does it have one of these athermic and /or heated front screen? If so this will affect signal reception. If you have one of these then there are a couple of solutions. Move unit to another part of car - tricky if it has in-built GPS - or install external GPS aerial - there will be a small connector (MCX or MMCX) on your P550 if it supports this.

Also: moving whilst the GPS is trying to get a lock is usually not a good idea as it will be waiting for certain information from the sats and moving is likely to disrupt this process. It can extend the TTF (time to fix) to several minutes. Turn it on and leave it in car for a couple of minutes before setting off. If you use it each day the TTF should be less than 1 minute usually.
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Border_Collie · Posted: Thu Jul 05, 2007 5:43 pm Post subject:

Having a Citroen with an athermic screen I'd second philpugh's reply other than to say, get a lock outside the car first then set-up inside with the unit on the centre of the dash, below the clear dotted area at the top of the screen behind the rear view mirror. Once you have the lock everything should run fine.

Having said that, I've just tested i-Go software on a Mio P350 and never experienced any of the problems getting locks when starting the unit inside my car. It appears to me that TT, for whatever reason, is the cause of the problem, not necessarily the screen. (Not with Sirf3 anyway).
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PH68 · Occasional Visitor Joined: Jul 04, 2007 Posts: 9

Took about 5 minutes to get just a one-bar lock when on works car park.
I stayed in the car as it was chucking it down.

Again, once locked it went to 3, then 5 bars, and remained good all the way home.

Car is a Skoda Octavia.

philpugh · Posted: Fri Jul 06, 2007 9:39 am Post subject:

Shouldn't be a problem with the windscreen then.

When (if) you get a dry day so you can stand outside, find a place with a clear view of the sky (i.e. no tall buildings/trees etc) and time how long it takes to get a lock. Turn unit off and try again 10mins minutes later. The lock time now should be in low number of seconds. Try this with the different applications to see if there is really any difference in times. Tomtom is probably a little more conservative on deciding when to decide there is a good enough lock. My Garmin nuvi does something similar. When first switched on it will display the map and position the car with a lock but when I try to set a route it sometimes displays a message "Waiting for better accuracy" or some such. So perhaps some applications look for the HDOP to be below a certain figure before showing a lock?
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philpugh · Posted: Fri Jul 06, 2007 9:52 am Post subject:

Border_Collie · Posted: Fri Jul 06, 2007 4:39 pm Post subject:

PH68 · Occasional Visitor Joined: Jul 04, 2007 Posts: 9

The bars are those on the main TT screen, not those on the Satelite screen.

Buildings should not be a problem as there are about a handfull of houses in the village, then nowt for miles.

I don't want to use an external aerial thats why a bought a PDA with GPS built in.

It's now locking on in about 2-3 minutes... why does it feel like a loooong 2-3 minutes though.

Border_Collie · Posted: Fri Jul 06, 2007 8:38 pm Post subject:

There was a free programme WinCE Monitor with which you could check the NMEA $trings received by your device and save to a file to view on your desktop. Using it would tell you if you were receiving all the necessary data. I checked the link before adding here and it appears it is no longer available.

I'm still convinced TomTom software is a problem, as WinCE would find and lock on so much faster than TT, as does i-Go.

I see you have only just purchased the P550 but I'm wondering how long it's been 'on the shelf'. The reason is there was a problem with a batch of P550's last year, slow lock ons, and they had to be returned to Mio for a free fix. It may be worth while contacting Mio and ask if the serial number of yours is one of those affected and if so ask for the free repair.
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