Normal number of satellites?

djohnson · Occasional Visitor Joined: Jun 12, 2004 Posts: 35

Hi,

I've got an Emtac GPSJAQ with an H5550 IPAQ. Standing outside with a clear view to the sky on a clear day, what would be the normal number of satellite fixes? I get between 1 and 6 at the most. And the same inside the car near the windscreen.

Also, if I am sitting in the car waiting. The navigator (Tom Tom 3) moves my position (floats) and never stays on the same street. I have a friend who got a Fiat Punto Sporting with built in Nav. It's so accurate that it even knows when the car is parked on the kerb. It tells him that he's off street. And when he reaches his destination, it tells him which side of the street the destination is. Do you think maybe if I had a seperate Antenna, I'd get this kind of accuracy?

DavidW · Posted: Sun Jun 13, 2004 1:45 am Post subject:

He's not getting that kind of accuracy - his system is using snap to road and damping the position to make it appear that he is getting that kind of accuracy.

Your number of satellites sounds low and that could be related to the jumping between roads you're seeing (which I see only in some particularly GPS hostile parts of Central London and only then with bad satellite geometry on my setup). You need at least four satellites to get a 3D position fix, and you can usually manage at least four. I commonly have somewhere between five and nine. I have had anything from 0 to 12 satellites on my setup, which is different hardware to yours.

The results being the same whether or not the GPS is behind your windscreen indicates that your windscreen isn't the problem. I wonder if you have a faulty GPS, though the jackets do tend to have lower numbers of satellites fixed than other solutions.

I don't know whether the antistatic bag trick helps any with the Emtac hardware (it can help particularly with early Navman hardware). Maybe someone else who knows will reply.

David

djohnson · Occasional Visitor Joined: Jun 12, 2004 Posts: 35

Hi David,

What's the anti-static bag trick? :D

Also, do you think a seperate Antenna will make much difference?

Darren

DavidW · Posted: Sun Jun 13, 2004 3:23 pm Post subject:

The antistatic bag trick was originally found with earlier Navman hardware. If you put a piece or two of the material used to make conductive antistatic bags between the iPAQ and the GPS, it seems to improve the shielding tremendously and can improve GPS reception.

External antenna - no idea, I'm afraid - you can only try it.

Personally I'd try the antistatic bag trick first.

David

djohnson · Occasional Visitor Joined: Jun 12, 2004 Posts: 35

Great. I'll try this. I've got some anti-static bags somewhere.

Cheers,

Darren.

DavidW · Posted: Sun Jun 13, 2004 4:52 pm Post subject:

It's certainly worth five minutes with some scissors and sticky tape to try it out. Just make sure you keep the material away from the connector - you don't want to short anything out (not that the material is that conductive, but it's best making sure there's no loose bits of conductive material floating around).

It'd be great if you can reply to let us know whether or not it helped any.

David

djohnson · Occasional Visitor Joined: Jun 12, 2004 Posts: 35

Will do

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