GPS Ublox7 Dongle connection problems

[AlanB]

I'm having the same problem as described.

I'm using an iPAD. UBlox GPS showing as available and receiving messages but no mode or satellites or at best 2-3 satellites. No flashing green light indicating GPS lock.

The GPS I'm using is the standard UBlox and was working on previous version of software but seem to have problems now.

Power supply and cable provide 2.4amp capacity so don't think that is the problem.

Screen shot posted direct to Lee as too large to attach.

Alan

[Admin]

I left the unit on all night, but not outside and there was no difference this morning. However when I plug in a USB extension lead I get 7 satellites and a 3D fix without any problems and all works. Remove the extension lead and plug the GPS dongle directly into the Pi and I momentarily may get 4 satellites but mostly 0. So I guess I am getting some shielding effect. When installed for real use then the GPS dongle will be on a USB extension lead so the Pi can be positioned protected from the sun.
Power supply is currently a mains iPad transformer (not an iPhone charger).

Thats strange, can I ask which slot you are inserting the GPS Dongle, is it the same as per the guide here ?
http://pilotawarehardware.com/dl/QuickStart.pdf

[exfirepro]

Hi all,

Very frustrating - I did experience this briefly with one of my beta test units when I first tried to get it running indoors. (Over the Beta test period, I built 4 units and have since used them with both the GPS dongle and a remote 'mouse' version without any problems, so this will just be a temporary glitch)

It seems to be critical, especially for initial startup, that the unit has a good clear view of the sky to the south (where most of the satellites are) and even then, it can still take a considerable time for the gps to establish its 'ephemeris' data (i.e. work out where it is). This is not normally a problem with subsequent operation.

The establishment of initial 'ephemeris' data can fail if you try to do it inside. To check progress, you can monitor satellite acquisition on the configuration screen once you get your tablet connected to the PAW WiFi.

Probably a silly question, but I take it you have tried removing power and rebooting out in the open?

If not, definitely worth a try. If that doesn't work, don't get disheartened - Lee and Dave will sort it out for you!

Regards

Peter

[Paul_Sengupta]

Funnily enough, when I first made mine and tested indoors, I found that it wouldn't pick up the satellites. I also found, as above, that if I moved the GPS onto a USB extension that it worked better. However, I don't get any problems in the aeroplane with the GPS plugged directly into the PI. I assume/assumed that the Wifi dongle will deafen the GPS, so I have my DVB-T dongle underneath the GPS and the wifi dongle alongside the DVB-T. I haven't looked at the guide yet to see if that's what's recommended! 

Edit: It isn't.

I have the GPS in the slot above (1), the DVB-T in (1) and the Wifi in (2).

[Chris-TT]

Hi Chris,

The dongle which shipped with the unit would definitely have been working when it was dispatched.
There are a lengthy set of automated installation checks which run checking on all of the interfaces.
If the GPS had not managed to get a good lock, then many other tests would have failed in addition
to the GPS failure

I am not an _expert_ on these matters but if the GPS needs to reload its ephemeris data this can take a while, how long has it been running, and I presume it has a good view of the sky

https://en.wikipedia.org/wiki/Time_to_first_fix

Thx
Lee

Hi Lee,

I had a play for another 3 hours yesterday, I even plugged the dongle into my laptop, downloaded the Ublox U-centre software, tried using the AssistNow feature, and still couldn't get a fix. I've got it outside pointing south at the moment, plugged into slot 3 (above the wifi adapter), and it's still not getting a fix. I'm using your cable, and I've tried both a 2.1amp power bank, and an iPad charger.

Chris

[JCurtis]

I had a friend drop by briefly with his new PAW today, tinkering in the office the dongle would not get a signal although other GPS receivers in there could.  Once the unit was outside the office, facing NW, it acquired in about 45 seconds. 

That does look like an iffy dongle.

[Chris-TT]

It seems bizarre to have 2 faulty ones though, I already have one exactly the same for the original unit I'm building which doesn't seem to work ether.
Taking money out of the equation what is the very best USB Dongle which is compatible? Ideally one which remembers where the satellites are?

[JCurtis]

It seems bizarre to have 2 faulty ones though, I already have one exactly the same for the original unit I'm building which doesn't seem to work ether.
Taking money out of the equation what is the very best USB Dongle which is compatible? Ideally one which remembers where the satellites are?

It can happen.  Whilst these should have a u-Blox chip inside I've not taken one apart to physically check...

Some modules will keep an almanac for a day or two, but it isn't precise just a kind of primer to speed up acquisition.  Modern GPS receivers will acquire from cold/factory in a couple of minutes or less with a good view if the sky.

Don't go out and buy one until Lee can confirm what USB drivers are within the PAW product itself or it may not work.  Personally I'd go for an external unit on a cable, so it can always be positioned for optional view and stuck down.

Come to think about that for a minute, I would urge anyone putting a PilotAware into a cockpit to have some means of holding things down.  In the event of turbulence, or worse, having bits flying around isn't going to make your day get any better.

[trapdoor]

When I was beta testing, I bought one of the Ublox7 dongles and it was never terribly reliable. I had dialogue with Lee about it and elected to use a different 'mouse type' GPS/GLONASS GPS that was on the end of a cable rather than a dongle.

I dismantled the dongle and I believe(d) there was an issue with the 'antenna' in the dongle; it certainly wasn't terribly well manufactured and I attempted a repair on the antenna and it did improve matters a bit but it was never a patch on either the in-built GPS in the iPad, my Bad Elf or the cheap Chinese 'mouse type' GPS that I eventually used for all PAW testing.

There was a belief that perhaps not all of the UBLOX7 GPS dongles were all the same, made by different manufacturers but they all look externally alike.

Cannot comment about those supplied with the new kit as mine hasn't arrived yet, but I am hoping my old GPS Mouse will still work as I didn't want to rely on the UBLOX dongle

[Chris-TT]

Well the good news is I just got a fix, I left it for another 10 minutes just to let its database populate… I then turned it to North, and lost all satellites.

[brinzlee]

Best only go in a southerly direction then.!!

[Chris-TT]

I probably should mention this was outside too...

Its still outside, and has only found 3 satellites. I think I have a faulty one, I'd much rather spend a bit more and get a decent one that Lee's going to keep supporting rather than only flying South

[david.phillips31]

Firstly, thanks to Lee and David for sorting my SD card problem; excellent service.

Like others, I'm having difficulty finding satellites when the GPS dongle is connected directly to the Pi.  If I run a USB extension lead I get a signal.

Secondly, the DVB dongle gets rather warm. Is this normal?

[Paul_Sengupta]

Have you tried the positions for the dongles in my post above?

Top left: GPS
Bottom left: DVB-T
Bottom right: Wifi

And yes, the DVB-T dongle does get a bit hot.

[DaveStyles]

Hi David,

could you change to Pauls recommendation and see if that helps ?
We may change the recommendation of placement if it helps as a few are having problems with it.

I must admit that our test ones sometimes take up to 5 mins to get a fix *on the ground* but we just leave them to it and they do.

regards

David Styles