Author Topic: Pilotaware gps stops working  (Read 3896 times)

DavidIOW

Pilotaware gps stops working
« on: November 19, 2022, 05:39:01 pm »
Today we had a second incidence of PAW Rosetta stopping working for no apparent reason. We have it connected to SD and suddenly SD showed it had lost gps position. The Trig transponder, which has gps input from PAW, also showed it had lost gps position. Switching PAW off (actually switching off the Charge 4 power supply that feeds PAW and several other things) and back on again restored gps to Trig but you then have to re-link it to SD, and reconnect igrid etc. which is not ideal to do in flight.

We also saw that when the Trig lost its gps input from PAW it didn’t function at all in any mode. Awkward as it happened in the middle of a zone transit and controller had to confirm which dot on his radar we were. Is that usual when a Mode S ES/ADS-B transponder loses its gps input then it doesn’t just revert to being a Mode S?

Any idea why PAW should suddenly cut out like that? Other than these two incidences of spontaneous shutdown it has worked really well and we love it! Many thanks. David

grahambaker

Re: Pilotaware gps stops working
« Reply #1 on: November 19, 2022, 05:42:13 pm »
You weren't transiting Birmingham airspace today were you?

There are GPS jamming trials going on there this weekend.

(FWIW my Trig gets its position data from a GNS430W. If I switch that off, or it loses integrity, the Trig keeps working but you just get a message to say that the position source has been lost).
« Last Edit: November 19, 2022, 05:45:13 pm by grahambaker »

DavidIOW

Re: Pilotaware gps stops working
« Reply #2 on: November 19, 2022, 09:28:34 pm »
It was Solent zone and all was working fine before and then again after the reset so probably only offline for a couple of minutes but enough to give the controller a scare! The Trig did show a message that position info had been lost but it seems that the controller couldn’t then see things you’d expect them to see under the Trig’s basic Mode S such as call sign, altitude etc which was a surprise.

Admin

Re: Pilotaware gps stops working
« Reply #3 on: November 20, 2022, 06:45:32 pm »
Hi David

That all sounds very odd
A controller will only see your mode S data anyway, NATS do not have any infrastructure for ADSB
Thx
Lee

DavidIOW

Re: Pilotaware gps stops working
« Reply #4 on: November 21, 2022, 05:02:51 pm »
Yes it does seem odd but the controller was clear that we had just turned into a simple dot on his radar at the point where the message came up about loss of gps. I’ll take this up directly with Trig and see if they have come across this before.

Going back to the original question about the blip in gps feed from PAW to SD and Trig, is there anything we can do to stop this happening? I know intermittent and infrequent faults like this are really hard to diagnose! Many thanks.

DavidIOW

Re: Pilotaware gps stops working
« Reply #5 on: November 25, 2022, 06:58:17 pm »
Latest situation: Today we had three incidences of the PAW gps stopping. The first was in Manchester low level corridor inbound to Barton which was a bit hairy. We didn’t try to restart PAW as it’s an intense bit of airspace but just switched to iPad gps. The second time was just pre take off from Barton. This time we restarted PAW and reconnected it. Later in the day it happened again, this time while we were in contact with Solent radar on our return. This time we had time to restart PAW and the gps came back on and Solent didn’t comment (perhaps because we hadn’t yet entered their zone though we had their clearance).  Seems to be a PAW gps drop-out issue but it is certainly a concern, especially when it happens in LL corridor! Feedback from Trig is that they would expect the Trig to maintain Mode S so were surprised by what happened in the original post.

Any ideas why the gps keeps dropping out and what we can do to avoid it? Thanks!

Ian Melville

Re: Pilotaware gps stops working
« Reply #6 on: November 26, 2022, 08:06:10 pm »
Just change the GPS, it seems to happen often enough to soon find out if that is where the issue is. Watch out for failing ADSB dongles as well as they can draw enough current to cause outages

DavidIOW

Re: Pilotaware gps stops working
« Reply #7 on: November 28, 2022, 05:11:34 pm »
I don’t have a second gps input source to hand at the moment. By ‘ads-b’ dongle do you mean the special usb to serial cable I have from PAW to the Trig?

Ian Melville

Re: Pilotaware gps stops working
« Reply #8 on: November 28, 2022, 07:25:13 pm »
No I am not refering to the USB to serial cable adaptor which will connect to your trig.
I don't know what version you have, so cannot describe it. It is the USB dongle that has the shorter antenna attached to it. If you do remove it and the PAW works for GPS position, it will not show ADSB or mode S traffic, but this is just a test.

Cheers
Ian

DavidIOW

Re: Pilotaware gps stops working
« Reply #9 on: November 28, 2022, 08:51:46 pm »
Thanks Ian. I have the 2022 Rosetta. The two PAW aerials are external and their coax leads are attached to the PAW box by the screw on aerial terminals at one end of the box. The PAW gps mouse aerial plugs into one of the 4 USB sockets on the PAW. Hope that helps!

Ian Melville

Re: Pilotaware gps stops working
« Reply #10 on: November 29, 2022, 07:41:28 am »
When you removed that cover to plug in the RS232 cable and GPS cable there was another dongle plugged in with a thin coax cable connected. That is the ADSB dongle. Make a note of which socket.

Was your Rosetta only supplied with the USB mouse on the long cable?

DavidIOW

Re: Pilotaware gps stops working
« Reply #11 on: November 29, 2022, 12:33:42 pm »
Thanks for your help, Ian. The only long cable supplied with the PAW was the gps mouse one. Looking at the sockets ( from their open side and with the RJ45 socket on the left side of the unit) we have the following use of the 4x USB sockets: Bottom right: ADSB dongle you describe. Top right: GPS mouse. Bottom left: Serial cable to Trig transponder. Top left: iGrid USB stick. Does that help? Do we need to rearrange them? Thanks. David

Ian Melville

Re: Pilotaware gps stops working
« Reply #12 on: November 29, 2022, 10:05:32 pm »
Wasn't aware you had iGrid. If it worked after adding the iGrid, then don't swap anything around.

ADSB dongles are SDR Radio dongles. when these fail they can draw high currents and pull down you PAW causing intermitant or even full failure of the PAW. Suggest you remove it to see if your GPS returns to working normally.

If that makes no change, it is possible the GPS reciever has failed.
« Last Edit: November 30, 2022, 07:05:34 am by Ian Melville »

steveu

Re: Pilotaware gps stops working
« Reply #13 on: November 29, 2022, 10:11:53 pm »
Though they may be of different types both iGrid and ADSB dongles are both SDR Radio dongles.
If that makes no change, it is possible the GPS reciever has failed.

Erm, isn't the iGRid dongle a small wireless USB adaptor?

Ian Melville

Re: Pilotaware gps stops working
« Reply #14 on: November 30, 2022, 07:03:54 am »
Correct Steve, I'm having a brain fart :-\

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