Stupid question about the direction you are facing - SOLVED!

[francoisvl]

Hi there - when using GPS on the iPad, the direction I'm facing is right from the get go - I assume based on the way the iPad is facing? How does the PilotAware system know which way you are facing before you start moving? It does seem to jump around a bit, even when stationary. [Edit to say I realise that is not true! You just face north on the iPad until you start moving - however, PilotAware does seem to move around a bit - am I imagining that too?]

Also, if you have GPS on your iPad is there a way to use that rather than the dongle? At the moment I am getting some GPS dropouts on the unit, which I never saw when using the iPad mini in-built GPS.

Having great fun with the unit but stuck on the ground and realise these 'issues' may just resolve when I get into the air!

Cheers and thanks for this great bit of kit.
Francois

[brinzlee]

all issues will resolve in the air......there is some jitter when on the ground using the ublox GPS.
There is also no orientation. This will resolve itself when data is sent from the the ublox to the iPad. Each progressive output of the ublox will send co-ordinates to the iPad and translate into the direction of travel. It's not like a magnetic compass.

[Richard]

If getting airborne is a problem for you at the moment, you could find your self a driver and ride as pasanger to try out your Pilotaware on the move in the car.

[francoisvl]

Thanks all - is it also correct that you have to use the dongle GPS, you can no longer use the iPad GPS?
Cheers!

[Admin]

Thanks all - is it also correct that you have to use the dongle GPS, you can no longer use the iPad GPS?
Cheers!

The recommendation is to use the GPS dongle. I think there is some confusion over the quality of iPad GPS, that it is better than the u-blox, in my experience this is not the case.

It is misleading to think that iOS is providing GPS data for location services, it in fact uses a number of sources including
- 3G data (if equipped)
- WiFi data
- GPS data

So when you are sitting in your living room at home, you can be pretty sure the fix data is coming from either WiFi or 3G and not GPS.
Unfortunately when you go flying it will only be using its GPS data - that is the condition to use for the comparison.

If you really want to use GPS sharing - then you can, such as NMEAGPS, but ensure you remove your GPS dongle, you should only provide data from a single source

[francoisvl]

Great - thanks for that reply which makes a lot of sense. I will definitely wait until I have been able to test this in flight before I make any changes, but it helps to know what the issues are, and to know a bit more about iPad location services. Cheers!

[Moffrestorer]

Hi Francios,

I don't know which Navigation software you are using;  I use EasyVFR in conjunction with a cellular iPad.

I have the GPS dongle on my adsb only PAW, as recommended  (still awaiting delivery of the new Bridge plus licence so I will gain full functionality using a Pi2B), but generally use the internal iPad GPS for actual navigation. Never had any problems with it, including a flight last year from Shobdon to Alderney. Granted this trip predated slightly, my involvement with PAW.

EasyVFR gives you the choice which GPS source to use within its Flarm interface settings. I normally use the iPad GPS for flight planning and then just go flying, without sodding about having to changeover settings to use the PAW dongle.  Having the dongle allows for rapid trouble free boot-up of PAW and provides visual confirmation that all is well when the dongle green led starts flashing. It also gives you a measure of redundancy if one of the GPS's plays up.

Lee's comments regarding the iPad GPS are correct. It is "assisted" GPS meaning that the Wifi and cellular triangulation etc allows for more rapid position fixing, particularly when indoors, but when under a clear sky the GPS engine functions as well as any other "tablet" or car navigation source that I have ever used.

[Paul_Sengupta]

In my experience, the UBlox GPS isn't as sensitive as those in tablets and phones generally. However, when out in the open it is more accurate, as it's a WAAS/EGNOS unit with both GPS and GLONASS. You won't see this that much in azimuth, but in elevation (i.e. altitude) it makes a fair bit of difference.

The EGNOS signal is from a geostationary satellite, so you need a clear view to the south (think Sky dish) to pick it up...much easier in the air stuck on a coaming than in back gardens in urban areas.

I also have a hunch, as stated somewhere else on here, that the Wifi dongle interferes a bit with the GPS. Putting the GPS on an extension lead seems to bring in more satellites. As it is, my layout of plug-ins to the PI is:

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

Which seems to work ok. It means the Wifi dongle isn't directly in line with the GPS.

[Moffrestorer]

Thanks for that Paul. I'd forgotten what was written on the dongle and its implications for height accuracy! I'll have to give it a try in the air.

I was thinking of trying extending the Dongle on a USB cable, have already bought some female back to back USB adaptors for this purpose because I currently Velcro the PAW to a cockpit longeron and the dongles hang down into the cockpit. Still seems to pick up GPS signals OK when mounted like this!

[exfirepro]

Hi Guys,

FWIW, I have been using the U-Blox VK-162 'Mouse' version GPS as an alternative to the standard version during recent testing, as I have my PAW mounted inside my flexwing pod

http://www.ebay.co.uk/itm/GPS-Receiver-VK-162-Magnetic-2Metre-USB-Cable-Ublox-GPS-RasPi-Win-7-8-CE-Linux-/262138841022?hash=item3d08b147be:g:320AAOSwhcJWQ0W5

It can be mounted remotely so as to be out in the clear (velcro'd on top of the pod in my flexwing) and works great. I know Lee has also used one. I got mine from the UK e-bay site listed above, though rather expensive (cheaper from China), but there was talk that it might be made available as an 'option' on the hardware site in due course along with some of the other goodies to come.

Regards

Peter

[DaveStyles]

Will be up on the hardware site the next couple of days.

regards

David Styles

Edit: ooh, look at that, they've appeared.