Using mobile GPS in flight

[Odai]

Hello,

I am currently getting on with my PPL training, and have been doing some solo cross country flying. I recently had an idea that might help with my training.

I was thinking of using software on my phone, in conjunction with a GPS connection, to log a track, which can be imported to a program like Google Earth. The idea is that I can see exactly what the actual track made good was on a solo flight. This would all be for review purposes, post-flight, as opposed to using it in lieu of a proper inflight GPS device to help with navigation.

I am just wondering whether it would be safe to use such a setup in flight. The phone would be accessing both the cellular network and GPS satellies. Should I be concerned about interference with radios etc?

This is all assuming of course that the phone can accurately log and store the data whilst moving at around 100kts.

Thanks

Odai.

[riverrock83]

Very unlikely to be a problem - people use iPads with 3G and GPS receivers all the time. Don't leave the phone near the compass...
If you leave the mobile signal on - it will use extra battery due to it trying harder to find a signal. I've left mine in my pocket before with no issues.

There are many apps that can do this, on pretty much any phone which has a GPS receiver (I've an old Nokia and use sports tracker). If you can keep a signal in the car then you should be able to in a GA plane. Just set it up before you start, then forget about it until after you've parked the plane.

[peterh337]

Should work just fine.

I have used AFtrack which is about the only option for my Nokia 700 (Symbian Belle) to log a track, which can then be exported to GPX, KML, etc. and plotted directly on google earth.

It does run the phone battery down pretty fast :)

[pilot2bornot2b...]

I recently used an app called Ultra GPS Logger on Android Samsung Galaxy S2 to track my 1st solo cross country flight. I enabled flight mode to avoid interference and just used the in built GPS. I have also used it in the circuit and it is amazingly accurate.

You can view the track on the phone using either Google Maps or Google Earth, email it etc

Here is the track imported into Google Earth:
https://www.dropbox.com/s/dup7eev9738lfgp/soloxc.jpg

[RTN11]

Why would you need to it to access mobile phone signals? If you're only using a GPS tracking app, you could have your phone in flight safe mode as gps only receives signals, the phone doesn't need to transmit anything.

Worst case is it will make some annoying noise on the intercom/radio which might piss your instructor off so he'll ask you to turn it off. More than likely your instructor has left his phone on anyway :}

[BobD]

You can also use the 'breadcrumbs' file from a GPS device (such as Skydemon) to create a simulated flight of your track using Google Earth, and add your own commentary. The file needs to be converted to the correct format, but the instructions on how to do this are available on-line. Here is an example of a flight I made last year in Portugal and Spain, to show some friends who have Apartments on the same complex as me.

www.rjdawson.co.uk/esuri.kmz (http://www.rjdawson.co.uk/esuri.kmz)

[riverrock83]

Just to say - if you are in "flight mode", then start the gps logger, don't be worried if out takes much longer to aquire a position initially because it has to download the satellite positions from the satellites rather than via the mobile signal.

[Odai]

Many thanks for your responses guys.

My understanding is that the phone will definitely access the cellular network to make the initial connection to GPS satellites quicker (due to the very basic GPS hardware), which won't be an issue as I'll set it up before starting the flight.

I am not sure however if it continues downloading data through the cellular network once it has got a fix from GPS satellites. This is my main concern. I could try disabling this so that it is only receiving from GPS satellites once a fix is made, but I am concerned also that this may make the tracking less accurate.

If the phone loses its connection to GPS satellites in-flight for whatever reason, then re-establishing this would be a lot slower if, for example, flight mode was enabled.

I tried using this tracking software on the train, for around 30 minutes. It was mostly fine, but there were blips, some big, and these happened to correspond to areas where the cellular network coverage is poor (where, for example, it is not possible to even get a GPRS connection), even though the GPS signal was not lost.

pilot2bornot2b..., that was actually the exact application for this setup I was thinking of. It would be a great opportunity to use this in the debrief after my QXC.

[peterh337]

My understanding is that the phone will definitely access the cellular network

It will try but for the most part won't succeed because there is little or no signal at altitude.

This is why a lot of "modern consumer" GPSs work so poorly when in the air. Their GPS is optimised for low power consumption and is compromised so that adequate performance is obtained with the assistance of the GSM data. The Iphone/Ipad is one example.

I would make sure the phone is ON and has obtained a GPS fix before you take off, because it may fail to get it afterwards.

[sycamore]

Go to e-*ay and buy a cheap(<£40) GPS data logger...`tape` it onto the coaming and go fly..simples..

[Angel_1_five]

I used GPS tracking on my android phone in the aircraft up to 3000ft and works fine, i use GPS essentials its free .

[Jim59]

This sort of device will do what you want simply and cheaply:

FlyWithCE Flight Recorder FR300 89 Euros.
It is starting to be used in gliders and is recognised by the BGA as a position recorder.
Price includes analysis software to show the route taken on a map and a barogram.

£93 inc shipping from LX avionics Ltd - IGC approved flight recorders (loggers) (http://www.lxavionics.co.uk/flightrecorders.htm)

flyWithCE - Flight Recorder (http://www.flywithce.com/recorder.html)

I have no connection / interest with either maker or UK distributor.

[squidie]

Yep a lot of people use 3G/GPRS for flight navigation – Just don’t let your school know you’re doing it!

[Gertrude the Wombat]

Worst case is it will make some annoying noise on the intercom/radio which might piss your instructor off
I believe that at least one case of it also causing the VOR needle to point in the wrong direction has been reported, although this won't matter (as long as you're not relying on the VOR needle for visual navigation!) except when doing the radio nav part of the course.

[ianwild]

I used an iPhone App called MotionX for exactly this purpose. I'm pretty sure it was free, but if not it was certainly inexpensive.

Track with a Google Map overlay, vertical and speed profile recorded etc, are all very interesting in reviewing the flight. As well as the novelty it's helped when discussing with my instructor (post-mortem style) things like the execution of my solo overhead joins.

As for interference, I hear the typical mobile phone interference when on the ground and when near full power. It disappears from my headset completely in the air below 2400 RPM and either way it's not too disturbing, albeit if it was a passengers phone I would have them turn it off.

Now I have my PPL, I plan to upgrade to Skydemon and an IPAD.

Ian

[peterh337]

Yep a lot of people use 3G/GPRS for flight navigation

I think you got your acronyms mixed up :)

The one you are looking for does start with a G but has only 3 letters in total.

[OpenCirrus619]

You probably won't get a phone connection at cruising altitude (at least in the South of England). The reason is, oddly, the reverse of that stated above. It's not that the signal is too weak - it's that you can see too many base stations.

On a network the base stations re-use frequencies - but arrange it so that a phone can't see 2 base stations using the same frequency from any one point FROM THE GROUND.

In the air your phone can "see" much further (line of sight). If the phone can see/be seen by 2 base stations the network interprets that as 2 phones with the same serial - which must mean it's been cloned. The network then reacts by preventing "both" accessing the network.

The only way of preventing this is to fly "really low".

OC619

[Steve6443]

Quote:
Yep a lot of people use 3G/GPRS for flight navigation
I think you got your acronyms mixed up

The one you are looking for does start with a G but has only 3 letters in total.

Nope, I think you are confusing your acronyms. GPRS stands for General Packet Radio Service and is a method of transmitting data to a mobile phone, running on 2G (the predecessor of 3G) or 3G networks.

As the poster was referring to a mobile device and data transmission, 3G / GPRS is correct from a point of intention, even if one refers to a network standard and the other is a service....

[dublinpilot]

How would you use a data connection for flight navigation?

Surely you need a GPS signal, not a data connection?

[F4TCT]

When you look at the specs on these mobile phones, they are intact assisted gps, therefore requiring the help of triangulation from the phone masts, as well as the basic gps hardware in the phone.

I personally use iPad running sky demon with a Bluetooth link to a standalone gps. I can therefore switch off the data service on the iPad or use the iPad to download nats approach plates or live up to date weather through Skydemon.

dan

[stevelup]

When you look at the specs on these mobile phones, they are intact assisted gps, therefore requiring the help of triangulation from the phone masts, as well as the basic gps hardware in the phone.

That's not what AGPS means. Assisted GPS can use a data connection to get a quicker first fix, but it doesn't require it.

[peterh337]

It doesn't require it but there are a fair few devices which are totally incapable of getting a GPS fix if turned on while already moving at some speed.

I have seen this in multiple PDAs, in a Thuraya 7100 satphone, and some other stuff.

I think the Ipad GPS, which is superb on the ground and even working pretty well indoors, is so good because it gets the fix over GSM first. In the aircraft it is much worse.

[Odai]

Hello,

Apologies for taking so long to respond, and thanks once again for all the helpful responses.

I did give the GPS on my phone a go during a recent flight. I allowed the phone to get a fix first (using a data connection) before getting in the plane. Then, when it was all stable I enabled Flight Mode (therefore disabling what was alternating between a GPRS and an EDGE connection) and leaving the GPS feature enabled.

I thought it worked OK, but when I got home and reviewed the track what I found was bizarre. The initial position was fine, and the track shown as I taxied around the airfield, took up position for power checks, and finally lined up for the runway was fine. However, after that, the software indicates I did not go further than 1.17km over the course of an hour and the track simply shows the flight doing zig zags all over the airfield for that time (I did in reality end up about 30 miles away on a navigational exercise).

Not sure what happened exactly, but I get the sense the phone's hardware simply isn't up for the job.

I don't intend to buy any hardware just for the purpose of tracking my student flights at the moment. I may in the future (after my PPL) get a proper GPS and in that case I would look for one that has software capable of producing logged tracks in a format I could use for purposes mentioned in this thread.

Thanks anyway guys!

[stevelup]

You never said which phone you had?

On Apple devices, the GPS doesn't work at all when you are in flight mode.

[dublinpilot]

And on Android they are often turned off by default and you need to turn it back on after going into flight mode.

Also where did you put your phone? Leaving it in a position where it doesn't have a reasonable view of the sky will most likely mean that it won't work.