iPhone GPS software

[HardyW]

Hello!

I have seen that there has been a thread concerning GPS systems using the iPhone. I am actually also writing a software for the iPhone tracking flights. Recently somebody asked me whether it is allowed to use this software on a cellular phone on bord of an airplane.

I am European so I am a bit familiar with the laws here but not in the US. I have checked the FAA regulations. They do not seem to be a problem because they mostly refer to instrument operated flights.
But then I found FCC 22.925 that says: "Cellular telephones installed in or carried aboard airplanes, balloons or any other type of aircraft must not be operated while such aircraft are airborne (not touching the ground)".

So, if you now use this kind of software on cellular phone you are violating this regulation, or? Do I miss anything?

BTW: FCC does not care if you operate it on an aircraft or if you through up your phone high enough. Their only concern is the operation of cellular phones at a certain altitude.

So, what is your opinion? I have seen statements that FCC wanted to lift the ban but I have not seen any regulations actually doing that.

I am interested in your comments and reactions!

Hartwig

[FresnoR]

I cannot speak of FCC regulations, but the GPS on my Iphone 3GS only works when it is in Cellular range, I have found it relatively difficult to get reception at altitude unless directly over a city.

Maybe thats just my area though.

[Greg Arehart]

Hartwig,

My understanding is that all cellular phone operations that transmit or receive certain frequencies are prohibited on airplane flights (all, not just commercial or instrument). One can use the iPhone in "airplane mode" where it will still get GPS signals, so if your software tracks and caches, then that might work. That said, there are a lot of folks out there using the phone part of cell phones in light aircraft for various purposes, but as Fresno said, the reception is generally marginal to none at any altitude and away from major centers with lots of cell towers. I accidentlly () turned mine on a couple times while flying and it is very difficult to get a 3G signal above 2500 AGL and one often loses the E signal a couple thousand feet higher. If your software relies on two-way communication of lots of data, the E signal probably will not provide enough connectivity.

All that said, I'm just a novice at any of this stuff, so hope some more knowledgable folk will chime in and provide more complete information (and correct me if I'm wrong)

greg

[Snowflake]

FWIW, in Canada we have no restriction on use of Cellular phones aboard aircraft. I have tried mine as high as 4000', over a mostly built-up area but not a major city. No problems with voice reception or GPS signal.

My understanding is that the GPS in the iPhone *will* lock in outside cellular range, but it takes longer to do so. If you're moving, that may be enough to make it impossible for it to lock in.

[plehrke]

Originally Posted by Snowflake

My understanding is that the GPS in the iPhone *will* lock in outside cellular range, but it takes longer to do so. If you're moving, that may be enough to make it impossible for it to lock in.

GPS does not use cell towers it uses the GPS satilites. The iPhone does not have a real good antenna for GPS therefore the lock-on is not all that realiable. Of coarse the GPS signal is worthless without the internet connection because the iPhone map (and all apps I have seen) use the internet for the map.

Originally Posted by Greg Arehart

One can use the iPhone in "airplane mode" where it will still get GPS signals, so if your software tracks and caches, then that might work.

The GPS function is not active when the iPhone is in airplane mode. This is because GPS devices are a pohibited devices while the plane is in the air (makes sense right). [see last paragraph of American Airlines policy]

[SvingenB]

Originally Posted by plehrke

GPS does not use cell towers it uses the GPS satilites. The iPhone does not have a real good antenna for GPS therefore the lock-on is not all that realiable. Of coarse the GPS signal is worthless without the internet connection because the iPhone map (and all apps I have seen) use the internet for the map.

All phones (at least 99%) use AGPS, or Assisted GPS. Cell towers are used actively together with the GPS. This is very usefull during lock-on from a cold start, but also during difficult conditions; indoor, tall buildings and so on.

[FresnoR]

That is true and unfortunate about the iphone. I was exciting when they came out with the GPS function. I had planned to use it while hiking and backpacking up in the mountains. Too bad the GPS became useless out of cell range.

If Apple can find a way to unlock the GPS allowing it to be standalone, developers can create programs where the maps are downloaded and have no reliance on the cell network. Much like our Garmins do.

[777drvr]

They already do . I use an app called MotionX-GPS . It allows maps to be downloaded so you have something when out of Wifi or 3G coverage . Check it out . Not a bad one but I use more traditional GPS when flying such as my Garmin Aera 510 .

Marc

[bruceh]

Not an iPhone, but since I'm a Verizon customer I recently bought the Motorola Droid.
Yesterday I was on a commercial flight from SAN to SFO. Put the Droid in "Airplane mode", so no wifi or G3 signals. Tried to bring up the Google map application (awesome app!) and it couldn't get a lock on the GPS signal or display any map information without the wifi/G3 signal. I have another application called GPS Tracker that will show you your lat/long and where the GPS satellites are, along with a compass. It was struggling to get a lock on the satellites and was only able to do so briefly. Kind of hard to get a good signal from a small side window. My Garmin eTrex Vista handheld GPS works fine from inside a commercial jet as long as I have a window seat.

[HardyW]

Originally Posted by FresnoR

That is true and unfortunate about the iphone. I was exciting when they came out with the GPS function. I had planned to use it while hiking and backpacking up in the mountains. Too bad the GPS became useless out of cell range.

If Apple can find a way to unlock the GPS allowing it to be standalone, developers can create programs where the maps are downloaded and have no reliance on the cell network. Much like our Garmins do.

Hi Fresno,

I can not subscribe that the iPhone does not work without telekom cells. Initializing the iPhone without antennas for cellular networks takes more time but it also works.
When I wrote my app I did a lot of testing under various conditions. So, I have quite some experience.
Another hint: start the GPS before you have moved too far. Otherwise it also takes time to find the satellites again.

Hartwig