All
Trying to end this once and for all with some actual screen
shots. I did a test last night of real world GPS functionality (photo). I
turned off the cell data and did not put the IPad into airplane mode (settings
pic). Therefore it will not be able to get cell data to assist the GPS chip to
ring in. I took off from Holloman AFB to the east, then I flew for 50 miles or
so, leveled off at FL190, and made sure there was no assistance from cell
towers to be of any assistance. I then called up ForeFlight and the GPS rang
in no problem, and matches the GPS on the Chelton system (IPad GPS pic). You
can put whatever map behind this (except weather or sat data) to navigate or
use as a backup) and as long as you have battery, you have a good setup. The
pics are a little blurry (bumpy night) but you get the idea.
If you are going to save battery though, and turn the IPad off
for a while until you need it, you might not get the same result. After a
couple of hours of leaving it off, I was unable to get the GPS signal back. So
I think both camps are correct in a way –
The IPad does have some sort of GPS ability, but does not have
the ability to locate itself way off from where it was last used (without cell
data to bring it close, which allows the GPS to know where it is enough to find
the correct satellites). It does not have the ability to wake up hundreds of
miles away and ring in, but 50 miles worked last night. This is probably due
to the lack of Ephemeris and Almanac data on the IPad, which tells the receiver
where to look when its calculating position upon startup. The cell tower data
fills in for this (my guess).
So for those of you who want to have complete GPS ability go the
Bluetooth way. If you don’t want another toy in the cockpit in addition to the
IPad, you can still have GPS if you want to keep the IPad up and running after
takeoff then let it ring in with cell tower assist (or soon after you lose cell
coverage, and make sure you turn the cell data off) and make sure you have
enough battery.
Hope this helps some folks
Bob Rickard
IV-P
From: Lancair Mailing
List [mailto:lml@lancaironline.net] On Behalf Of John Barrett
Sent: Tuesday, November 23, 2010 10:42 AM
To: lml@lancaironline.net
Subject: [LML] Re: iPad in the cockpit
Thanks to the several responses to my request for info on
tethering. Isaac’s solution sounds good since I already own a
Bluetooth GPS device. Will check it out.
John Barrett
From: Lancair Mailing
List [mailto:lml@lancaironline.net] On Behalf Of Isaac Heizer
Sent: Monday, November 22, 2010 3:05 PM
To: lml@lancaironline.net
Subject: [LML] Re: iPad in the cockpit
I've
been using a wi-fi only ipad plus external bluetooth gps receiver plus
foreflight since July and it works great.
I had to jailbreak my ipad to get the GPS to work. I used Cydia to
jailbreak the ipad, loaded BTStack to enable ipad bluetooth GPS devices, and
purchased a MobileMate 886 Mini Bluetooth GPS receiver ($56 on amazon) that i
set on the glareshield at the start of a flight.
I'm able to turn the ipad on and off in flight, and Foreflight immediately
resumes as though i never turned the ipad off because the bluetooth GPS
receiver stays locked on the satellites while I have the ipad turned off.
Does it work the same way on an ipad with its internal GPS? In other
words, can you turn the ipad off in flight, leave it off for 30 minutes, turn
the ipad on and have an immediate GPS location?
Does the internal ipad GPS work just fine through a carbon fiber fuselage top,
or do you have to position the ipad in some special way?
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1153 / Virus Database: 424/3272 - Release Date: 11/22/10