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?
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