REFLECTOR: IPad

Mark Magee edjonesbrady at gmail.com
Tue Jun 18 16:31:57 CDT 2013


The iPad does have accelerometers to estimate 'movement', the same ones that auto-rotate the screen. They are fairly crude in comparison to the commercial grade ones that GRT and other AHRS makers use. They may 'pickup' where the wifi data loses heading/speed info.

Mark B. Magee
N34XL

Sent from my iPad

On Jun 18, 2013, at 4:13 PM, Dave Philipsen <velocity at davebiz.com> wrote:

> Interesting. I've done some further experimentation and found what you have said to be true. Oddly, though, there are places where Google Maps will report a position but ForeFlight will not.  Or, perhaps Google Maps has a little longer persistence in indicating that it has a valid position after the wi-fi method has failed.
> 
> Sent from my iPad
> 
> On Jun 18, 2013, at 3:32 PM, Don Johnston <numa at comcast.net> wrote:
> 
>> I have a WiFi iPad. So no 3g or GPS available.
>> 
>> On Tue, Jun 18, 2013 at 3:26 PM, Dave Philipsen <velocity at davebiz.com> wrote:
>>> Hmmm....I have not found that to be true in my case. Are you sure that your iPad is in "airplane mode" with only the wifi turned on? ForeFlight does not determine my location when I do that.
>>> 
>>> Sent from my iPad
>>> 
>>> On Jun 18, 2013, at 2:59 PM, Don Johnston <numa at comcast.net> wrote:
>>> 
>>>> Actually, ForeFlight will use WiFi location services. When I use ForeFlight on the ground without a GPS but with WiFi enabled, it always knows my location via the access point database mentioned previously.
>>>> 
>>>> Don Johnston
>>>> 
>>>> On Tue, Jun 18, 2013 at 2:24 PM, Dave Philipsen <velocity at davebiz.com> wrote:
>>>>> Apparently ForeFlight is programmed to only use the GPS for determining location.  You can experiment with this by turning on "airplane mode" and then forcing the wi-fi back on.  You'll find that ForeFlight will not attempt to display your location but Google Maps *will*.  I suppose that this is because Google Maps is content to use the rougher approximation of wi-fi only whereas the ForeFlight programmers decided to only utilize the most accurate method.
>>>>> 
>>>>> Another experiment you can do is to turn wi-fi and cellular data off without forcing "airplane mode". This will allow only the GPS to be used for determining location.  You'll find that ForeFlight will be perfectly fine in that situation.  And, it's probably the best way to use ForeFlight while you're flying. There will be less drain on the battery if that concerns you since both the cell radio and the wi-fi radio are turned off leaving the GPS turned on.
>>>>> 
>>>>> Sent from my iPad
>>>>> 
>>>>> On Jun 18, 2013, at 10:18 AM, Howard Woodruff <hgwoodruff at me.com> wrote:
>>>>> 
>>>>> > So following this thread it seems to me that your real question is... Shouldn't Foreflight work Even on my WIFI only iPad. The best way to solve that mystery would be to take your iPad flying, crank up Foreflight, and see if you get a moving map with your airplane symbol, GND speed readout, ect. . I've been using Foreflight for about 3years with my iPad (3G) and I know that if I have the unit in "airplane mode" (cell towers off), Foreflight will not work even if I have WIFI turned on. The same switch that controls cell tower operation (the airplane mode switch) also turns on and off the internal GPS unit. fWIW
>>>>> >
>>>>> > Howard Woodruff
>>>>> >
>>>>> > Sent from my iPad
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