CONFIRMED: WiFi Only iPad Air 2 CAN INDEED Reset Home Point to RC Transmitter Location

[jephoto]

One other silly question- can the Bad Elf be paired with multiple devices simultaneously or only 1 device at a time?
My guess is only one ...

 

[yblaser]

Depends upon how accurate you want the reset of the Home Point to the RC location to be. I already independently own the Bad Elf Pro and Bad Elf Pro+, because I use them for a golf club tracking app (GolfLogix) which tracks my clubs used and club distances around the course. Before I had an iPhone 6+, I used WiFi only iPads for this purpose with the Bad Elf unit. It is what Bad Elf was designed for, used by private pilots with WiFi only iPad avionic apps. The iPhone 6+ cellular assisted GPS just isn't accurate enough for me with the GolfLogix app, so I still BT pair it with the Bad Elf at the golf course.

Cellular iPad GPS accuracy is 5-15 meters. Bad Elf Pro+ is 1 meter accuracy, with the Bad Elf Pro very close to that. It's your choice.

Lastly, if you don't pay for a data plan for the cellular iPad Air 2, the internal GPS chip will not be as accurate as with cellular service. Apple calls it "location assisted GPS." It uses the cell service location to enhance the speed and accuracy of the internal GPS chip, which does not have GLONASS. It is like setting your takeoff homepoint with the minimum number of satellites rather than as many as possible. More is better. The Bad Elf can even tell you it's current accuracy in feet at all times, before using its data with the Pilot app. Private pilots rely on Bad Elf units rather than cellular GPS for their iPad avionics. That's good enough for me!

Thanks for all the testing. I couple of points... The assisted GPS only improves the time to aquire the sats and calculate a fix. The accuracy of the fix is independent of being connected to a cell network. Newer iPads with cellular support GLONASS. The bad elf pro+ has a spec'd accuracy of 2.5 M. I also wonder what the accuracy of the P3's receiver is.

 

[GadgetGuy]

You are welcome. Just download the maps over Wifi before you fly, or hotspot your phone in the field to download them that way. No rush on the Bad Elf, until you want to set the Home Point to the RC. No need for cellular iPads. It's the complete WiFi only solution, now that iOS 8.4 brought back support for BT GPS like the Bad Elf Pro and Pro+.

 

[GadgetGuy]

One other silly question- can the Bad Elf be paired with multiple devices simultaneously or only 1 device at a time?
My guess is only one ...

Up to FIVE devices at once!

 

[GadgetGuy]

Thanks for all the testing. I couple of points... The assisted GPS only improves the time to aquire the sats and calculate a fix. The accuracy of the fix is independent of being connected to a cell network. Newer iPads with cellular support GLONASS. The bad elf pro+ has a spec'd accuracy of 2.5 M. I also wonder what the accuracy of the P3's receiver is.

Thanks for the clarifications and corrections! The delay in the calculating the fix without connection to a cell network could be an issue, as without the fix, the location could be way off, if the Pilot app permits using it before the fix is acquired. Once the fix is acqired, how often does it get updated and does it require a new delay without cell service each time it changes, or only upon intial lock? Any delay when you want to reset to the RC could be problematic. Once Dynamic home point becomes available on the P3, and Follow Me, the Bad Elf Pro and Pro+ options will shine with their 8 foot accuracy. Good to know about GLONASS in the newer cellular iPads. I, too, would also like to see the spec'd accuracy of both the P3's receiver and the cellular iPads. At least we now better understand all our options!

 

[yblaser]

Thanks for the clarifications and corrections! The delay in the calculating the fix without connection to a cell network could be an issue, as without the fix, the location could be way off, if the Pilot app permits using it before the fix is acquired. Once the fix is acqired, how often does it get updated and does it require a new delay without cell service each time it changes, or only upon intial lock? Any delay when you want to reset to the RC could be problematic. Once Dynamic home point becomes available on the P3, and Follow Me, the Bad Elf Pro and Pro+ options will shine with their 8 foot accuracy. Good to know about GLONASS in the newer cellular iPads. I, too, would also like to see the spec'd accuracy of both the P3's receiver and the cellular iPads. At least we now better understand all our options!

I think follow me is a great application for this. You are following the GPS receiver rather than filming a guy holding a big remote control with a huge iPad attached.

 

[GadgetGuy]

I think follow me is a great application for this. You are following the GPS receiver rather than filming a guy holding a big remote control with a huge iPad attached.

Good point! So, would you still get the cellular iPad, if starting over? How long is the delay to a fix without paying for cellular service? I have an iPhone 6+ and could just pop the SIM out. Is the cellular Air 2 heavier? There is something to be said for having everything self-contained within the cellular iPad Air on top of the transmitter.

 

[yblaser]

Good point! So, would you still get the cellular iPad, if starting over? How long is the delay to a fix without paying for cellular service? I have an iPhone 6+ and could just pop the SIM out. Is the cellular Air 2 heavier? There is something to be said for having everything self-contained within the cellular iPad Air on top of the transmitter.

Propbably. I don't think I will use the functionality much. At first I considered the WiFi version, but thought I might regret it later. Thought of the possibility of using an external GPS, but saw they were similar in price to the cellular upgrade and I wasn't sure if it would work (I didn't consider the accuracy at the time).

In the end I decided the upgrade to the cellular version was not a significant amount of money above what I was spending already (I was getting a good discount through an employee) and since the tablet is not dedicated to the P3, having the cellular data option added other benefits. You can also get 200 MB per month of free data from tmobile even if you are not a current customer, although I have yet turn on the cellular functionality. The apple spec says the cellular version is 7g heavier which is about 2% of the weight.

I haven't paid close attention to time to fix and accuracy. I'll see if I can do some experiments to get a sense of the position the iPad reports relative to what the P3 reports as well as too how often it is updating position.

 

[AirApparent]

Using the iPad Air 2 64GB Cellular, and it's stellar.

Works like a magic charm, with endless wishes.

It's great and no more glare from the Sun star...
The A8X CPU lets the iPad 2 remain cool as a cucumber? ;-)

So happy to have traded up...

RedHotPoker

I am using the iPad Air 2 also, but I find the glare to be unbearable. Is there some sort of film to put over it? Love the unit; hate the glare.

 

[RedHotPoker]

I don't have a Sun star glaring screen, only my Phantom 3 revues...
Guessing my fun experiences are different from many others here. ;-)
We found the iPad Mini 2, to act like a mirror in the bright day light.

RedHotPoker

 

[GadgetGuy]

Propbably. I don't think I will use the functionality much. At first I considered the WiFi version, but thought I might regret it later. Thought of the possibility of using an external GPS, but saw they were similar in price to the cellular upgrade and I wasn't sure if it would work (I didn't consider the accuracy at the time).

In the end I decided the upgrade to the cellular version was not a significant amount of money above what I was spending already (I was getting a good discount through an employee) and since the tablet is not dedicated to the P3, having the cellular data option added other benefits. You can also get 200 MB per month of free data from tmobile even if you are not a current customer, although I have yet turn on the cellular functionality. The apple spec says the cellular version is 7g heavier which is about 2% of the weight.

I haven't paid close attention to time to fix and accuracy. I'll see if I can do some experiments to get a sense of the position the iPad reports relative to what the P3 reports as well as too how often it is updating position.

Thanks for the input. At least the cellular antenna and chipset don't measurably add to the weight. I'd be interested in the results of those experiments, so we can better quantify the GPS accuracy difference between a cellular iPad Air 2 and the known Bad Elf accuracy of 8 feet.

 

[Poundofnuts]

Depends upon how accurate you want the reset of the Home Point to the RC location to be. I already independently own the Bad Elf Pro and Bad Elf Pro+, because I use them for a golf club tracking app (GolfLogix) which tracks my clubs used and club distances around the course. Before I had an iPhone 6+, I used WiFi only iPads for this purpose with the Bad Elf unit. It is what Bad Elf was designed for, used by private pilots with WiFi only iPad avionic apps. The iPhone 6+ cellular assisted GPS just isn't accurate enough for me with the GolfLogix app, so I still BT pair it with the Bad Elf at the golf course.

Cellular iPad GPS accuracy is 5-15 meters. Bad Elf Pro+ is 1 meter accuracy, with the Bad Elf Pro very close to that. It's your choice.

Lastly, if you don't pay for a data plan for the cellular iPad Air 2, the internal GPS chip will not be as accurate as with cellular service. Apple calls it "location assisted GPS." It uses the cell service location to enhance the speed and accuracy of the internal GPS chip, which does not have GLONASS. It is like setting your takeoff homepoint with the minimum number of satellites rather than as many as possible. More is better. The Bad Elf can even tell you it's current accuracy in feet at all times, before using its data with the Pilot app. Private pilots rely on Bad Elf units rather than cellular GPS for their iPad avionics. That's good enough for me!

Do you work for Bad self or something? Lol. I personally wouldn't want to have to carry around a separate GPS...it's just something else to worry about, not to mention charging it all of the time. I believe you may have misinformed some people with your statement that the iPad Air 2 doesn't have GLONASS, because the iPad Air 2 cellular version Actually DOES HAVE GLONASS and is very very accurate. You may want to check your sources here. https://www.apple.com/ipad-air-2/specs/

 

[yblaser]

Thanks for the input. At least the cellular antenna and chipset don't measurably add to the weight. I'd be interested in the results of those experiments, so we can better quantify the GPS accuracy difference between a cellular iPad Air 2 and the known Bad Elf accuracy of 8 feet.

I did a very quick, very un-scientific test with the iPad on its own. Unfortunately, I had the iPad acquire a fix before I started and I rebooted after realizing it, but it probably does not fully simulate a full cold start.

After the reboot with the cellular and wifi off, I opened up the dji pilot app and observed the position on the map. It took about 30-60 seconds to acquire an accurate fix and then updated the position on the map at approximately a 1s interval. I walked around in my backyard and relative to the images on the map the location of the iPad was off by 3-3.5 m. This obviously includes the map error which could help or hurt the estimate. Also as a one time measurement I could have gotten lucky. When I get a chance I will perform the same experiment with the P3 connected and on so i can see its relative location to the iPad.

At this point I would take the results with a grain of salt. Other things to consider is that at least with android devices, the device will still use wifi signals for location even with wifi turned off. I don't know if iOS devices have similar behaviors, but that could obviously affect the tests.

 

[GadgetGuy]

Do you work for Bad self or something? Lol. I personally wouldn't want to have to carry around a separate GPS...it's just something else to worry about, not to mention charging it all of the time. I believe you may have misinformed some people with your statement that the iPad Air 2 doesn't have GLONASS, because the iPad Air 2 cellular version Actually DOES HAVE GLONASS and is very very accurate. You may want to check your sources here. https://www.apple.com/ipad-air-2/specs/

No, but I am a happy customer of theirs, and have been using their devices for several years, as do private pilots, for whom they were initially designed. I am open to being convinced that a cellular Air 2 is worth the extra $130, especially if the GPS accuracy is reliable and comparable.
As to charging, the battery life of the Bad Elf is 16 to 35 hours, depending upon which unit you purchase, and it displays its current accuracy at all times. No guessing. Its battery will outlast our iPads! Once Follow Me and Orbit are enabled, being able to separate the GPS from the Transmitter could be very handy. I acknowledged above learning that the cellular iPad Air 2 does have GLONASS. Very, very accurate isn't quantifiable, away from cell service, and all WiFi sources. We are trying to quantify the location accuracy of the cellular iPad Air 2 with hard numbers. For the Bad Elf units, it is 8 feet. Do you have any numbers from Apple that would help us here? The helpful link you supplied unfortunately doesn't include any hard numbers for location accuracy. I would be very surprised if the numbers are comparable to the Bad Elf 8 feet. From my own iPhone 6+ experience, my best guess is 5 to 15 meters, but how often is it updated, and how dependent upon iPad orientation are the internal GPS antennas? A landscape orientation may also not be ideal. Let's figure this out together! This link may help http://ipadpilotnews.com/2014/12/choosing-right-ipad-gps/

 

[GadgetGuy]

I did a very quick, very un-scientific test with the iPad on its own. Unfortunately, I had the iPad acquire a fix before I started and I rebooted after realizing it, but it probably does not fully simulate a full cold start.

After the reboot with the cellular and wifi off, I opened up the dji pilot app and observed the position on the map. It took about 30-60 seconds to acquire an accurate fix and then updated the position on the map at approximately a 1s interval. I walked around in my backyard and relative to the images on the map the location of the iPad was off by 3-3.5 m. This obviously includes the map error which could help or hurt the estimate. Also as a one time measurement I could have gotten lucky. When I get a chance I will perform the same experiment with the P3 connected and on so i can see its relative location to the iPad.

At this point I would take the results with a grain of salt. Other things to consider is that at least with android devices, the device will still use wifi signals for location even with wifi turned off. I don't know if iOS devices have similar behaviors, but that could obviously affect the tests.

Sounds promising. Obviously, if we can reproduce the 3-3.5 meter accuracy, that compares very favorably with the touted 2.5 meter accuracy of the Bad Elf, which self-reports numbers in the 10 to 14 feet range when I check it indoors with sufficient satellites that the P3P also says Safe to Fly. I'll see if a Google search turns up anything more dispositive about the iPad Air 2 cellular GPS accuracy. I found this: http://ipadpilotnews.com/2014/12/choosing-right-ipad-gps/ which states that the main difference is in the reliability of the immediate availability of the GPS location data. The Pilot app would likely keep the iPad from going to sleep, and most are not app switching while using the Pilot app.The RC is also being used on the ground, for which the A-GPS was designed.
"The onboard GPS is subject to Apple’s power management, so it can drop offline sometimes when you sleep the screen or switch programs. Most of the time it works fine, but it’s not 100%."

"But while the on-board GPS does work with all popular aviation apps, it was really designed for ground use and it’s not always reliable in the air. It has a tendency to drop offline, especially when switching between apps or when the iPad goes to sleep. It’s not necessarily a question of accuracy, but of reliability. You don’t want the GPS to lose its signal right at the final approach fix in the clouds. For this reason, most iPad pilots – even those with an LTE iPad – opt for an external GPS. It’s pretty cheap insurance."

I also found this article helpful: http://ipadpilotnews.com/2015/01/does-ipad-have-real-gps/ .
...and this one, too: http://ipadpilotnews.com/2013/02/do-i-really-need-an-external-gps-2/
If you read all the comments in the last article, they were all struggling with exactly these same issues back in February of 2013. Very insightful. There is no one "right" answer.

 

[Panotaker]

So what about the maps with these add on GPS devices? Do you have to cache the maps ahead of time? The advantage of a Cell iPad mini2 is that it downloads the maps automatically. So you can fly anywhere you want without preplanning since it downloads the maps wherever you are. Can these add on gps devices do the same thing, or do you have to cache the maps first.

 

[Poundofnuts]

No, but I am a happy customer of theirs, and have been using their devices for several years, as do private pilots, for whom they were initially designed. I am open to being convinced that a cellular Air 2 is worth the extra $130, especially if the GPS accuracy is reliable and comparable.
As to charging, the battery life of the Bad Elf is 16 to 35 hours, depending upon which unit you purchase, and it displays its current accuracy at all times. No guessing. Its battery will outlast our iPads! Once Follow Me and Orbit are enabled, being able to separate the GPS from the Transmitter could be very handy. I acknowledged above learning that the cellular iPad Air 2 does have GLONASS. Very, very accurate isn't quantifiable, away from cell service, and all WiFi sources. We are trying to quantify the location accuracy of the cellular iPad Air 2 with hard numbers. For the Bad Elf units, it is 8 feet. Do you have any numbers from Apple that would help us here? The helpful link you supplied unfortunately doesn't include any hard numbers for location accuracy. I would be very surprised if the numbers are comparable to the Bad Elf 8 feet. From my own iPhone 6+ experience, my best guess is 5 to 15 meters, but how often is it updated, and how dependent upon iPad orientation are the internal GPS antennas? A landscape orientation may also not be ideal. Let's figure this out together! This link may help http://ipadpilotnews.com/2014/12/choosing-right-ipad-gps/

Here is a link to some numbers that can help us. http://anatumfieldsolutions.com/2015/01/04/bad-elf-gps-compared-iphone-ipad/

These test show the Bad Elf accuracy average around 2 meters and the IPad Air around 4 and a half. So while the Bad Elf's are in fact more accurate, the iPad Air isn't far off. I their it really depends on how accurate someone really needs or wants to be. I like your idea about having a separate GPS for orbit and follow me mods, however I wouldn't bet on the option of DJI adding a feature to select which GPS unit you would like orbit or follow to track. I point this out because while the device is seperate from your iPad and transmitter, it has to talk to DJI through the iPad and Bluetooth and the range for Bluetooth isn't very far at all. Any thoughts on this, or how the follow me and orbit modes will actually work regarding registration and tracking of GPS? Would the GPS point have to maintain connectivity through the DJI iPad app, or would DJI give us the option to select a seperate GPS orbit or follow me device?

 

[Hessam]

Oh boy, too much different information here...
But here is my experience after 15 flights

Model : Phantom 3 Pro Firmware 1.2.8
Tablet : iPad Air WiFi (no internet connection at all during flight or before that in the field hence no map cached most of the time)
App : Latest version of DJI Pilot

>>> Each and every time I start the app, turn on RC, Turn on aircraft, wait for green top bar, calibrate compass and... home point has been updated!
Do my recordings and most of the time because I reach low battery warnings, I press RTH button on the RC and it perfectly flies back to the take off point and starts landing process.

So please let me know how's that even possible if an external GPS device is a must have with a wifi iPad with no internet connection to use the... say RTH.

 

[yblaser]

Oh boy, too much different information here...
But here is my experience after 15 flights

Model : Phantom 3 Pro Firmware 1.2.8
Tablet : iPad Air WiFi (no internet connection at all during flight or before that in the field hence no map cached most of the time)
App : Latest version of DJI Pilot

>>> Each and every time I start the app, turn on RC, Turn on aircraft, wait for green top bar, calibrate compass and... home point has been updated!
Do my recordings and most of the time because I reach low battery warnings, I press RTH button on the RC and it perfectly flies back to the take off point and starts landing process.

So please let me know how's that even possible if an external GPS device is a must have with a wifi iPad with no internet connection to use the... say RTH.

The P3 sets the home point based on its internal GPS. The discussion above is about resetting the home point to the current controller position or using follow me type of functionality.

 

[Hessam]

The P3 sets the home point based on its internal GPS. The discussion above is about resetting the home point to the current controller position or using follow me type of functionality.

That was the answer I was waiting for. Thanks for clearing this up for me