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RC's GPS Location - Does the RC Communicate with an iPad to get a GPS Fix?

Discussion in 'Inspire 1 Help' started by DavidB, Feb 27, 2016.

  1. DavidB

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    I have been following the dynamic home point discussions with interest and can see why it can be confusing. A few people have mentioned the RC's poor ability to obtain a useful GPS signal and how having an iPad (or similar) with a cellular connection can help. I have a Garmin device connected to my iPad Air 2 as it doesn't have a cellular connection. The answer to this question may seem obvious but does the RC utilize the attached iPad's better GPS location capabilities to help it set a new "dynamic" home point or when using the Follow Me function? I didn't think the RC could use the iPad's GPS's location.
    Thanks in anticipation.
     
  2. MacDyver

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    I'm not sure if the cellular connection is necessary, I only use a hotspot and everything works fine.
     
  3. Scotflieger

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    It is the GPS-derived position of the iPad, and used by the GO App, that is the key. This is sourced from its own GPS (if equipped with a SIM), the RC GPS receiver (poor reliability) or an external GPS receiver (like your Garman). The Follow Me function uses the difference between the aircraft position and that of the App.
     
  4. The Editor

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    As @Scotflieger says above and also do not forget it is NOT dynamic.
    You have to manually keep setting it - it does not auto update your position so should not be called dynamic home point. Very poor/bad advertising/description by DJI.
     
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  5. Steve Domigan

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    Just to clarify, an iPad does NOT need a cellular connection, or even a SIM card installed, to be able to get a GPS location. However, Apple in all of there wisdom only installed GPS in units that are of a model that is cellular capable.....ie the models that can have a SIM card installed and can have cellular connection.
     
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  6. Scotflieger

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    Correct. Apple devices (iPhone/iPad with SIM) use a combination of mast signal triangulation, WiFi location and the GPS to improve location information in built up areas and indoors where the satellite reception can be poor or non existent. In open country they can work by GPS positioning only.

    [Edited to add WiFi location]
     
    #6 Scotflieger, Feb 27, 2016
    Last edited: Feb 28, 2016
  7. DavidB

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    Thanks for the responses to my query. I appreciated the comments about the “Dynamic Home Point” which is not very dynamic and the iPad’s GPS limitations in various guises. The initial title of the Help question was my main area of interest “Does the RC Communicate with an iPad to get a GPS Fix?” In the cause of science I decided to investigate the question.

    I set things up in the backyard. Our new Westie Pup was somewhat perplexed about the intruder. I believe his bravery was only because there were no moving props on the I1.

    RC-GPS.jpg


    My wife reluctantly lent me a heavy metal baking dish, and suggested I should put it on my head, as clearly radio type waves from up in the sky had changed the brain she thought she had married. Anyway I digress.

    With the iPad in Airplane Mode I was able to set the Home Point to the RC Position (image below). It can take a few presses of the Set Home Point (for both Aircraft and RC position). I find idling the props briefly always helps the process with the “The Home Point has been updated. Please check it on the map” - quickly following.

    RC-GPS_2.jpg

    Next, I had to block the RC’s access to GPS satellites, hence the baking dish.

    RC-GPS_1.jpg

    Not surprising, this successfully killed the GPS signal. (Surprisingly my wife was really encouraged by this.)

    RC-GPS_3.jpg

    Finally to answer my question I provided the iPad with three methods for obtaining GPS co-ordinates.
    You will see on the image below that the family Wi-Fi still works in the backyard. I set up my iPhone as a hotspot and connected the iPad to the Garmin. Despite all of this, the message “Warning - The Remote Controller’s GPS signal is weak and its location cannot be acquired” persisted.

    RC-GPS_4.jpg

    My conclusion is that my RC can’t acquire GPS co-ordinates from anything but its internal unit. I presume there is no DJI Go App setting that can change this limitation.

    As I was putting everything away I noticed my wife searching EBay for a head shaped baking dish. This maybe my last post.
     
  8. Scotflieger

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    I love a good experiment to test out a theory. The one point I missed earlier is that Apple devices also use WiFi to improve location data. I think they must geo locate the position of the IP address.
     
  9. MrTVR

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    Thank you to DavidB for your detailed experimenting with GPS and dynamic RTH.

    As I am just about to purchase a new iPad, is there actually any benefit in paying extra for the cellular (4g) option in terms of using the iPad with the Inspire 1 or Inspire 2 (when it arrives) ?
     
  10. Scotflieger

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    Having a good internet connection in thefield is essential for updating the DJI GO or Autopilot maps, giving you a good GPS position and for authorising any no fly zones. The 4G/SIM iPad gives you this. I tether to my iPhone for the internet and have a third-party Bluetooth GPS unit for the position.
     
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  11. DavidB

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    I agree with part of what Scot says but not everything. Yes "a good internet connection in the field" helps to update the DJI GO app and the Autopiot maps (as well as the map in the DJI app), but these can be done earlier before leaving home or where you have access to WiFi. The RC does not utilize the connected iPad, iPhone or Android device for determining its GPS co-ordinates. Sure you can have a cellular connection for the iPad for better GPS co-ordinates for the Autopilot app (or as "a good internet connection in the field") but its an unnecessary cost. In Australia the cheapest plan with 1G of data plus the extra cost of buying the iPad doesn't justify itself. My iPad, an Air 2 is pretty much used only for the I1. I personally use a Garmin device for providing GPS co-ordinates for the iPad, as it doesn't need cellular connectivity and therefore no plan. Occasional if I get caught out in the field and need connectivity for the iPad, I use my cellular phone as a Hotspot. All of the above applies for I1 and P4, I am awaiting delivery of the I2.
     
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  12. Cornscot

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    Are you connecting an external gps by wifi from the gps unit?

    I paid an extra £2/month for more data on my phone rather than a cellular iPad and contract and tether. But I fly in areas with no mobile signal a lot so the external gps is a top idea.
     
  13. Scotflieger

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    My Dual GPS X160 external unit connects by Bluetooth. I normally stuff it is a pocket while flying.


    Sent from my iPad using InspirePilots
     
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  14. DavidB

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    Similar to Scot, I have the Garmin connected to the iPad via Bluetooth.
     
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  15. Alastair

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    I agree David, a cell plan is a waste of money for this application. As you noted, I preload the maps at home connected to wifi with an iPad Air two. Out in the field, the iPad is in airplane mode when I'm flying. If I need to upload further maps, I use the phone as a hotspot. Never had an issue with the home point or GPS issues for that matter.
     
  16. Bob Stekeur

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    I have a cellular ipad, but I don't have a paid plan. If I need internet for maps, If I forgot to cache them I turn on the hotspot on my phone for internet.