Question re Dynamic Home Point using RC/Device with GPS

daisy-girl · Mar 28, 2018

Could magnetic or other interference cause a misreading of my current location with my RC/GPS-equipped Device, with the result that the aircraft lands somewhere far from me upon pressing RTH?

Assuming I'm receiving data from AT&T, could I avoid this possibility by checking whether Google maps correctly locates me before pressing RTH?

If I see that Google maps does not correctly locate me, is the only solution to continuously change my position until Google locates me correctly?

lisadoc · Mar 29, 2018

daisy-girl said:
Could magnetic or other interference cause a misreading of my current location with my RC/GPS-equipped Device, with the result that the aircraft lands somewhere far from me upon pressing RTH?

There are a lot of things that could interfere with your GPS signal, causing the inaccurate determination of your position (just like it can for your Mavic). Simply standing under cover (trees, roofline, etc), for example, out of view of the GPS sats, can cause DJI GO to not know where you are in order to return to a controller home point. (The standard home point is determined upon takeoff by the GPS position of the AC). Many folks have had flyaways when they accidentally pushed the RTH and answered the question to return to their location, only to find it fly off towards the last known position, potentially a point 100s of miles away from where they were currently.

daisy-girl said:
Assuming I'm receiving data from AT&T, could I avoid this possibility by checking whether Google maps correctly locates me before pressing RTH?

Yes, for controller home point. If it sees where you are correctly, it can then instruct the AC to return to that point (as long as it had contact with the RC at some point to relay the correct location).

daisy-girl said:
If I see that Google maps does not correctly locate me, is the only solution to continuously change my position until Google locates me correctly?

You can always fly your Mavic back to you. RTH is an emergency function to be used if/when you end up with a loss of signal or low battery condition. Relying on sending a correct GPS location to your AC upon signal loss, when you don't have a signal (hence the RTH being triggered), makes it impractical. Otherwise, RTH is only really flying the AC back to your position, something you should be capable of doing yourself. Some pilots use RTH to fly the AC back to their position automatically while they focus on other functions (like gimbal control, etc) but if there's any question about whether or not the AC has an accurate home point determination, one should not rely on it to assist in the return and instead fly it back themselves.

daisy-girl · Mar 29, 2018

lisadoc said:
There are a lot of things that could interfere with your GPS signal....

Thank you very much for taking the time to write such a thoughtful reply. Thumbswayup

BD0G · Mar 29, 2018

The RTH Button should not be relied upon as a method to always fly back to your current position.

Its a bit of automation that makes the drone easier for newbie flyers to feel safe about the drone returning to thier Home Point.

90 + percent of the time I manually fly sticks to direct the Mavic Pro back to my position. Why? To keep my skills sharp and not rely on some piece of automation to make flying choices for me.

Its a learning experience to fly with sticks manually in a multitude of conditions. If I loose connection to the Mavic Pro well then of course it will enter RTH and hopefully fly back in my direction so I can re-establish connection and take over manually flying.

Simmo · Mar 29, 2018

I know where you are coming from above however you need to clarify your wording.
In DJI Go4, Dynamic homepoint is only available in Active track, and updates the Homepoint to the position of the Aircraft, not you. It will mark homepoints dynamically as the Aircraft moves about 15 mtrs.
Homepoint ME, will mark the homepoint as your controller (if your device has GPS) when selected in the App.

daisy-girl · Mar 29, 2018

Simmo said:
I know where you are coming from above however you need to clarify your wording.
In DJI Go4, Dynamic homepoint is only available in Active track, and updates the Homepoint to the position of the Aircraft, not you. It will mark homepoints dynamically as the Aircraft moves about 15 mtrs.
Homepoint ME, will mark the homepoint as your controller (if your device has GPS) when selected in the App.

Oops!

Yes, continuously updating the HP to the RC/GPS-enabled device is not automatic/dynamic. Pilots must manually re-adjust the HP to their latest position -- and then double-check on their map that the position is correct.

Thanks for pointing that out.

BTW, true Dynamic Home Point would be useful if the subject is the pilot, and s/he wants to land the AC wherever s/he is currently located. But I don't understand why a pilot would wish to use this when the Active Track subject is someone/something else that is moving away from the pilot's location. Can you think of a reason in such a case?

daisy-girl · Mar 29, 2018

BD0G said:
Its a learning experience to fly with sticks manually in a multitude of conditions.

For sure.

BTW, when calibrating the sticks, I am unable to complete the process because I don't understand what it means to, if memory serves, "rotate the base."

Please enlighten me.

Thank you.

BD0G · Mar 29, 2018

Simmo · Mar 29, 2018

I think in LItchi, the Dynamic home point is the RC, and in any mode too, I agree it would make sense to have that option. I think DJI's take on it is lets say you were in a car, tracking it. If it lost connection, you wouldn't want it going 3 km''s back up the road to where it started? But it would do that if it were set to the device too??

daisy-girl · Mar 30, 2018

BD0G said:
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Thank you!

daisy-girl · Mar 30, 2018

Simmo said:
I think in LItchi, the Dynamic home point is the RC, and in any mode too, I agree it would make sense to have that option. I think DJI's take on it is lets say you were in a car, tracking it. If it lost connection, you wouldn't want it going 3 km''s back up the road to where it started? But it would do that if it were set to the device too??

Please clarify what you mean.