Mavic does RTH without GPS signal!!!

[Alex ROV]

if it had an IRU that was accurate enough in theory it could find its way back without GPS.
also why cannot it detect nearby wifi for rough location?
plus how difficult would it have been for dji to include onboard 4g?

The importance of GPS is also to give feedback in a way that Mavic can correct her vectors and speed in order to keep in route to come back... This way the aircraft can compensate the wind's effects, for example... Without GPS (or any other precise positioning reference) isn't possible even to confirm if Mavic is moving in relation to the ground.

 

[Alex ROV]

Any reason to actually use slide to land? I never ever use that even under ideal conditions...

I really don't see... I'm not using that anymore, same as auto take off... Maybe it's just something COOL to impress our friends...

 

[Alex ROV]

I always set my machine to hover, even outside, in case of signal loss.

But than, if you don't get the signal back you can lose it in a disastrous landing when battery dies... Have you considered that?

 

[msinger]

Ok... But... Was that tested with LoS set to hover? Because you could still possibly hit a situation when it's hovering because it has lost signal and it's far enough that smart rth would kick in BEFORE any other automated landing scenario..

Smart Return-to-Home cannot be initiated while the remote controller is disconnected from the Mavic.

 

[Plawa]

Smart Return-to-Home cannot be initiated while the remote controller is disconnected from the Mavic.

Source?

 

[msinger]

Source?

Experience.

I've been flying DJI drones for about 3 years. I own a Mavic Pro, P3S, P34K, P3A, P3P, P4, P4A, P4P, and an Inspire 1 V2. I spend a lot of time testing DJI drones, studying DJI drones, reviewing DJI flight logs, and helping people in DJI drone forums.

 

[Grey Wolf]

What's the difference between smart return to home and regular rth?

 

[Grey Wolf]

But than, if you don't get the signal back you can lose it in a disastrous landing when battery dies... Have you considered that?

Yes, but since I fly according to the rules of vlos, I know where it is.
If you set rth when signal is lost, you better make sure your rth is always above whatever you film otherwise, kaboom! Collision!

 

[Grey Wolf]

For us newbies can you explain your reasoning for this.
I am keen to learn but I would of thought if you are set to hover due to signal loss and the drone is without operater knowledge hovering over a body of water would the drone just drop in the water if signal does not return and the battery runs out.

By putting it into hover, it gives me a chance to find it and then decide what to do.
Rth could fly the machine into a tree or building if you haven't set the height accordingly first. A lot of people forget to do this and this is the main reason for rth crashes.
Also, I never fly bvlos so I know where drone is all the time.

 

[mfc]

Though it is theoretically possible to implement a GPSless RTH function with reasonable accuracy. Because the drone has 2 IMUs, 2 Compasses and a FVS and VPS, .... <snip>

Unfortunately not .. the snag is that the only sensors that relate to distance are the accelerometers, and the results from those have to be integrated twice to get distance. The errors from this build up extremely quickly due to drift and the effects of vibration (if one has an occasional static reading you can correct for drift, but that isn't possible for a drone). Hence, 'reasonable accuracy' is not achievable (at least with the MEMS sensors most likely used in the Mavic).

Mike

 

[Alex ROV]

Yes, but since I fly according to the rules of vlos, I know where it is.
If you set rth when signal is lost, you better make sure your rth is always above whatever you film otherwise, kaboom! Collision!

I understand your point but don't you flight over trees, cliffs, water, roads? Is going to land wherever she is... You might have only a few minutes to try hand catch her, if possible...

Yes! I set it high above anything... And also I turned OFF the Obstacle Avoidance, so Mavic won't stuck in middle air due to a false detection caused by sunlight reflection on sensors... I believe this "interference" is actually causing lots of unhappy RTH, as it happens quite a lot according to reports...

 

[msinger]

What's the difference between smart return to home and regular rth?

Here are the 3 types of RTH:

• Failsafe RTH (triggered 3 seconds after the remote controller disconnects from the Mavic)
  
• Smart RTH (when you manually initiate RTH from DJI GO or the remote controller)
  
• Low Battery RTH (triggered by the Smart Return-to-Home feature)

Check out the "Return-to-Home (RTH)" section of the Mavic manual for more details.

Note: While the names are similar, "Smart RTH" has nothing to do with "Smart Return-to-Home".