What's the difference between "Smart" & "Failsafe" RTH?

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Ok, so I just got the P4P and was reading through the manual...

Can anyone explain what the difference is between "Smart Return to Home" and "Failsafe Return to Home"?

The manual describes how to operate between the two modes, but doesn't explain what they are and how they're used.
 
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I'm not certain, but under there's a kind of hidden setting under "MC Settings' - 'Advanced' and the option 'RTH Remote Obstacle Avoidance', which says:

'When enabled, aircraft will adjust the aircraft RTH route in remote to avoid obstacles, and aircraft will not respond to stick commands'

I think that this must be enabled for Smart RTH (where the aircraft actually backtracks), but again not sure. DJI's documentation on this subject is very confusing.
 

Mark The Droner

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There's another guy who asked similar questions a little while ago.

RTH Clarification

The P4P is so new, not many are expert on it yet. My understanding is that Failsafe RTH is what happens when it loses the control signal. It will hover 3 secconds and if it still doesn't sense a control signal, it will head home.

Smart RTH is something you must have enabled. If it's enabled, it will keep track of how far you are relative to battery strength, and it will start heading for home if it believes you are at risk of not having enough battery to make it back.

Watch the above thread for more...
 

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Smart RTH: When you initiate RTH by pressing and holding the RTH button on the remote controller or from the left side of the DJI GO app.
Failsafe RTH: When RTH is auto initiated after the remote controller connection has been lost for 3 seconds.

Note: The Smart Return-to-Home feature in DJI GO is not related to Smart RTH.
 
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msinger

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DJI really needs to change the name of that feature.
 
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So failsafe RTH doesn't avoid obstacles by backtracking?
 
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Hello

At first, excuse me for my english, i am french and live near Bordeaux at Lacanau on the sea side

Here is what i understand about Failsafe RTH and Smart RTH

Failsafe RTH
"(...) The aircraft will plan its return route and retrace its original flight route home"...
-> The system saves a "real-time map of its flight route as it flies" so it doesn't need collision system because it follows the same road but in opposite direction
-> Problem: the road is probably a lot longer than the straight line

Smart RTH
"(...) The aircraft will then automatically return to the last recorded home point" (...) As the aircraft returns, it will use the primary camera to identify obstacles as far as 300 m in front, allowing it to plan a safe route home"
-> The aircraft returns in a straight line, but first it takes the configured elevation and turns on itself to identify obstacles in front it

Is my explanation is the right one?

What i don't understand : which mode for which situation especially in emergency situations (low battery or loss of signal...) where the system automatically decides a RTH what choice? Failsafe or Smart ?

Best Regards and Enjoy your flights !
 
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Failsafe occurs when it loses connection with the TX. If at any point the connection is regained, it still stop retracing steps and instead switches to "smart" RTH where it beelines back to home.

Smart RTH is when you tell it via the controller to RTH.

Please note that by default, obstacle avoidance is turned OFF for RTH, and you have to enable it.
 
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Please note that by default, obstacle avoidance is turned OFF for RTH, and you have to enable it.
Obstacle avoidance is turned OFF by default during RTH? I would think that's when it would be needed most, especially if it was not retracing its flightpath. Is there any way to set the default obstacle avoidance to ON during RTH?
 
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Obstacle avoidance is turned OFF by default during RTH? I would think that's when it would be needed most, especially if it was not retracing its flightpath. Is there any way to set the default obstacle avoidance to ON during RTH?
Yes it's a setting you have to turn on. Settings > aircraft > advanced settings > enable RTH remote obstacle avoidance
 

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Note: The Smart Return-to-Home feature in DJI GO is not related to Smart RTH.
Okay, I'll bite. So what is the difference?
 

msinger

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Okay, I'll bite. So what is the difference?
When you enable the Smart Return-to-Home setting, your Phantom will auto return home when it calculates it's time to turn back based on the distance from the home point and amount of battery remaining. The DJI GO app will give you 10 seconds to cancel that auto RTH before it initiates.
 
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When you enable the Smart Return-to-Home setting, your Phantom will auto return home when it calculates it's time to turn back based on the distance from the home point and amount of battery remaining. The DJI GO app will give you 10 seconds to cancel that auto RTH before it initiates.
Yep, I vote to name this function "Low Battery Beeline Return" or LBBR. It would certainly reduce confusion.

HELLO !... DJI?
 
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I really feel a lot of the above is not correct.
I have never read in any documentation that the Phantom will RTH by retracing it's recent course under any circumstances. After reading the manual, this is what I understand.
“Smart Return Home” denotes that the remaining battery capacity can only support the aircraft from return to the home point from the current position hence the app will prompt a message to notify that RTH is being invoked to bring the aircraft back to the home point at that moment. Object avoidance is active. You can cancel if you don’t want this to activate.
"Failsafe Return Home" will do the same as above, except it is invoked upon signal loss of 3 seconds or more duration.
 
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msinger

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I really feel a lot of the above is not correct.
I have never read in any documentation that the Phantom will RTH by retracing it's recent course under any circumstances. After reading the manual, this is what I understand.
“Smart Return Home” denotes that the remaining battery capacity can only support the aircraft from return to the home point from the current position hence the app will prompt a message to notify that RTH is being invoked to bring the aircraft back to the home point at that moment. Object avoidance is active. You can cancel if you don’t want this to activate.
"Failsafe Return Home" will do the same as above, except it is invoked upon signal loss of 3 seconds or more duration.
There is a fair amount of info not in the manual. Documentation or not the backtrack feature is there. A DJI rep even verified with the engineers it tries to backtrack a max of 60 seconds and if no TX signal is restored it switches to failsafe RTH. Plus there are plenty of videos out there showing the backtrack behavior including a video I posted recently.
 
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