Should I turn of RTH?

discv said:
Not sure we are going to solve this. Without doubt, the assistant states that the craft will auto land when failsafe is activated- except if in GPS mode where it will RTH.

And Damon, your Phantom going into full RTH on low battery!! Surely not.
Huh? Please clarify your statement..are you saying it does not initiate RTH at 20% or I shouldn't allow it to do this by un checking the RTH and setting it to Auto Land.

From my testing my phantom does initiate RTH at 20% if I override RTH by moving it back to GPS mode (or off GPS and Back to it) it will fly to 15% or roughly 10.7 volts before initiating auto land. In which applying roughly 90% throttle will sustain altitude to allow me to select a safe landing area. FACT
 
I'm clear on it now... 'tapping out' of this one.
 
Guys... GPS is ALWAYS "on", and searching for satellites, regardless of current flight mode.

If you manually switch to ATTI or Manual flight mode, the Phantom simply ignores the GPS data, it doesn't actually turn the GPS off. As long as there are a minimum of 6 satellites available for lock, the GPS always knows the position of the Phantom as well as the position of the home location (assuming it was able to lock prior to take off).

So it doesn't matter what flight mode you are currently in... if the Phantom loses tx connection it will perform a full RTH... unless there are fewer than 6 satellites available, in which case it will auto-land where it is.

This is why, regardless of what flight mode you'll be using, you still wait for a full start-up and initialization sequence and a decent GPS lock.

RTH is not inherently faulty. It is the pre-flight preparation that, when not performed correctly, can make it behave badly. So the answer is not to "turn off" RTH, but to always be diligent about preparing for flight.
 
Sorry I'm 'tapping back in'...

Gotta disagree with ya' Professor (unless a newer manual conflicts), as far as the P2 is concerned, here's a cut/paste from page 23 of the P2 Manual v1.1:


Failsafe works differently depending on the mode the aircraft is in when Failsafe mode is initiated
whether it is in the Ready to Fly or Ready to Fly (non-GPS) mode.

>Ready to Fly (non-GPS) ---- Automatic landing
The flight control system will try to keep the aircraft level during descent and landing. Note that
the aircraft may be drifting during the descent and landing process.

>Ready to Fly (GPS)---- Automatic go home and land
The flight control system will automatically control the aircraft to fly back to the home point and
land.
 
Damon said:
discv said:
Not sure we are going to solve this. Without doubt, the assistant states that the craft will auto land when failsafe is activated- except if in GPS mode where it will RTH.

And Damon, your Phantom going into full RTH on low battery!! Surely not.
Huh? Please clarify your statement..are you saying it does not initiate RTH at 20% or I shouldn't allow it to do this by un checking the RTH and setting it to Auto Land.

From my testing my phantom does initiate RTH at 20% if I override RTH by moving it back to GPS mode (or off GPS and Back to it) it will fly to 15% or roughly 10.7 volts before initiating auto land. In which applying roughly 90% throttle will sustain altitude to allow me to select a safe landing area. FACT

I think we are all at cross purposes here. And I think we're talking different models and firmware. My perspective is from a naza v2 bolted on a Flamewheel. I was just surprised that a low battery should initiate RTH.
And RTH on flashing reds would be the last thing I want. That 20m climb, return and hover would amount to a pile of bits ;)
 
discv said:
Damon said:
discv said:
Not sure we are going to solve this. Without doubt, the assistant states that the craft will auto land when failsafe is activated- except if in GPS mode where it will RTH.

And Damon, your Phantom going into full RTH on low battery!! Surely not.
Huh? Please clarify your statement..are you saying it does not initiate RTH at 20% or I shouldn't allow it to do this by un checking the RTH and setting it to Auto Land.

From my testing my phantom does initiate RTH at 20% if I override RTH by moving it back to GPS mode (or off GPS and Back to it) it will fly to 15% or roughly 10.7 volts before initiating auto land. In which applying roughly 90% throttle will sustain altitude to allow me to select a safe landing area. FACT

I think we are all at cross purposes here. And I think we're talking different models and firmware. My perspective is from a naza v2 bolted on a Flamewheel. I was just surprised that a low battery should initiate RTH.
And RTH on flashing reds would be the last thing I want. That 20m climb, return and hover would amount to a pile of bits ;)
I was about to ask what model and what firmware :0

That's kind of funny. I believe we are older stubborn alpha males posturing at times. ;)
 
N017RW said:
Sorry I'm 'tapping back in'...

Gotta disagree with ya' Professor (unless a newer manual conflicts), as far as the P2 is concerned, here's a cut/paste from page 23 of the P2 Manual v1.1:


Failsafe works differently depending on the mode the aircraft is in when Failsafe mode is initiated
whether it is in the Ready to Fly or Ready to Fly (non-GPS) mode.

>Ready to Fly (non-GPS) ---- Automatic landing
The flight control system will try to keep the aircraft level during descent and landing. Note that
the aircraft may be drifting during the descent and landing process.

>Ready to Fly (GPS)---- Automatic go home and land
The flight control system will automatically control the aircraft to fly back to the home point and
land.

The confusion is in the terminology. "Ready to Fly (GPS)/Ready to Fly (non-GPS)" is not a flight mode. It is not synonymous with "GPS/ATTI/MANUAL" It is simply, given that the Phantom is ready to fly, does it have enough satellites to provide a GPS lock or not.
- GPS can lock onto 6 or more satellites = "Ready to Fly (GPS)"
- GPS can only lock onto 5 or fewer satellites = "Ready to Fly (non-GPS)"

As I said, your Phantom will lock onto satellites (assuming you provide enough pre-flight time to allow it to do so) regardless of what flight mode you are in. You can have your S1 in "GPS ATTI" (top position), and still have the Phantom in "Ready to Fly (non-GPS)" mode because it can't find enough satellites (in which case it will fly as if it was in ATTI flight mode). Likewise, you can be in "ATTI" (middle position), and still your Phantom is in "Ready to Fly (GPS)" mode because it has access to 6 or more satellites.

See the following flowchart:
http://download.dji-innovations.com/dow ... 1.0_en.pdf

You'll see that, once you're in flight, the only variable taken into account when failsafe is invoked is how many satellites are available... not what flight mode you are in.
 
Fair enough then.
 
N017RW said:
Failsafe works differently depending on the mode the aircraft is in when Failsafe mode is initiated
whether it is in the Ready to Fly or Ready to Fly (non-GPS) mode.

>Ready to Fly (non-GPS) ---- Automatic landing
The flight control system will try to keep the aircraft level during descent and landing. Note that
the aircraft may be drifting during the descent and landing process.

>Ready to Fly (GPS)---- Automatic go home and land
The flight control system will automatically control the aircraft to fly back to the home point and
land.

I think this is where the confusion is coming in.

For P2's in Phantom mode, the failsafe RTH will happen regardless of switch position, and as long as the Phantom has enough satellites locked. If not enough Sat's are seen ("non-GPS" in DJI's terms above), auto-land is the failsafe behavior.

Kinda similar for NAZA mode and P1's, RTH will work even if the switch is in ATTI mode, but again only if there's enough sat's locked. In other words, manually switching to ATTI won't prevent RTH, but ATTI mode that's forced by the NAZA due to lack of GPS lock will prevent it and use auto-land instead if failsafe is triggered.

Note: I haven't tested any of these behaviors other than triggering failsafe RTH when in (manually-selected) ATTI mode, and not on a P2...but when I did that it flew up then home just like normal. What I've described is just my understanding based on my personal interpretation of DJI's documentation and what little bit I've tested.

EDIT: I think Prof said the same thing but better :D
 

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