P4P New RTH Features

smiller · Nov 26, 2016

mudman said:
hopefully the smart rth will be like 3dr had for solo in beta testing, when signal is lost it will retrace its path for a set distance like say 70 feet and if signal isn't regained at that point it will go into normal rth mode.

That logic makes sense, i.e. gingerly back out of a movement that causes contact to be lost but if contact seems gone for good then hightail it back home.

GadgetGuy · Nov 26, 2016

smiller said:
That logic makes sense, i.e. gingerly back out of a movement that causes contact to be lost but if contact seems gone for good then hightail it back home.

Elevation is the key to signal restoration in almost all cases. Simple yawing the aircraft can also help, which is part of RTH. Unless the aircraft backs up flying backwards, as part of the route retracing, flying forwards back along the path may actually further worsen the signal strength, because the antennas depend upon the orientation of the aircraft for optimal signal strength.

AmirChar · Nov 26, 2016

butlerc said:
The return to home description from the store splash page says: "... can automatically choose the best route to return home depending on environmental conditions." I think depending on the conditions like low battery, it may go to the return to home altitude and come directly back.

Sent from my iPad using PhantomPilots

I would hope this is the case... obviously you should be aware of battery life, but I tend to roam around a lot, so if for whatever reason I need RTH, I want it coming back the quickest way possible. If you have done your homework and planned for the area, you should have set the RTH height ahead of time.

Raptorman0909 · Nov 27, 2016

I wonder why there isn't a "Retrace RTH" option that would have the drone head back following the route it took getting to the place where it lost its signal so long as there's enough battery to do so. Odds are that in a few seconds the signal would be restored and RTH could be cancelled. And, so long as the route out wasn't overly close to objects it would pretty much be a safe/known route.

Brian

GadgetGuy · Nov 27, 2016

Raptorman0909 said:
I wonder why there isn't a "Retrace RTH" option that would have the drone head back following the route it took getting to the place where it lost its signal so long as there's enough battery to do so. Odds are that in a few seconds the signal would be restored and RTH could be cancelled. And, so long as the route out wasn't overly close to objects it would pretty much be a safe/known route.

Brian

That's my understanding of how it is supposed to work.

John Locke · Nov 27, 2016

Raptorman0909 said:
I wonder why there isn't a "Retrace RTH" option that would have the drone head back following the route it took getting to the place where it lost its signal so long as there's enough battery to do so. Odds are that in a few seconds the signal would be restored and RTH could be cancelled. And, so long as the route out wasn't overly close to objects it would pretty much be a safe/known route.

I believe the retrace RTH is the default when you lose signal, assuming you have adequate battery. At that point you can't tell it what to do, you've lost signal. However it should reconnect by backtracking. When you reconnect and you want the RTH as a beeline, push and hold the RTH button. Low battery auto-RTH will likely default to a beeline return.

We'll know more about this when these craft arrive this week. Oh the anticipation.

Raptorman0909 · Nov 27, 2016

GadgetGuy said:
That's my understanding of how it is supposed to work.

Really, it was my understanding that RTH climbed to the RTH height then made a bee line for home. If RTH does what I refereed to as 'Retrace RTH' then why do we have videos of drones running into hills during RTH?

Brian

GadgetGuy · Nov 27, 2016

Raptorman0909 said:
Really, it was my understanding that RTH climbed to the RTH height then made a bee line for home. If RTH does what I refereed to as 'Retrace RTH' then why do we have videos of drones running into hills during RTH?

Brian

1. Because this new retrace RTH is a P4P feature, only available on the P4P.
2. Because of operator error, where the pilot foolishly or ignorantly did not set a proper RTH height for the environment they were flying in.

AnchorageAk · Nov 27, 2016

I used RTH a lot when I was learning. It saved my bacon more than once, and no I didn't name my drone Bacon. To me it was like training wheels for a bicycle. Also, a sort of insurance policy for when I screwed up. I bought into what DJI was saying. RTF out of the box. So simple any one could do it. Well there is a lot to it, in my opinion. Now I am more hands on. It is fun to fly it back, and learn how to control it.
The more you learn the better off you are, and RTH does have a place. I would bet that every one has used it at least once.

GadgetGuy · Nov 27, 2016

AnchorageAk said:
I used RTH a lot when I was learning. It saved my bacon more than once, and no I didn't name my drone Bacon. To me it was like training wheels for a bicycle. Also, a sort of insurance policy for when I screwed up. I bought into what DJI was saying. RTF out of the box. So simple any one could do it. Well there is a lot to it, in my opinion. Now I am more hands on. It is fun to fly it back, and learn how to control it.
The more you learn the better off you are, and RTH does have a place. I would bet that every one has used it at least once.

I have never voluntarily used RTH. The only time it is ever activated is upon signal loss, and then, as soon as the elevation restores signal (set to 250m), I immediately cancel it, and sally forth. If I need to fly directly home, I just rotate the nose of the aircraft towards the Home Point and fly back along the green line at full throttle. However, if the app crashes and the iPad locks up, causing a total loss of all telemetry, and the green LED is still lit on the controller, press and hold RTH to activate it, and bring her home!

Raptorman0909 · Nov 27, 2016

GadgetGuy said:
1. Because this new retrace RTH is a P4P feature, only available on the P4P.
2. Because of operator error, where the pilot foolishly did not set a proper RTH height for the environment they were flying in on a prior aircraft.

OK, so we have a difference of opinion on RTH with some thinking retrace was how it always worked and others, such as yourself, saying it's new to the P4P. It has always been my understandign the RTH, at least prior to the P4P, was climb then beeline back to home. A retrace RTH won't 100% prevent hitting things if the course out comes close to some things the +/-10m potential error of the gps could result in hitting somehting you were clear of on the outbound leg. In practice, the error will likely be more like +/-3m but it could be more. And if the battery is too low for a retrace then it will do a climb and beeline as before.

I have never used RTH with my Inspire though I have had several loss of signal events though thankfully the loss of signal has always been for a very short time. Typically, when I see something go wrong I switch to "A" mode for a few seconds to make sure I have control then switch back to "P" mode and so far that has always worked. It's probably the case that my loss of signal issues have all be transient.

Looking forward to getting my P4P and taking it on a road trip before the end of the year.

Brian

GadgetGuy · Nov 27, 2016

Raptorman0909 said:
OK, so we have a difference of opinion on RTH with some thinking retrace was how it always worked and others, such as yourself, saying it's new to the P4P. It has always been my understandign the RTH, at least prior to the P4P, was climb then beeline back to home. A retrace RTH won't 100% prevent hitting things if the course out comes close to some things the +/-10m potential error of the gps could result in hitting somehting you were clear of on the outbound leg. In practice, the error will likely be more like +/-3m but it could be more. And if the battery is too low for a retrace then it will do a climb and beeline as before.

I have never used RTH with my Inspire though I have had several loss of signal events though thankfully the loss of signal has always been for a very short time. Typically, when I see something go wrong I switch to "A" mode for a few seconds to make sure I have control then switch back to "P" mode and so far that has always worked. It's probably the case that my loss of signal issues have all be transient.

Looking forward to getting my P4P and taking it on a road trip before the end of the year.

Brian

I'm confused, as you say we have a difference of opinion, but then reconfirm the facts. It's not an opinion, but a fact that the RTH retrace feature has never existed before the P4P on any other DJI product, and is a brand new feature on the P4P. All previous RTH functions have been on a straight line to the Home Point, after elevation to the set RTH height, as you also state, with the P4 potentially offering obstacle avoidance during the return flight.

Raptorman0909 · Nov 27, 2016

GadgetGuy said:
I'm confused, as you say we have a difference of opinion, but then reconfirm the facts. It's not an opinion, but a fact that the RTH retrace feature has never existed before the P4P on any other DJI product, and is a brand new feature on the P4P. All previous RTH functions have been on a straight line to the Home Point, after elevation to the set RTH height, as you also state, with the P4 potentially offering obstacle avoidance during the return flight.

No, just pointing out that OTHERS have said or implied the retrace RTH was the way its always been -- I'd always understood RTH in prior DJI drones was via the climb then beeline method.

Looking at the preliminary manual for the P4P they indicate three different RTH modes: Smart RTH, Low Battery RTH, and Failsafe RTH. It appears the Failsafe RTH is the one that does the retrace if the RC comm is lost for more than 3 seconds. The Smart RTH appears to be what you get if you press the RTH button on the RC or in the Go app and while it can use the collision sensors it's route appears to be more of the beeline type. Low Battery RTH will return home via the beeline method after a 10 second countdown.

There's not much reason I can think of why there other drones can't also have the Failsafe RTH mode with retrace so it will be interesting to see if this mode is added to the other drones at some point. It may be wise to limit this feature to the P4P for the time being and once its proven itself then rolled out to the other models.

Brian

mudman · Nov 27, 2016

After looking at the manual it looks like when failsafe RTH kicks in after signal loss it will retrace it's path till it gains signal again then it will hover, so it won't necessarily fly back to launch point.