8 REPLIES
foundobjectwind
Commander Pilot

Re: RTH In Pictures

@mountkidd

I tested the RTH home location once and determined it to be the location at takeoff time and not first fix.   I powered up the bebop in location A and allowed it to get a fix.  Then I move it to location B and let it sit a few minutes and see the flight plan icon stabilize.  Then I took off and flew away and did rth it came back to location B.

Did yours do differently?     ..or maybe im confusing my tests. I remember trying ipad location.


mountkidd wrote:

Tim84 wrote:

foundobjectwind wrote:

 

the RTH either rises first to 20m or stays at its current elevation if its higher than 20m 


Thanks FOW. Do you know what it rises to 20m above? 20m above home location, or 20m above current position? 

 

As per (c) this is quite vital to know!

 

I'll update the images later to reflect the drop to 2m incase anyone else views this post as I don't want to mislead anyone. It's good to know in detail how RTH works before I lose my BB or crash it into something terminal...!


Altitudes are relative to the home position.  Home position can be First Fix, Takeoff Position or Pilot Position.  By default in FF3/FFPro, home position is First Fix.  So, watch out, as First Fix can have low accuracy...


 

 

foundobjectwind
Commander Pilot

Re: RTH In Pictures

The bebop can also drift around a lot when its hovering at 2m.   If there is an RTH due to connection failure they have been known to fly sideways into windows, etc, after returning to hover.   I've been trying a large black square with a white + on it to give the bottom cam something to lock onto and it seems to help with that... but the bebop often  doesnt  come down overtop of it.     But the bebop should be low enough to catch if connection can't be re-established.

Probably a rare case though.  I've only had rth after disconnect once and that was intentional, I just wanted to see it work.  It works great, but the bebop crash landed in a holly tree 20 feet from the launchpad. oops.  no harm done.

 

Probably good to know that rth after disconnect doesnt happen unless the wifi link is completely down.   The app can report disconnected and have no control.,, but if the bebop can see the wifi signal its not "disconnected".    Turning off the wifi on the controller is a sure way to disconnect.   I keep my rth on disconnect timer set low.. 10 seconds. maybe less.  Disconnects are rare here.

 

Also, the  altitude used in rth is determined entirely by the drones altimiter and is independent  of the 2D gps location used as home location.   Altitude is zero at the takeoff point.  If I take off from a 2 meter tall tripod then land on the ground next to the tripod the altimeter reads -2 meters.   Rth would hover 4 meters above the ground (2 meters above the tripod).

 

 

 

 

 

 

 

 

 

 

 

Tim84
Master navigator

Re: RTH In Pictures

Thanks for the input everyone. I've updated the original post so it is hopefully helpful to anyone else that wants to learn about how RTH works.

mountkidd
Commander Pilot

Re: RTH In Pictures


Tim84 wrote:

foundobjectwind wrote:

 

the RTH either rises first to 20m or stays at its current elevation if its higher than 20m 


Thanks FOW. Do you know what it rises to 20m above? 20m above home location, or 20m above current position? 

 

As per (c) this is quite vital to know!

 

I'll update the images later to reflect the drop to 2m incase anyone else views this post as I don't want to mislead anyone. It's good to know in detail how RTH works before I lose my BB or crash it into something terminal...!


Altitudes are relative to the home position.  Home position can be First Fix, Takeoff Position or Pilot Position.  By default in FF3/FFPro, home position is First Fix.  So, watch out, as First Fix can have low accuracy...

Highlighted
Tim84
Master navigator

Re: RTH In Pictures


foundobjectwind wrote:

 

the RTH either rises first to 20m or stays at its current elevation if its higher than 20m 


Thanks FOW. Do you know what it rises to 20m above? 20m above home location, or 20m above current position? 

 

As per (c) this is quite vital to know!

 

I'll update the images later to reflect the drop to 2m incase anyone else views this post as I don't want to mislead anyone. It's good to know in detail how RTH works before I lose my BB or crash it into something terminal...!

foundobjectwind
Commander Pilot

Re: RTH In Pictures

funny. I was just getting resdy to mention RTH per your previous question. It is different than the way the bebop changes elevation in a flight plan.

 

the RTH either rises first to 20m or stays at its current elevation if its higher than 20m

it flies in a straight level path to the home position, then descends to 2m if not interrupted.

the RTH can be stopped at any time by using the controls, but its a good idea to have a clear landing area in case it rth due to connection failure the gps may not be perfect.

 

 

Tim84
Master navigator

Re: RTH In Pictures


GabbyParrot wrote:

Very nicely illustrated.  I believe you hit the nail on the head with a, b and d.   I have no experience with C. but there has been discussion on the forum about flying below your starting altitude and the return altitude.  If I find it I will attach here. 


Thanks GabbyParrot. I'm now not so sure about the final RTH hovering altitude as I read in the Parrot instruction manual that it'll hover at 2m. This could be old information, however, as the rest of their literature seems to be out of date.

 

(c) is important as I don't want to lose my Bebop to a watery grave if I lose WiFi connectivity whilst flying off the dam! I'll have to find somewhere safe to test it first (once I have a Bebop which actually has a working RTH feature!)

GabbyParrot
Commander Pilot

Re: RTH In Pictures

Very nicely illustrated.  I believe you hit the nail on the head with a, b and d.   I have no experience with C. but there has been discussion on the forum about flying below your starting altitude and the return altitude.  If I find it I will attach here. 

Tim84
Master navigator

RTH In Pictures

Am I right that RTH works as per the four following scenarios? Any other important scenarios to think of? (c) is particularly important as I want to fly the Drone off a dam in a couple of weeks...

 

(a) drone is lower than 20m so rises to 20m then RTH and drops to hover at 2m:

 

 

(b) Drone already higher than 20m so remains at that height and RTH, dropping to hover at 2m:

 

 

 

 

(c) Drone is lower than home position so it rises to 20m above home then RTH and hovers at 2m:

 

 

(d) There is an obstacle higher than 20m between Drone and Home. Drone was flying at under 20m. Drone rises to 20m then RTH and smashes into the obstacle:

 

[Edit: above images and text edited since I first posted them. This is to reflect actual scenarios as advised by community members]