Servers by jDrones

Waypoint addition, replacement and change in altitude during flight


(Muhammad Usman Rafiq) #1

Hello, I want to a question. Can we add, replace or change altitude during flight? For both arducopter and arduplane.


(Hunt0r) #2

Yes, there are several ways to do this, depending on what exactly you want.

Have you read the standard documentation yet? Check it out: http://ardupilot.org/ardupilot/


(Muhammad Usman Rafiq) #3

Thanks hunt0r for your reply.
One method which I observe in simulation of mission planner, flight planner. In the normal flight data window I cant even touch any of the waypoint, but in flight planner I can add, replace whatever i want to do with the mission. I just need to press write WP again.
I just want to confirm will this happen exactly same in real flight?


(Hunt0r) #4

Yes, this might work, but be very careful. I do not recommend uploading a new mission to a plane during flight, as any errors in the transmission might cause unexpected results.


(Muhammad Usman Rafiq) #5

so what method do you recommend? I’m trying this on arduplane, if I only want to replace my waypoints.


(Hunt0r) #6

Would you clearly describe what behavior you want?

Do you want to change just altitude, or do you want to actually change the waypoints?
Do you know before takeoff what new altitudes/waypoints that you might want during flight?
Are you flying only in AUTO mode?


(Muhammad Usman Rafiq) #7

Actually i want to change preloaded waypoints, I mean if I plan a flight and load some waypoints, after flying in manual mode, I switch to auto mode and during this time

  1. if I change target waypoint’s altitude
  2. Replace the target waypoint to another coordinates(new Lat/long).
  3. if I add a new waypoint during auto mode to move my plane to that waypoint.
    What method will be suitable? Any recommendation.

(Hunt0r) #8

It sounds like you want the ability to 1) command the plane to change altitude, but keep it’s current waypoint, AND 2) to instruct the plane to fly to a different (new) waypoint via the Ground Control Station.

Have you considered GUIDED mode?


(Muhammad Usman Rafiq) #9

In guided mode, it just go that location and start loitering there. My question is,
Is it possible to place the target waypoint to new location in AUTO mode? or using any other mode?


(Kuto) #10

Actually, it is pretty safe to transmit new waypoints also during flight to the vehicle (in your case, your plane). The reason for this is that the wireless transmission protocol which ardupilot uses (mavlink) uses a checksum and counter to verify that the message is transmitted correctly (This is for example documented here, or in this blog) .
Therefore to summarize: Yes you can transmit new waypoints via the flight planner software in the way to describe. You can even add new waypoints or modify existing waypoints in the way you described. This method is safe thanks to the mavlink protocol (*).
Even if your wireless transmission link is not good, and you try to transmit new waypoints, only correctly sent waypoints will be accepted by the flight vehicle. If the messages sent by the groundstation are corrupted by a faulty wireless link, the flight vehicle will request a retransmission, so that the groundstation will try to send the message again. You can see this process working, therefore in flight it might take a little bit longer to transmit new waypoints. But this system is design such that it is possible to transmit new messages such as waypoints, changes to waypoints etc to the vehicle WHILE the vehicle performs an auto mission.

Hope this clarifies.
Best Phil

*Safe is of course a relative measure. We are talking about drone technology here, this is not aircraft level safe with a failure probability of 10^-9 but rather something which someone programmed and then people tested extensively (which is why it is so reliable today). Therefore you should always be very careful how you fly your drone.