Open tizianofiorenzani opened 1 month ago
Airspeed would be great to add to the interface. Airspeed doesn't have a rotational component though, so twist seems overkill and wasteful of data. Did you consider publishing just a geometry_msgs/msg/Vector3
with the body frame component of estimated airspeed? Plane's zero sidesplip assumption means it would only be populating the X component, but copter could populate more fields.
I like this idea, we could use the three components to publish.
/ap/airspeed
, where the frame_id = wind_axis
Sideslip is only for plane. Why not just XYZ relative to body frame.
You mean airspeed in body frame? That would work. length of vector is what we call "airspeed", which most of the times will result in only the x component unless you have AOA and sideslip measurements, or they are estimated internally.
You mean airspeed in body frame? That would work. length of vector is what we call "airspeed", which most of the times will result in only the x component unless you have AOA and sideslip measurements, or they are estimated internally.
Yea, that's what I meant.
I can work this out in a PR and we can move ahead from there.
Well, from inspecting the code it seems pretty easy to obtain the TAS vector:
Vector3f airspeed_vec_bf;
if (AP::ahrs().airspeed_vector_true(airspeed_vec_bf)) {
// we are running the EKF3 wind estimation code which can give
// us an airspeed estimate
return airspeed_vec_bf.length();
}
Awesome, at what rate do you think it should be published?
Here is the PR: https://github.com/ArduPilot/ardupilot/pull/28319
Awesome, at what rate do you think it should be published?
I publish it within the same velocity timer, if airspeed is available.
Airspeed for planes
The DDS interface does not provide the airspeed, which is an essential information for planes (subs?).
Solution
/ap/twist/filtered
topic, with a dedicatedframe_id = "airspeed"
.frame_id
empty for standard Inertial/BodyAlternative
/ap/airspeed/
topic of typestd_msgs/Float32
, as the timestamp might not be crucial.Platform [ ] All [ ] AntennaTracker [ ] Copter [ x ] Plane [ ] Rover [ ? ] Submarine