Why the navdata topic doesnt show Linear z velocity in ardrone_autonomy?
Hi there, I am working with the ardrone_autonomy package, and all seems right, except for the detail that when I echo the /ardrone/navdata topic, all the values seem ok except the Vz, linear Z velocity value. Here is an example of what im getting:
batteryPercent: 18.0
state: 2
magX: -31
magY: -73
magZ: 51
pressure: 75088
temp: 403
wind_speed: 0.0
wind_angle: 45.0000190735
wind_comp_angle: -0.0
rotX: -4.86100006104
rotY: 0.421000003815
rotZ: 4.75699996948
altd: 0
vx: 56.8887748718
vy: 83.2262802124
vz: -0.0
ax: -0.0310622174293
ay: -0.0128604527563
az: 1.00342142582
As you can see, Vz displays 0, and it is constant all the time. I think i saw a person with the same problem, but i couldnt find the web or question again. I hope someone can help me.
Thanks
It shows your altitude as 0. Was the drone flying when you captured this?
No, for the picture it wasnt flying. But i have tried also when the drone is flying, and the altitude shows the correct value, bit the linear z velocity, dont
You can try checking out the source code to track down the issue, or you can differentiate the altitude data to get Vz.
From my own experience with the AR.Drone 2.0, it never publishes data about vertical velocity (vz). I'm guessing here, but it may because it estimates its speed using the vertical camera and to estimate it's vz then it would have to the size of the objects on the ground which it can't.