What topic should I subscribe to know when the drone is in "hover state"?

Question

Basically, I'm trying to write a piece of code that waits for the drone to enter hover state and then take a picture from the drone's camera. I've manage to take the picture (by subscribing to ardrone/image_raw topic). I only need to know what topic should I subscribe so I can set up a subscriber and using a callback function I will be able to take pictures from the drone only when it is in hovering state.

Thank you in advance.

p.s: I use tum_ardrone and ardrone_autonomy to communicate with the drone. I've also created a package that uses some opencv code to take the picture from the drone's camera.

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Originally posted by Michael Panayiotou on ROS Answers with karma: 61 on 2015-01-24

Post score: 0

Answer 1

• ardrone/navdata topic. ======================

Information received from the drone will be published to the ardrone/navdata topic. The message type is ardrone_autonomy::Navdata and contains the following information:

• header: ROS message header
• batteryPercent: The remaining charge of the drone's battery (%)
• state: The Drone's current state: * 0: Unknown * 1: Inited * 2: Landed * 3,7: Flying * 4: Hovering * 5: Test (?) * 6: Taking off * 8: Landing * 9: Looping (?)
• rotX: Left/right tilt in degrees (rotation about the X axis)
• rotY: Forward/backward tilt in degrees (rotation about the Y axis)
• rotZ: Orientation in degrees (rotation about the Z axis)
• magX, magY, magZ: Magnetometer readings (AR-Drone 2.0 Only) (TBA: Convention)
• pressure: Pressure sensed by Drone's barometer (AR-Drone 2.0 Only) (Pa)
• temp : Temperature sensed by Drone's sensor (AR-Drone 2.0 Only) (TBA: Unit)
• wind_speed: Estimated wind speed (AR-Drone 2.0 Only) (TBA: Unit)
• wind_angle: Estimated wind angle (AR-Drone 2.0 Only) (TBA: Unit)
• wind_comp_angle: Estimated wind angle compensation (AR-Drone 2.0 Only) (TBA: Unit)
• altd: Estimated altitude (mm)
• motor1..4: Motor PWM values
• vx, vy, vz: Linear velocity (mm/s) [TBA: Convention]
• ax, ay, az: Linear acceleration (g) [TBA: Convention]
• tm: Timestamp of the data returned by the Drone returned as number of micro-seconds passed since Drone's boot-up.

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Originally posted by Michael Panayiotou with karma: 61 on 2015-03-08

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by yasser on 2016-02-10:
Hello what means TBA unit