Uses VIO tracking camera such as the Intel RealSense T265 used with ROS to facilitate non-GPS flight.
Connect to the autopilot with a ground station (i.e. Mission Planner) and check that the following parameters are set: For ArduPilot-4.1 (and later):
- AHRS_EKF_TYPE = 3 (EKF3)
- EK2_ENABLE = 0 (disabled)
- EK3_ENABLE = 1 (enabled)
- EK3_SRC1_POSXY = 6 (ExternalNav)
- EK3_SRC1_VELXY = 6 (ExternalNav)
- EK3_SRC1_POSZ = 1 (Baro which is safer because of the camera’s weakness to high vibrations)
- EK3_SRC1_VELZ = 6 (ExternalNav)
- GPS_TYPE = 0 to disable the GPS
- VISO_TYPE = 2 (IntelT265)
If you wish to use the camera’s heading:
COMPASS_USE = 0, COMPASS_USE2 = 0, COMPASS_USE3 = 0 to disable all compasses EK3_SRC1_YAW = 6 (ExternalNav)
There are 3 ROS nodes running in this setup: realsense-ros, mavros and vision_to_mavros. Launch in 3 separated terminals on:
- realsense-ros node: roslaunch realsense2_camera rs_t265.launch. The topic /camera/odom/sample/ and /tf should be published at 200Hz.
- mavros node: roslaunch mavros apm.launch (with fcu_url and other parameters in apm.launch modified to your setup). rostopic echo /mavros/state should show that FCU is connected. rostopic echo /mavros/vision_pose/pose is not published.
- vision_to_mavros node: roslaunch vision_to_mavros t265_tf_to_mavros.launch rostopic echo /mavros/vision_pose/pose should now show pose data from the T265. rostopic hz /mavros/vision_pose/pose should show that the topic is being published at 30Hz.
