Unable to listen to ATTITUDE_QUATERNION attribute

[zealtv]

I'm running a Navio 2 board on a Pi 3 with a simple script listening to telemetry, formatting it and forwarding it as Open Sound Control. I have been struggling for the past week to get access to the ATTITUDE_QUATERNION message. Relevant code below:

#@vehicle.on_message('ATTITUDE_QUATERNION')  #<- NOT WORKING. 
#but:
@vehicle.on_message('*')
def listener(self, name, message):
    print(message.name)

Printing all messages returns the following:
RAW_IMU SCALED_IMU2 SCALED_PRESSURE SYS_STATUS POWER_STATUS MEMINFO MISSION_CURRENT NAV_CONTROLLER_OUTPUT SERVO_OUTPUT_RAW RC_CHANNELS_RAW RC_CHANNELS AHRS HWSTATUS SYSTEM_TIME EKF_STATUS_REPORT VIBRATION GLOBAL_POSITION_INT ATTITUDE AHRS2 AHRS3 VFR_HUD

I have tried updating pymavlink bindings as suggested in this related issue (#747)

cd
git clone https://github.com/mavlink/mavlink.git
git clone https://github.com/ArduPilot/pymavlink.git
cd ~/pymavlink
sudo MDEF=$HOME/mavlink/message_definitions pip install . -v
sudo MDEF=$HOME/mavlink/message_definitions python setup.py build install --user --force

then testing with mavproxy seems to show ATTITUDE_QUATERNION is not present...

pi@navio:~ $ mavproxy.py --master=udpin:127.0.0.1:14550
Connect udpin:127.0.0.1:14550 source_system=255
Failed to load module: No module named adsb. Use 'set moddebug 3' in the MAVProxy console to enable traceback
Log Directory:
Telemetry log: mav.tlog
Waiting for heartbeat from 127.0.0.1:14550
 MAV> GPS lock at 3 meters
fence breach
online system 1
STABILIZE> Mode STABILIZE
APM: APM:Copter V3.5.7 (b11c6af3)
APM: Frame: QUAD
Received 763 parameters
Saved 763 parameters to mav.parm
status ATTITUDE
STABILIZE> 473: ATTITUDE {time_boot_ms : 1434220, roll : -0.0131699889898, pitch : -0.00505013763905, yaw : -0.161463707685, rollspeed : -0.00045908355969, pitchspeed : -0.00226206961088, yawspeed : 0.000840358843561}
status ATTITUDE_QUATERNION
STABILIZE>

I can see the quaternion in MAVROS so I'm pretty sure dronekit/pymavlink is where the issue is.
I'm at a loss! Wondering if this is replicable and if anyone can suggest what might be going on.

[phildunphytoo]

Hi, I was able to make it work:
First, you need to request the ATTITUDE_QUATERNION data:

msg = vehicle.message_factory.command_long_encode(
        0,          # target_system
        0,          # target_component
        511,        # command MAV_CMD_SET_MESSAGE_INTERVAL
        0,          # confirmation
        31,         # desired MAVLink message’s id - 31 = ATTITUDE_QUATERNION
        100000,     # time interval between messages in microseconds
        0,0,0,0,0)  # param 3-7 not used

vehicle.send_mavlink(msg)

Then you can listen to it normally:

@vehicle.on_message("ATTITUDE_QUATERNION")
def on_message(self, name, message):
    print(message)