Error from send_mavlink() function when simulating the mavlink ADSB_VEHICLE ( #246 ) message

[C. Wayne Wright]

I'm attempting to generate a simulated ADSB traffic message which I'm hoping to display

on the Qgroundcontrol and MIssionPlanner GCS programs.  I have a Copter SITL

vehicle, and I have two QGCs connected an a MissionPlanner all via UDP and

mavlink-router to connect them.  

I'm getting a strange error message from send_mavlink() when I send it a 

packet encoded with message_factory_encode.  The entire output from the test program 

is below ending with the error message.  

Any help or guidance on what the problem is appreciated.

W. Wright

wright@wright-VirtualBox:~/sitl$ python dk-sim-adsb-traffic.py 

('Attempting to connecting to:%s', 'udp:192.168.66.152:14573')

Connected

LocationGlobal:lat=27.6427039,lon=-82.5583236,alt=34.35

ADSB_VEHICLE {ICAO_address : 1, lat : 276427011.0, lon : -8255832930.0, altitude_type : 0, altitude : 30000.0, heading : 0, hor_velocity : 0, ver_velocity : 0, callsign : Leader, emitter_type : 14, tslc : 1, flags : 33215, squawk : 640}

Traceback (most recent call last):

  File "dk-sim-adsb-traffic.py", line 28, in <module>

    v.send_mavlink( adsb_msg )

  File "/home/wright/.local/lib/python2.7/site-packages/dronekit/__init__.py", line 2215, in send_mavlink

    self._master.mav.send(message)

  File "/home/wright/.local/lib/python2.7/site-packages/dronekit/mavlink.py", line 146, in newsendfn

    return sendfn(mavmsg, *args, **kwargs)

  File "/home/wright/.local/lib/python2.7/site-packages/pymavlink/dialects/v10/ardupilotmega.py", line 11894, in send

    buf = mavmsg.pack(self, force_mavlink1=force_mavlink1)

  File "/home/wright/.local/lib/python2.7/site-packages/pymavlink/dialects/v10/ardupilotmega.py", line 11339, in pack

    return MAVLink_message.pack(self, mav, 184, struct.pack('<IiiiHHhHHB9sBB', self.ICAO_address, self.lat, self.lon, self.altitude, self.heading, self.hor_velocity, self.ver_velocity, self.flags, self.squawk, self.altitude_type, self.callsign, self.emitter_type, self.tslc), force_mavlink1=force_mavlink1)

struct.error: 'i' format requires -2147483648 <= number <= 2147483647

wright@wright-VirtualBox:~/sitl$ 

The Python 2. test program source code is here:

# Python 2.7
# W. Wright lidar532(AT)gmail.com
# Example Dronekit python to generate a simulated ADSB message.


import dronekit as dk
from time import sleep


v_UDP = 'udp:192.168.66.152:14573'              # Simulated Quad.
print('Attempting to connecting to:%s', v_UDP)
v  = dk.connect( v_UDP, wait_ready = True )
print( 'Connected' )


print( v.location.global_frame )


aflags  = 1+2+4+8+0x10+0x20+0x80+0x100+0x8000           # See flags at https://uavionix.com/downloads/integration/uAvionix%20Ping%20Integration%20Guide.pdf
icao    = 0xA01234
ads_lat =  27.6427011
ads_lon = -82.5583293
ads_alt = 30.0
squawk  = 0o1200
callsign = 'Leader'


# Generate ADSB packet
adsb_msg = v.message_factory.adsb_vehicle_encode(1,ads_lat*1e7,ads_lon*10e7,0,ads_alt*1e3,  0,0,0,'Leader',14,  1, aflags, 01200 )
print(adsb_msg)


# Transmit.   Intended ito be received by ground stations
v.send_mavlink( adsb_msg )

[C. Wayne Wright]

I managed to figure this one out.   I had accidentally multiplied ads_lon by 10e7 instead of 1e7 thus overflowing the packed 32 bit integer space reserved for it.  

It is interesting that it passed the “message factory” with the bug, but not the send_mavlink.

W.  Wright

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