code: def trk50(msg):
      
      d = hex2bin(data(msg))
  
      if d[11] == '0':
          return None
  
      sign = int(d[12])   # 1 -> west
      value = bin2int(d[13:23])
  
      if sign:
          value = value - 1024
  
      trk = value * 90.0 / 512.0
  
      # convert from [-180, 180] to [0, 360]
      if trk < 0:
          trk = 360 + trk
  
      return round(trk, 3)
docs: True track angle, BDS 5,0 message
  
      Args:
          msg (String): 28 bytes hexadecimal message (BDS50) string
  
      Returns:
          float: angle in degrees to true north (from 0 to 360)