Connecting the Drone to the Server

Connecting the drone

Connect to the server from the drone control app using websocket. See the example of a simple Python client script. The script reads a text file containing pre-recorded flight data (see the example file) and sends the data to the server. The procedure is to handshake with the server, where the server assigns a unique ID, which needs to be used in the following communication.

Handshake

• Send a JSON message with the following structure:

  {
     "type":"hello",
     "data":{
        "ctype":0,
        "drone_name":"MavicPro",
        "serial":"12345"
     }
  }

  where ctype is 0 for the drone, or 1 for the visualization client, drone_name is the type of the drone (e.g. MavicPro, Phantom, Matrice, etc.), and serial is the drone serial number (optional parameter).

• Receive a JSON message with the following structure:

  {
     "type":"hello_resp",
     "data":{
        "client_id":"41f28cb6",
        "rtmp_port":1935
     }
  }

  where client_id is an auto-generated unique 8-digit hex string, which the drone needs to use as its unique ID in the following communication, and rtmp_port is port to RTMP server. Drone should use RTMP URI address in following format for streaming media:

  rtmp://<host>[:<port>]/live/<client_id>
  

  where host is hostname or address of server. RTMP server port and client_id are received from hello response message.

Data broadcast

After the handshake, the drone can start broadcasting its flight data. The JSON message is expected to have the following structure:

{
   "type":"data_broadcast",
   "data":{
      "client_id":"41f28cb6",
      "altitude":234.6,
      "gps":{
         "latitude":49.24031521243185,
         "longitude":16.613207555321484
      },
      "aircraft_orientation":{
         "pitch":-4.0,
         "roll":-1.2,
         "yaw":81.2,
         "compass":81.2
      },
      "aircraft_velocity":{
         "velocity_x":0.1,
         "velocity_y":1.0,
         "velocity_z":0.1
      },
      "gimbal_orientation":{
         "pitch":0.0,
         "roll":0.0,
         "yaw":81.1,
         "yaw_relative":0.0
      },
      "timestamp":"2023-04-05 14:45:06.843",
      "frame":"$jpeg_string_encoded_to_base64"
   }
}

where the client_id needs to be the same ID assigned in the handshake phase. To visualize the drone in the DroCo client, the mandatory data are altitude, gps, and aircraft_orientation.