cometa-dronekit

Cloud API for drones and unmanned vehicles

Overview

Low-latency, secure cloud communication for connected UAVs and ROVs using the Cometa server. Cometa is a two-way message broker for device-to-cloud and cloud-to-device secure communication. It runs on a server in the cloud and it uses HTTPS and secure WebSockets for efficient remote interaction of applications and vehicles.

cometa-dronekit is a DroneKit script running on a UV that manages the connection to the Cometa server and exposes methods for JSON-RPC remote procedure calls to the vehicle. Applications use the JSON-RPC API documented below to interact with one or many connected UVs using HTTPS and to receive real-time telemetry on secure WebSockets.

This software relies on DroneKit and it runs natively on 3DR Solo drones and on any UV’s Companion Computer such as RPI, Odroid, Edison, and Volta's 4Gmetry.

If you are interested in receiving beta tester credentials and access to a Cometa cloud server for testing the cometa-dronekit API send an email to marco@cometarobotics.com

Dependencies

pip install dronekit
pip install dronekit-sitl
pip install http-parser
pip install pymavlink

Usage

cometa-dronekit is a stand-alone application. Configuration is in the config.json file.

./application.py

To run in the background, detach it from the terminal and re-direct output to a log file:

nohup python ./application.py > /tmp/dronekit.log 2>&1 &

Connecting to autopilot

DroneKit relies on a ArduPilot APM compatible stack and controller, such as the Pixhawk. The autopilot connection string for the cometa-dronekit script is specified in the config.json file. To use cometa-dronekit with DroneKit's embedded SITL, set the sitl parameter to true and use the appropriate connection string.

DroneKit connection strings options are documented in Connecting to a Vehicle

Cloud API

Once the cometa-dronekit application is started on the vehicle, it will connect to the Cometa server and the Application Key specified in the config.json file. This connection will be kept open permanently and used for full-duplex communication through the Cometa message broker. Since the connection is initiated from within a NAT or a firewall on stadard port 443, which is typically open for outgoing traffic, the vechicle becomes accessible from an application using the cometa-dronekit API without exposing or even knowing its public IP address.

An application sends JSON-RPC requests to a connected vehicle through the Cometa cloud server send method.

To use the Cometa API and the send method, an APPLICATION_KEY and a COMETA_SECRET are needed as credentials for authentication. Users of the Cometa Robotics cloud service can create applications and manage their vehicles in the cloud as well as develop applications using the API provided by cometa-dronekit.

Public availability of Cometa Robotics cloud service is planned for 1Q 2017. Send an email to marco@cometarobotics.com to request early access.

Cometa Authentication

An application is authenticated by including an Authorization HTTPS request header in every request.

HTTP HEADER	DESCRIPTION	VALUE
`Authorization`	authorization token	OAuth {`COMETA_SECRET`}

Example:

Authorization: OAuth b4f51e1e6125dca873e5

Send RPC Message

Send a JSON-RPC message to a vehicle.

POST /v1/applications/{APPLICATION_KEY}/devices/{DEVICE_ID}/send

The message containing the JSON-RPC request is in the POST body.

URL PARAMETER	DESCRIPTION	TYPE
`APPLICATION_KEY`	Cometa Application Key	String
`DEVICE_ID`	Device Cometa Id	String

The DEVICE_ID is the vehicle ID provided by cometa-dronekit when a vehicle is connected to a Cometa server. The default value is the vehicle's MAC address.

The cometa-dronekit vehicle agent always reply to a JSON-RPC message with a JSON response.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0", "method":"takeoff","params":{"alt":20.0},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{"jsonrpc": "2.0", "result": {"success": true}, "id": 7}

WebSockets Endpoint

The Cometa server exposes a WebSockets endpoint for each vehicle connected to it. A vehicle WebSocket can be opened only once. To obtain an endpoint, an application must request a new WebSockets DEVICE_KEY every time is needed using the following HTTPS method:

GET /applications/{APPLICATION_KEY}/devices/{DEVICE_ID}/websocket

URL PARAMETER	DESCRIPTION	TYPE
`APPLICATION_KEY`	Cometa Application Key	String
`DEVICE_ID`	Device Cometa Id	String

The method returns a DEVICE_KEY that is used to obtain the WebSocket vehicle's endpoint as follows:

wss://{COMETA_HOST}:{PORT}/websockets/{DEVICE_ID}/{DEVICE_KEY}

Example:

$ curl -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/websocket

{
    "device_id":"e984060007",
    "device_key":"dc670dae876ee4f919de9e777c9bd98a5e182cd8"
}

WebSocket endpoint (one-time use only):

wss://dronekit.cometa.io/v1/websockets/e984060007/dc670dae876ee4f919de9e777c9bd98a5e182cd8

Opening a device WebSocket would fail if the vehicle is not connected. Upon vehicle disconnection, the WebSocket is closed by the server after the inactivity timeout period. Immediately after opening a WebSocket, and without any other request, an application starts receiving telemetry messages at expiration of every period of the duration indicated in the config.json file.

On an open WebSocket an application receives both telemetry messages without requesting them, and responses to JSON-RPC requests.

WebSockets are asynchronous, full-duplex channels to exchange messages directly between an application and a remote vehicle running dronekit-cometa. A WebSocket send() is relaying the message to the vehicle the same way as an HTTPS send. From the vehicle's standpoint messages are received the same way regardless the method used by an application, that is using WebSockets send() or a Cometa HTTPS send. On an open WebSocket an application receives both telemetry messages without requesting them, and responses to JSON-RPC requests.

Before sending a message to a WebSocket an application should always check its readyState attribute to check the WebSocket connection is open and ready to communicate (readyState === WS_OPEN).

Connected Vehicles

Get a list of vehicle connected to the Cometa server.

GET /v1/applications/{APPLICATION_KEY}/devices

The message containing the JSON-RPC request is in the POST body.

URL PARAMETER	DESCRIPTION	TYPE
`APPLICATION_KEY`	Cometa Application Key	String

Example:

$ curl -H 'Authorization: OAuth b4f51e1e6125dcc873e9' -H 'Content-type: application/json' \
    http://dronekit.cometa.io/v1/applications/a0353b75b8fa61889d19/devices

{
    "num_devices": 11, 
    "devices": [
        "cc79cf45f1b4", 
        "cc79cf45f1d4", 
        "cc79cf45f421", 
        "cc79cf45f1ba", 
        "cc79cf45f400", 
        "cc79cf45f401", 
        "cc79cf45f2ab", 
        "cc79cf45f307", 
        "cc79cf45f221", 
        "cc79cf45f314", 
        "cc79cf45f2d8"
    ]
}

Cometa Vehicle Presence

Get vehicle connection state and statistics information from the Cometa server.

GET /v1/applications/{APPLICATION_KEY}/devices/{DEVICE_ID}

The message containing the JSON-RPC request is in the POST body.

URL PARAMETER	DESCRIPTION	TYPE
`APPLICATION_KEY`	Cometa Application Key	String
`DEVICE_ID`	Device Cometa Id	String

Example:

$ curl -H 'Authorization: OAuth b4f51e1e6125dcc873e9' -H 'Content-type: application/json' \
    http://dronekit.cometa.io/v1/applications/a0353b75b8fa61889d19/devices/e984060007

{
    "device_id": "e984060007", 
    "ip_address": "73.202.12.128:64471", 
    "heartbeat": "1478378638", 
    "info": "APM:Copter-3.3.0", 
    "connected_at": "1478373655", 
    "latency": "45", 
    "websockets": "1", 
    "net": {
        "received": {
            "bytes": "4237", 
            "messages": "12"
        }, 
        "sent": {
            "bytes": "34789", 
            "messages": "781"
        }
    }
}

Latency is in milliseconds and indicates the average time of a round-trip from the server to the vehicle (message/response). Latencies of less than 100 msec for a round-trip are typical for vehicles connected in the US.

Vehicle connections are maintained by a regular heartbeat message sent by cometa-dronekit to the server (60 seconds period). The Cometa server times out and disconnects a vehicle 90 seconds after receiving the last heartbeat message. A disconnected vehicle may appear to be connected for up to an additional 90 seconds, if it disconnect abruptly without cleanly close its socket connection.

Vehicle Attributes and Parameters

DroneKit exposes most state information (position, speed, etc.) through vehicle Attributes, while vehicle settings are in vehicle Parameters.

Vehicle parameters provide the information used to configure the autopilot for the vehicle-specific hardware/capabilities. The available parameters for each platform are documented in the ArduPilot wiki: Copter Parameters, Plane Parameters, Rover Parameters.

The JSON-RPC methods below allow applications to access and when allowed, set the Attributes and Parameters values.

List of vehicle Attributes and Parameters.

Get Veichle Attributes

vehicle_attributes

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"vehicle_attributes","params":{},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "airspeed": 0, 
        "gimbal": {
            "yaw": null, 
            "roll": null, 
            "pitch": null
        }, 
        "battery": {
            "current": 0, 
            "voltage": 12.587, 
            "level": 100
        }, 
        "ekf_ok": true, 
        "state": "STANDBY", 
        "armable": true, 
        "attitude": {
            "yaw": -0.41401541233062744, 
            "roll": -0.0011191728990525007, 
            "pitch": -0.0010953218443319201
        }, 
        "rangefinder": {
            "distance": null, 
            "voltage": null
        }, 
        "location": {
            "relative": {
                "lat": 37.423455, 
                "alt": 0.01, 
                "lon": -122.1763939
            }, 
            "global": {
                "lat": 37.423455, 
                "alt": 40, 
                "lon": -122.1763939
            }, 
            "local": {
                "down": null, 
                "east": null, 
                "north": null
            }
        }, 
        "groundspeed": 0, 
        "velocity": [
            0.01, 
            -0.02, 
            0
        ], 
        "mode": "STABILIZE", 
        "last_heartbeat": 0.3592782229970908, 
        "armed": false, 
        "heading": 336, 
        "gps": {
            "epv": 65535, 
            "fix_type": 3, 
            "eph": 121, 
            "satellites_visible": 10
        }
    }, 
    "id": 7
}

Set Veichle Attributes

set_attributes

Writable attributes are: armed, airspeed, groundspeed, and mode. The method allows for one or more name/value pairs to be set at a time.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"set_attributes","params":{"mode":"GUIDED","groundspeed":3.2},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Get Autopilot Attributes

autopilot_attributes

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"autopilot_attributes","params":{},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send
{
    "jsonrpc": "2.0", 
    "result": {
        "release": {
            "version": 0, 
            "type": "rc", 
            "stable": true
        }, 
        "firmware": {
            "major": 3, 
            "version": "APM:Copter-3.3.0", 
            "minor": 3, 
            "patch": 0
        }, 
        "capabilities": {
            "mission_float": true, 
            "ftp": false, 
            "command_int": false, 
            "param_float": true, 
            "set_actuator_target": false, 
            "param_union": false, 
            "terrain": true, 
            "set_attitude_target_local_ned": true, 
            "mission_int": false, 
            "set_attitude_target": false, 
            "set_altitude_target_global_int": true, 
            "compass_calibration": false, 
            "flight_termination": true
        }
    }, 
    "id": 7
}

Get Vehicle Parameters

vehicle_parameters

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"vehicle_parameters","params":{},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "RC7_REV": 1, 
        "GPS_INJECT_TO": 127, 
        ... 
            omitted total of 525 vehicle parameters
        ...
        "SIM_FLOW_DELAY": 0, 
        "BATT_CURR_PIN": 12
    }, 
    "id": 7
}

Set Vehicle Parameters

set_parameters

Set one vehicle parameter, using an object with a key and a value attribute. Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"set_parameters","params":{"key":"THR_MIN","value":100},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send
    
{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Telemetry Settings

Telemetry messages on a WebSockets start as soon as the vehicle WebSocket is open. The initial period in seconds is specified in the app_params object in the config.json file.

"app_params":{
    "debug":false,
    "telemetry_period":1
}

Attributes that are initially in the message by default are:

attitude
location
velocity
groundspeed
airspeed
battery
mode
armed
state

Example of telemetry message:

{
    'type': 1,
    'id': 'e984060007',    
    'time': 1478386938, 
    'battery': {
        'current': 0.0, 
        'voltage': 12.587, 
        'level': 100
    }, 
    'groundspeed': 0.0, 
    'state': 'STANDBY', 
    'airspeed': 0.0, 
    'attitude': {
        'yaw': -0.20035716891288757, 
        'roll': -0.006740430369973183, 
        'pitch': -0.0021510079968720675
    }, 
    'location': {
        'relative': {
            'lat': 37.423455, 
            'alt': 0.0, 
            'lon': -122.1763939
        }, 
        'global': {
            'lat': 37.423455,  
            'alt': 39.99, 
            'lon': -122.1763939
        }, 
        'local': {
            'down': None, 
            'east': None, 
            'north': None
        }
    },  
    'velocity': [0.02, -0.13, -0.01], 
    'armed': False, 
    'mode': 'STABILIZE'
}

Set Telemetry Attributes

set_telemetry_attributes

Set the attributes in the array passed as parameter to be included in the telemetry message. Attributes can be one of the following: 'attitude','location','velocity','groundspeed','airspeed','battery','mode','armed','state'

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"set_telemetry_attributes","params":["attitude","location"],"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send
    
{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

After receiving the method above, the telemetry message from the vehicle becomes as follows:

{
    'type': 1,
    'id': 'e984060007', 
    'time': 1478389239,
    'attitude': {
        'yaw': -0.4880271553993225, 
        'roll': 0.006115585565567017, 
        'pitch': 0.003535753581672907
    }, 
    'location': {
        'relative': {
            'lat': 37.423455, 
            'alt': 0.07, 
            'lon': -122.1763939
        }, 
        'global': {
            'lat': 37.423455, 
            'alt': 40.06, 
            'lon': -122.1763939
        }, 
        'local': {
            'down': None, 
            'east': None, 
            'north': None
        }
    }
}

Set Telemetry Period

set_telemetry_period

Set the period of telemetry messages in seconds.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"set_telemetry_period","params":{"period":5},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send
    
{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Home Location

The Home location is set when a vehicle first gets a good location fix from the GPS. The location is used as the target when the vehicle does a “return to launch”.

Get Home Location

home_location

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"home_location","params":{},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send
    
{
    "jsonrpc": "2.0", 
    "result": {
        "lat": 37.42345428466797, 
        "local_frame": null, 
        "alt": 39.9900016784668, 
        "global_frame": null, 
        "lon": -122.17639923095703
    }, 
    "id": 7
}

Set Home Location

set_home_location

Set the vehicle's home location to the specified global location object. The latitude and longitude are relative to the WGS84 coordinate system. The altitude in meters is relative to mean sea-level (MSL).

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"set_home_location","params":{"lat":-34.3,"lon":149.23,"alt":33},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Guiding and Controlling Vehicle

Methods to control vehicle movement and to fly/drive vehicles autonomously without a predefined a mission. They allow an application, for instance a Ground Control Station (GCS), to control the vehicle “on the fly” and react to new events or situations as they occur.

Takeoff

takeoff

Vehicle takes off to the specified altitude in meters.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"takeoff","params":{"alt":12.0},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Goto Position

goto

Move the vehicle to the specified position. The new position can be either in the absolute or relative to the home position, depending on the value of the 'relative' attribute.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"goto","params":{"lat":-32.2,"lon":149.2,"alt":3.0,"relative":false},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Goto Destination

goto_destination

Move the vehicle to the specified destination North and East of the current position. The North and East distances are in meter.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"goto_destination","params":{"dNorth":1.5,"dEast":29.3},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Goto Global Destination

goto_position_global_int

Set vehicle position, velocity and acceleration setpoint in the WGS84 coordinate system. This method sends a SET_POSITION_TARGET_GLOBAL_INT MAVLink message to the autopilot, which is used to directly specify the target location of the vehicle. As used in cometa-dronekit, this method is effectively the same as goto.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"goto_position_global_int","params":{"lat":-32.2,"lon":149.2,"alt":3.0},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Goto Local Destination

goto_position_local_ned

Goto the specified location in NED co-ordinates relative to the home location or the vehicle itself. This method sends a SET_POSITION_TARGET_LOCAL_NED MAVLink message to the autopilot, which is used to directly specify the target location in the North, East, Down frame. In the NED frame positive altitudes are entered as negative “Down” values. So if down is “10”, this will be 10 metres below the home altitude.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"goto_position_local_ned","params":{"north":1.5,"east":29.3,"down":-2},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Set Velocity Local Frame

send_ned_velocity

Controlling vehicle movement using velocity. This method sends a SET_POSITION_TARGET_LOCAL_NED MAVLink message to the autopilot, which is used to directly specify the speed components of the vehicle in the MAV_FRAME_LOCAL_NED frame (relative to home location).

From Copter 3.3 the vehicle will stop moving if a new message is not received in approximately 3 seconds. Prior to Copter 3.3 the message only needs to be sent once, and the velocity remains active until the next movement command is received.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"send_ned_velocity","params":{"velocity_x":1.5,"velocity_y":2.3,"velocity_z":0.2},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Set Velocity Global Frame

send_global_velocity

Controlling vehicle movement using velocity. This method sends a SET_POSITION_TARGET_GLOBAL_INT MAVLink message to the autopilot, which is used to directly specify the speed components of the vehicle in the NED frame.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"send_global_velocity","params":{"velocity_x":1.5,"velocity_y":2.3,"velocity_z":0.2},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Mission Control

DroneKit provides basic methods to download and clear the current mission commands from the vehicle, to add and upload new mission commands, and to start a mission. These methods allow applications to remotely create high-level mission planning functionality.

New Mission

new_mission

Reset the existing waypoints and start a new mission. This method must be called before setting any waypoint for a mission.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"new_mission","params":{},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Add Waypoint to Mission

add_mission_item

Add a mission item, such as a waypoint object to a mission. This method encodes an item command with 14 parameters in an array.

The mission item can be either in x, y, z meters (type: LOCAL), or x:lat, y:lon, z:alt. Local frame is Z-axis down, right handed (NED). Global frame is Z-axis up, right handed (ENU). See http://qgroundcontrol.org/mavlink/waypoint_protocol

Parameters:

target_system - This can be set to any value (DroneKit changes the value to the MAVLink ID of the connected vehicle before the command is sent).
target_component - The component id if the message is intended for a particular component within the target system (for example, the camera). Set to zero (broadcast) in most cases.
seq - The sequence number within the mission (the autopilot will reject messages sent out of sequence). This should be set to zero as the API will automatically set the correct value when uploading a mission.
frame - The frame of reference used for the location parameters (x, y, z). In most cases this will be mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, which uses the WGS84 global coordinate system for latitude and longitude, but sets altitude as relative to the home position in metres (home altitude = 0). For more information see http://ardupilot.org/planner/docs/common-mavlink-mission-command-messages-mav_cmd.html#frames-of-reference.
command- The specific mission command (e.g. mavutil.mavlink.MAV_CMD_NAV_WAYPOINT). The supported commands (and command parameters are listed on http://ardupilot.org/planner/docs/common-mavlink-mission-command-messages-mav_cmd.html.
current - Set to zero (not supported).
autocontinue - Set to zero (not supported).
param1 - Command specific parameter (depends on specific `Mission Command (MAV_CMD) http://planner.ardupilot.com/wiki/common-mavlink-mission-command-messages-mav_cmd.
param2 - Command specific parameter.
param3 - Command specific parameter.
param4 - Command specific parameter.
x - (param5) Command specific parameter used for latitude (if relevant to command).
y - (param6) Command specific parameter used for longitude (if relevant to command).
z (param7) Command specific parameter used for altitude (if relevant). The reference frame for altitude depends on the "frame".

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"add_mission_item","params":[0, 0, 0, 3, 22, 0, 0, 0, 0, 0, 0, 0, 0, 10],"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Start Mission

start_mission

Start current flight plan. Uploads all the commmands added with add_mission_items and set the vehicle mode to AUTO to start the mission.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"start_mission","params":{},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Streaming Video

The Cometa Robotics cloud service includes a video management platform to ingest, record and playback live and recorded video. It uses the open source ffmpeg streamer and the RTMP protocol to ingest video from vehicles. The ffmpeg streaming software must be available on the vehicle's Companion Computer.

Cloud video management is at the moment in private beta and some methods are not implemented in the available version of cometa-dronekit. However, the methods documented below are available for immediate use.

If you are interested in testing the video streaming API send an email to marco@cometarobotics.com

Set Vehicle Yaw

condition_yaw

Point the vehicle at a specific heading (in degrees) relative to the direction or as asbsolute value.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"condition_yaw","params":{"heading":353.0, "relative":false},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Point Camera to ROI

point_camera

Point the camera at the specified global position.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"point_camera","params":{"lat":34.1, "lon": -129.2, "alt": 3.0},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "success": true
    }, 
    "id": 7
}

Get Video Devices

video_devices

List connected V4L video devices.

Example:

$ curl -X POST -H 'Authorization: OAuth a724dc4811d507688' -H 'Content-type: application/json' \
    -d '{"jsonrpc":"2.0","method":"video_devices","params":{},"id":7}' \
    https://dronekit.cometa.io/v1/applications/a94660d971eca2879/devices/e984060007/send

{
    "jsonrpc": "2.0", 
    "result": {
        "names": [
            "Logitech, Inc. HD Pro Webcam C920", 
        ], 
        "devices": [
            "/dev/video0"
        ]
    }, 
    "id": 7
}

Name		Name	Last commit message	Last commit date
Latest commit History 32 Commits
postman		postman
.gitignore		.gitignore
LICENSE		LICENSE
README.md		README.md
application.py		application.py
cometalib.py		cometalib.py
config.json		config.json
runtime.py		runtime.py
utils.py		utils.py

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cometa/cometa-dronekit

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cometa-dronekit

Overview

Dependencies

Usage

Connecting to autopilot

Cloud API

Cometa Authentication

Send RPC Message

WebSockets Endpoint

Connected Vehicles

Cometa Vehicle Presence

Vehicle Attributes and Parameters

Get Veichle Attributes

Set Veichle Attributes

Get Autopilot Attributes

Get Vehicle Parameters

Set Vehicle Parameters

Telemetry Settings

Set Telemetry Attributes

Set Telemetry Period

Home Location

Get Home Location

Set Home Location

Guiding and Controlling Vehicle

Takeoff

Goto Position

Goto Destination

Goto Global Destination

Goto Local Destination

Set Velocity Local Frame

Set Velocity Global Frame

Mission Control

New Mission

Add Waypoint to Mission

Start Mission

Streaming Video

Set Vehicle Yaw

Point Camera to ROI

Get Video Devices

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