AIS (for boats)

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Rover supports Automatic identification system (AIS) sensors allowing the position of manned boats to be displayed on the ground station

Note

Support for this peripheral is also available for Planes and Copters using the Custom Firmware Build Server , by creating a firmware build including this feature listed under the IDENT category.

What to Buy

AutoPilot connection

The dAISy2 should be connected to one of the autopilot’s serial ports as shown below

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Autopilot Configuration

Connect to the autopilot with a ground station and set these parameters and then reboot the autopilot

  • AIS_TYPE = 1 (NMEA AIVDM message)

  • SERIAL1_PROTOCOL = 40 (AIS) if the sensor is connected to serial port 1. If another serial port is used please set the appropriate SERIALx_PROTOCOL parameter

  • SERIAL1_BAUD = 38 (38400 bps) if using serial port 1. If another serial port is used please set the appropriate SERIALx_BAUD parameter instead

  • MAV1_ADSB = 5 to enable sending AIS mavlink messages to the ground station over Serial0 (the USB port). If a telemetry radio is used the MAVx_ADSB param corresponding to its stream should also be set to 5(Hz).(Streams are numbered from first in order of Serial ports configured for MAVLink, MAV1 the first, MAV2 the second, etc.)

dAISy2 Configuration and Testing

  • Connect dAISy2 to your PC using a USB cable

  • Download, install and run a terminal program such as Putty

  • Connect to the dAISy2’s COM port at 38400 baud and press <ESC> to view the setup menu

  • Type “3” to enable the serial port. “38400 8N1 serial output (NMEA HS w/ adapter)” should be displayed

  • Type “#” to save this change and retain this baudrate on boot

  • Type “T” to enable entering a test NMEA message and then copy-paste this message, “!AIVDM,1,1,,A,3815;hUw00wfUdHMPfQ4s8WT0D`r,0*00”, or hit “Enter” and use the default location

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  • Connect to the autopilot with Mission Planner (or another ground station) and a boat should appear on the South West coast of England

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  • press <ESC> to stop sending test messages

Avoidance

When path-planning based object avoidance is enabled, AIS vessel positions are automatically pushed into the Object Avoidance Database so that the vehicle can plan routes around them.

The database and path planning then operate as they would with any other obstacle source (lidar, proximity sensor, etc.). However, as AIS messages are sent infrequently a much larger OA_DB_EXPIRE value is needed so the database does not forget about a vessel in between AIS messages being received. A value of at least 600 seconds should be used (10 mins).

If the AIS message includes valid vessel dimensions (bow, stern, port, starboard distances from the transponder), ArduPilot computes the obstacle radius from those dimensions. If no valid dimensions are available, the database uses its configured OA_DB_BEAM_WIDTH for the obstacle size.

Logging

The AIS_OPTIONS parameter specifies which AIS messages are logged. These messages are useful for debugging purposes and contain the following information

  • TimeUS : System time that the AIS message was received

  • Num : Number of fragments in the currently accumulating message

  • Total : Fragment number of this sentence

  • ID : Sequential message ID for multi-sentence messages

  • Payload : Data payload

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