obstacle avoidance with Ardurover + AIS

ArduRover
1

Hello everyone,

I am currently working on Ardurover 4.6.0.
I have successfully connected a Class B AIS to my surface boat, and it works. I can see all the ships around me.
To do this, I connected my AIS to my Raspberry Pi, which is connected to my Pixhawk. Then, I created a script to convert the NMEA data sent by the AIS into MAVLink AIS_VESSEL messages. The goal is to display the other AIS signals received on Mission Planner.
I’m wondering if anyone has already set up an AIS-based collision avoidance system with Rover, using a companion computer to steer the vehicle away from AIS targets in AUTO or GUIDED mode ?

Thanks in advance for your help!

2

AIS does feed into the avoidance database, so it should all work. However, the AIS lib will not receive MAVLink messages, currently if only supports native NMEA 0183.

3

Hi All.

I’m also busy testing AIS avoidance using a rover SITL sim and a live AIS feed.

I have data coming through and appearing on the map. This will be used in an electric surface vehicle. I’m struggling with getting avoidance working properly.

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This is me playing in the harbor with SITL and a live feed, running straight through another vessel…
Any suggestions for params that would suite this use case?

Working towards open ocean avoidance.

Thanks

4

What version are you using and how have you set it up?

5

Hi Pete

I’m running ArduPilot-4.6.0-beta1 for testing.

I have a live AIS receiver in the lab that I forward to SITL using socat.

Params I’ve been fiddling with:

AIS_TYPE 1
MAV1_ADSB 5
SERIAL5_PROTOCOL 40
SERIAL5_BAUD 38
FRAME_CLASS 2
AVOID_ENABLE 7
OA_TYPE 1
OA_BR_LOOKAHEAD 100
OA_MARGIN_MAX 50
OA_DB_OUTPUT 3
ADSB_LIST_MAX 50

also

module load ais
ais set timeout 600
ais set threat_radius 200
adsb set threat_radius 500
adsb set timeout 600
adsb set threat_radius 500

I’m new to Ardupilot, the sheer volume of parameters is a bit overwhelming, navigating waypoints in the harbour in SITL was a big win for me…

6

For AIS avoidance you will need at least 4.7.0, were on beta 7 currently.

Params look mostly OK. For the avoidance data base I would also set:

OA_DB_EXPIRE to 500 +. AIS (particularly for anchored vessel) has quite slow update rates so you need the large timeout to make sure we don’t forget about a vessel too soon.

ADSB_LIST_MAX and AVOID_ENABLE are not needed.

7

Brilliant thanks Pete! A few niggles with missing some targets, and some param massaging needed, but we’re avoiding ships!

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