Standard messages for marine radars

Maritime Robotics
21

Update on creating a standard marine radar message

I have iterated over the format with your suggestions (Thanks all!) and collected new data. So far, everything is still working fine for my application.

Now that I finally learned how to write bag migration rules, I was able to add a few tweaks to the format and update my data.

With @lindzey and others work with related marine messages, I’d like to get radar messages ready to be added to the proper upcoming marine messages package.

So, here’s what I have so far: marine_sensor_msgs/msg at standard_proposal · rolker/marine_sensor_msgs · GitHub

I welcome your feedback!

22

Thanks to @peci1 for the great comments. I updated the format again and clarified some inline comments.

I’m hoping to soon have some example data to share with a few tools to help visualize it.

I welcome any further feedback!

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23

I haven’t checked the migration rules, but the new definitions look good to me!

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24

It might be better for community input to create a pull request from your branch against noetic so that it is easier to comment the changes.

25

I actually do have a pull request!

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26

Hi rolker, I am using this GitHub - rolker/halo_radar: ROS node to interact with Halo series marine radar. for Simrad halo Radar 20 in ROS-noetic as a publisher node. I am just wondering if there is any display type to visualize marine_sensor_msgs/RadarSector in rviz. Or we have to change the message type to available display types like PointCloud2.

27

Hi Hamza,

I use this node to convert to a point cloud for use with rviz: marine_radar_tracker/marine_radar_to_pointcloud.cpp at noetic · rolker/marine_radar_tracker · GitHub

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28

Thanks to all that have contributed so far.

To go along with the new naming conventions used for marine messages, A new pull request can now be found here: Add radar message and migration rules. by rolker · Pull Request #40 · apl-ocean-engineering/marine_msgs · GitHub

29

Hi rolker,
When compiling this repo marine_radar_tracker/marine_radar_to_pointcloud.cpp at noetic · rolker/marine_radar_tracker · GitHub I am facing the errors about echo. I have define LaserEcho msg in marine_sensor_msg in RadarSector but I think it’s not the right way. I also do not saw any echo msg in this node GitHub - rolker/halo_radar: ROS node to interact with Halo series marine radar..

30

Hi Hamza,

Sorry you got cought is some out-of-sync repos as I work on this message standardaization effor.

I’m in the process of updating repositories and documentation and will report back when I’m done and have clear instructions for you.

Roland

31

Yeah that would be great. Also I made a little changes in halo_radar.cpp file while debugging it for my radar because after running the node it constantly saying that “No radar found”, Now I am able to change the state from ‘standby’ to 'transmit’ and under rostopic echo /radar/HaloA/data, I am able to see the angle, range and intensities.

changes
changes950×633 68.3 KB

32

OK, I just updated the repos and added a bit of documentation.

Now, for the changes you had to make, it seems like the size of packet you are recieving differes from when I was expecting? I wonder if that’s caused by different firmware on the radar or something similar. Which model are you using?

33

Hi, thanks for the update. I am using Halo 20 simrad B&G (halo pulse compression radar).
Now after cloning the updated repos I got this new error.

error_9
error_91640×467 118 KB

Did you change the struct definition? I think in the RadarDisplay::radarCallback () is not calling the correct memeber or? I am not sure.

34

Looks like your camp package has not been updated. Is it up to date with the default (noetic) branch from GitHub - CCOMJHC/camp: Planning software for autonomous surface and underwater vehicles.?

35

Hi, Yes I have updated the repos and compiled it. Now I see under rostopic echo /radar/HaloA/data (echoes instead of angle range and intensities which was before the update) I don’t know why.

radar_viz
radar_viz2560×1440 500 KB

But yes now I can visualize the in rviz in dsplay option pointcloud. the changes I had to made was only in marine_radar_to_pointcloud.cpp. I have changed the name of the topic “/radar/HaloA/data”.
And also a ctrl+c keyboard interrupt :wink:

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36

Hi Roland, I am helping a colleague out with a Marine Radar (Simrad HALO3004 and HALO24) and wondered if you could direct me to something that helps explain what these marine radars are doing to the data internally before spitting out spoke data. Although they use pulse compression and have a range resolution, I think, of 15m, the radar’s output is “pixelised” and so it seems to lose this resolution for targets? I was suggesting they get raw data out from the radar but that may not be possible. Thanks Len

37

Roland will know for sure, but I think these radar systems output 512 data points per spoke without regard to the range setting.

So if your range setting is 500 m, you get about one point per meter, 5000 m range setting gives one point per 10 m, etc. It is not clear exactly if the radar itself changes its transmit signal with range setting, but it is clear that small contacts can easily be aliased when the range setting is large. We use the dual-range capability of our Halo20+ and operate a short range and a long range radar to compensate.

-Val

38

These radars are not high end gear, I’ve heard them referred to as “fishing radars”.

From memory HALO24 spoke data has a 4bit resolution and Doppler was binary. Quite disappointing. I never looked inside the radar but am curious if it’s a FPGA doing the conversions or an embedded machine running some flavour of linux.