navsat_transform_node not broadcasting UTM to map transform anymore after GPS signal is lost

Hi,

We're working with an AUV and once we've got a GPS fix and the UTM to map transform, we dive and we'd like that transform to still be broadcasted during the dive. This doesn't seem to be the case. Is there a reason for it? And if so, is there a workaround to get this behavior on our setup?

We're running on Ubuntu 18.04.

Thanks

Asked by ignaciotb on 2020-11-12 06:17:45 UTC

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Answers

The transform is published via a static transform broadcaster:

https://github.com/cra-ros-pkg/robot_localization/blob/2a03b084de1b709c9d068e28317d37c356e5ea77/include/robot_localization/navsat_transform.h#L352

https://github.com/cra-ros-pkg/robot_localization/blob/2a03b084de1b709c9d068e28317d37c356e5ea77/src/navsat_transform.cpp#L332

If you wan to confirm, do a rostopic echo /tf_static and look for the transform in question.

Are you sure you have the parameters set correctly to broadcast it? What version are you using?

Asked by Tom Moore on 2020-11-13 06:16:51 UTC

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Hi Tom, thanks for the quick response. We're looking into the rosbags now that we're back from the test. I'll let you know what we find out. I've been looking into our setup (https://github.com/smarc-project/smarc_navigation/blob/noetic-devel/sam_dead_reckoning/launch/dual_ekf_test.launch) and it seems things should have worked out, so it might be an error somewhere else in the system.

Asked by ignaciotb on 2020-11-16 09:48:34 UTC

Just a heads-up that if you are working from bags, recording tf_static can be a problem. I seem to recall that, during playback, only the last node to publish on tf_static will be respected. Or something like that. Look at the raw tf_static publications in your bag and go from there.

Asked by Tom Moore on 2020-11-23 08:41:16 UTC