[GUI] [Err] [Conversions.cc:1198] Attempting to convert a NavSat SDF sensor, but the sensor pointer is null.

[ashBabu]

Ubuntu 22.04, ROS2 Humble, Gazebo Fortress. Installed everything from apt repos

I have a differential drive robot on to which I have added a navsat sensor. I launch the simulation with ros2 launch skidy_bringup bringup_sim.launch.py. As soon as press the play button in gazebo, the following error comes up although I am able to see the msg being published at the topic that I specified.

[GUI] [Err] [Conversions.cc:1198] Attempting to convert a NavSat SDF sensor, but the sensor pointer is null.

[azeey]

It looks like we are missing a msgs -> sdf conversion for NavSat in gz::sim::convert(const msgs::Sensor) . Interestingly, it was left as a TODO in the original PR #1248. @ashBabu would you be able to add the conversion similar to how

gz-sim/src/Conversions.cc

Lines 1084 to 1116 in f55212e

	else if (_in.Type() == sdf::SensorType::GPS ||
	_in.Type() == sdf::SensorType::NAVSAT)
	{
	if (_in.NavSatSensor())
	{
	auto sdfSensor = _in.NavSatSensor();
	// \TODO(chapulina) Update to navsat on Garden
	auto sensor = out.mutable_gps();
	if (sdfSensor->HorizontalPositionNoise().Type() != sdf::NoiseType::NONE)
	{
	sim::set(sensor->mutable_position()->mutable_horizontal_noise(),
	sdfSensor->HorizontalPositionNoise());
	}
	if (sdfSensor->VerticalPositionNoise().Type() != sdf::NoiseType::NONE)
	{
	sim::set(sensor->mutable_position()->mutable_vertical_noise(),
	sdfSensor->VerticalPositionNoise());
	}
	if (sdfSensor->HorizontalVelocityNoise().Type() != sdf::NoiseType::NONE)
	{
	sim::set(sensor->mutable_velocity()->mutable_horizontal_noise(),
	sdfSensor->HorizontalVelocityNoise());
	}
	if (sdfSensor->VerticalVelocityNoise().Type() != sdf::NoiseType::NONE)
	{
	sim::set(sensor->mutable_velocity()->mutable_vertical_noise(),
	sdfSensor->VerticalVelocityNoise());
	}
	}
	else

is done, but in the reverse direction in gz::sim::convert(const msgs::Sensor)

gz-sim/src/Conversions.cc

Line 1366 in f55212e

else if (out.Type() == sdf::SensorType::ALTIMETER)

[ashBabu]

Hi @azeey. I will try to update and create a PR asap

[ashBabu]

Hi @azeey : I did make a quick code edit as you can see here. However it doesnt solve the error but added another one

[GUI] [Err] [Conversions.cc:1198] Attempting to convert a NavSat SDF sensor, but the sensor pointer is null.
[Err] [Conversions.cc:1453] Attempting to convert an navsat sensor message, but the message does not have a navsat nested message.

Wondering if Im on the right track? Any pointers?

[ashBabu]

@azeey : Please ignore the above. I found out what I was doing wrong and a PR #2176 was made. Pls review it

[23pointsNorth]

I am attempting to use GPS/navsat sensor in Gazebo Garden, but I am hitting the same issues. Would the above PR make it in gz-sim7 or 8 as well?

[ashBabu]

@23pointsNorth : Although the error appears, the navsat sensor still publishes msgs. ign topic -e -t topic_name. If you want it in ROS, use the bridge

bridge = Node(
        package='ros_gz_bridge',
        executable='parameter_bridge',
        arguments=[
                   '/topic_name@sensor_msgs/msg/NavSatFix@ignition.msgs.NavSat',
                   ],
        output='screen'
    )

But to answer your question, someone from gazebo has to step in

[mjcarroll]

Closed by #2176

[23pointsNorth]

Is there a schedule on how quickly these changes will get propagated to published 6.x and 7.x?

[azeey]

Is there a schedule on how quickly these changes will get propagated to published 6.x and 7.x?

Generally, we wait for PRs that are close to getting in for the version/branch in question before making a release, but we can make a release sooner if necessary.