global_position.cpp plugin

[TSC21]

Creating this plugin has a reason: gps.cpp gives us GPS_RAW_INT handle, which is the global position, as returned by the Global Positioning System, which means, a RAW sensor value.

For getting the filtered global position, we need to read the GLOBAL_POSITION_INT, which is fused with IMU sensor data onboard the FCU. This can be useful to add some features regarding global<->local conversions.

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What do you think of this? It's feasable?

[vooon]

Yeah, but need find standard messages for this.

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Probably sensor_msgs/NavSatFix.msg for lat/lon/alt, sensor_msgs/MagneticField.msg for compass and geometry_msgs/Vector3Stamped.msg to GPS velocities.

Still in doubt relative to the relative altitude (maybe a custom stamped message with a float64 rel_alt field needs to be created - mavros/global_position/rel_alt). But probably it's not the best way. Maybe it can be thrown away in this case, since we have the barometer (or sonar) measures.

To convert to local coordinates, LOCAL_POSITION_NED_SYSTEM_GLOBAL_OFFSET should be considered. A origin should be take in account in this case, I think. Don't know if it's active but there's SET_GPS_GLOBAL_ORIGIN to do that job.

@LorenzMeier I'm calling you also to this topic so you can please clarify and give your opinion in what should be done in this case if we want to do a conversion from GPS to local coordinates. Thanks!

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Found what can be used to convert into a pose (GPS to UTM): http://wiki.ros.org/gps_common?distro=hydro

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I already started to develop this! I will let you know when I am to finish it out. Probably going to need some help in one or two particular cases.

[vooon]

Reopen: plugin not complete.

[TSC21]

I think as is, it can be closed ;) Next thing to do should be add the possibility to handle GLOBAL_POSITION_INT_COV.