Mavsdk: Adding DISTANCE_SENSOR and possibly other raw sensor messages.

[physicsman]

For offboard work I feel it would be useful to have access to the the raw sensor data. For example I am using Attitude+Lidar Rangefinder+Thermal Sensor to create a heat map during a survey.

Suggestions/Ideas:

A telemetry subclass ie telemetry.raw() that gathers sensor information and current readings available through mavlink. Also, IMO the sensor reading timestamp "time_boot_ms" (ex: https://mavlink.io/en/messages/common.html#DISTANCE_SENSOR) is especially useful from my perspective for sensor fusion and filtering to approximate vehicle state.

[irsdkv]

@JonasVautherin I think I can participate in part of implement receiving and handling DISTANCE_SENSOR message.
In which plugin this should implemented in your opinion?
In Telemetry (whenever it already large)?

[JonasVautherin]

Maybe in telemetry... I'm just wondering what happens when you don't have a distance sensor at all. What if you subscribe to that stream? You just get no event?

@julianoes: do you have an opinion?

[irsdkv]

You just get no event?

It seems that yes:
https://github.com/irsdkv/Firmware/blob/master/src/modules/mavlink/mavlink_messages.cpp#L4277

[JonasVautherin]

Ok! Let's put that in the telemetry plugin then! Thanks @irsdkv!

[physicsman]

I don't know the implementation however I think multiple distance sensor support will be coming for object avoidance (i.e. a face-forward and face-downward sensor).

[julianoes]

DISTANCE_SENSOR has been implemented in #1222.