[WIP] add support for range finders via uavcan (for HEX flow module)

[DanielePettenuzzo]

On the HEX optical flow module (pmw3901) we receive flow and gyro data in the custom flow message while the distance sensor data comes in with the default range_sensor message. This pr adds support for the default range_sensor message.

I haven't tested this on hardware yet. Will do it some time this week.

Remaining issues:

• The max distance and min distance for the sensor is not available in the uavcan message. I haven't checked yet in the ekf but this could cause some issue. The message although has a reading_type field that looks like this:
  uint3 READING_TYPE_UNDEFINED = 0 # Range is unknown
  uint3 READING_TYPE_VALID_RANGE = 1 # Range field contains valid distance
  uint3 READING_TYPE_TOO_CLOSE = 2 # Range field contains min range for the sensor
  uint3 READING_TYPE_TOO_FAR = 3 # Range field contains max range for the sensor
  uint3 reading_type

I currently use this field to assign the signal_quality to -1 if unknown, 100 if valid range and 0 if too close or too far.

• uavcan sensor orientation is given in roll, pitch, yaw so for now since we will use this sensor for optical flow I hardcoded it to distance_sensor_s::ROTATION_DOWNWARD_FACING but we will have to add a conversion to be compatible with any uavcan rangefinder.

[DanielePettenuzzo]

FYI @dagar @RomanBapst

[dagar]

Can you rebase?

[stale]

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[dagar]

Still interested in this?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Thank you for your contributions.

[dagar]

UAVCAN range finder support came in separately.