There is a Lidar that can be applied to detect height over ground. The Benewake TF03 is able to measure up to 180m (590ft). This can be used for height advisory like a radio altimeter but also as gear reminder.
The protocole can be CAN or UART. It says that the device serial port rate can be customized as also the format, Format: Output format configured in the TF03. 0x01 (standard data format output), 0x02 ( Pixhawk data format output ).
I don?t know how difficult would be to implement this on the AFS5600 but I guess it would be great to have the function. The equipment seams to be flexible on the output.