The building of an autonomous robot that roams farm/forest tracks in Germany

Key Design Questions Going In

What sensors to be used to avoid collision with osbtacles on the path? Right now I focus on the pico flexx module from pmd.

Which battery type to use and how to power required microcontrollers, engines, sensors and telemetry? led or lipo is the question, charged from solar panel.

What to use for telemetry (e.g. if rover is stuck, if interaction with bypassers via speakerphone is needed, for condition monitoring or to give general directions to the rover)? GSM is probably the best initially.

What configuration of wheels, motors and steering to be used that is simple? Right now I'm thinking of 2 wheels with a gear driver motor with encoder for the front left and right and swiveling wheels for the back.

How to protect against water, beeing overrun and vandalism? Main cover will be the solar panel, underneath i will have to create a sturdy box that contains all electronics and sensors. I need to have a 50 cm flag sticking out in the back and white leds in the front, red ones in the back and green and red on the side blinking to make the device more visible to everyone. I plan to write "vogelzählung - bitte lärm vermeiden" on top. If people are approaching I would like to record in a closed circuit what they do to the machine in the cloud - if nothing happens the recording will be deleted.

October 12th, 2018: The pmd pico flexx seems to not provide enough range outdoors. If you look at https://pmdtec.com/picofamily/wp-content/uploads/2017/09/pmd_outdoor_performance_pico_family.png you will see, that the left and right side of a farm track will be hardly visible. Due to this I now consider using a 360 rotating lidar. I plan to tilt the lidar foward to allow to understand the profile of the ground in front of me. I also plan to use 2 mirrors to use the rear-facing 90° for another level of scanning further into the distance looking forward. This way I get 2 scans 5 times a second and If I get a distant line like this: ^^^\___/^^^and a closer line like this ^\_____/^ then I get a good impression of the how the track runs.