I am part of a team of engineering students who are new to drones. We have been tasked with building a hexacopter survey drone and are going to be using the Pixhawk 4 with obstacle avoidance using MB1242 I2CXL-MaxSonar-EZ4. We want to use mission planner so that we can tell the drone to take photos to use in photogrammetry and also geotag the photos. Since we are inexperienced, we have a few questions.
We understand that we can set up basic flight functions with the PX4 software that would be installed on the Pixhawk 4. In order to use mission planner, do we have to upload it to the Pixhawk 4, or do we need to only have it installed on a computer?
Is it required to use a companion computer to have simple collision prevention when using the MB1242 plugged directly into the Pixhawk 4?
If there is a planned mission and an obstacle is detected, will the drone know to go around the obstacle?