When switched into Follow, the vehicle will attempt to follow another vehicle (or anything publishing its position) at a specified offset. The vehicle lead vehicle’s position must be published to the vehicle in Follow mode using a telemetry system.
The altitude is maintained with the altitude hold controller so the vehicle will attempt to hold its current altitude when the sticks are placed with 10% of mid-throttle. It will climb or descend at up to 2.5m/s (this speed is adjustable with the PILOT_SPEED_UP and PILOT_SPEED_DN parameters). The acceleration used to establish these speeds is set by PILOT_ACCEL_Z.
The following parameters can be used to tune Follow Mode’s performance:
FOLL_ENABLE: set to 1 to enable follow mode and refresh parameters
FOLL_SYSID: MAVLink system id of lead vehicle (“0” means follow the first vehicle “seen”)
FOLL_DIST_MAX: if lead vehicle is more than this many meters away, give up on following and hold position
FOLL_OFS_TYPE: set to 0 if offsets are North-East-Down, 1 if offsets are relative to lead vehicle’s heading
FOLL_YAW_BEHAVE: controls whether follow points in the same direction as lead vehicle or always towards it
FOLL_ALT_TYPE: allows selecting whether to use lead vehicle’s relative-to-home or relative-to-sea-level altitude