Follow took the present distance to the lead vehicle as its offset
What ArduPilot says:
- Relative follow offset loaded
- N-E-D follow offset loaded
Follow keeps the aircraft at a fixed offset from a lead vehicle: FOLL_OFS_X, FOLL_OFS_Y and FOLL_OFS_Z, in metres. All three were 0, so ArduPilot took the separation at this moment as the offset: the aircraft will hold the place it now has relative to the lead. “Relative follow offset loaded”: FOLL_OFS_TYPE is 1, so the offset turns with the lead's heading (in 4.6 that heading must be known). “N-E-D follow offset loaded”: the offset is fixed to north, east and down, and FOLL_OFS_TYPE has been set to 0 to match.
To follow at a distance you choose, set FOLL_OFS_X, FOLL_OFS_Y and FOLL_OFS_Z yourself; this line then does not appear. On a copter, offsets taken this way are put back to 0 when Follow mode is left.
Parameters to look at
| Parameter | What it is |
|---|---|
FOLL_OFS_X | Follow offsets in meters north/forward |
FOLL_OFS_Y | Follow offsets in meters east/right |
FOLL_OFS_Z | Follow offsets in meters down |
FOLL_OFS_TYPE | Follow offset type |
FOLL_ENABLE | Follow enable/disable |
The code that sends it
Relative follow offset loaded
libraries/AP_Follow/AP_Follow.cpp AP_Follow::init_offsets_if_required() · Open in ArduPilot Copter-4.7.1
N-E-D follow offset loaded
libraries/AP_Follow/AP_Follow.cpp AP_Follow::init_offsets_if_required() · Open in ArduPilot Copter-4.7.1