If IMU is on cab it will compensate for cab and tractor tilt, error from cab suspension is measured from antenna to cab tilt plane. If tilt plane is half distance from ground error will be 1/2 if tractor is level but cab is at an angle.
Potential problem is AOG thinks that whole tractor is at 10deg tilt so it will compensate ~52cm for 10deg on 3m height of antenna, this will over compensate ~26cm to other side of line.
(Lower cab tilt plane is IMU will work better down to ground where error will be 0).
IMU on chassis will read 0 deg tilt and with antenna on cab with 10deg roll and 1.5m height to tilt plane error will be ~26cm.
No IMU error will be ~26cm.
Theoretically there is no difference in error in this example but in reality cabs will be on different heights, suspensions, there will be combination of tractor/chassis tilit with cab tilt and other factors.
