A sensor unit mountable on a rotatable element on a platform that is itself movable, and includes an orientation sensor arranged to take measurements that are dependent on the orientation of the sensor unit, a processor arranged to derive a rotational position signal representing the orientation of the rotatable element from the measurements, and a buffer arranged to buffer a series of recent measurements taken by the orientation sensor over a predetermined period of time. The processor derives the rotational position signal making a correction to compensate for the effect of the motion of the platform on the measurements on the basis of the overall series of measurements buffered in the buffer.

An attitude sensor system with automatic bias correction having a primary attitude sensor wherein the primary attitude sensor comprises at least one accelerometer and an auxiliary sensor system configured to automatically estimate a bias of the accelerometer of the primary attitude sensor such that the resulting error is removed from an output of the attitude sensor system.

An attitude sensor system with automatic bias correction having a primary attitude sensor wherein the primary attitude sensor comprises at least one accelerometer and an auxiliary sensor system configured to automatically estimate a bias of the accelerometer of the primary attitude sensor such that the resulting error is removed from an output of the attitude sensor system.

A roll sensor is configured to detect a first roll angle at a corresponding first point of a path plan of a vehicle, or its implement, based on the estimated current position. A roll sensor is configured to detect a second roll angle at a corresponding second point of a path plan of a vehicle, or its implement, based on the estimated current position. A data processor is configured to determine a roll angle delta or difference between the first roll angle and the second roll angle. If the roll angle delta is greater than a reference roll value, the roll angle delta is evaluated over an evaluation period. For example, if the roll angle is greater than the reference roll value for equal to or greater than a target percentage or target ratio for the evaluation period, the data processor is configured to designate the roll angle sensor for possible recalibration.

A roll sensor is configured to detect a first roll angle at a corresponding first point of a path plan of a vehicle, or its implement, based on the estimated current position. A roll sensor is configured to detect a second roll angle at a corresponding second point of a path plan of a vehicle, or its implement, based on the estimated current position. A data processor is configured to determine a roll angle delta or difference between the first roll angle and the second roll angle. If the roll angle delta is greater than a reference roll value, the roll angle delta is evaluated over an evaluation period. For example, if the roll angle is greater than the reference roll value for equal to or greater than a target percentage or target ratio for the evaluation period, the data processor is configured to designate the roll angle sensor for possible recalibration.

A posture control apparatus, comprising a control unit that determines, on a basis of a static acceleration component, a gravity direction in a holding apparatus holding an object to be held, the static acceleration component being computed on a basis of a first acceleration detection signal and a second acceleration detection signal, the first acceleration detection signal being acquired by detecting a dynamic acceleration component acting on the holding apparatus, the second acceleration detection signal being acquired by detecting the dynamic acceleration component and the static acceleration component acting on the holding apparatus, and controls, by controlling posture of the holding apparatus on a basis of the gravity direction, posture of the object to be held.

A posture control apparatus, comprising a control unit that determines, on a basis of a static acceleration component, a gravity direction in a holding apparatus holding an object to be held, the static acceleration component being computed on a basis of a first acceleration detection signal and a second acceleration detection signal, the first acceleration detection signal being acquired by detecting a dynamic acceleration component acting on the holding apparatus, the second acceleration detection signal being acquired by detecting the dynamic acceleration component and the static acceleration component acting on the holding apparatus, and controls, by controlling posture of the holding apparatus on a basis of the gravity direction, posture of the object to be held.

An agricultural distribution machine, such as a field sprayer or a pneumatic fertilizer spreader is described. The agricultural distribution machine includes a carrier vehicle and a distributor boom for spreading material, such as a fertilizer, a plant protection agent, or seed. The boom is indirectly or directly arranged on the carrier vehicle so as to be movable at least about a pivot axis running in the direction of travel. The boom has segments which are pivotable relative to one another about upright axes and/or in a plane arranged perpendicular to the direction of travel of the agricultural distribution machine. The boom includes an acceleration-compensated inclinometer apparatus for determining a rotational position of the distributor boom.

An agricultural distribution machine, such as a field sprayer or a pneumatic fertilizer spreader is described. The agricultural distribution machine includes a carrier vehicle and a distributor boom for spreading material, such as a fertilizer, a plant protection agent, or seed. The boom is indirectly or directly arranged on the carrier vehicle so as to be movable at least about a pivot axis running in the direction of travel. The boom has segments which are pivotable relative to one another about upright axes and/or in a plane arranged perpendicular to the direction of travel of the agricultural distribution machine. The boom includes an acceleration-compensated inclinometer apparatus for determining a rotational position of the distributor boom.

An attitude estimation apparatus includes an attitude estimation unit for estimating the roll angle and pitch angle of a movable body and for using a calculation process to estimate an offset error for at least one of first, second and third angular velocity detection units and first, second and third acceleration detection units. The attitude estimation unit estimates the roll angle and pitch angle of the movable body and the offset error for at least one detection unit based on detected values from the first, second and third angular velocity detection units, detected values from the first, second and third acceleration detection units, a detected value from the velocity information detection unit, an estimated value of the roll angle from a previous estimation operation, an estimated value of the pitch angle from the previous estimation operation, and an estimated value of the offset error from the previous estimation operation.