A method for determining a declination of an object (102a, 102b, 102c), the method comprising the steps of: pivoting a gyroscope (101a, 101b, 101c), which gyroscope (101a, 101b, 101c) is mounted to the object (102a, 102b, 102c), at a pivoting angular velocity (ω car-ousel) about a swivel axis (4, 7, 9); measuring an undetermined pivoting of the object (102a, 102b, 102c) about an axis with the gyroscope (101a, 101b, 101c), wherein the axis is different from the swivel axis (4, 7, 9); determining a component of the rotation of the Earth acting on the gyroscope (101a, 101b, 101c) using the undetermined pivoting, and the pivoting angular velocity (ω carousel); and determining the declination of the object (102a, 102b, 102c) with respect to true north from the component of the rotation of the Earth acting on the gyroscope (101a, 101b, 101c); wherein the object is a vehicle or a part of a vehicle (102a, 102b, 102c), which vehicle comprises a first vehicle part and a second vehicle part; wherein the first vehicle part is pivotable about the swivel axis (4, 7, 9) relative to the second vehicle part; wherein the gyroscope (101a, 101b, 101c) is mechanically mounted to the first vehicle part; and the method being characterised by further comprising the step of: determining the pivoting angular velocity (ω carousel) of the gyroscope (101a, 101b, 101c) about the swivel axis (4, 7, 9) with a second sensor, which second sensor (103a, 103b, 103c) is distinct from the gyroscope (101a, 101b, 101c) and capable of providing a measurement of the pivoting angular velocity (ω carousel) that is not affected by Earth rate, wherein the vehicle comprises a manipulator arm, wherein the first vehicle part is a first arm section of the manipulator arm, and wherein the second vehicle part is a second arm section of the manipulator arm or the second vehicle part is a frame or a body of the vehicle. pivoting a gyroscope (101a, 101b, 101c), which gyroscope (101a, 101b, 101c) is mounted to the object (102a, 102b, 102c), at a pivoting angular velocity (ω car-ousel) about a swivel axis (4, 7, 9); measuring an undetermined pivoting of the object (102a, 102b, 102c) about an axis with the gyroscope (101a, 101b, 101c), wherein the axis is different from the swivel axis (4, 7, 9); determining a component of the rotation of the Earth acting on the gyroscope (101a, 101b, 101c) using the undetermined pivoting, and the pivoting angular velocity (ω carousel); and the undetermined pivoting, and the pivoting angular velocity (ω carousel); and determining the declination of the object (102a, 102b, 102c) with respect to true north from the component of the rotation of the Earth acting on the gyroscope (101a, 101b, 101c); wherein the object is a vehicle or a part of a vehicle (102a, 102b, 102c), which vehicle comprises a first vehicle part and a second vehicle part; wherein the first vehicle part is pivotable about the swivel axis (4, 7, 9) relative to the second vehicle part; wherein the gyroscope (101a, 101b, 101c) is mechanically mounted to the first vehicle part; and the method being characterised by further comprising the step of: determining the pivoting angular velocity (ω carousel) of the gyroscope (101a, 101b, 101c) about the swivel axis (4, 7, 9) with a second sensor, which second sensor (103a, 103b, 103c) is distinct from the gyroscope (101a, 101b, 101c) and capable of providing a measurement of the pivoting angular velocity (ω carousel) that is not affected by Earth rate, wherein the vehicle comprises a manipulator arm, wherein the first vehicle part is a first arm section of the manipulator arm, and wherein the second vehicle part is a second arm section of the manipulator arm or the second vehicle part is a frame or a body of the vehicle.