Device and method for detecting the relative position of a rotatable body

An apparatus for detecting the angular position of a first rotatable body (10, L), which has a number n of uniform angle markings or teeth (11), with at least two rotatable gear wheels (12, 13, 14, 15), which respectively have n1, n2, n3, n4 uniform angle markings or teeth, wherein the angle markings of the at least two rotatable gear wheels (12, 13, 14, 15) cooperate with the angle markings (11) of the first rotatable body (10) in such a way that by detecting the angular positions θ, ψ of the at least two rotatable gear wheels (12, 13, 14, 15), the angular position α of the first rotatable body can be determined, characterized in that when there are two of said at least two rotatable gear wheels (12, 13;

• 12, 14;
• 12, 15;
• 13, 14;
• 13, 15;
• 14, 15), ¦ni-nj¦>1 and (ni, nj)=1 ni, nj are relatively prime and when there are more than two of said at least two rotatable gear wheels, (ni, nj)=1, where 1=i<j=N, with N being the total number of the at least two rotatable gear wheels (12, 13, 14, 15), wherein the angular positions θ and ψ can be detected by means of periodic angle sensors (22, 23, 24, 25) and the angular position a can be determined in an evaluation circuit (16) by taking into consideration the angular positions θ and ψ and the numbers n, ni, nj of the angle markings.