A method for estimating angular errors of angle coders for a looped system including at least one actuator for rotating an axis and an angle coder producing a signal of position measurement of said axis, and including a calculation device for at least controlling said actuator, the calculation device receiving, on the one hand, a setpoint signal at the system input, in particular a position setpoint signal y c ( t ) and, on the other hand, the measurement signal, for looping the system, the rotation actuator generating torque undulations d m ( t ), the coder producing coder errors d c ( t ) which, for a setpoint signal y c ( t ) that corresponds to a rotation of the axis at a speed ω r supposed to be constant, have a spectrum consisted of the fundamental rotation frequency ω r and its harmonics kω r , k ∈ N , the calculating device calculating a command signal in a corrector, characterized in that , in a test phase, for a speed of rotation indexed j, ω rj , supposed to be constant, a specific corrector C ωr j ( q ) of said constant speed of rotation ω rj is synthesized, said corrector C ωr j ( q ) being such that, for the frequency domain comprising the fundamental frequency ω rj and a determined number of its first harmonics kω rj , k ∈ N , 1 < k ≤ N l , the corrector having a substantially zero gain at theses frequencies ω rj , kω rj , which causes an opening of the loop at said frequencies, and a matrix relationship is established between the position measurements and a function of parameters characterizing the coder errors and the torque undulations, on the system with the specific corrector and at the constant speed of rotation ω rj , the test phase is repeated a determined number n of times with different setpoints of rotation at speed ω rj supposed constant, where , j ∈ N , 1 < j ≤ n, the matrix relationships are concatenated in order to obtain an identifiable global matrix relationship, the parameters characterizing the coder errors and the torque undulations are estimated by solving the global matrix relationship. the calculation device receiving, on the one hand, a setpoint signal at the system input, in particular a position setpoint signal y c ( t ) and, on the other hand, the measurement signal, for looping the system, the rotation actuator generating torque undulations d m ( t ), the coder producing coder errors d c ( t ) which, for a setpoint signal y c ( t ) that corresponds to a rotation of the axis at a speed ω r supposed to be constant, have a spectrum consisted of the fundamental rotation frequency ω r and its harmonics kω r , k ∈ N , the calculating device calculating a command signal in a corrector, characterized in that , in a test phase, for a speed of rotation indexed j, ω rj , supposed to be constant, a specific corrector C ωr j ( q ) of said constant speed of rotation ω rj is synthesized, said corrector C ωr j ( q ) being such that, for the frequency domain comprising the fundamental frequency ω rj and a determined number of its first harmonics kω rj , k ∈ N , 1 < k ≤ N l , the corrector having a substantially zero gain at theses frequencies ω rj , kω rj , which causes an opening of the loop at said frequencies, and a matrix relationship is established between the position measurements and a function of parameters characterizing the coder errors and the torque undulations, on the system with the specific corrector and at the constant speed of rotation ω rj , the test phase is repeated a determined number n of times with different setpoints of rotation at speed ω rj supposed constant, where , j ∈ N , 1 < j ≤ n, the matrix relationships are concatenated in order to obtain an identifiable global matrix relationship, the parameters characterizing the coder errors and the torque undulations are estimated by solving the global matrix relationship. <EOS>