A method for estimating a distance (d) of a transmitting device (2; 2a) from at least one receiving device (3; 3a; 3b) comprises the following steps: - generating with said transmitting device (2; 2a) a first sinusoidal signal at a first frequency f1; - generating with said transmitting device (2; 2a) a second sinusoidal signal at a second frequency f2, synchronized with the first sinusoidal signal; - transmitting said first sinusoidal signal and said second sinusoidal signal at the receiving device (3, 3a, 3b); - estimating the phase of said first sinusoidal signal and said second sinusoidal signal received by said receiving device (3; 3 a; 3b); - estimating said distance (d) on the basis of said the phase estimation of the first sinusoidal signal and said second sinusoidal signals. A localization system that comprises a transmitting device (2) and at least 3 receiving devices (3; 3a; 3b), placed in known positions, and is capable of estimating the position (p) of said transmitting device (2) with respect to the receiving devices (3; 3a; 3b).