Method for obtaining the profile of the outer surface of a medium having a median plane comprising the following steps: - Obtaining two time signals A and B , from a measurement system having a relative speed V in a direction U with respect to an outer surface having a median plane , each signal being the result of the electromagnetic interferences between an incident wave and its wave backscattered by the outer surface along a readout line of at least one electromagnetic wave that is Gaussian, coherent, directional along at least one path and focused at a geometrical point (d1, d2) on the at least one path , the two geometrical points (d1, d2) being situated on either side of the median plane and, the distance between the two geometrical points (d1, d2) being greater than the greatest of the Rayleigh lengths of each electromagnetic wave, with respect to the normal to the median plane , the angle of incidence (θ 1 , θ 2 ) of the electromagnetic wave along each path on the outer surface being greater than one degree in a plane defined by the normal to the median plane and the direction U; for, at each instant, a same geometrical target on the readout line of the outer surface , the two time signals being differentiated in terms of Doppler frequency, when they are generated by the use of of a single electromagnetic wave source, i.e;the two time signals each associated with a wave path which are differentiated only by the angle of incidence (θ 1 , θ 2 ) on the outer surface; - Determining at least one Doppler frequency associated with each time signal A and B; - Sampling each time signal A and B at a frequency greater than 2 times, preferentially 10 times, the at least one Doppler frequency to obtain a payload signal; - Determining an envelope of the payload signal of each signal A and B; - Performing a relative combination between the envelopes of each signal A and B to obtain a monotonic and bijective function F; and - Determining the profile of the outer surface using a calibration of the function F. - Obtaining two time signals A and B , from a measurement system having a relative speed V in a direction U with respect to an outer surface having a median plane , each signal being the result of the electromagnetic interferences between an incident wave and its wave backscattered by the outer surface along a readout line of at least one electromagnetic wave that is Gaussian, coherent, directional along at least one path and focused at a geometrical point (d1, d2) on the at least one path , the two geometrical points (d1, d2) being situated on either side of the median plane and, the distance between the two geometrical points (d1, d2) being greater than the greatest of the Rayleigh lengths of each electromagnetic wave, with respect to the normal to the median plane , the angle of incidence (θ 1 , θ 2 ) of the electromagnetic wave along each path on the outer surface being greater than one degree in a plane defined by the normal to the median plane and the direction U; for, at each instant, a same geometrical target on the readout line of the outer surface , the two time signals being differentiated in terms of Doppler frequency, when they are generated by the use of of a single electromagnetic wave source, i.e;the two time signals each associated with a wave path which are differentiated only by the angle of incidence (θ 1 , θ 2 ) on the outer surface; - Determining at least one Doppler frequency associated with each time signal A and B; - Sampling each time signal A and B at a frequency greater than 2 times, preferentially 10 times, the at least one Doppler frequency to obtain a payload signal; - Determining an envelope of the payload signal of each signal A and B; - Performing a relative combination between the envelopes of each signal A and B to obtain a monotonic and bijective function F; and - Determining the profile of the outer surface using a calibration of the function F. <EOS>