An adaptive method for estimating the electron content of the ionosphere, comprising the following steps: - collecting a set of measurements carried out by a plurality of ground-based reception beacons receiving radiofrequency signals transmitted by a plurality of transmitting navigation satellites in orbit; - computing, for each of said signals of said set of measurements, space coordinates of the pierce point between a transmission axis of said signal and a layer surrounding the earth and a vertical total electron content (VTEC) determined at said pierce point, with a cluster of points made up of space coordinates of said pierce point and a vertical total electron content (VTEC) thus being defined; said method being characterised in that it further comprises the following steps: - computing, by means of a statistical estimator, a vertical total electron content (VTEC i) for each of the nodes (N i) of an initial mesh of the layer; - performing a statistical dispersion analysis of the vertical total electron content (VTEC i) on each of said nodes (N i) of said initial mesh, allowing a selection to be made between two predetermined disturbance levels, a weak disturbance (P 1) or a strong disturbance (P 2), of the ionosphere; - a step comprising: • a computation, in the case of a weak disturbance (P 1), for defining an adapted statistical estimator (ESCA) on the basis of said initial statistical estimator; • a computation, in the case of a strong disturbance (P 2), for generating a new adapted mesh (IPMA) of said layer on the basis of said initial mesh; - performing a statistical error analysis of the determined vertical total electron content (VTEC i) by means of said adapted statistical estimator (ESCA) and of said initial mesh in the case of a weak disturbance (P 1) or by means of said initial statistical estimator and of said adapted mesh (IPMA) in the case of a strong disturbance (P 2), said statistical error analysis allowing a selection to be made between two predetermined error levels, a weak error (E 1) that involves validating the adaptation of the method or a strong error (E 2) that involves stopping the method. - collecting a set of measurements carried out by a plurality of ground-based reception beacons receiving radiofrequency signals transmitted by a plurality of transmitting navigation satellites in orbit; - computing, for each of said signals of said set of measurements, space coordinates of the pierce point between a transmission axis of said signal and a layer surrounding the earth and a vertical total electron content (VTEC) determined at said pierce point, with a cluster of points made up of space coordinates of said pierce point and a vertical total electron content (VTEC) thus being defined; - computing, by means of a statistical estimator, a vertical total electron content (VTEC i) for each of the nodes (N i) of an initial mesh of the layer; - performing a statistical dispersion analysis of the vertical total electron content (VTEC i) on each of said nodes (N i) of said initial mesh, allowing a selection to be made between two predetermined disturbance levels, a weak disturbance (P 1) or a strong disturbance (P 2), of the ionosphere; - a step comprising: • a computation, in the case of a weak disturbance (P 1), for defining an adapted statistical estimator (ESCA) on the basis of said initial statistical estimator; • a computation, in the case of a strong disturbance (P 2), for generating a new adapted mesh (IPMA) of said layer on the basis of said initial mesh; • a computation, in the case of a weak disturbance (P 1), for defining an adapted statistical estimator (ESCA) on the basis of said initial statistical estimator; • a computation, in the case of a strong disturbance (P 2), for generating a new adapted mesh (IPMA) of said layer on the basis of said initial mesh; - performing a statistical error analysis of the determined vertical total electron content (VTEC i) by means of said adapted statistical estimator (ESCA) and of said initial mesh in the case of a weak disturbance (P 1) or by means of said initial statistical estimator and of said adapted mesh (IPMA) in the case of a strong disturbance (P 2), said statistical error analysis allowing a selection to be made between two predetermined error levels, a weak error (E 1) that involves validating the adaptation of the method or a strong error (E 2) that involves stopping the method.