A pilot sequence includes pilot vectors to be transmitted in a communication channel. A method of determining the pilot sequence comprises determining an orthogonal basis of a real vector space that is an image of a matrix having, respectively as columns, the partial derivatives of the model vector with respect to the different real parameters; and constructing the pilot vectors using the determined orthogonal basis, by grouping the orthogonal vectors of the orthogonal basis in at least one pair and by producing, for each of the at least one pair comprising a first vector and a second vector, a pilot vector by summation of the first vector and a product of the second vector by an imaginary number.