A method is provided for improving the acquisition of a data set transmitted repeatedly in a difficult environment, which is particularly appropriate to satellite radionavigation systems. The main characteristic of the method is to provide “contextual” aid relating to the transmitted data by indicating the nature and the possible updating of these data so that the receiver can accumulate the energy when the data are repeated in an identical manner. These aid data being short, it is possible to obtain good quality of reception and protection of this aid by virtue of its longer coding than that of the data.