A method is provided for demodulating a signal carrying a message transmitted by a terrestrial beacon, executed by a system comprising a constellation of satellites suitable for detecting said signal and for repeating it towards receiving stations on the ground, and an analysis module suitable for receiving signals from said stations. Each receiving station transmits the signals that it receives from the satellite to the analysis module, said module realigning said signals in frequency and/or in time relative to one another, combining the realigned signals to generate a synthetic signal having an enhanced signal-to-noise ratio, and determining the content of said message and/or the modulation parameters of said synthetic signal. The method applies notably to the accurate and reliable location of distress beacons by a satellite system.