1. A method for detecting an electromagnetic signal of interest contained in an electromagnetic signal received by an antenna array comprising a plurality of antenna elements, said method comprising the following steps: applying to said electromagnetic signal received by each antenna element a plurality of time-frequency transforms in order to obtain a representation of said received electromagnetic signal in a form of a plurality of time-frequency cells each containing a spectrum of said received electromagnetic signal for a given frequency interval and a given time interval, for each time/frequency cell of a given set of cells, calculating an energy of a vector made up of spectra over all of the antenna elements so as to produce a plurality of spectra, applying the following nonlinear function T to the result of the preceding energy calculation, so as to cancel the time/frequency cells containing substantially only noise: if a norm of the energy of the vector of spectra is below a first predetermined threshold s, the result of the nonlinear function T is zero, if the norm of the energy of the vector of the spectra is above or equal to said first predetermined threshold s, the result of the nonlinear function T is equal to the norm of the energy of the vector of spectra minus the first predetermined threshold s, integrating, over said plurality of time/frequency cells, a result of said nonlinear function T, comparing the result of the integration to a second predetermined threshold, called detection threshold S det , to detect the presence of the electromagnetic signal of interest.