Interfering signal detection device for a global navigation satellite system

An interfering signal detection device, including: a receiver stage for an input signal (s i (t)) an oscillator (52), which generates a local signal (s l (n)) having a local frequency (f sweep ) and a plurality of correlation branches (24) to generate, at each integration period (T=L/f s ), samples of corresponding correlation signals (s d , -1 (w), s d,0 (w), s d,1 (w)), indicative of the correlation of the input signal with a plurality of local periodical signals (cr -1 (n), cr 0 (n), cr 1 (n)) time shifted with respect to each other. The device also includes: a correlator (54), which determines a value vector on the basis of samples of the correlation signals generated during a detection period (T r ) formed by at least one integration period and a detection stage (54), which computes the eigenvalues of an estimated covariance matrix, on the basis of the value vector, and detects the interfering signal by comparison with a threshold. During the detection period, the oscillator varies the local frequency independently of the input signal.