Method for the detection especially of small sea targets

Abstract

A method for the detection of a target by a radar in the presence of noise, the detection being performed on M antenna rotations, comprises at least: a first step for the estimation of the Doppler frequency ({circumflex over (f)}) of the target; a detection step, the target being detected if an associated variable Z is greater than or equal to a predetermined threshold S, the variable Z being defined according to the following relationship: Z = MAX t ∈ D t , f ∈ D f ⁢ ( ∑ k = - N d N d ⁢ ⁢ ∑ i = 1 M - 1 ⁢ ⁢ [LeftBracketingBar] C z , z i k ⁡ ( t , f , G ) [RightBracketingBar] N ⁢ ( 0 , 0 , i , k ) + [AutoRightMatch] ⁢ ∑ k = - N d N d ⁢ ⁢ ∑ l = - N d N d ⁢ ⁢ ∑ i = 1 M - 1 ⁢ ⁢ ∑ j = i + 1 M - 1 ⁢ ⁢ [LeftBracketingBar] C z , i k ⁢ z ⁢ , j l ⁢ ( t , f , G ) [RightBracketingBar] N ⁢ ( i , k , j , l ) ) Dt being the time domain [−t0, t0], t0 being fixed as a function of the possible errors of framing of the signals from rotation to rotation; D being the frequency domain └{circumflex over (f)}d−f0, {circumflex over (f)}d+f0┘, f0 fixed as a function of the possible errors of estimation of the Doppler frequency; z being the signal at the analyzed antenna rotation referenced “0”, at the analyzed range gate references “0”; zik being the signal obtained by tracking at the rotation i of the signal z, in taking account of the tracking error in any, i.e., offset by k range gates with respect to the estimated range gate; Cz,zfk (t,f,G)being the Cohen transform of the signals z and zik with a kernel G, computed at the time t and the frequency f; Czik,zjl(t,f,G) being the Cohen transform of the signals zik and zjl of the kernel G, computed at the time t and at the frequency f; 2Nd+1 being the number of range gates taken into account, according to the tracking error if any; N(i, k, j, 1) being a standardization.

Dependencies are inferred from the claim text.