A method for the improvement of the data detected by means of radar

摘要

PCT No. PCT/SE95/01339 Sec. 371 Date May 9, 1997 Sec. 102(e) Date May 9, 1997 PCT Filed Nov. 10, 1995 PCT Pub. No. WO96/15462 PCT Pub. Date May 23, 1996A method of improving data obtained by radar by interpolation over frequency bands jammed by narrow-band interference, at which the following steps (A)-(J) are carried out. (A) It is determined what frequency values are affected by narrow-band interference. (B) Every radar return which is continuously connected in time and represented by a time-discrete real or complex signal f(ti), containing N sample, i=1, 2, . . . , N, is Fourier-transformed into a frequency-discrete function F( omega i), given by N sample. (C) A series of integers N1, N2, . . . , NM is fixed, such that 1/=N1N2 . . . NMN. (D) The signal processing device sets Fk( omega i)=Hk( omega i) within intervals having narrow-band interference. (E) H1( omega i) is equated to 0 and Hk( omega i) for k/=2 is constructed according to the following steps (F)-(H). (F) Fk-1( omega i) is inversely Fourier-transformed into a time-discrete function fk-1(ti). (G) The signal processing device sets hk(ti)=fk-1 (ti) for i=1, 2, . . . , Nk-1, wherein |fk-1(ti)| constitute the Nk-greatest values of |fk-1(ti)| and hk-1(ti)=0 for the remaining N-Nk-1 values of the function. (H) hk-1(ti) is Fourier-transformed into a frequency-discrete function Hk( omega i). (I) Steps (D)-(H) are repeated M times, wherein 1/=k/=M. (J) FNM( omega i) is inversely Fourier-transformed to give the finally filtered radar return fNM(ti).