c=3.e8;
lamd=0.6;0.246;3.e-2;
T0=100.e-6; %pluse t width  100us  脈沖寬度100us
B=3.e6;   %pluse f width
PRF=1000.;1.*2439.02; %  PRF  1Khz
Nt=12;
Ns=12;
R0=10000.;00.;
L0=50.;     %  range gate 距離門 0.25us
;f0=PRF/nt;%doppler gate

m1=round(R0/L0)
R=400.e3;
h=10000.
ksai_center=asin(h/R);%the number of range
;ksai_center=10.*!pi/180.;   %center dive angle
sita_center=90.*!pi/180.; center azimuth angle;
v=150.;
;R=h/sin(ksai_center)
d=0.5*lamd
seed=5000
sd=2*!pi*d/lamd*cos(ksai_center)
st=4*!pi*v/lamd*cos(ksai_center)/PRF
cov=complexarr(Ns*Nt,Ns*Nt)
z0=1.0313;1.0175;cosh(1/Ns*acos(1./kesi));
cheb=fltarr(Ns);
for k=1,Ns/2 do begin
   for q=k,Ns/2 do begin
        cheb(Ns/2+k-1)=cheb(Ns/2+k-1)+(-1.)^(Ns/2-q)*z0^(2*q-1)*(2*Ns/2-1)*factorial(q+Ns/2-2)/(factorial(q-k)*factorial(q+k-1)*factorial(Ns/2-q));
   endfor
endfor
for i=0,Ns/2-1 do begin
    cheb(Ns/2-i-1)=cheb(i+Ns/2);
endfor
f_antena=complexarr(180)
for k=0,180-1 do begin

             sita=0+k*!pi/180.
             ksai=cos(ksai_center)*(cos(sita)-cos(sita_center))
             for s=0,Ns-1 do begin
             f_antena(k)=f_antena(k)+exp(complex(0,2*s*!pi*d/lamd*ksai))*cheb(s)
             endfor
endfor
for ii=0,Ns-1 do begin
  for jj=0,Nt-1 do begin
    for i=0,Nt-1 do begin
       for j=0,Ns-1 do  begin
          for k=0,180-1 do begin

             sita=0.+k*!pi/180.
             sita1=sita;+5.*!pi/180.
             ;ksai=cos(sita);*cos(ksai_center)
             ss=j-ii
             tt=i-jj
             p=1.;f_antena(K)*conj(f_antena(k))
             cov(jj*Ns+ii,i*Ns+j)=cov(jj*Ns+ii,i*Ns+j)+p*exp(complex(0,-(ss)*cos(sita)*sd-(tt)*st*cos(sita)))
          endfor
          ;Br=4*!pi*v/lamd*cos(ksai_center)/PRF*0.05
          ;te=exp(-0.125*tt*tt*Br^2)
          ;se=(1+0.0008*abs(ss))*exp(complex(0,!pi/180.*abs(ss)/8));sensor(abs(ss))
         ;te=exp(-0.125*tt*tt*Br^2)
          ;cov(jj*Ns+ii,i*Ns+j)=cov(jj*Ns+ii,i*Ns+j);*te
       endfor
    endfor
   endfor
endfor
for i=0,nt*ns-1 do begin
    cov(i,i)=cov(i,i)+0.01;*randomn(seed)
endfor

incov=invert(cov)

ksai0=1.
ksai1=-1.
delta_ksai=(ksai0-ksai1)/100.
stevec=complexarr(nt*ns)
spectrum=complexarr(100,100)
;spectrum1=complexarr(100,100)

im=complexarr(100,100)
;im1=complexarr(100,100)
fd1=prf/2.
  for ii=0,100-1 do begin

       ksai=ksai0-ii*delta_ksai
         for jj=0,100-1 do begin

          fd=(fd1-jj* fd1/50.);+20.;*cos(ksai)

          for j=0,nt-1 do begin
             st=exp(complex(0,-j*2*!pi*fd/PRF))
             for i=0,ns-1 do begin

             stevec(j*ns+i)=exp(complex(0,-2*!pi*i*d/lamd*ksai))*st

             endfor
         endfor
       spectrum(ii,jj)=1./(conj(stevec) ##incov## transpose(stevec))
       ;im1(ii,jj)=1./(abs(spectrum1(ii,jj))+0.00001)*trace(cov1)/(transpose(conj(stevec1))##stevec1);
        ;im1(ii,jj)=( transpose(conj(stevec1)) ##incov1## (stevec1))*trace(cov1)/(transpose(conj(stevec1))##stevec1);
        im(ii,jj)=(conj(stevec) ##incov## transpose(stevec))*trace(cov)/(conj(stevec)##stevec)
        ;if (abs(spectrum(ii,jj)) le 5.e-5) then spectrum(ii,jj)=5.e-5
        ;im(ii,jj)=1./abs(spectrum(ii,jj))*trace(cov)/(conj(stevec)## transpose(stevec))
        endfor
    endfor
; save,spectrum,filename='d:\spectrum.sav'

end