I have simulated a phased array antenna. I have also simulated a point source. I don't get how to calculate pseudo spectrum vector without using the position of the source. Algorithms such as Capon and Bartlett use the position of the source for calculate the auto- correlation matrix which is further used to calculate pseudo spectrum. How is the angle of arrival being estimated if the source position is required to run the algorithm in the first place?

I have simulated a phased array antenna. I have also simulated a point source. I don't get how to calculate pseudo spectrum vector without using the position of the source. Algorithms such as Capon and Bartlett use the position of the source for calculate the auto- correlation matrix which is further used to calculate pseudo spectrum. How is the angle of arrival being estimated if the source position is required to run the algorithm in the first place?

Here is the code:

M=6;

sig2=.1;

th1=-3*pi/180;

th2=3*pi/180;

a1=[1];

a2=[1];

a=[1];

for i=2:M

a1=[a1 exp(-1j*i*pi*sin(th1))]; 

a2=[a2 exp(-1j*i*pi*sin(th2))]; 

end

A=[a1' a2'];

Rss=[1 0;0 1];

Rrr=ARssA'+sig2*eye(6);

for k=1:180;

th(k)=-pi/6+pik/(3180);

clear a

a=[1];

for jj=2:M

  a = [a exp(-1j*jj*pi*sin(th(k)))]; 

end

P(k)=real(1./(conj(a)*inv(Rrr)*a.'));

end

figure;

plot(th180/pi,10log10(P/max(P)),'k')

grid on

xlabel('Angle')

ylabel('|P(\theta)| (dB)')