monpat.m

此程序给出了不同情况的雷达距离测量仿真平台

% Monopulse Antenna Pattern
% --------------------------

clear,clc,clf;

% Normalized Aperture Width
na=4;

% Sampling Frequeny=Number elements per norm aperture
fs=8;

% Norm aperture with N elements
N=fs*na;
xna=na*(-1/2:1/(N-1):1/2);

% Illumination Function

wxna(1:N/2)=ones(1,N/2);
wxna(N/2+1:N)=-ones(1,N/2);
wxnb(1:N/2)=ones(1,N/2);
wxnb(N/2+1:N)=ones(1,N/2);

% Fill with M/2 zeros front and back

M=1024;
xna=na*(-1/2:1/N+M-1:1/2);
wxna=[zeros(1,M/2) wxna zeros(1,M/2)];
wxnb=[zeros(1,M/2) wxnb zeros(1,M/2)];
 
% Beam Functions from -fs/2 to fs/2 in sine space

Nfft=length(wxna);
Esine=fft(wxna,Nfft);
Esine=fftshift(Esine);

Esum=fft(wxnb);
Esum=fftshift(Esum);

% Azimuth vector

sinfi=fs/4*(-Nfft/2:Nfft/2-1)/Nfft;

% Azimuth vector in radians

fi=asin(sinfi);

% Beam gain functions

Gfi= Esine.*conj(Esine)/Nfft;
Gfs=Esum.*conj(Esum)/Nfft;

Gfi(1:Nfft/2)=sqrt(Gfi(1:Nfft/2));
Gfi(Nfft/2+1:Nfft)=-sqrt(Gfi(Nfft/2+1:Nfft));
Gfs=sqrt(Gfs);

% Plot Monopulse Antenna Pattern

plot(fi,Gfi,fi,Gfs);grid;
axis([ -.25 .25 -.8 1]);
ylabel('Amplitude');
xlabel('Angle - radians');
title(['Monopulse Antenna Patterns']);
text(.04,.8,'Sum Pattern');
text(-.22,.6,'Difference Pattern');