function [ Ia , Ir ] = P_Islr( Ga )
%%%%% 求矩阵方位向和距离向的峰值旁瓣比与积分旁瓣比
%%%%% Ga:输入矩阵,设第一维为方位向，第二维为距离向
%%%%% Pa,Ia:方位向PSLR,ISLR
%%%%% Pr,Ir:距离向PSLR,ISLR
%%%%%
%%%%% Modified by Tao Fu on 2011.11.16
[Na,Nr]=size(Ga);
if Na == 1 || Nr == 1
error('请输入矩阵')
end
[maxR,RI]=max(max(Ga));%%RI是距离向最大值出现的位置
[maxA,AI]=max(Ga(:,RI));%%AI是方位向最大值出现的位置
%%%%%%%求方位向积分旁瓣比%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for i=1:(Na-AI-3)
if Ga(AI+i,RI) > Ga(AI+i+1,RI) & Ga(AI+i+1,RI) < Ga(AI+i+2,RI) %%%直到找到第一个旁瓣
side_right=AI+i+1;
break;
end
end
for i=1:(AI-3)
if Ga(AI-i,RI)> Ga(AI-i-1,RI)& Ga(AI-i-1,RI)<Ga(AI-i-2,RI) %%%直到找到第一个旁瓣
side_left=AI-i-1;
break;
end
end
%%计算主瓣能量
mainEa=0;
for i=side_left:side_right
mainEa=mainEa+(Ga(i,RI)-(sum(Ga(:,RI))-Ga(AI,RI))/(Nr-1))*(Ga(i,RI)-(sum(Ga(:,RI))-Ga(AI,RI))/(Nr-1));
end
%%计算总能量
Ea=0;
for i=1:Na
Ea=Ea+(Ga(i,RI)-(sum(Ga(:,RI))-Ga(AI,RI))/(Nr-1))*(Ga(i,RI)-(sum(Ga(:,RI))-Ga(AI,RI))/(Nr-1));
end
%%计算旁瓣能量
sideEa=Ea-mainEa;
Ia=-10*log10(abs(mainEa/sideEa));
Pa=20*log10(abs(Ga(:,RI))./abs(Ga(AI,RI)));
figure;
plot(Pa);
title('方位向峰值旁瓣比'),grid on
%%%%%%%求距离向积分旁瓣比%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for i=1:(Nr-RI-3)
if Ga(AI,RI+i) > Ga(AI,RI+i+1) & Ga(AI,RI+i+1) < Ga(AI,RI+i+2) %%%直到找到第一个旁瓣
side_right=RI+i+1;
break;
end
end
for i=1:(RI-3)
if Ga(AI,RI-i)> Ga(AI,RI-i-1)& Ga(AI,RI-i-1)<Ga(AI,RI-i-2) %%%直到找到第一个旁瓣
side_left=RI-i-1;
break;
end
end
%%计算主瓣能量
mainEr=0;
for i=side_left:side_right
mainEr=mainEr+(Ga(AI,i)-(sum(Ga(AI,:))-Ga(AI,RI))/(Na-1))*(Ga(AI,i)-(sum(Ga(AI,:))-Ga(AI,RI))/(Na-1));
end
%%计算总能量
Er=0;
for i=1:Nr
Er=Er+(Ga(AI,i)-(sum(Ga(AI,:))-Ga(AI,RI))/(Na-1))*(Ga(AI,i)-(sum(Ga(AI,:))-Ga(AI,RI))/(Na-1));
end
%%计算旁瓣能量
sideEr=Er-mainEr;
Ir=-10*log10(abs(mainEr/sideEr));
Pr=20*log10(abs(Ga(AI,:))./abs(Ga(AI,RI)));
figure;
plot(Pr);
title('距离向峰值旁瓣比'),grid on
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