Matlab高频雷达海洋回波谱的模拟仿真

%------------------------------一、二阶海杂波谱仿真图------------------------%%-------------------线性调频连续波发射信号仿真------------------------------%clc;clearall;closeall;%---------------------初始参数设置-----------------------------------------%T=0.25;%脉冲宽度(即脉冲重复周期)TT=64;%相干积累时间N=TT/T;%相干积累时间内的脉冲数%Fs=B*2;%采样频率saNum=5;%每个周期的采样点数Ts=T/saNum;%采样间隔sig_ran=60;%目标所在的距离单元Fs=10e2;%--------------------------------发射信号仿真------------------------------%tt=Ts:Ts:T;t=0:1/(Fs):TT;%--------------------------------海杂波信号仿真-----------------------------%%------------------------------------第一种--------------------------------%%一阶海杂波f0=18e6;%雷达载频g=9.8;%重力加速度c=3e8;lambda=c/f0;%电磁波波长alfa=8.1e-3;beita=0.74;U=25;%待变参数，海面上19.5m处的风速kc=g/U^2;%截止波束theta=180;%雷达波束方向到海浪波列前进方向的转角fi=0;%雷达波束方向的方位角%theta+fi%表示海浪波列前进方向的方位角fw=90;%海面风向的方位角k0=2*pi/lambda;fd1=0.1012*(f0/1e6)^0.5;%一阶Bragg峰的多普勒频率,存在洋流时偏移fd2=-fd1;S1=0.005*(-2*k0)^-4*exp(-0.74*(kc/(2*k0))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)S2=0.005*(-2*k0)^-4*exp(-0.74*(kc/(2*k0))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)G1_1=4/(3*pi)*(cos((180-fw)*pi/180/2))^4;G2_1=4/(3*pi)*(cos((0-fw)*pi/180/2))^4;=2^6*k0^4*pi*S1*G1_1*exp(2*pi*1i*fd1.*t).*exp(-(t).^2./((2^2)*0.4))./((2*pi)^0.5*0.4);%正轴一阶Bragg峰Bragg1_2=2^6*k0^4*pi*S2*G2_1*exp(2*pi*1i*fd2.*t).*exp(-(t).^2./((2^2)*0.4))./((2*pi)^0.5*0.4);%负轴一阶Bragg峰%Noise=1.2358e-004*randn(1,length(t));%2^9也行freq=linspace(-Fs/2,Fs/2,length(t));B_1=fftshift(abs(fft(Bragg1_1+Bragg1_2)));=B_1/max(B_1);%B_11=20*log10(B_11);%figure(1);%plot(freq,B_11);%一阶bragg峰%xlim([-22]);%二阶海杂波f4=linspace(-1.1*fd1,-2*fd1,20);f3=linspace(-0.9*fd1,-0.1*fd1,80);f1=linspace(0.1*fd1,0.9*fd1,80);f2=linspace(1.1*fd1,2*fd1,20);delta_k=k0/40;delta=0.011-i*(0.0121);forn=1:79=n*delta_k;fori=1:length(f1)%m=-1,m^=1%ifk_n-2*k0k_pk_n+2*k0theta=linspace(0,180,181);k_p=(2*pi*f1(i)+(g*k_n)^0.5)^2/g;%theta_1=acos((k_p^2-k_n^2-4*k0^2)/4*k_n*k0);theta_2=asin(k_n*sin(k_n*sin(theta.*pi/180)./k_p))-pi;kafang1=-i*0.5*(k_n+k_p-k_n*k_p*((2*pi*f1(i))^2+(2*pi*fd1)^2)/(k_n*k_p)^0.5/((2*pi*f1(i))^2-(2*pi*fd1)^2));kafang2=0.5*(k_n*k0*-cos(theta.*pi/180).*(k_p*k0*-cos(theta_2.*pi/180))./k0^3/delta);kafang=(abs(kafang1+kafang2)).^2*2^6*k0^4*pi*n*(delta_k^2);S1=0.005*(-k_n).^-4*exp(-0.74*(kc/(-k_n))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)S2=0.005*(k_p).^-4*exp(-0.74*(kc/(k_p))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)G1=4/(3*pi)*(cos((theta-fw).*pi/180/2)).^4;G2=4/(3*pi)*(cos((theta_2-fw).*pi/180/2)).^4;X(i)=trapz(kafang.*G1.*G2.*S1.*S2,theta.*pi/180);theta=linspace(-180,0,181);k_p=(2*pi*f1(i)+(g*k_n)^0.5)^2/g;%theta_1=acos((k_p^2-k_n^2-4*k0^2)/4*k_n*k0);theta_2=asin(k_n*sin(k_n*sin(theta.*pi/180)./k_p))+pi;=-i*0.5*(k_n+k_p-k_n*k_p*((2*pi*f1(i))^2+(2*pi*fd1)^2)/(k_n*k_p)^0.5/((2*pi*f1(i))^2-(2*pi*fd1)^2));kafang2=0.5*(k_n*k0*-cos(theta.*pi/180).*(k_p*k0*-cos(theta_2.*pi/180))./k0^3/delta);kafang=(abs(kafang1+kafang2)).^2*2^6*k0^4*pi*n*(delta_k^2);S1=0.005*(-k_n).^-4*exp(-0.74*(kc/(-k_n))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)S2=0.005*(k_p).^-4*exp(-0.74*(kc/(k_p))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)G1=4/(3*pi)*(cos((theta-fw).*pi/180/2)).^4;G2=4/(3*pi)*(cos((theta_2-fw).*pi/180/2)).^4;Y(i)=trapz(kafang.*G1.*G2.*S1.*S2,theta.*pi/180);%m=1,m^=-1theta=linspace(0,180,181);k_p=(2*pi*f1(i)-(g*k_n)^0.5)^2/g;%theta_1=acos((k_p^2-k_n^2-4*k0^2)/4*k_n*k0);theta_2=asin(k_n*sin(k_n*sin(theta.*pi/180)./k_p))-pi;kafang1=-i*0.5*(k_n+k_p-k_n*k_p*((2*pi*f1(i))^2+(2*pi*fd1)^2)/(k_n*k_p)^0.5/((2*pi*f1(i))^2-(2*pi*fd1)^2));kafang2=0.5*(k_n*k0*-cos(theta.*pi/180).*(k_p*k0*-cos(theta_2.*pi/180))./k0^3/delta);kafang=(abs(kafang1+kafang2)).^2*2^6*k0^4*pi*n*(delta_k^2);S1=0.005*(k_n).^-4*exp(-0.74*(kc/(k_n))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)S2=0.005*(-k_p).^-4*exp(-0.74*(kc/(-k_p))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)G1=4/(3*pi)*(cos((theta-fw).*pi/180/2)).^4;G2=4/(3*pi)*(cos((theta_2-fw).*pi/180/2)).^4;A(i)=trapz(kafang.*G1.*G2.*S1.*S2,theta.*pi/180);theta=linspace(-180,0,181);k_p=(2*pi*f1(i)-(g*k_n)^0.5)^2/g;%theta_1=acos((k_p^2-k_n^2-4*k0^2)/4*k_n*k0);theta_2=asin(k_n*sin(k_n*sin(theta.*pi/180)./k_p))+pi;kafang1=-i*0.5*(k_n+k_p-k_n*k_p*((2*pi*f1(i))^2+(2*pi*fd1)^2)/(k_n*k_p)^0.5/((2*pi*f1(i))^2-(2*pi*fd1)^2));kafang2=0.5*(k_n*k0*-cos(theta.*pi/180).*(k_p*k0*-cos(theta_2.*pi/180))./k0^3/delta);kafang=(abs(kafang1+kafang2)).^2*2^6*k0^4*pi*n*(delta_k^2);S1=0.005*(k_n).^-4*exp(-0.74*(kc/(k_n))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)S2=0.005*(-k_p).^-4*exp(-0.74*(kc/(-k_p))^2);%两个Bragg峰的幅度不同(随海面风向的方向角)G1=4/(3*pi)*(cos((theta-fw).*pi/180/2)).^4;G2=4/(3*pi)*(cos((theta_2-fw).*pi/180/2)).^4;B(i)=trapz(kafang.*G1.*G2.*S1.*S2,theta.*pi/180);Bragg(i,:)=(X(i)+Y(i)+A(i)+B(i))*exp(2*pi*1i*f1(i)*t);endBragg1(n,:)=sum(Bragg,1);%endendBB2=sum(Bragg1,1)./10;B_2=fftshift(abs(fft(BB2)));%BB2=B_2/max(B_2);%BB2=20*log10(BB2);%figure(3)%plot(freq,B_2);%xlim([-22]);forn=1:79k_n=n*delta_k;fori=1:length(f3)%m=1,m^=-1%ifk_n-2*k0k_pk_n+2*k0theta=linspace(0,180,181);k_p=(2*pi*f1(i)-(g*k_n)^0.5)^2/g;%theta_1=acos((k_p^2-k_n^2-4*k0^2)/4*k_n*k0);theta_2=asin(k_n*sin(k_n*sin(theta.*pi/180)./k_p))-