雷达系统仿真设计报告

f_doppler=0.4e3; %动目标的多普勒频差 t_frame=0:ts:T_frame-ts; t_mobj=400e-6;%% 动目

60km

echo_mobj_pulse=[zeros(1,fix(t_mobj/ts)),s,zeros(1,fix((T_frame-t_mobj)/ts)-length(s))];%%%%%%%%动目标相距距离单元

echo_mobj=repmat(echo_mobj_pulse,1,N_echo_frame);%%复制18遍，组成18

个脉冲

t_doppler=0:ts:N_echo_frame*T_frame-ts; s_doppler=cos(2*pi*f_doppler*t_doppler);

s_echo_mobj=echo_mobj.*s_doppler; %信号受到正弦信号调制

%静目标反射回波信号%%%%%%%%%%%%% t_fobj=450e-6; %静目标 位置67.5km

echo_fobj_pulse=[zeros(1,t_fobj/ts),s,zeros(1,fix((T_frame-t_fobj)/ts)-length(s))];

s_echo_fobj=repmat(echo_fobj_pulse,1,N_echo_frame);

%杂波，设为整个周期均存在%%%%%%%%%%%%%%%% t_clutter=0;%杂波位置

t_clutter_pulse=100e-5; %杂波宽度 sigma=2;%瑞利分布的参数sigma t1=0:ts:t_clutter_pulse-ts; rand('state',0); u=rand(1,length(t1));

echo_clutter=0.08*sqrt(2*log(1./u))*sigma;

s_echo_clutter_pulse=[zeros(1,t_clutter/ts),echo_clutter,zeros(1,(T_frame-t_clutter)/ts-length(echo_clutter))];

s_echo_clutter=repmat(s_echo_clutter_pulse,1,N_echo_frame);

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雷达系统仿真设计报告

%%%噪声，整个周期都存在噪声% L=fix(T_frame/ts); s_noise=0.1*rand(1,N_echo_frame*L);

%得到了加入噪声，杂波，固定目标回波和动目标回波的雷达回波信号 s_echo=s_echo_mobj+s_echo_fobj+s_echo_clutter+s_noise; t=0:ts:N_echo_frame*T_frame-ts;

subplot(231),plot(t,s_echo),xlabel('t（单位：s）'),title('雷达回波信号'); clear s_echo_mobj; clear s_echo_fobj; clear s_echo_clutter; clear s_echo_clutter_pulse; clear s_noise; clear echo_mobj; clear echo_mobj_pulse; clear echo_fobj_pulse; clear echo_clutter; clear s_doppler; clear t_doppler;

%%%%%%%正交解调%%%%%%%%%%%%%%%% N=N_echo_frame*L; n=0:N-1;

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雷达系统仿真设计报告

local_oscillator_i=cos(n*f0/fs*2*pi); %i路本振信号 local_oscillator_q=sin(n*f0/fs*2*pi); %q路本振信号 s_echo_i=local_oscillator_i.*s_echo; %i路解调 s_echo_q=local_oscillator_q.*s_echo; %q路解调 window=chebwin(51,40); [b,a]=fir1(50,2*B/fs,window); s_echo_i=[s_echo_i,zeros(1,25)]; s_echo_q=[s_echo_q,zeros(1,25)]; s_echo_i=filter(b,a,s_echo_i); s_echo_q=filter(b,a,s_echo_q); s_echo_i=s_echo_i(26:end); s_echo_q=s_echo_q(26:end); s_echo_mf=s_echo_i+j*s_echo_q; clear s_echo;

clear local_oscillator_i; clear local_oscillator_q; clear s_echo_i; clear s_echo_q; clear n;

%%%%%%%%%%%%数字脉冲压缩处理%%%%%%%%%%%%%

%%%%%%%%%%%%脉冲压缩处理%%%%%%%%%%%%%%%%% s_pc_result=zeros(N_echo_frame,M);

for i=1:N_echo_frame

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雷达系统仿真设计报告

s_echo_fft_result=fft(s_echo_mf(1,(i-1)*L+1:i*L),M); s_pc_fft_1= s_echo_fft_result.*match_filter_1_fft; s_pc_fft_2=s_pc_fft_1.*match_filter_2_fft; s_pc_result(i,:)=ifft(s_pc_fft_2,M); end

s_pc_result_1= zeros(1,N_echo_frame*L); for i=1:N_echo_frame

s_pc_result_1(1,L*(i-1)+1:L*i)=s_pc_result(i,1:L); end subplot(232),

plot(0:ts:length(s_pc_result_1)*ts-ts,abs(s_pc_result_1)), xlabel('t（单位：s）'),title('脉冲压缩处理后结果'); clear s_echo_mf; clear s_pc_fft_1; clear s_pc_fft_2; clear s_pc_result1;

%%%固定杂波二次对消处理%%%%%%%%%%%%%%% s_MTI_result=zeros(N_echo_frame-2,M); for i=1:(N_echo_frame-2)

s_MTI_result(i,:)=s_pc_result(i,:)+s_pc_result(i+2,:)-2*s_pc_result(i+1,:); end

s_MTI_result_1= zeros(1,(N_echo_frame-2)*L); for i=1:N_echo_frame-2

s_MTI_result_1(1,L*(i-1)+1:L*i)=s_MTI_result(i,1:L); end

subplot(233),plot(0:ts:length( s_MTI_result_1)*ts-ts,abs( s_MTI_result_1)),

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