Matlab code
3.6: Matlab file “Figure 3-19.m”
%--------------------------------------------------------------------
% This code can be used to generate Figure 3.19
%--------------------------------------------------------------------
clear all
close all
%%
migration and broadening of range profile induced by micromotion
c = 3e8;
j = sqrt(-1);
fc = 35e9;
% carrier frequency
Tp = 1e-3;
% pulse duration
B =
500e6; % bandwidth
u = B/Tp; % frequency modulation rate
lambda = c/fc;
% wavelength
fs = 10e6;
tk = 0:1/fs:Tp-1/fs; % fast time
nt = length(tk);
df = fs/nt; % frequency
sampling interval
R0 =
5e3; % distance between the reference point and radar
R_delta = 0;
Rref = R0 - R_delta;
v =
[0,-30,30,100]; % translational velocity of target
s = zeros(1,nt);
hrrp =
zeros(length(v),nt);
for kj = 1:length(v)
R = R0 - v(kj)*tk;
td = tk - 2*R/c;
s = exp(j*2*pi*(fc*td+0.5*u*td.^2)).*(td>=0&td<=Tp);
td0 = tk - 2*Rref/c;
s0 = exp(j*2*pi*(fc*td0+0.5*u*td0.^2)).*(td0>=0&td0<=Tp); % reference signal
sd
= s.*conj(s0); % dechirp
hrrp(kj,:) = fftshift(fft(sd));
end
hrrp = abs(hrrp)./max(max(abs(hrrp)));
figure(1)
hold on
for kj = 1:length(v)
plot(linspace(-fs/2,fs/2-df,length(interp(hrrp(kj,:),10)))*(-c/2/u),10*log10(abs(interp(hrrp(kj,:),10))))
end
figure(1)
xlabel('Range
(m)')
ylabel('Normalized
magnitude (dB)')
axis([-15,15,-1.5-15,0.33])
box on
hold off