%%?Simulation?of?pulse?doppler
%?editor:???
%?data:?????2017.11.29
%?notes:

clear?all;
close?all;
clc;

%?Parameters?setting
C?=?3e8;?%?light?velocity
Rinti?=?3e3;?%?initial?range
Vr?=?60;?%?Radial?velocity
Nprt?=?64;?%?PRT?numbers
prt?=?1e-4;?%?PRT
fc?=?1e10;?%?carrier?frequency
lamda?=?C/fc;?%?wave?length
Tp?=?1e-5;?%?pulse?duration
B?=?1e7;?%?bandwidth
beta?=?B/Tp;?%?Chirp?rate
fs?=?1e8;?%?sampling?frequency
Nsimu?=?4096;?%?number?of?simulation?points
tt?=?（0:Nsimu-1）*1/fs;?%?time?axis
rr?=?tt*C/2;?%?range?axis

%?%%?pulse?compression
%?%?received?signal
%?tao?=?2*Rinti/C;
%?Srec?=?rectpuls（tt-tao-Tp/2Tp）.*exp（1i*pi*beta.*（tt-tao-Tp/2）.^2）.*exp（-1i*2*pi*fc*tao）;
%?%?reference?signal
%?tao?=?0;
%?Sref?=?rectpuls（tt-tao-TpTp）.*exp（1i*pi*beta.*（tt-tao-Tp/2）.^2）.*exp（-1i*2*pi*fc*tao）;
%?%?pulse?compression
%?Srec_fft?=?fft（Srec）;
%?Sref_fft?=?fft（Sref）;
%?Spc?=?ifft（Srec_fft.*conj（Sref_fft））;?%?signal?after?pulse?compression
%?Spc_dB?=?db（abs（Spc）/max（abs（Spc）））;
%?%?plot?
%?figure（‘name‘‘signal?after?pulse?compression‘）;
%?plot（rrSpc_dB）;
%?xlabel（‘Range[km]‘）;ylabel（‘Amplitude[dB]‘）;
%?title（‘signal?after?pulse?compression‘）;
%?grid?on;
%?ylim（[-300]）;

%%?pulse?doppler
Srec?=?zeros（NprtNsimu）;
Spc?=?zeros（NprtNsimu）;
%?reference?signal
tao?=?0;
Sref?=?rectpuls（tt-tao-Tp/2Tp）.*exp（1i*pi*beta.*（tt-tao-Tp/2）.^2）.*exp（-1i*2*pi*fc*tao）;
Sref_fft?=?fft（Sref）;
Anoise?=?1;
%%?step1:Pulse?compression?along?range?direction?for?each?pulse
for?mm?=?1:Nprt
????%?received?signal
????noise?=?Anoise/sqrt（2）*（randn（1Nsimu）+1i*randn（1Nsimu））;
????noise?=?0;
????taomm?=?2*（Rinti-mm*prt*Vr）/C;
????Srec（mm:）?=?rectpuls（tt-taomm-Tp/2Tp）.*exp（1i*pi*beta.*（tt-taomm-Tp/2）.^2）.*exp（-1i*2*pi*fc*taomm）+noise;
????Srec_fft?=?fft（Srec（mm:））;
????Spc（mm:）?=?ifft（Srec_fft.*conj（Sref_fft））;?%?signal?after?pulse?compression
end

%?mesh?the?signal?after?pulse?compression-3D
figure（‘name‘‘signal?after?pulse?compression?-?3D‘）
mesh（rr1:Nprtabs（Spc））;
xlabel（‘Range[km]‘）;ylabel（‘time[PRT]‘）;?zlabel（‘Amplitude‘）;
title（‘signal?after?puls