%?========================================================================
%?Chirp?Scaling?Algorithm
%?========================================================================
%?Implementation?of?the?basic?algorithm?for?Extended?Chirp?Scaling?after
%?the?paper:
%?“Extended?Chirp?Scaling?Algorithm?for?Air-?and?Spaceborne?SAR?Data
%?Processing?in?Stripmap?and?ScanSAR?Imaging?Modes“.?A.?Moreira
%?J.?Mittermayer?R.?Scheiber.?IEEE?Trans?Geoscience?and?Remote?Sensing
%?34（5）:?1123-1136?1996
%?========================================================================

clear?all;?
close?all;
doPlot?=?0;?%?1?to?draw?plots?0?to?skip?all?plots
doMesh?=?0;?%?1?to?draw?meshs?0?to?skip?all?meshs

%?========================================================================
%?set?parameters?read?parameters
%?========================================================================
%?example?raw?data?point?target?from?file?‘pointtarget.raw‘
c?=?299702547;?%?in?air?vacuum:?299792458;
f_c?=?10000000000;?%?carrier?frequency
f_s?=?100000000;?%?data?sampling?rate
echoes?=?348;?%?number?of?echoes?in?data?file
samples?=?152;?%?number?of?samples?per?echo
tau?=?2.83529480918429e-006:1/f_s:2.83529480918429e-006+samples/f_s-1/f_s;?%?fast?time
f_dc?=?0;?%?Doppler?centroid
v?=?200;?%?SAR?platform?velocity
PRF?=?1000;?%?pulse?repetition?frequency
t_p?=?5e-7;?%?chirp?pulse?duration
B?=?100000000;?%?chirp?bandwidth

%?envisat?swath?IS7?IM?Mode:
%?f_c?=?5331004416;
%?f_s?=?19207680;
%?echoes?=?2048;
%?samples?=?2048;
%?tau?=?0.00691589:1/f_s:0.00691589+samples/f_s-1/f_s;
%?f_dc?=?-97.341634;
%?v?=?7065.51587;
%?PRF?=?2067.120103315;
%?t_p?=?2.160594095e-5;
%?B?=?16000000;

r_ref?=?（tau（1）+samples/2/f_s）/2*c;%--------------參考距離
alpha?=?1;
f_a?=?-PRF/2+f_dc:PRF/echoes:f_dc+PRF/2-PRF/echoes;
f_r?=?-f_s/2:f_s/samples:f_s/2-f_s/samples;
lambda?=?c/f_c;

%?read?the?raw?data
data=readMatrix（‘pointtarget.raw‘1samples1echoes）;
data0=data;
G=abs（data）;
xg=max（max（G））;?ng=min（min（G））;?cg=255/（xg-ng）;
figure;
colormap（gray（256））
image（256-cg*（G-ng））;
axis（‘image‘）;axis（‘xy‘）
xlabel（‘range‘）
ylabel（‘azimuth‘）
title（‘SAR?raw?data‘）

%?========================================================================
%?azimuth?fft
%?========================================================================
data?=?ftx（data）;

if?（doPlot==1）
????G=angle（data）;
????xg=max（max（G））;?ng=min（min（G））;?cg=255/（xg-ng）;
????figure;
????colormap（jet（256））
????image（256-cg*（G-ng））;
????axis（‘image‘）;axis（‘xy‘）
????xlabel（‘range‘）
????ylabel（‘Doppler?frequency‘）
????title（‘range?signal/Doppler?domain‘）
end;
%%

%?========================================================================
%?chirp?scaling?range?scaling:?H1
%?========================================================================
beta?=?（1?-?（f_a*lambda/2/v）.^2）.^0.5;
a?=?1./beta?-?1;%----（4-29式）
R?=?r_ref./beta;%----（4-28式）
a_scl?=?a?+?（1-alpha）.*（1+a）./alpha;
k_

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件????????8231??2016-01-04?10:39??cs0\chirpscaling.m
?????文件????????6646??2016-01-04?10:39??cs0\cs.m
?????文件?????????336??2016-01-04?10:39??cs0\ftx.m
?????文件?????????338??2016-01-04?10:39??cs0\fty.m
?????文件?????????344??2016-01-04?10:39??cs0\iftx.m
?????文件?????????350??2016-01-04?10:39??cs0\ifty.m
?????文件????????1600??2016-01-04?10:39??cs0\readMatrix.m
?????目錄???????????0??2016-01-06?23:18??cs0\