clear?all;
%%%（I）?parameters‘?definition
c=3e+8;										%?speed?of?light
pi=3.1415926	?					???	%?pi
j00=sqrt（-1）;								%?square?root?of?-1

res_a=1;										%?required?azimuth?resolution
res_r=1;										%?required?range?resolution
k_a=1.2;										%?azimuth?factor
k_r=1.2;										%?range?factor

Ra=4000.;									%?radar?working?distance
va=70.;?										%?radar/platform?forward?velocity
Tp=1.e-6;?									%?transmitted?pulse?width??????
fc=1.e+9;	?						???	%?carrier?frequency?
FsFactor?=?1.0

lamda=c/fc;									%?wavelength
B=k_r*c/2./res_r;							%?required?transmitted?bandwidth
Fs=B*FsFactor;								%?A/D?sampling?rate
bin_r=c/2./Fs;								%?range?bin
gama=B/Tp;									%?range?chirp?rate	

delta_theta=k_a*lamda/2/res_a;		%?required?azimuth?opening?angle
												%?corresponding?to?processed?bandwith
												%?（should?be?less?than?azimuth?3dB?opening?angle）
La=Ra*delta_theta;						%?required?synthetic?aperture
Ta=La/va;									%?required?synthetic?aperture?time
thetas_c=pi/2;								%?zero?squint
fdc=2*va*cos（thetas_c）/lamda;??		%?doppler?centriod
fdr=-2*va*va*sin（thetas_c）^2/lamda/Ra;					%?doppler?rate
Bd=abs（fdr）*Ta;							%?doppler?bandwidth
prf=100.;									%?PRF	

%%%（II）?echo?return?modelling（point?target）
na=fix（Ta*prf/2）;							%?azimuth?sampling?number
ta=-na:na;											
ta=ta/prf;									%?slow?time?along?azimuth
xa=va*ta;									%?azimuth?location?along?flight?track
na=2*fix（na）;

%x0=[0??0?0?0?0?0???-60?-30?30?60];?
%R0=[-10?0?10?20?30?40?0?0?0?0];???????????%%%%%%%?more?than?one?point?target
x0=[0?];?
R0=[0?];

Npt_num?=?length（x0）;
												%?single?point?target‘s?azimuth?location?
												%?positive?towards?forward?velocity
												%?single?point?target‘s?slant?range?location
ra=zeros（Npt_num?length（xa））;??????%?positive?towards?far?range
for?i=1:Npt_num????????????????????????????????????
	ra（i:）=sqrt（（Ra+R0（i））.^2+（xa+x0（i））.^2）;		%?single?point?target‘s?slant?range?history?
end???
rmax=max（max（ra））;						%?max.?slant?range
rmin=min（min（ra））;						%?min.?slant?range
rmc=fix（（rmax-rmin）/bin_r）;			%?range?migration	
rg=0*ra;
rg=fix（（ra-rmin）/bin_r+1）;				%?range?gate?beause?of?range?migration
rgmax=max（max（rg））;
rgmin=min（min（rg））;

nr=round（Tp*Fs）;							%?min?range?samples
tr=1:fix（nr）+1;									
tr=tr/Fs-Tp/2;								%?fast?time?along?range
???????????????????????????????????????????????
[mNa]=size（ta）;
Nr=nr+rgmax;
Na
Nr

sig=zeros（NaNr）;
for?i=1:Na			
	for?k=1:Npt_num
??		sig（irg（ki）:rg（ki）+nr）=sig（irg（ki）:rg（ki）+nr）+exp（-j00*4*pi/lamda*ra（ki））*exp（-j00*pi*gama*（tr）.^2）;
???end??
end
disp（‘end?of?echo?return?modelling‘）
figure（1）
contour（abs（sig））


%%%===============================================================================

for?i=1:Na
???sig（i:）=fftshift（fft（sig（i:）））;		
end
disp（‘end?of?range?fft‘）

dfr=Fs/Nr;
fr=（（0:Nr-1）-Nr/2）*dfr;??				
phase1=exp（-j00*pi*（fr）.^2/gama）

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????3951??2005-12-21?19:18??RD.m

-----------?---------??----------?-----??----

?????????????????4169????????????????????2