Moving Target Indicator (MTI) and Clutter Mitigation - MATLAB Simulations for Radar Systems Design - page 312

range = linspace(25,120,500); % radar slant range 25 to 120 Km, 500 points
% calculate the clutter RCS and the associated CNR for both targets
[sigmaCa,CNRa] = clutter_rcs(sigma0, thetaE, thetaA, SL, range, hr, hta, pt,
f0, b, t0, f, l,2);
[sigmaCm,CNRm] = clutter_rcs(sigma0, thetaE, thetaA, SL, range, hr, htm, pt,
f0, b, t0, f, l,2);
close all
%%%%%%%%%%%%%%%%%%%%%%%%
np = 4;
pfa = 1e-7;
pdm = 0.99945;
pda = 0.99812;
% calculate the improvement factor
Im = improv_fac(np,pfa, pdm);
Ia = improv_fac(np, pfa, pda);
% caculate the integration loss
Lm = 10*log10(np) - Im;
La = 10*log10(np) - Ia;
pt = pt * 1000; % peak power in watts
range_m = 1000 .* range; % range in meters
g = 34.5139; % antenna gain in dB
sigmam = 0.5; % missile RCS m squared
sigmaa = 4; % aircraft RCS m squared
nf = f; %noise figure in dB
loss = l; % radar losses in dB
losstm = loss + Lm; % total loss for missile
lossta = loss + La; % total loss for aircraft
% modify pt by np*pt to account for pulse integration
SNRm = radar_eq(np*pt, f0, g, sigmam, t0, b, nf, losstm, range_m);
SNRa = radar_eq(np*pt, f0, g, sigmaa, t0, b, nf, lossta, range_m);
snrm = 10.^(SNRm./10);
snra = 10.^(SNRa./10);
CNRm = CNRm - clutter_attenuation;
CNRa = CNRa - clutter_attenuation;
cnrm = 10.^(CNRm./10);
cnra = 10.^(CNRa./10);
SIRm = 10*log10(snrm ./ (1+cnrm));
SIRa = 10*log10(snra ./ (1+cnra));
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
figure(3)
plot(range, SNRm,'k', range, CNRm,'k :', range,SIRm,'k -.')
grid
legend('Desired SNR; from Chapter 5' ,'CNR','SIR with 3-pulse','MTI filter')
xlabel('Slant Range in Km')