Introduction to Radar Basics - MATLAB Simulations for Radar Systems Design - page 55

Listing 1.9. MATLAB Program Ðfig1_21.mÑ
%use this figure to generate Fig. 1.21 of text
clear all
close all
np = linspace(1,10000,1000);
snrci = pulse_integration(4,94.e9,47,20,290,20e6,7,10,5.01e3,np,1);
snrnci = pulse_integration(4,94.e9,47,20,290,20e6,7,10,5.01e3,np,2);
semilogx(np,snrci,'k',np,snrnci,'k:')
legend('Coherent integration','Non-coherent integration')
grid
xlabel ('Number of integrated pulses');
ylabel ('SNR - dB');
Listing 1.10. MATLAB Function Ðpulse_integration.mÑ
function [snrout] = pulse_integration(pt, freq, g, sigma, te, b, nf, loss,
range,np,ci_nci)
snr1 = radar_eq(pt, freq, g, sigma, te, b, nf, loss, range) % single pulse SNR
if (ci_nci == 1) % coherent integration
snrout = snr1 + 10*log10(np);
else % non-coherent integration
if (ci_nci == 2)
snr_nci = 10.^(snr1./10);
val1 = (snr_nci.^2) ./ (4.*np.*np);
val2 = snr_nci ./ np;
val3 = snr_nci ./ (2.*np);
SNR_1 = val3 + sqrt(val1 + val2); % Equation 1.87 of text
LNCI = (1+SNR_1) ./ SNR_1; % Equation 1.85 of text
snrout = snr1 + 10*log10(np) - 10*log10(LNCI);
end
end
return
Listing 1.11. MATLAB Program Ðmyradarvisit1_1.mÑ
close all
clear all
pt = 724.2e+3; % peak power in Watts
freq = 3e+9; % radar operating frequency in Hz
g = 37.0; % antenna gain in dB
sigmam = 0.5; % missile RCS in m squared
sigmaa = 4.0; % aircraft RCS in m squared
te = 290.0; % effective noise temperature in Kelvins
b = 1.0e+6; % radar operating bandwidth in Hz