www.pudn.com > programradarsystemdisign.zip > fig1_19.m

% Use this program to reproduce Fig. 1.19 and Fig. 120 of text. 
close all 
clear all 
pt = 4; % peak power in Watts 
freq = 94e+9; % radar operating frequency in Hz 
g = 47.0; % antenna gain in dB 
sigma = 20; % radar cross section in m squared 
te = 293.0; % effective noise temperature in Kelvins 
b = 20e+6; % radar operating bandwidth in Hz 
nf = 7.0; %noise figure in dB 
loss = 10.0; % radar losses in dB 
range = linspace(1.e3,12e3,10000); % range to target from 1. Km 12 Km, 1000 points 
snr1 = radar_eq(pt, freq, g, sigma, te, b, nf, loss, range); 
index = find(snr1>9.99999 & snr1<10.0099); 
test = isempty(index); 
if(test==1) 
    'Error; Tighten values in line 14, and re-run again' 
    break 
else 
end 
snr_ref = snr1(index); 
r_ref = range(index); 
R_ref_ci = (94^0.25) .* r_ref; 
snrCI = snr_ref + 40*log10(R_ref_ci ./ range); %Eq. (1.60) 
% plot SNR versus range 
figure(1) 
rangekm  = range ./ 1000; 
plot(rangekm,snr1,'k',rangekm,snrCI,'k -.') 
axis tight 
grid 
legend('single pulse','94 pulse CI') 
xlabel ('Detection range - Km'); 
ylabel ('SNR - dB'); 
% Generate Figure 1.20 
% first find the new reference range 
snr_b10 = 10.^(10/10); 
SNR_1 = 10/(2*94) + sqrt(((10^2) / (4*94*94)) + (10 / 94)); % Equation 1.80 of text 
LNCI = (1+SNR_1) / SNR_1; % Equation 1.78 of text 
%snrnci_ref = snrCI -10*log10(LNCI); 
NCIgain = 10*log10(94) - 10*log10(LNCI); 
R_ref_nci = ((10^(0.1*NCIgain))^0.25) * 2.245e3; 
snrNCI = snr_ref + 40*log10(R_ref_nci ./ range); %Eq. (1.60) 
figure (2) 
plot(rangekm,snr1,'k',rangekm,snrNCI,'k -.', rangekm,snrCI,'k:') 
axis tight 
grid 
legend('single pulse','94 pulse NCI','94 pulse CI') 
xlabel ('Detection range - Km'); 
ylabel ('SNR - dB');