Electronic Countermeasures (ECM) - MATLAB Simulations for Radar Systems Design - page 491

val1 = (num32 ./ demo3).^2;
val2 = (pt * tau * G * sigma * Ar)/(4^2 * pi^2 * loss * sir0 * k *T0);
val3 = sqrt(val1 + val2);
val4 = (ERP .* Ar) ./ demo3;
Range = sqrt(val3 - val4) ./ 1000;
figure (1)
plot (10*log10(ERP), Range,'k')
xlabel (' Jammer ERP in dB')
ylabel ('Burnthrough range in Km')
grid
Listing 10.4. MATLAB Function Ðsoj_req.mÑ
function [BR_range] = soj_req (pt, g, sigma, b, freq, loss, range, ...
pj, bj,gj, lossj, gprime, rangej)
% This function implements equations for SOJs
c = 3.0e+8;
lambda = c / freq;
lambda_db = 10*log10(lambda^2)
if (loss == 0.0)
loss = 0.000001;
end
if (lossj == 0.0)
lossj =0.000001;
end
sigmadb = 10*log10(sigma);
range_db = 10*log10(range * 1000.);
rangej_db = 10*log10(rangej * 1000.)
pt_db = 10*log10(pt);
b_db = 10*log10(b);
bj_db = 10*log10(bj);
pj_db = 10*log10(pj);
factor = 10*log10(4.0 *pi);
BR_range = ((pt * 10^(2.0*g/10) * sigma * bj * 10^(lossj/10) * ...
(rangej)^2) / (4.0 * pi * pj * 10^(gj/10) * 10^(gprime/10) * ...
b * 10^(loss/10)))^.25 / 1000.
s_at_br = pt_db + 2.0 * g + lambda_db + sigmadb - ...
3.0 * factor - 4.0 * 10*log10(BR_range) - loss
index =0;
for ran_var = .1:1:1000;
index = index + 1;
ran_db = 10*log10(ran_var * 1000.0);
s(index) = pt_db + 2.0 * g + lambda_db + sigmadb - ...
3.0 * factor - 4.0 * ran_db - loss + s_at_br;