Figure 28. SINR Improvement Factor for the Optimum and Tapered Fully Adaptive STAP.

Contents

Coded by Ilias Konsoulas, 16 Sept. 2018. Code provided for educational purposes only. All rights reserved.

clc; clear; close all;

Radar System Operational Parameters

radar_oper_params;

Thermal Noise Power Computation

thermal_noise_power;

Thermal Noise Covariance Matrix

Rn = sigma2*eye(M*N);

Clutter Patch RCS Computation

clutter_patch_rcs;

Calculate the Array Transmit and Element Receive Power Gains

Tx_Rx_power_gains;

Calculate the Clutter to Noise Ratio (CNR) for each clutter patch:

ksi = Pt*Gtgain.*Grec*lambda^2*sigma/((4*pi)^3*Pn*10^(Ls/10)*Rcik^4);   % Eq. (58)

Clutter Covariance Matrix Computation

beta = 1;   % beta parameter.
phia = 0;   % Velocity Misalignment Angle.

Rc = clutt_cov(ksi,beta);

Jamming Covariance Matrix Calculation

jamm_cov;

Total Interference Covariance Matrix

Ru = Rc + Rj + Rn;                                        % Eq. (98)

SINR Improvement Factor Calculation

ta = chebwin(N,30);                                       % 30 dB Chebychev Spatial Tapper.
tb = chebwin(M,40);                                       % 40 dB Chebychev Doppler Taper.
t = kron(tb,ta);
phit = 0; thetat = 0;                                     % Target Azimuth and Elevation Angles.
fspt = d/lambda*cos(thetat*pi/180)*sin(phit*pi/180);      % Target Spatial Frequency.
fd = 0:.5:300;   Lfd = length(fd);
omega = fd/fr;
a = exp(1i*2*pi*fspt*(0:N-1));                            % Target Spatial Steering Vector.
ISINRopt = zeros(1,Lfd);
ISINRtap = zeros(1,Lfd);
InvRu = inv(Ru);
ksiin = sum(ksi) + sum(ksi_j) ;                           % Input Interference-to-Noise-Ratio on a single element for a single pulse.
SINRin = 1/(1+ ksiin);                                    % Eq. (121)
for n=1:Lfd
    b = exp(1i*2*pi*omega(n)*(0:M-1));                    % Dummy Target Doppler Steering Vector
    v = kron(b,a).';
    gt = t.*v;
    w = InvRu*v; %#ok<*MINV>
    wtap = InvRu*gt;
    ISINRopt(n) = w'*v/SINRin;                            % Eq. (124) for the Optimum Fully Adaptive Case.
    ISINRtap(n) = abs(wtap'*v)^2/real(wtap'*gt)/SINRin;   % Eq. (124) for the Tapered Fully Adaptive Case.
end

Plot the SINR Improvement Factors

figure('NumberTitle', 'off','Name', ...
       'Figure 28. SINR Improvement Factor for the optimum and tapered fully adaptive STAP',...
       'Position', [1 1 600 500]);
plot(fd,10*log10(abs(ISINRopt)),'LineWidth',1.5)
hold on;
plot(fd,10*log10(abs(ISINRtap)),'r','LineWidth',1.5)
ylabel('SINR Improvement Factor (dB)');
xlabel('Target Doppler Frequency (Hz)');
ylim([45 76]);
xlim([-2 302]);
legend('Optimum Fully Adaptive', 'Tapered Fully Adaptive', 'Location','South')
grid on;