Figure 25. SINR 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;
Warning: The value of local variables may have been changed to match the
globals.  Future versions of MATLAB will require that you declare a
variable to be global before you use that variable. 

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)

Calculate the SINR for Optimal and Tapered Fully Adaptive STAP

ta = chebwin(N,30);                                      % 30 dB Chebychev Spatial Taper.
tb = chebwin(M,40);                                      % 40 dB Chebychev Doppler Taper.
t = kron(tb,ta);                                         % Composite Space-Time Taper.
phit = 0; thetat = 0;                                    % Target Azimuth and Elevation Angles.
fspt = d/lambda*cos(thetat*pi/180)*sin(phit*pi/180);     % Target Spatial Frequency.
fd = 0:300;   Lfd = length(fd);
omega = fd/fr;
a = exp(1i*2*pi*fspt*(0:N-1));                           % Target Spatial Steering Vector.
SINRopt = zeros(1,Lfd);
SINRtap = zeros(1,Lfd);
InvRu = inv(Ru);

for n=1:Lfd
    b = exp(1i*2*pi*omega(n)*(0:M-1));                   % Target Dummy Doppler Steering Vector
    v = kron(b,a).';
    gt = t.*v;
    w = InvRu*v; %#ok<*MINV>                             % Eq. (104)
    wtap = InvRu*gt;                                     % Eq. (106)
    SINRopt(n) = w'*v;                                   % Eq. (114)
    SINRtap(n) = abs(wtap'*v)^2/real(wtap'*gt);          % Eq. (115)
end

Plot the SINR

figure('NumberTitle', 'off','Name', ...
       'Figure 25. SINR for the Optimum and Tapered Fully Adaptive STAPs', ...
       'Position',[1 1 600 500]);
plot(fd,10*log10(abs(SINRopt)),'LineWidth',1.5)
hold on;
plot(fd,10*log10(abs(SINRtap)),'r','LineWidth',1.5)
ylabel('SINR (dB)');
xlabel('Target Doppler Frequency (Hz)');
ylim([-5 26]);
xlim([-2 302]);
legend('Optimum Fully Adaptive', 'Tapered Fully Adaptive', 'Location','South')
grid on;