# Figure 6. The β=1 Clutter Ridge.

## Contents

clc; clear; close all;


radar_oper_params;

% Azimuth angle in degrees:
phi = -180:.5:180;
Lphi = length(phi);


## Platform Parameters:

va = 50;                      % Platform velocity in m/sec.
ha = 9e3;                     % Platform altitude in meters.
Rc = 13e4;                    % (clutter) range of interest in meters.
psi = asin(ha/Rc);            % Grazing angle at the clutter patch in rad (flat earth model).
theta = psi;                  % Depression angle to ik-th clutter patch (flat earth model).


## Spatial Frequency of ik-th Clutter Patch:

fsp = d/lambda*cos(theta)*sin(phi*pi/180);         % Eq. (54)


## Doppler Frequency of ik-th Clutter Patch:

fd = 2*va/lambda*cos(theta)*sin(phi*pi/180);       % Eq. (69)


## Normalized Doppler Frequency:

omegac = 2*va*Tr/d*fsp;                            % Eq. (70)

beta = 2*va*Tr/d;                                  % Eq. (71)


## Plot Doppler Frequency vs Azimuth and Normalized Doppler Frequency vs Spatial Frequency.

figure('NumberTitle', 'off','Name',...
['Figure 6. The β=1 Clutter Ridge for Side Looking Airborne Radar (SLAR). The PRF is ', ...
num2str(fr),' Hz.'],'Position', [50  50  900 400] );
subplot(1,2,1);
plot(sin(phi*pi/180),fd,'.');
grid on;
ylabel('Doppler Frequency f_c(\theta_c,\phi_c) (Hz)');
xlabel('sin(\phi_c)');

subplot(1,2,2);
plot(fsp,omegac,'.');
grid on;
ylabel('Normalized Doppler Frequency \omega_c');
xlabel('Spatial Frequency \vartheta_c'); 