www.gusucode.com > phased 案例源码 matlab代码程序 > phased/BackscatterPolarizedSignalExample.m
%% Backscatter Polarized Signal % Calculate the polarized radar signal scattered from a Swerling1 % fluctuating point target. Assume the target axis is rotated from the % global coordinate system. Use simple expressions for the scattering % patterns for illustration. Real scattering patterns are more complicated. % For polarized signals, you need to specify the _HH_, _HV_, and _VV_ % components of the scattering matrix for a range of incident angles. In % this example, the patterns cover the range 10°–30° in % azimuth and 5°–15° in elevation. Angles are with respect to % the target local coordinate system. Assume that the radar operating % frequency is 1 GHz and that the signal is a sinusoid with a frequency of % 1 MHz. The incident angle is 13.0° azimuth and 14.0° elevation % with respect to the target orientation. %% % *Note:* This example runs only in R2016b or later. If you are using an earlier % release, replace each call to the function with the equivalent |step| % syntax. For example, replace |myObject(x)| with |step(myObject,x)|. %% % Create and plot the scattering matrix patterns. azmax = 20.0; elmax = 10.0; azpattern = [10.0:0.1:30.0]; elpattern = [5.0:0.1:15.0]; shhpat = cosd(4*(elpattern - elmax))'*cosd(4*(azpattern - azmax)); shvpat = 1i*cosd(4*(elpattern - elmax))'*sind(4*(azpattern - azmax)); svvpat = sind(4*(elpattern - elmax))'*sind(4*(azpattern - azmax)); subplot(1,3,1) imagesc(azpattern,elpattern,abs(shhpat)) axis image axis tight title('HH') xlabel('Azimuth (deg)') ylabel('Elevation (deg)') subplot(1,3,2) imagesc(azpattern,elpattern,abs(shvpat)) axis image axis tight title('HV') xlabel('Azimuth (deg)') subplot(1,3,3) imagesc(azpattern,elpattern,abs(svvpat)) axis image axis tight title('VV') xlabel('Azimuth (deg)') %% % Create the |phased.BackscatterRadarTarget| System object(TM). target = phased.BackscatterRadarTarget('EnablePolarization',true,... 'Model','Swerling1','AzimuthAngles',azpattern,... 'ElevationAngles',elpattern,'ShhPattern',shhpat,'ShvPattern',shvpat,... 'SvvPattern',svvpat); %% % Generate 50 samples of a polarized radar signal. foper = 1.0e9; freq = 1.0e6; fs = 10*freq; nsamp = 50; t = [0:(nsamp-1)]'/fs; signal.X = exp(1i*2*pi*freq*t); signal.Y = exp(1i*2*pi*freq*t + pi/3); signal.Z = zeros(size(signal.X)); tgtaxes = azelaxes(60,10); ang = [13.0;14.0]; %% % Reflect the signal from the target and plot its components. refl_signal = target(signal,ang,tgtaxes,true); figure plot(t*1e6,real(refl_signal.X)) hold on plot(t*1e6,real(refl_signal.Y)) plot(t*1e6,real(refl_signal.Z)) hold off xlabel('Time \mu seconds') ylabel('Amplitude') grid