rainscr

Estimate the signal-to-clutter-ratio due to rain of a side-looking airborne SAR. The SAR moves at 50 m/s in a direction orthogonal to the antenna boresight and operates at a frequency of 1.5 GHz. The rain rates are 0.25 mm/hr, 1 mm/hr, 4 mm/hr, and 16 mm/hr. The rain clutter volume is 20 m$${}^3$$. The SAR module has aperture processing length of 100 m. Assume the target RCS is 1 m$${}^2$$ and the velocity bandwidth of the rain is 4 m/s.

v = 50;
f = 1.5e9;
lambda = freq2wavelen(f);

rr = [0.25 1 4 16];
vol = 20;

L = 100;
tgtrcs = 1;
vbrain = 4;

Compute the signal-to-clutter ratio. Use rainreflectivity and clutterVolumeRCS to compute the rain radar cross-section. Use sarinttime to compute the aperture collection interval.

volref = rainreflectivity(f,rr);
rrcs = clutterVolumeRCS(volref,vol);
t = sarinttime(v,L);
scr = rainscr(lambda,rrcs,tgtrcs,t,vbrain);

Plot the signal-to-clutter ratio as a function of the rain rate.

semilogx(rr,scr,'o-')
xlabel('Rain Rate (mm/rr)')
ylabel('Signal-to-Clutter Ratio (dB)')