Signal-to-clutter ratio due to rain
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. The SAR module has aperture processing length of 100 m. Assume the target RCS is 1 m 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
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)')
lambda— Radar wavelength
Radar wavelength in meters, specified as a positive real scalar or a vector.
rrcs— Rain radar cross-section
Rain radar cross-section (RCS) in square meters, specified as a scalar or a vector.
tgtrcs— Target radar cross-section
Target RCS in square meters, specified as a scalar.
t— Aperture collection interval
Aperture collection interval in seconds, specified as a positive real scalar.
vbrain— Rain velocity bandwidth
4(default) | positive scalar
Rain velocity bandwidth in meters per second, specified as a positive scalar.