Radar cross-section of target for SAR
Estimate the target radar cross-section (RCS) of a side-looking airborne SAR operating at frequencies between 16 GHz to 17 GHz and grazing at 30. The target reflectivity is –25 dB at the Ku band (nominally 16.7 GHz). The radar has a slant range resolution of 15 m and an azimuth resolution of 18 m. Assume a frequency-dependent proportionality factor of 1.
f = 16e9:1e7:17e9; sigmaref = -25; fref = 16.7e9; rngazres = [15 18]; grazang = 30;
Convert the reflectivity to linear units. Compute the target RCS.
sigma = sarSurfaceRCS(db2pow(sigmaref),f,fref,rngazres,grazang);
Plot the RCS in decibels as a function of frequency.
plot(f/1e9,pow2db(sigma),'.-') xlabel('Frequency (GHz)') ylabel('Target RCS (dBsm)')
sigmaref— Reflectivity at nominal reference frequency
Reflectivity at nominal reference frequency in square meters per square meter, specified as a positive real scalar.
freq— Radar frequency
Radar frequency in hertz, specified as a positive real scalar or a vector.
freqref— Nominal reference frequency
Nominal reference frequency in hertz, specified as a positive real scalar.
rngazres— Slant range and azimuth resolutions
Slant range and azimuth resolutions, specified as a 1-by-2 row vector of positive real scalars.
The first element of
rngazres specifies the slant range
resolution in meters.
The second element of
rngazres specifies the azimuth or
cross-range resolution in meters.
grazang— Grazing angle
Grazing angle in degrees, specified as a scalar in the range [
n— Frequency-dependent proportionality factor
1(default) | positive real scalar
Frequency-dependent proportionality factor, specified as a real scalar. For distributed
n varies between 0 and 1. For nondistributed targets,
n is a positive real scalar.
nrcs— Surface normalized radar cross-section
Surface normalized radar cross-section in square meters per square meter, specified as a nonnegative scalar or row vector. The surface normalized radar cross-section is also known as the reflectivity or σ0.