sarSurfaceRCS

Radar cross-section of target for SAR

Since R2021a

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    Syntax

    rcs = sarSurfaceRCS(sigmaref,freq,freqref,rngazres,grazang)
    rcs = sarSurfaceRCS(sigmaref,freq,freqref,rngazres,grazang,n)
    rcs = sarSurfaceRCS(nrcs,rngazres,grazang)

    Description

    rcs = sarSurfaceRCS(sigmaref,freq,freqref,rngazres,grazang) returns the target radar cross-section (RCS) for SAR as projected on the ground.

    example

    rcs = sarSurfaceRCS(sigmaref,freq,freqref,rngazres,grazang,n) specifies a frequency-dependent proportionality factor that depends upon the target characteristics.

    example

    rcs = sarSurfaceRCS(nrcs,rngazres,grazang) uses as input the surface normalized radar cross-section, also known as the reflectivity or σ0.

    Examples

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    Open Live Script

    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)')

    Figure contains an axes object. The axes object with xlabel Frequency (GHz), ylabel Target RCS (dBsm) contains an object of type line.

    Input Arguments

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    Reflectivity at nominal reference frequency in square meters per square meter, specified as a positive real scalar.

    Data Types: double

    Radar frequency in hertz, specified as a positive real scalar or a vector.

    Data Types: double

    Nominal reference frequency in hertz, specified as a positive real scalar.

    Data Types: double

    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.

    Data Types: double

    Grazing angle in degrees, specified as a scalar in the range [0, 90].

    Data Types: double

    Frequency-dependent proportionality factor, specified as a real scalar. For distributed targets, n varies between 0 and 1. For nondistributed targets, n is a positive real scalar.

    Data Types: double

    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.

    Data Types: double

    Output Arguments

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    Target radar cross-section for SAR as projected on the ground in square meters, returned as a scalar or a vector. rcs has the same dimensions as either freq or nrcs.

    Extended Capabilities

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    C/C++ Code Generation
    Generate C and C++ code using MATLAB® Coder™.

    Version History

    Introduced in R2021a

    See Also

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