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sarSurfaceRCS

Radar cross-section of target for SAR

    Description

    example

    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.

    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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    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 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

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

    Introduced in R2021a