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Billingsley’s intrinsic clutter motion (ICM) model


P = billingsleyicm(fd,fc,wspeed)
P = billingsleyicm(fd,fc,wspeed,c)


P = billingsleyicm(fd,fc,wspeed) calculates the clutter Doppler spectrum shape, P, due to intrinsic clutter motion (ICM) at Doppler frequencies specified in fd. ICM arises when wind blows on vegetation or other clutter sources. This function uses Billingsley’s model in the calculation. fc is the operating frequency of the system. wspeed is the wind speed.

P = billingsleyicm(fd,fc,wspeed,c) specifies the propagation speed c in meters per second.

Input Arguments


Doppler frequencies in hertz. This value can be a scalar or a vector.


Operating frequency of the system in hertz.


Wind speed in meters per second.


Propagation speed in meters per second.

Default: Speed of light

Output Arguments


Shape of the clutter Doppler spectrum due to intrinsic clutter motion. The vector size of P is the same as that of fd.


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Calculate and plot the Doppler spectrum shape predicted by the Billingsley ICM model. Assume the PRF is 2 kHz, the operating frequency is 1 GHz, and the wind speed is 5 m/s.

v = -3:0.1:3;
fc = 1e9;
wspeed = 5;
c = physconst('LightSpeed');
fd = 2*v/(c/fc);
p = billingsleyicm(fd,fc,wspeed);
xlabel('Doppler frequency (Hz)')
ylabel('P (dB)')

Figure contains an axes. The axes contains an object of type line.


[1] Billingsley, J. Low Angle Radar Clutter. Norwich, NY: William Andrew Publishing, 2002.

[2] Long, Maurice W. Radar Reflectivity of Land and Sea, 3rd Ed. Boston: Artech House, 2001.

Extended Capabilities

Introduced in R2021a