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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.


collapse all

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)')


[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 R2011b

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