Billingsley’s intrinsic clutter motion (ICM) model
calculates the clutter Doppler spectrum shape,
P = billingsleyicm(
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.
Compute Billingsley Doppler Spectrum
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); plot(fd,pow2db(p)) xlabel('Doppler frequency (Hz)') ylabel('P (dB)')
fd — Doppler frequencies
scalar | vector
Doppler frequencies in hertz, specified as a scalar or a vector.
fc — Operating frequency of the system
Operating frequency of the system in hertz, specified as a scalar.
wspeed — Wind speed
Wind speed in meters per second, specified as a scalar.
c — Propagation speed
physconst("LightSpeed") (default) | positive scalar
Propagation speed in meters per second, specified as a positive scalar.
343 meters per second approximates the speed of
sound at sea level and at a temperature of 20 °C under normal atmospheric
P — Shape of the clutter Doppler spectrum
scalar | vector
Shape of the clutter Doppler spectrum due to intrinsic clutter motion,
returned as a scalar or vector.
P is the same size as
 Billingsley, J. Low Angle Radar Clutter. Norwich, NY: William Andrew Publishing, 2002.
 Long, Maurice W. Radar Reflectivity of Land and Sea, 3rd Ed. Boston: Artech House, 2001.
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
Does not support variable-size inputs.
Introduced in R2021a