  Simulation of radar cross-sections (RCS) of pedestrians at automotive radar
frequencies forms a key tool for software verification test beds for advanced
driver assistance systems. Two commonly used simulation methods are: the
computationally simple scattering center model of dynamic humans; and the
shooting and bouncing ray technique based on geometric optics. The latter
technique is more accurate but due to its computational complexity, it is
usually used only for modeling scattered returns of still human poses. In this
work, we combine the two methods in a linear regression framework to accurately
estimate the scattering coefficients or reflectivies of point scatterers in a
realistic automotive radar signal model which we subsequently use to simulate
range-time, Doppler-time and range-Doppler radar signatures. The simulated
signatures show a normalized mean square error below 10% and a structural
similarity above $81\%$ with respect to measurement results generated with an
automotive radar at 77 GHz.
