Use of apparent source position in multiple knife-edge diffraction

This paper addresses the implication of a local description of a wavefield undergoing multiple knife-edge diffraction. As a consequence of the local shape of the wavefield, corrections are proposed to the standard calculations of geometrical optics with respect to both the angle of incidence and the source distance. This approach originates from Whitteker (1984) who proposed a modified line source for near-field ray calculations. We call this the concept of “apparent source position”. Applying these corrections renders UTD calculations more accurate for the case of multiple knife-edge diffraction. It can also be used in modelling radio signal transport from rooftop down to street level