The current paper investigates the shallow layers of the lunar regolith
at the Chang'E-4 landing site. Four layers between 0-10 meters were
identified using lunar penetrating radar. Based on these outputs, a
revised stratigraphic model is suggested for the post-Imbrian ejecta at
the Von Karman crater. The layers were previously unseen due to the
smooth boundaries between them. The revised model was inferred using an
advanced hyperbola-fitting scheme. Applying conventional
hyperbola-fitting to non-homogeneous media results in errors and
inaccuracies that are often wrongly assumed to be negligible. We propose
a novel hyperbola-fitting scheme that is not constrained to homogeneous
media and can be applied subject to any arbitrary one-dimensional
permittivity distribution. Via this approach, we can estimate the
permittivity profile of an investigated area and detect layered
structures that were previously transparent to electromagnetic waves due
to the gradational dielectric properties at their interfaces.