Influence of Digital Map Discreteness on Low Angle Land Clutter Modeling

The earth’s surface can be divided into various types of cover (grass, forests, bare ground, etc.), each of which has unique reflecting properties. However, even within the same type of cover, reflections can vary due to differences in the composition and structure of the surface. In this case, the reflectivity of the earth with heterogeneities is a random variable with an exponential correlation function. The correlation radius affects the requirements for model discreteness, that is, the size of the cells into which the surface is divided during modeling. This work considers the effect of the discreteness of the digital terrain map on the spread of the power of the signal reflected from such areas. Statistical and spectral characteristics of the reflected signals are considered. The presented general relations are specified for commonly used approximations of the radiation pattern and probing pulses. The resulting relations can be used in simulating reflections from the earth’s surface for radar operation modeling.