# Accession Number:

## ADA169327

# Title:

## Surface Correlation Relationships in Rough Surface Scattering.

# Descriptive Note:

## Rept. for Sep 84-Sep 85,

# Corporate Author:

## ROME AIR DEVELOPMENT CENTER GRIFFISS AFB NY

# Personal Author(s):

# Report Date:

## 1986-03-01

# Pagination or Media Count:

## 36.0

# Abstract:

There are a number of approaches to the calculation of the electromagnetic scattering from rough surfaces. These techniques are important in the determination of the effects of the real environment on radar and communications systems. The models contain descriptions of the surface in terms of the statistical distribution of the heights and their degree of correlation. These features are then related to a normalized radar cross section for the terrain, sigma deg, through an electromagnetic analysis. In this report we are concerned with questions involving the application of physical optics principles to the analysis. This is important since this approach is used extensively both as a complete solution and as part of composite models. Secondly, we discussed several areas where the statistics and correlation have important roles in determining the scattering from a random rough surface. This is significant in that the usual assumption of a Gaussian distribution of heights with Gaussian correlation may not apply to all types surfaces. Power spectra results suggest that other forms would be more appropriate for some cases. In the beginning of this report, we examine statistical descriptors of a surface and establish the relationship between them and the conditions for applying a physical optics model to the scattering from that surface. We then examine the sensitivity of the distribution of scattered power to changes in the form of the surface height statistics and correlation function. Specifically, we examine the effect of three different correlation functions on the normalized bistatic cross section of a rough surface.

# Descriptors:

- *SURFACE ROUGHNESS
- *ELECTROMAGNETIC SCATTERING
- MATHEMATICAL MODELS
- OPTICS
- SCATTERING
- ENVIRONMENTS
- MODELS
- STATISTICS
- POWER SPECTRA
- RADAR
- TERRAIN
- SURFACES
- CORRELATION
- CROSS SECTIONS
- RADAR CROSS SECTIONS
- POWER
- STATISTICAL DISTRIBUTIONS
- RADAR SIGNALS
- RADIO WAVES
- DETERMINATION
- ELECTROMAGNETISM
- HEIGHT
- FUNCTIONS(MATHEMATICS)
- BISTATIC RADAR

# Subject Categories:

- Radiofrequency Wave Propagation