Effects of Ground Reflections on Frequency Modulated Signals
Abstract
It is well known that ground reflections cause ambiguities in radar detection and tracking. A more serious problem is the interference that occurs when the phase difference between the direct signal and the ground reflected signal is small. This has been well studied in the context of the usual pulsed signals. There is little that can be done to entirely eliminate this problem. In this report the effect on frequency modulated signals of reflections from surfaces with different statistics is investigated. The ground reflection studied in this report is the coherent reflection. Four different kinds of rough surfaces (normal, exponential, Rayleigh and skew-normal) are considered. In each case an explicit expression for the received signal is obtained. Although the normal distribution is the most commonly used model, in applications the surfaces often have asymmetric characteristics. The three other distributions considered in this report are asymmetric. It is found that the received signals for normal and exponential surfaces have quite different amplitude characteristics. It is found that the Gaussian model may be a reasonable approximation for such asymmetric surfaces only when the Rayleigh roughness parameter is small.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1992
- Accession Number
- ADA275685
Entities
People
- Saba Mudaliar
Organizations
- Rome Laboratory