Maximum Likelihood Adaptive Neural Systems (MLANS) Application to High Frequency (HF) Propagation
Abstract
The feasibility of applying a model-based neural network technique to investigate the properties of ionospheric clutter observed in the operation of high frequency (HF) propagation systems was examined. Individual ionospheric clutter structures found in the amplitude-range-Doppler (ARD) spectra of over-the-horizon (OTH) radar data were successfully segmented and characterized. A multi-mode Gaussian clutter model was formulated using the Maximum Likelihood Adaptive Neural System (MLANS) to fit the observations. The results indicate that either a three or a four mode Gaussian model is sufficient for MLANS to segment and characterize the observed clutter. High Fidelity simulations of time slices of the raw data were achieved by combining time-varying Gaussian together with a time-varying uniform distribution to represent the noise floor. Each Gaussian mode (or model) is characterized by a time-varying set of three parameters: amplitude, Doppler spread, and Doppler shift.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1997
- Accession Number
- ADA339150
Entities
People
- C. P. Plum
- L. I. Perlovsky
- T. C. Marzetta
- V. H. Webb