Over-the-Horizon Propagation Measurements at Six Radar-Frequency Bands at the Atlantic Ocean Coast
Abstract
In the autumn of 1989 the propagation subgroup of NATO AC/243 has conducted a propagation experiment near Lorient France, at the Atlantic Ocean. The purpose of this experiment was to gain an insight into the influence of the evaporation duct above the sea on the propagation of radar signals of different frequencies in an over-the-horizon situation, and into the applicability of model predictions. The geometry of the experiment has been chosen to represent a typical ship defence situation. The measurements have shown that for the present case the nearly always present evaporation duct results in a signal enhancement with the strongest effects at the 10.5 and 16 GHz frequencies. An extended study of the quality of the model predictions, possible by the unique set of measurement results, shows some interesting matters. If we divide the process of prediction into two parts, the calculation of the duct height from the meteorological data and the path loss calculation from this duct height, we come to the conclusion that the first part is responsible for the largest inaccuracies. The used duct height calculation method showed systematic deviations for different meteorological conditions. The inaccuracy of the duct height calculation makes useful path loss predictions at the millimeter-wave frequencies (35 and 94 GHz) impossible for this over-the-horizon situation. The predictions at the lower frequencies are much better, but not always satisfactory. The deviation analyses in this report can be useful to improve propagation models.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1993
- Accession Number
- ADA274151
Entities
People
- R. B. Boekema
Organizations
- Netherlands Organisation for Applied Scientific Research