Experimental measurements of ground reflection elevation multipath characteristics and its effects on a small aperture elevation tracking radar
Abstract
Field measurements for collecting ground reflection data at L-band have been taken at several sites at the Hanscom Air Force Base and Fort Devens. These field data were used for (1) characterization of the multipath environment; (2) validation of propagation models developed for elevation multipath; (3) simulation of elevation angle estimation; and (4) evaluation of various spectral estimation methods and elevation angle estimation algorithms. 'Classical' and 'data adaptive' angular power spectral estimators have been employed as a means to characterize the multipath environment. The maximum entropy angular power spectral estimates appeared to yield better resolution of various multipath arrivals. For propagation model validation, the field measurement results and the computer simulation results have been compared in terms of the angular power spectrum for a variety of measurements made at these sites with various terrain conditions. In most cases, especially when the terrain variation was simple and could be quite accurately modeled as a series of simple rectangular ground plates, fairly good agreement between the propagation model predictions and the field measurement results was obtained in terms of the estimated elevation angles of the direct signal and the ground reflected signals, the number of the ground reflected signals and their multipath levels.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- March 1979
- Bibcode:
- 1979STIN...8019327S
- Keywords:
-
- Ground Wave Propagation;
- Multipath Transmission;
- Radar Echoes;
- Tracking Radar;
- Computerized Simulation;
- Elevation Angle;
- Mathematical Models;
- Power Spectra;
- Predictions;
- Communications and Radar