Detection of Radar Signal Modulations Induced by Target Aircraft Structural Vibrations
Abstract
The possibility of aircraft identification using radar signal modulations induced by target airframe vibrations is analyzed. Emphasis is placed on detectability of the signal modulation, but attention is given to dependence on the angle of incidence since a major concern is identification at angles where engine effects are not observable. The approach is to compare the strength of the backscatter modulation relative to the unmodulated signal from the aircraft. Since it is the modulation of the signal that is significant, and not the exact radar cross section, a simple wire model representation of the aircraft is used. The radar backscatter results at 7 MHz and 28 MHz are calculated using a modified method-of-moments solution. The method employs successive static electromagnetic scattering solutions from a target where the position of the wing has been changed between calculations. The results are considered as discrete samples of the continuous, modulated signal. The power of the modulation is then estimated by determining the relative power spectra of the modulated signal. An approach that explicitly derives continuous time dependent scatter is included. This uses a simple crossed dipole theory with wing dipole oscillations. The Dipole model, however, requires external information on the location of the appropriate scattering centers along the dipoles. Since this is incident angle dependent, the model becomes cumbersome.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1979
- Accession Number
- ADA085570
Entities
People
- John F. Lennon
Organizations
- Rome Laboratory