Signal enhancement for ship mounted sonar by overlapping sectional synthetic aperture method
| Autor: | Shoji Fujii, Fujita Hajime, Osamu Sekiguchi |
|---|---|
| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | The Journal of the Marine Acoustics Society of Japan. 20:37-43 |
| ISSN: | 1881-6819 0916-5835 |
| DOI: | 10.3135/jmasj.20.37 |
| Popis: | This paper proposes a new method in sonar signal processing using “Overlapping sectional synthetic aperture.” This method is developed to provide high azimuthal resolution in a synthetic aperture operation even when a ship cannot keep moving on a straight “base” line. Three errors in a ship positioning are assumed, i.e., in travel distance, lateral location and aperture direction.The aperture direction is at first detected with a gyroscope and made parallel to the base line using mechanical feedback system. The travel distance error is measured with an accelerometer and fed into the signal processing procedure. The lateral distance is then corrected as follows.Signals from the overlapping part of two successive apertures overlapping in the base line direction with the lateral deviation in position are compared and the phase difference between two signals are detected. Signal of the non-overlapping part of the second aperture is corrected using this phase difference. It is possible to obtain much higher azimuthal resolution than a single aperture by repeating this procedure. This method does not require to change most of conventional sonar system and the signal processing is performed mostly using Fourier transform. Results of computer simulation prove the effectiveness of this method. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|