PROCESSING REQUIREMENTS FOR SYNTHETIC APERTURE SONAR SYSTEMS

Abstract

This paper develops expressions which relate the parameters of a sonar to the processing power and memory required for the system. These expressions can be used when designing a sonar t o ensure that realistic demands are placed on the processing engine. Benchmark test results are also presented for simulation algorithms running on a variety of machines. RESUME Ce document ddveloppe des expressions mettant en relation les paramgtres d'un sonar avec la puissance et la memoire traitements requises pour le systhme. Ces expressions peuvent dtre utilisBes lois de I'Btude du sonar de f a ~ o n B s'assurer que les exigences r6elles sont placees sur I'appareil traitant. Les resultats des tests de reperage sont Bgalement donn6s pour les simulations algorithmiques d'une vari6tB de machines. INTRODUCTION High resolution mapping of the sea-bed has traditionally been met by side-scan sonars. In radar, synthetic aperture processing is applied t o side-scan systems t o improve the resolution and this technique is now being investigated for side-scan sonar systems. The side-scan technique involves towing a transducer array along a straight path at a constant velocity. Sound is transmitted in a beam perpendicular to the motion of the transducer (fig 1). Range (acrosstrack) resolution is obtained by either transmitting a short pulse, or by transmitting a longer modulated pulse which can later be compressed into a short pulse. Azimuth (along-track) resolution is obtained by using a narrow beam, which means that a traditional side-scan sonar needs to operate at a high frequency which in turn reduces the operating range or with a long antenna which makes the system more costly and more cumbersome. Scanning Fleorns SIDE VlEW PI