Parallel algorithms for split-aperture conventional beamforming

Quiet submarine threats and high clutter in the littoral,undersea:environme nt increase the processing demands on beamforming arrays, particularly for applications which require in-array autonomous operation. Whereas tradition al single-aperture beamforming approaches may falter, the Split-Aperture Co nventional Beamforming (SA-CBF) algorithm can be used to meet stringent req uirements for more precise bearing estimation. Moreover, by coupling each t ransducer node with a microprocessor, parallel processing of the split-aper ture beamformer on a distributed system can glean advantages in execution s peed, fault tolerance, scalability, and cost. In this paper, parallel algor ithms for SA-CBF are introduced using coarse-grained and medium-grained for ms of decomposition. Performance results from parallel and sequential algor ithms are presented using a distributed system testbed comprised of a clust er of workstations connected by a high-speed network. The execution times, parallel efficiencies, and memory requirements of each parallel algorithm a re presented and analyzed. The results of these analyses demonstrate that p arallel in-array processing holds the potential to meet the needs of future advanced sonar beamforming algorithms in a scalable fashion.