Application of the MLPDA to bistatic sonar

Approximately a decade ago the maximum likelihood probabilistic data association (MLPDA) tracking architecture was proposed; it was found, via simulation, to be a very effective (perhaps the only) way to track very low-observable contacts - down to 7-8dB (post signal processing), meaning that in a large field of view a given true contact might only rank consistently among the top five or six of those obtained. The MLPDA is based on maximizing statistical likelihood according to a precise model. Its application to real multistatic data (which is unlikely to fit MLPDA assumptions) is both a test of its effectiveness and an opportunity to explore new ways to improve it. We shall see in what follows: bistatic operation; automatic registration via the "direct blast"; the use of the Savage amplitude feature; false-alarm density modification; and a smart grid-search