Explosive Echo Ranging

[glmm]

A bit late, but still……

The development of the narrow band analysis was a revolution. Problem was LOFAR buoys were omnidirectional and it was possible to get long range contacts when acoustic conditions were good with no bearing information. At the time there were active sonobuoys, but they were large, expensive, omnidirectional and had low radiated power. The use of an explosive, high intensity source, was a cheap abd efective way to solve the bearing ambiguity with early LOFAR bouoys and also provided range to the target if close enough to the explosive charge. A P-2 or P-3 could carry a large number of SUS charges, which could also be used for communications with submerged submarines. The Emerson AQA-5 sonobuoy analyzer added CODAR, which used paired groups of ommi sonobuoys to solve the bearing ambiguity problem passively , but needed a well trained crew. CODAR was superseded by DIFAR (Directional LOFAR) in the 1960s so the bearing could be solved using DIFAR buoys like the SSQ-53, still in widespread use. Directional active buoys were also deployed (DICASS) and, used in combination, DIFAR/DICASS was the mainstay of VP aircraft well into the 1990s. The development of quieter nuclear subs by the Soviets in the 1980s eroded the passive advantage enjoyed by the West as passive detection ranges would fall sharply. Also, the rise of the moder SSK menace, a very quiet foe by nature, forced a rethink. Biestatic techniques were dusted off, using both an active or explosive source, and became again in use. Surface ships also moved to bistatic long range search using towed arrays mating a powerful, LF active component and a very large passive array for listening. Using modern computer power, long range adquisition against very quiet targets has become again possible, at least on paper.

[Aktungbby]

Originally Posted by gimm

a bit late but still

gimm! ...finlly surfaced after 16 year's silent running' by an errant explosive SUS charge!??

[glmm]

It was a well placed SUS!