Very‐low‐frequency scattering experiments from proud targets in a littoral environment using a 55‐m rail

Scattering measurements from proud targets were conducted in the littoral environment of St. Andrews bay. A 55‐m long rail was assembled 2.3 m above the sandy bottom to position transducers using an attached robot. The rail provided a straight and level structure that repeatably scanned the target field. This system was used in both a bistatic and monostatic configuration to produce synthetic array measurements of the target field. The bistatic experiments used a stationary source at the center of the rail to insonify the target field while the receiver was moved to synthesize a 55‐m array. The monostatic experiments had both a source and receiver mounted together on the robot, and both were moved together to scan the target field. All the experiments were conducted using a very‐low‐frequency band (1 to 12 kHz). The results of these experiments will be presented along with signal processing of the target field to study the physical responses of the individual targets to the low‐frequency acoustic insonification. [Work supported by ONR.]