Omnitech Electronics' Passive Acoustic Surveillance System (PASS) consists of a 56-element bottom-laid low-noise acoustic array tethered to shore via 1500m long light-weight electro-optical cable. The PASS Data Collection Unit (DCU) located onshore powers the array and distributes array data to one or more client computers for analysis and display. Typical applications for the Omnitech PASS are harbor and port security, acoustic signature measurements to aid in reducing self-noise of subsurface and surface vessels, diver detection, and acoustic front-end for development of advanced underwater tracking and detection algorithms. Ancillary sensors on the array measure depth, orientation (magnetic heading) and water temperature.
The array connects to an underwater Array Receiver (AR) that manages power to the array, controls gain, synchronous sampling, and streams the digitized data to the DCU on shore over Ethernet. The DCU contains a PC, Array Interface (AI), two Network Attached Storage (NAS) drives, GPS, and all data routing and power management electronics. Each NAS can have up to 24 TBi of redundant storage. Data logging can be switched between the NAS units in real-time to allow for easy removal of data. In addition to storing data, the DCU can stream real-time data over TCP to any additional processing clients. The DCU can send data in the raw array format and/or reformat the data for simplified post processing by client applications.
The DCU has one universal AC power input and an optional DC power inverter for battery powered operation.
All hydrophones across multiple PASS-2447 arrays have synchronized samples to UTC, referenced via GPS. Hydrophones are spaced in groups of sixteen forming six linear apertures from 100 to 3200 Hz. Additional hydrophones and alternate spacing options are available. PASS arrays can be expanded to include hundreds of mixed sensors.