Digital air gun source controller apparatus and control method

An in-water distributed control system for use in marine seismic survey. The system includes a shipboard interface and power supply coupled to an in-water subsystem via a high bandwidth communication link. The in-water subsystem includes a remote control module for generating firing commands based on synchronizing and position parameters transmitted by the interface. The remote control module transmits power, data, and commands to a plurality of gun control modules. Each gun control module operates an air gun. An individually addressable remote cut-off valve controls air to each air gun. Depth and pressure at the gun control module is sensed by at least one DT/PT module. An optional expansion unit provides additional DT/PT capability.