Air gun monitoring and synchronizing method and apparatus

Abstract

Disclosed is an improved air gun construction which lends itself to use with a plurality or array of similarly improved air guns which enables easy synchronization and timing of such array of air guns relative to one another. The synchronization and timing is achieved by controlling and monitoring the movement of the shuttle in the air gun. Various sensors are used such as an electrical coil having a constant current flowing therein which produces a flux pattern which is modified when the shuttle is accelerated, thereby inducing a voltage in said coil which is processed by appropriate processing circuitry. Another embodiment employs a magnetic sensor which includes a permanent magnet and coil wrapped therearound; the permanent magnet produces a flux pattern which is altered when the shuttle is accelerated and comes into proximity to the sensing end of said permanent magnet, thereby inducing a voltage in the coil which is then processed in appropriate processing circuitry. The processing circuitry associated with both embodiments generates a timing signal for each air gun which provides accurate phasing of each of the air guns to thereby fire such guns at a predetermined time. The timing signals from each of the air guns are used in conjunction with additional signals to accurately indicate auto fire and no fire conditions of the air guns.