Abstract: Disclosed is a protocol for transmitting data in a towed hydrophone streamer, including a transmission method and a data frame. The method comprises the steps of (1) receiving a portion of the data frame into a data transmission circuit within a particular module of the streamer, the portion of the data frame representing telemetry data derived from an adjacent module, the transmission circuit transmitting the portion of the data frame to a desired destination, (2) receiving an end-of-data signal into the transmission circuit, the end-of-data signal commanding the transmission circuit to add telemetry data derived from the particular module to the portion of the data frame and (3) adding the data derived from the particular module to the portion of the data frame, the data frame thereby transmitted to the destination and including the data derived from the particular module, the telemetry data ordered within the frame as a function of an order of modules within the streamer.

Abstract: Disclosed is a programmable data collection and relay circuit for a towed hydrophone array. The circuit is designed to prepare data concerning operation of the array to be interleaved with substantive data produced by the hydrophones to produce a single data stream for transmission to recording equipment. The circuit comprises (1) a plurality of sensor inputs, each of the sensor inputs adapted to be coupled to a sensor capable of sensing a physical characteristic within the towed hydrophone array, (2) a circuit for polling at least a portion of the plurality of sensor inputs to determine values of the inputs, (3) a circuit for storing programmed data concerning which of the plurality of inputs is to be polled and (4) a circuit for serially placing the input values in condition for insertion into a data stream transmitted along the towed hydrophone array.

Abstract: Disclosed is a telemetry data transmission circuit for a towed hydrophone streamer, the streamer comprised of a plurality of series-coupled modules. The transmission circuit comprises: (1) a slave clock input in a first module capable of receiving a master timing signal from a master clock source located in a second module, the master timing signal capable of synchronizing an operation of the transmission circuit to allow the transmission circuit to place local telemetry data on a data bus coupled to the transmission circuit and running a length of the streamer, (2) a local clock input in the first module capable of receiving a local timing signal from a local clock source located in the first module, the local timing signal alternatively capable of synchronizing the operation of the transmission circuit and (3) a clock source selection circuit capable of allowing the local clock source to synchronize the operation of the transmission circuit as a function of a condition of the master timing signal.

Abstract: A hydrophone module for a towed hydrophone array. The module comprises: (1) an elongated hydrophone module housing having a desired hydrophone group center associated therewith and (2) a plurality of hydrophone elements located substantially aperiodically along a length of the housing and electrically coupled together in a hydrophone group, the hydrophone group having an actual hydrophone group center proximate the desired hydrophone group center to thereby allow locations of the plurality of hydrophone elements to be altered without dislocating the actual hydrophone group center. Individual hydrophone elements within the group may therefore be moved within the module without disturbing the actual hydrophone group center.

Abstract: Disclosed is a vibration isolation module for a towed hydrophone streamer comprising: (1) a first transition unit, an outboard end of the first transition unit capable of receiving a first tension member, the first tension member terminating within the first transition unit, an inboard end of the first transition unit capable of receiving second and third tension members, the second tension member entering, looping back and exiting the inboard end of the first transition unit, the third tension member terminating within the first transition unit and (2) a second transition unit, an outboard end of the second transition unit capable of receiving a fourth tension member, the fourth tension member terminating within the second transition unit, an inboard end of the second transition unit capable of receiving the second and third tension members, the second tension member entering, looping back and exiting the inboard end of the second transition unit, the third tension member terminating within the second transi

Abstract: An integrated module coupler for a towed hydrophone streamer and a method of transmitting towing forces and electrical signals therethrough.

Abstract: Disclosed is a protocol for transmitting data in a towed hydrophone streamer, including a transmission method and a data frame. The method comprises the steps of (1) receiving a portion of the data frame into a data transmission circuit within a particular module of the streamer, the portion of the data frame representing telemetry data derived from an adjacent module, the transmission circuit transmitting the portion of the data frame to a desired destination, (2) receiving an end-of-data signal into the transmission circuit, the end-of-data signal commanding the transmission circuit to add telemetry data derived from the particular module to the portion of the data frame and (3) adding the data derived from the particular module to the portion of the data frame, the data frame thereby transmitted to the destination and including the data derived from the particular module, the telemetry data ordered within the frame as a function of an order of modules within the streamer.

Abstract: Disclosed is an encapsulated hydrophone assembly for use in a towed hydrophone array. The assembly comprises (1) a hydrophone element having a hydrophone electrical conductor, (2) an insulated input electrical lead and an insulated output electrical lead coupled to the hydrophone electrical conductor, (3) an electromagnetic shield surrounding the hydrophone element and the hydrophone electrical conductor, the input electrical lead and the output electrical lead extending from the electromagnetic shield and (4) a layer of encapsulating material surrounding the hydrophone element, the hydrophone electrical conductor, a portion of the input electrical lead, a portion of the output electrical lead and the electromagnetic shield to thereby form the hydrophone assembly.

Abstract: Disclosed are a filtered hydrophone circuit and a method of filtering hydrophone output signals. The circuit, in its most elemental embodiment comprises: (1) a hydrophone having first and second output conductors, the hydrophone producing an electrical signal of varying frequency, (2) an operational amplifier having first and second inputs and an output, the first amplifier input coupled to the first hydrophone output conductor, (3) a first resistor coupling the amplifier output to a second resistor, the second resistor further coupled to an electrical ground and (4) a capacitor coupling the second amplifier input to a point between the first and second resistors to thereby define a feedback path between the amplifier output and the second amplifier input for portions of the hydrophone electrical signal above a selected cutoff frequency, an output signal of the amplifier thereby substantially freed of the portions of the output signal below the selected cutoff frequency.

Abstract: Disclosed is a towed hydrophone streamer module comprising: (1) an elongated, fluid-resistant jacket having a substantially circular cross section, the water resistant jacket having mating connectors at ends thereof, (2) a plurality of sensors distributed in a spaced-apart relationship within the jacket, (3) a data bus positioned along a length of the jacket and terminating in electrical contacts in the mating connectors and (4) a plurality of cylindrical, fluid-resistant electronics housings disposed within the jacket in a spaced-apart relationship along a length thereof, each of the plurality of housings having a circuit board therein and spanning a length thereof and end caps at ends thereof, one of the end caps having electrical contacts coupled to components on the circuit board, a center-line of the housings substantially in alignment with a center-line of the jacket, the components coupling the plurality of sensors to the data bus for electrical communication therewith.

Abstract: Disclosed is a vibration isolation module for a towed hydrophone streamer comprising: (1) a first outboard transition unit having an outboard end and an inboard end, the outboard end of the first outboard unit capable of receiving a first tension member, the first tension member terminating within the first outboard unit, the inboard end of the first outboard unit capable of receiving second and third tension members, the second tension member entering, looping back and exiting the inboard end of the first outboard unit, the third tension member terminating within the first outboard unit and (2) a first inboard transition unit having an outboard end and an inboard end, the outboard end of the first inboard unit capable of receiving the second and third tension members, the second tension member passing through the first inboard unit, the third tension member terminating within the first inboard unit, the inboard end of the first inboard unit capable of receiving a fourth tension member, the fourth tension mem

Abstract: A compass dither device for use with a magnetic compass heading sensor unit for marine seismic streamers and the like having interrogating circuitry associated with the heading sensor to periodically provide a trigger pulse for interrogating a compass heading sensing components in the heading sensory unit and provide compass heading signals indicative of the heading of the compass the the time of interrogation, the compass dither device including a housing for the magnetic compass heading sensor unit having a dither coil encircling the portion where the headings sensory unit is positioned.

Abstract: Disclosed is a coupler for connecting together electrically and mechanically adjacent sections of a marine seismic streamer. The coupler includes a split cylindrical electrical connector housing assembly which establishes electrical interconnection between the adjacent streamer sections. The coupler includes an outer sleeve, which surrounds the electrical connector assembly and transmits tension forces across the coupler.

Abstract: A marine acoustical streamer cable having plural sections connected serially together with the streamer sections having connector couplers at opposite ends thereof adapted to be secured in mated relation without rotation to companion connector couplers of the same construction at the ends of adjacent streamer sections, each coupler comprising an axially elongated coupler body having a fully cylindrical anchoring head portion at one end and an axially elongated half cylindrical segment portion extending integrally from the anchoring head portion. The half cylindrical segment portions of the companion couplers when secured in mating relation collectively form a cylinder of the diameter of the streamer jacket.

Abstract: A marine seismic streamer section for a towed underwater streamer containing a buoyancy regulating fill liquid and the usual hydrophones, strain cables, signal wires and the like housed in a generally cylindrical tubular jacket sealed at its ends against loss of fill liquid and containing a depth sensor for producing electrical signals indicative of the depth of the streamer. The sensor is in a rigid housing whose interior is connected by a tube to a valved calibrating chamber having a valve member normally communicating the interior of the depth sensor housing to the fill liquid pressure conditions in the jacket. The chamber has an external access port normally closed by a plug, and the valve member is movable by a probe inserted through the port when the plug is removed and a source of gauged pressure connected to the access port to subject the interior of the depth sensor housing to the gauged pressure source.

Abstract: A differential charge amplifier for use in towed marine seismic streamers and the like involving towed hydrophone arrays wherein the hydrophone outputs are conducted by long twisted pairs of leads to signal processing equipment, the differential charge amplifier including operational amplifiers connected to form charge amplifier stages having resistance-capacitance feedback circuits and a differential amplifier stage coupled to the charge amplifier outputs providing cancellation of common mode signals.