Abstract: An improved solid state spark gap for use, for example, in firing munitions. The spark gap is formed by depositing a trigger electrode on a dielectric substrate, precisely covering the trigger electrode and an adjoining area with a dielectric layer, and forming an anode and a cathode on the dielectric layer with a spark gap there between. The anode and cathode do not overlap the trigger electrode. The spark gap may be enclosed within a hermetically sealed inert gas filled cover.

Abstract: A method for a phase-locked loop, which circuit includes, in a preferred embodiment, a resistor to unbalance phase detector outputs to an operational amplifier to cause the voltage output of the operational amplifier to sweep and thus cause the frequency output of a voltage controlled oscillator to sweep. Simple circuitry detects correct lock and terminates sweeping; or, if lock is not achieved, causes the output of the operational amplifier to remain at a low level until the operational amplifier is reset and then permits resweep. Very little auxiliary circuitry is required.

Abstract: A surface unit for a sonobuoy or similar device is disclosed and includes a variable volume sealed chamber and an arrangement including a pressurized carbon dioxide cartridge within the sealed chamber which, when energized, releases the carbon dioxide and increases the chamber volume from a collapsed volume to an expanded significantly greater volume. Electronic circuitry including radio transmitter circuitry is included within the sealed chamber along with a radio transmitter antenna which is within the sealed chamber and coupled to the radio transmitter circuitry. Expansion of the float sealed chamber functions to erect the antenna preparatory to transmission. The variable volume sealed chamber is formed of a semi-rigid plastic cup having a generally cylindrical corrugated sidewall portion, a closed end describing one of the chamber ends and a rigid base member sealed to the cup sidewall portion remote from the closed end and describing the other of the chamber ends.

Abstract: A technique for resolving whole-cycle ambiguity that is inherent in phase-angle measurements of signals received from multiple satellite-based transmitters in a global positioning system. The relative position of a secondary receiving antenna with respect to a reference antenna is approximately known or approximately initially determined and then measurements from a minimum number of satellites are used to determine an initial set of potential solutions to the relative position of the secondary antenna that fall within a region of uncertainty surrounding the approximate position. Redundant measurements are taken from one or more additional satellites and used to progressively reduce the number of potential solutions to close to one. Even if the number of potential solutions is not reduced to one true solution, the number can be further reduced by using additional measurements taken at different time intervals, at which different satellite geometries prevail.

Abstract: A digital-to-analog converter receives a stream of input words and selectively couples a plurality of current sources to produce a DAC output signal. The DAC includes a set of series-connected synchronizing switches and data switches between the current sources and the output lines, and operates the switches such that the current sources are not coupled to the data switches until the data switch transients have ended.

Abstract: In a preferred embodiment, a safe and arm device for spinning munitions that takes advantage of the conservation of momentum law to impart a differential angular velocity to a ball rotating in a race within the device. The rotating ball is used to established discrete time intervals that can be integrated with an electronic counter to determine a safe arm distance, which distance can be programmed to be well beyond the 400-800 caliber arming distance achievable with conventional arming devices.

Abstract: An improved ordnance arming knob assembly. An arbor is secured to a switch shaft. A knob is keyed to the arbor to move in an axial direction relative to the arbor while preventing rotation between the knob and the arbor. A pin on the knob extends in a direction parallel to the switch shaft axis into a stationary hole located, for example, on a panel on which the switch is mounted. The knob must be pulled in an axial direction against the force of one or more springs to withdraw the pin from the hole prior to turning to actuate the arming switch.

Abstract: A system for automatically compensating for changes in permanent magnetism in a vehicle in which a flux-gate compass is installed. Calibration is initially performed by rotating the vehicle through a full circle and determining from the flux-gate outputs the degree of distortion suffered by an ideally circular performance characteristic. Subsequent flux-gate readings are compensated in accordance with parameters generated during calibration. Parameters relating to offset or displacement of the characteristic are automatically and continually updated to compensate for changes in permanent magnetism of the vehicle, such as might be caused by loading or unloading the vehicle.

Abstract: A demodulation frequency plan for use in a global positioning system (GPS) receiver, having three demodulation stages for L1 and L2 signal channels, in which identical local oscillator frequencies are used in the L1 and L2 channels at each demodulation stage, to minimize phase error differences between the two channels. The third stage provides an output at an intermediate frequency high enough to carry the full information bandwidth, thereby simplifying digital sampling of the signal, which is also performed in the third stage. Sampling is performed at a high enough rate to facilitate subsequent conversion to baseband. Moreover, the sampling rate is a binary multiple of the intermediate frequency, and this binary relationship further simplifies conversion to baseband.

Abstract: A piezoelectric fuse, and safe and arm mechanism for a small active projectile is disclosed including a piezoelectric element mounted within the projectile near the leading end thereof with an impact deformable electrically conductive shell spaced from and at least partially surrounding the piezoelectric element and a resilient material substantially filling the space between the piezoelectric element and the shell. Electrical leads connect the detonator to the shell and to a rearward piezoelectric element contact so that upon projectile impact, the shell deforms compressing the piezoelectric element generating a voltage thereacross, and thereafter, the shell makes electrical connection with a piezoelectric element forward contact actuating the detonator. The safe and arm mechanism includes an interrupter located in a "safe" position between the detonator and a lead charge.

Abstract: In a preferred embodiment, an inter-element mounting for ceramic elements in a piezoelectric transducer stack, which mounting includes two metal plates disposed between adjacent surfaces of the ceramic elements. The metal plates are cantilevered with respect to the surfaces of the ceramic elements, such that a substantial portion of the areas of the plates between the adjacent surfaces is unsupported and, therefore, the plates have a high degree of resilience. This structure provides controlled vibrational characteristics, structural integrity for high hydrostatic pressure, versatility in design for spurious resonance suppression or elimination, dampening, and special utility for pressure gradient hydrophone stacks.

Abstract: An electronically controllable pneumatically powered valve actuating mechanism for use in an internal combustion engine is disclosed. The engine is of the type having engine intake and exhaust valves with elongated valve stems. The actuator has a power piston reciprocable along an axis and adapted to be coupled to an engine valve and a pneumatic arrangement for moving the piston. A pneumatic damping arrangement imparts a first decelerating force to the piston when the engine valve reaches a first separation from one of said valve-open and valve-closed positions to begin reducing engine valve velocity as the engine valve approaches said one position, and imparts a second lesser decelerating force to the piston when the engine valve reaches a second lesser separation from that one position.

Abstract: A pneumatically powered valve actuator is disclosed including a valve actuator housing, a main piston reciprocable within the housing along an axis and a pair of auxiliary pistons fixed to and movable with the main piston. The main piston has a pair of oppositely facing primary working surfaces. A pair of air control valves reciprocable along said axis relative to both the housing and the main piston between open and closed positions control air flow from a pressurized source causing the main piston and the pair of auxiliary pistons to move. Each auxiliary piston forms, in conjunction with a surface of the corresponding air control valve, a variable volume annular chamber. The variable volume chamber function during the early portion of piston movement to apply a reclosing force to the air control valve and during a latter portion of the piston movement to vent air compressed by the piston during damping. This venting of the residual air is in an axial rather than a radial direction.

Abstract: A fast acting valve actuator for actuating an intake or exhaust valve in an internal combustion engine of a type which is hydraulically powered and command triggered is disclosed and includes a cylinder with a power piston having a pair of opposed working surfaces or faces reciprocable within the cylinder along an axis between first and second extreme positions. A cylindrical control valve is located radially intermediate the reservoir and the cylinder, and is movable upon command to alternately supply high pressure fluid from a reservoir of high pressure hydraulic fluid to one face and then the other face of the power piston causing the piston to move from one extreme position to the other extreme position. The cylindrical control valve may be a shuttle valve which is reciprocable along the axis of the power piston between extreme positions with control valve motion along the axis in one direction being effective to supply high pressure fluid to move the piston in the opposite direction.

Abstract: Method and apparatus for use in a global positioning system (GPS), to obtain the benefit of L2 carrier signals and precise-code (P-code) signals transmitted from satellites in encrypted form. Received, encrypted P-code signals are correlated with a locally generated P-code sequence and the resulting signal is bandpass filtered and squared, to separate one satellite signal from the others, to recover the carrier signal and make accurate measurement of its phase and pseudorange, even though the received P-code sequence is encrypted. Because the squaring step is performed over a narrower bandwidth than the original P-code, there is less degradation in the signal-to-noise ratio of the received signal, as compared with squaring over the entire P-code bandwidth. Therefore, performance is more reliable under weak signal conditions or when there are interference signals present, and the improvement in signal quality means that cycle ambiguity of the carrier signals can be resolved more rapidly.

Abstract: Waveform inputs are sampled to provide vector inputs which are coupled to respective ones of a plurality of series connected time delay stages in a processing circuit. Each vector is weighted, or amplified, and time delayed by each stage between its input point and the circuit output. Each stage has switched capacitors and an operational amplifier. The delay of each stage is the period of the capacitor switching frequency. All of the components in the stages and vector input circuitry are solid state switches, capacitors or operational amplifiers and therefore are especially suitable for integration in a monolithic or film substrate. The circuit is particularly adapted to beam steering a plurality of waveform inputs from an array of hydrophones.

Abstract: A bistable electronically controlled pneumatically powered transducer for use, for example, as a valve mechanism actuator in an internal combustion engine is disclosed. The transducer has a piston which is coupled to an engine valve, for example. The pistion is powered by a pneumatic source and is held in each of its extreme positions by pneumatic pressure under the control of control valves which are in turn held in their closed positions by pressurized air and/or permanent magnet latching arrangements and are released therefrom to supply air to the piston to be pneumatically driven to the other extreme position by an electromagnetic neutralization of the permanent magnet field. A pair of auxiliary pistons movable with the piston compress air to a pressure above the pressure of the pneumatic source for aiding reclosure of the control valves as well as aiding maintenance of those control valves in their closed positions thereby reducing the size and cost of the latching permanent magnets.

Abstract: Shock mounting and enhanced conductive cooling of electrical components on printed circuit cards are achieved by mounting the non-component surface of the circuit card to a cold plate with a viscous, heat conductive, electrically insulating material sandwiched between the cold plate and circuit card. The cold plate may be an aluminum plate with a thermally conductive, electrcially insulative anodized surface. Typically, the cold plate is attached to a chassis of electrical equipment, or to a similar heat sink.

Abstract: A technique for resolving whole-cycle ambiguity that is inherent in phase-angle measurements of signals received from multiple satellite-based transmitters in a global positioning system. The relative position of a secondary receiving antenna with respect to a reference antenna is approximately known or approximately initially determined and then measurements from a minimum number of satellites are used to determine an initial set of potential solutions to the relative position of the secondary antenna that fall within a region of uncertainty surrounding the approximate position. Redundant measurements are taken from one or more additional satellites and used to progressively reduce the number of potential solutions to close to one. Even if the number of potential solutions is not reduced to one true solution, the number can be further reduced by using additional measurements taken at different time intervals, at which different satellite geometries prevail.

Abstract: A method of and apparatus for starting and accelerating a vehicle through a range of vehicle speeds during which the vehicle's internal combustion engine is operated in a plurality of different operating modes is disclosed. The engine may first be cranked in a compressionless mode preparatory to starting and then run in a second mode at a relatively low speed for a warm-up interval as a six-stroke cycle engine where each engine cylinder cycle includes an essentially adiabatic compression and expansion. The system may then convert to a third mode of operation as a four-stroke cycle engine during normal engine operation. Different operating modes are available during this normal engine operation. Under high demand conditions, the engine may be run as a conventional inefficient but effective throttled engine or converted to operate in a fourth mode as a two-stroke cycle engine.