Abstract: An underwater investigation system may include a host ship, a UUV including a propulsion device and a steering device, and at least one sonar system. The system may further include a guidance controller configured to initiate sonar range measurements between the host ship and the UUV using the at least one sonar system, and estimate a respective UUV position state relative to the host ship at the initiation of at least some of the sonar range value measurements to define a series of successive UUV position state estimates. The guidance controller may be further configured to update UUV position state estimates in the series based upon completion of their respective sonar range measurements, propagate the updates to subsequent UUV position state estimates in the series, and control the propulsion device and the steering device to guide movement of the UUV relative to the host ship based upon the updated position state estimates.

Abstract: A system and method for disabling a small boat comprises at least two hulls and an entanglement device disposed therebetween. In the illustrative embodiment, each hull is an unmanned underwater vehicle. The system is launched from a vessel to intercept the small boat. When close to the small boat, the separating distance between the two hulls is increased, thereby deploying the entanglement device and causing it to become entangled with the small boat (e.g., the small boat's propulsion system, etc.).

Abstract: An underwater vehicle includes systems for harvesting ambient hydrostatic pressure and storing the same as a gas pressure in a compressed gas system and as a water pressure in a pressurized electrolysis system. The gas pressure is used to perform mechanical work or to generate electrical power via a prime mover. The water pressure is used to release pressurized hydrogen and oxygen gases via electrolysis. The pressurized hydrogen and oxygen gases are used in a combustion chamber to generate propulsion power for the underwater vehicle.

Abstract: A method whereby a relatively faster-moving vessel recovers a relatively-slower moving vehicle includes, in some embodiments, causing a first faster-moving vehicle to move along a first circular path, deploying a cable radially inward from the first circular path such that a free end of the cable circumscribes a second circular path having a radius smaller than that of the first circular path, attracting a second slower-moving vehicle to the free end of the cable, and coupling the second vehicle to the cable.

Abstract: An underwater investigation system may include a host ship, a UUV including a propulsion device and a steering device, and at least one sonar system. The system may further include a guidance controller configured to initiate sonar range measurements between the host ship and the UUV using the at least one sonar system, and estimate a respective UUV position state relative to the host ship at the initiation of at least some of the sonar range value measurements to define a series of successive UUV position state estimates. The guidance controller may be further configured to update UUV position state estimates in the series based upon completion of their respective sonar range measurements, propagate the updates to subsequent UUV position state estimates in the series, and control the propulsion device and the steering device to guide movement of the UUV relative to the host ship based upon the updated position state estimates.

Abstract: A system and method for disabling a small boat comprises at least two hulls and an entanglement device disposed therebetween. In the illustrative embodiment, each hull is an unmanned underwater vehicle. The system is launched from a vessel to intercept the small boat. When close to the small boat, the separating distance between the two hulls is increased, thereby deploying the entanglement device and causing it to become entangled with the small boat (e.g., the small boat's propulsion system, etc.).

Abstract: A method whereby a relatively faster-moving vessel recovers a relatively-slower moving vehicle is disclosed.

Abstract: An apparatus includes at least three redundant signals each indicative of a sensed magnitude of a parameter. Parity space and fuzzy logic techniques may be used to provide a signal representing an estimate of the actual magnitude of the parameter. A method for generating an estimate of an actual magnitude of a parameter provides at least three redundant signals may use parity space and fuzzy logic to produce a signal representing an estimate of the actual magnitude of the parameter.

Abstract: Fuel flow and nozzle area are controlled by a multi-variable control. A requested fan speed is compared with measured fan speed, producing an error signal which is translated in a proportional-integral inner control loop into a requested compressor pressure signal that represents an acceptable rate of change in compressor pressure for difference between requested and measured fan speed. The error signal is compared with measured compressor pressure; the difference being used in a multi-variable control to adjust fuel flow and turbine exhaust area to achieve the requested compressor pressure.

Abstract: A centrifugal pump has a rising characteristic at low flows, leading to pressure pulsations in the fuel system at low flow. A pressure difference regulating valve at the pump discharge has a frequency response such that the valve does not significantly move in response to the pulsations. The valve responds to less rapid changes, thereby avoiding high pressure loss at high flows.

Abstract: A gas turbine engine control system sends a demand signal to a fuel throttle valve. The demand signal is modified by a measured fuel flow signal during normal operation. Operating parameters such as pump speed and recirculation valve portion are sensed. Combining these sensed parameters with the known geometry of the system, a calculated pressure differential between a point upstream of the throttle valve and a point in the combustor is determined. This calculated pressure differential is applied to the known geometry of the system from before the throttle valve to the combustor, including sensed opening of the throttle valve. A calculated flow is thus obtained and compared to the measured flow. An excessive difference between the measured and calculated flows indicates flow meter error. In such a case the calculated flow is substituted for the measured flow in modifying the demand signal.