Abstract: A method includes communicating first and second signals between a first node and a second node, where the first signal includes a sonic signal and the second signal includes an electromagnetic signal. The method also includes using the electromagnetic signal to one of start or stop a timer and using the sonic signal to another of stop or start the timer. The method further includes identifying a one-way time-of-flight associated with the sonic signal traveling between the first and second nodes using the timer. The one-way time-of-flight associated with the sonic signal is indicative of a distance between the nodes.

Abstract: A method includes transmitting a first electromagnetic signal from a first node to a second node and receiving a second electromagnetic signal from the second node at the first node. The method also includes repeating the transmission of the first electromagnetic signal and the reception of the second electromagnetic signal multiple times. The method further includes identifying, based on the repeated transmissions and receptions, a time-of-flight associated with a travel time for one of the electromagnetic signals to travel between the first and second nodes. The time-of-flight is indicative of a distance between the nodes.

Abstract: A flight vehicle includes a drone with a pair of shaped protrusions mechanically coupled to the drone. One of the shapes is a hollow lift-producing shape, such as being a balloon filed with a lighter-than-air gas, and the other of the shapes is below the drone. The shape below the drone may be a hollow shape that does not produce lift, for example being a balloon filled with air. The shapes may be similar in size and shape, so as to provide similar drag characteristics. The shapes may be opposite ends of a support, such as a stick, rod, or other (relatively) slender structure. The vehicle includes a payload, such as radar calibration equipment or an antenna. The drone may be used to counteract wind forces on the flight vehicle, and/or to otherwise position the flight vehicle.

Abstract: An apparatus includes first and second tanks each configured to receive and store a refrigerant under pressure. The apparatus also includes a cylinder defining a space configured to receive the refrigerant from the first and second tanks. The apparatus further includes a piston passing into the cylinder and having a head, where the head divides the space within the cylinder into a first volume for the refrigerant from the first tank and a second volume for the refrigerant from the second tank. In addition, the apparatus includes a converter configured to translate linear movement of the piston into rotational motion and a generator configured to produce electrical power based on the rotational motion.

Abstract: An apparatus includes first and second tanks each configured to receive and store a refrigerant under pressure. The apparatus also includes at least one generator configured to generate electrical power based on a flow of the refrigerant between the tanks. The apparatus further includes a collector configured to transfer solar thermal energy to one of the tanks to heat the refrigerant in that tank and/or radiate thermal energy from one of the tanks into an ambient environment to cool the refrigerant in that tank. In addition, the apparatus could include first and second insulated water jackets each configured to receive and retain water, where the first tank is located within the first insulated water jacket and the second tank is located within the second insulated water jacket.

Abstract: A system includes a first jacket that contains seawater and a first tank storing a first fluid under pressure. A second jacket contains seawater and a second tank storing a second fluid under pressure. An actuator cylinder defines a space that receives the fluids from the first and second tanks. The actuator cylinder includes an actuator piston that divides the space into a first volume for the first fluid and a second volume for the second fluid. A hydraulic cylinder includes a hydraulic piston configured to move and change an amount of hydraulic fluid in the hydraulic cylinder, wherein the hydraulic piston is fixedly coupled to the actuator piston. A buoyancy plug changes a position in connection with the amount of the hydraulic fluid in the hydraulic cylinder, wherein the position of the buoyancy plug affects a buoyancy of a vehicle.

Abstract: A carbon dioxide cycle power generation system includes a first carbon dioxide storage configured to store a first portion of carbon dioxide and a second carbon dioxide storage configured to store a second portion of the carbon dioxide. The carbon dioxide cycle power generation system also includes a generator configured to generate electrical power based on a flow of at least part of the carbon dioxide between the first and second carbon dioxide storages. The carbon dioxide cycle power generation system is configured to cycle between different underwater depths in order to employ water pressure and/or water temperature in creating the flow of the at least part of the carbon dioxide through the generator. The second carbon dioxide storage includes an annular region surrounding a central region, where the annular region has a variable internal volume configured to receive at least part of the second portion of the carbon dioxide.

Abstract: A method includes transmitting a first electromagnetic signal from a first node to a second node through free space. The method also includes transmitting a second electromagnetic signal from the first node to the second node through a communication link, where the communication link physically couples the first and second nodes. The method further includes identifying a distance between the first and second nodes based on a time-difference-of-arrival between reception of the first electromagnetic signal at the second node and reception of the second electromagnetic signal at the second node.

Abstract: A method includes communicating first and second signals between a first node and a second node, where the first signal includes a sonic signal and the second signal includes an electromagnetic signal. The method also includes using the electromagnetic signal to one of start or stop a timer and using the sonic signal to another of stop or start the timer. The method further includes identifying a one-way time-of-flight associated with the sonic signal traveling between the first and second nodes using the timer. The one-way time-of-flight associated with the sonic signal is indicative of a distance between the nodes.

Abstract: A method includes transmitting a first electromagnetic signal from a first node to a second node through free space. The method also includes transmitting a second electromagnetic signal from the first node to the second node through a communication link, where the communication link physically couples the first and second nodes. The method further includes identifying a distance between the first and second nodes based on a time-difference-of-arrival between reception of the first electromagnetic signal at the second node and reception of the second electromagnetic signal at the second node.

Abstract: A system and method for detecting concealed weapons using ultrawideband radar detects weapons based on circumference resonance that are characteristic of reflections for cylindrical or conic portions of a type of weapon, and based on barrel length resonances that are characteristic of barrel lengths of the type of weapon. The circumference resonances are detected using ultrawideband radar in the Mie scattering region based on a range of weapons' characteristic radii to ultrawideband wavelengths. The barrel length resonances are detected using ultrahigh frequency radar in the Mie scattering region based on range of weapons' characteristic lengths to ultrahigh frequency wavelengths. Circumferential resonance patterns and length resonance patterns are combined to provide improved weapon type identification without relying on orientation of the concealed weapons. An array of ultrawideband radar apparatus may be configured to provide synthetic aperture radar imaging of a target area.

Abstract: A system includes a first jacket that contains seawater and a first tank storing a first fluid under pressure. A second jacket contains seawater and a second tank storing a second fluid under pressure. An actuator cylinder defines a space that receives the fluids from the first and second tanks. The actuator cylinder includes an actuator piston that divides the space into a first volume for the first fluid and a second volume for the second fluid. A hydraulic cylinder includes a hydraulic piston configured to move and change an amount of hydraulic fluid in the hydraulic cylinder, wherein the hydraulic piston is fixedly coupled to the actuator piston. A buoyancy plug changes a position in connection with the amount of the hydraulic fluid in the hydraulic cylinder, wherein the position of the buoyancy plug affects a buoyancy of a vehicle.

Abstract: An apparatus includes first and second tanks each configured to receive and store a refrigerant under pressure. The apparatus also includes a cylinder defining a space configured to receive the refrigerant from the first and second tanks. The apparatus further includes a piston passing into the cylinder and having a head, where the head divides the space within the cylinder into a first volume for the refrigerant from the first tank and a second volume for the refrigerant from the second tank. In addition, the apparatus includes a converter configured to translate linear movement of the piston into rotational motion and a generator configured to produce electrical power based on the rotational motion.

Abstract: Method and apparatus for a flight vehicle including a wing having a high aspect ratio and first and second rotors having a high aspect ratio, with a ratio of the rotor diameter to wing length ratio is equal to or greater than about 0.25. In embodiments, the flight vehicle can include a first and second motor, each less than about one thousand HP, to drive a respective rotor and a second motor. The flight vehicle can include a cruise mode and a VTOL mode.

Abstract: An aerial platform having motive devices for obtaining and maintaining loft of the aerial platform, the motive devices being pivotable relative to a wing of the aerial platform for aerial maneuvering of the aerial platform while generally maintaining stable disposition of the wing relative to the ground. The motive devices may include blades having selectively adjustable pitch for varying output force of respective motive devices. The aerial platform may further include one or more bladed turbines outwardly coupled to the wing and drivable by wind for generating power for the aerial platform. In some cases, the aerial platform may be tethered via a flexible power cable to a power source.

Abstract: An aerial platform having motive devices for obtaining and maintaining loft of the aerial platform, the motive devices being pivotable relative to a wing of the aerial platform for aerial maneuvering of the aerial platform while generally maintaining stable disposition of the wing relative to the ground. The motive devices may include blades having selectively adjustable pitch for varying output force of respective motive devices. The aerial platform may further include one or more bladed turbines outwardly coupled to the wing and drivable by wind for generating power for the aerial platform. In some cases, the aerial platform may be tethered via a flexible power cable to a power source.

Abstract: A system and method for detecting concealed weapons using ultrawideband radar detects weapons based on circumference resonance that are characteristic of reflections for cylindrical or conic portions of a type of weapon, and based on barrel length resonances that are characteristic of barrel lengths of the type of weapon. The circumference resonances are detected using ultrawideband radar in the Mie scattering region based on a range of weapons' characteristic radii to ultrawideband wavelengths. The barrel length resonances are detected using ultrahigh frequency radar in the Mie scattering region based on range of weapons' characteristic lengths to ultrahigh frequency wavelengths. Circumferential resonance patterns and length resonance patterns are combined to provide improved weapon type identification without relying on orientation of the concealed weapons. An array of ultrawideband radar apparatus may be configured to provide synthetic aperture radar imaging of a target area.

Abstract: An apparatus includes a generator configured to generate electrical power. The apparatus also includes first and second tanks each configured to receive and store a refrigerant under pressure. The apparatus further includes a first piston assembly having a first piston that divides a volume within the first piston assembly into first and second spaces each configured to receive refrigerant from at least one of the tanks. In addition, the apparatus includes a second piston assembly having a second piston coupled to the first piston. The generator is configured to generate the electrical power based on movement of at least one of the first and second pistons. During use, flows of the refrigerant between the tanks and the spaces can be created based on a pressure differential, such as a pressure differential created by a temperature difference between the tanks.

Abstract: A system includes a vehicle having a body and a power generation system. The power generation system includes first and second tanks each configured to receive and store a refrigerant under pressure. The power generation system also includes at least one generator configured to generate electrical power based on a flow of the refrigerant between the tanks. The first tank is configured to be cooled by one of ambient air and water to a lower temperature, and the second tank is configured to be warmed by another of the ambient air and the water to a higher temperature. The first tank or associated heat exchanger can be positioned such that the first tank is above the water's surface when a portion of the body breaches the surface. The second tank or associated heat exchanger can be positioned such that the second tank is below the water's surface when a portion of the body breaches the surface.

Abstract: A carbon dioxide cycle power generation system includes a first carbon dioxide storage configured to store a first portion of carbon dioxide and a second carbon dioxide storage configured to store a second portion of the carbon dioxide. The carbon dioxide cycle power generation system also includes a generator configured to generate electrical power based on a flow of at least part of the carbon dioxide between the first and second carbon dioxide storages. The carbon dioxide cycle power generation system is configured to cycle between different underwater depths in order to employ water pressure and/or water temperature in creating the flow of the at least part of the carbon dioxide through the generator. The second carbon dioxide storage includes an annular region surrounding a central region, where the annular region has a variable internal volume configured to receive at least part of the second portion of the carbon dioxide.