Abstract:
Multiple RFID integrated circuit microradio chips are located at the feed point of an RFDD tag antenna for greater reliability, elimination of testing and to take advantage of coherent microradio operation for increased gain and power, better signal- to-noise ratios, improved range and low bit error rates.
Abstract:
Multiple RFID integrated circuit microradio chips are located at the feed point of an RFDD tag antenna for greater reliability, elimination of testing and to take advantage of coherent microradio operation for increased gain and power, better signal- to-noise ratios, improved range and low bit error rates.
Abstract:
An RFID tag, containing at least two independent microscopic RFID chips or microradios is programmed with the same unique identifier for each chip. The unique identifier is used in the RFID chips to key the RFID chip transmitting to produce outputs in the same time slot so that the outputs add coherently, thus to create an output that is identical to that of a conventional tag containing only one such chip.
Abstract:
Techniques for underwater detection of fully or partially buried objects such as sea mines and underwater cables are disclosed. An acoustical camera produces three dimensional volumetric images of a target area volume of an underwater floor. One or more first images are produced of the target area volume. An acoustical transducer pulse is then directed to the target area volume so as to disturb the loose particulate or elastic matter included in the target area. One or more second images are then produced while the pulse is present in the target area volume. The images can be compared for evidence of buried objects, or to otherwise evaluate objects included in the target area. The camera can be configured with an interferometer mode so as to produce volumetric images at a real time frame rate.
Abstract:
A linear actuator assembly (10), comprising a rotating lead screw (11) with external threads; and a nut assembly with threads engageable with the external threads of the lead screw (11); and a guide tube (13) having a hollow interior portion with at least one internal surface (51,52,53). The lead screw (11) and nut assembly are located within the hollow interior portion of the guide tube (13), and the guide tube (13) is configured to prevent the nut assembly from rotating with the lead screw (11). The nut assembly translates in a linear direction within the guide tube (13) as the lead screw (11) rotates. A portion of the nut assembly, such as a wedge (25), is radially biased against the at least one internal surface (51,52,53) of the guide tube (13) to minimize torsional backlash of the actuator assembly.
Abstract:
Whether or not one utilizes direct DC coupling of the microradios to the antenna feed points or couples the RF energy from the dipoles associated with the spaced-apart contact pads on the microradio, in the subject invention one selects only those microradios that are within a certain variance of a preferred direction and then makes sure that the polarization direction of all of these radios is in the preferred direction are identical, in one embodiment by utilizing digital coding, which both activates the microradio and is used to sense the polarity associated with the connection from the signal source to the contact pads.
Abstract:
Whether or not one utilizes direct DC coupling of the microradios to the antenna feed points or couples the RF energy from the dipoles associated with the spaced-apart contact pads on the microradio, in the subject invention one selects only those microradios that are within a certain variance of a preferred direction and then makes sure that the polarization direction of all of these radios is in the preferred direction are identical, in one embodiment by utilizing digital coding, which both activates the microradio and is used to sense the polarity associated with the connection from the signal source to the contact pads.
Abstract:
A real-time, three dimensional, acoustical camera (1) and a real-time, range-gated, intensified, electro-optical camera (5) have substantially overlapping fields of view (19, 21)for co-registered imaging of underwater objects at close ranges. The system is typically mounted in an unmanned underwater vehicle but may be used in other fixed or mobile configurations. The coupled fields of view (19, 21) are steerable in an arc around at least one axis over a large field of regard with a servo-controlled rotating mirror system, while the vehicle or the target is moving or hovering. An automated target recognition system uses the multi-modality images to provide enhanced target recognition and/or autonomous operation in unmanned missions.
Abstract:
A motorized anti-backlash linear actuator comprises a motor (10); a hollow shaft '(15) that is rotated about a central axis by the motor, an anti-backlash nut (16) that is nested at least partially inside the hollow shaft; and an externally threaded rod (12) or lead screw that engages with the anti-backlash nut such that the rotation of the hollow shaft and the nut imparts a linear motion to the rod that is substantially free of backlash. Nesting the anti-backlash nut at least partially within the hollow shaft provides greater stability to the actuator, and permits high speed operation. A mechanical element, such as a nut or a bushing, comprises a first cylindrical element comprising a first material; a second cylindrical element comprising a second material having a different coefficient of thermal expansion relative to the first cylindrical element, the second cylindrical element being disposed inside of and in contact with the first cylindrical element; and at least one interlocking structure between the first and the second cylindrical elements to prevent the second cylindrical element from separating from the first cylindrical element under thermal effects. The mechanical element can be a plastic nut secured to the interior of a hollow shaft of a motorized anti-backlash linear actuator.
Abstract:
A motorized anti-backlash linear actuator comprises a motor; a hollow shaft that is rotated about a central axis by the motor, an anti-backlash nut that is nested at least partially inside the hollow shaft; and an externally threaded rod or lead screw that engages with the anti-backlash nut such that the rotation of the hollow shaft and the nut imparts a linear motion to the rod that is substantially free of backlash. Nesting the anti-backlash nut at least partially within the hollow shaft provides greater stability to the actuator, and permits high speed operation. A mechanical element, such as a nut or a bushing, comprises a first cylindrical element comprising a first material; a second cylindrical element comprising a second material, the second cylindrical element having a different coefficient of thermal expansion relative to the first cylindrical element, the second cylindrical element being disposed inside of and in contact with the first cylindrical element; and at least one interlocking structure at an interface between the first cylindrical element and the second cylindrical element to prevent the second cylindrical element from separating from the first cylindrical element under thermal effects. The mechanical element can be a plastic nut secured to the interior of a hollow shaft of a motorized anti-backlash linear actuator.