Abstract: A tactical radio includes a radio frequency (RF) processing module having a receiving component path and a transmitting component path. A signal processing module coupled to the RF processing module includes a jammer detection stage for identifying a type of jamming signal on a channel over which communications signals are received simultaneously. A jammer model stage in the signal processing module produces a waveform model for the jamming signal, and a channel model stage replicates propagation conditions on the channel and produces a corresponding cancellation signal. The cancellation signal is coupled at such a level into the receiving component path so as to cancel the jamming signal from received communications signals at the front end of the radio. Any residual jamming signals may then be removed by a secondary jamming cancellation stage operating at baseband.

Abstract: Communications in a mobile network are scheduled by defining reservation frames having time slots during which network nodes can transmit certain traffic loads while avoiding interference. The nodes maintain maps that identify the slots as either free or reserved based on each node's existing reservations, and reservation information the node receives from neighboring nodes. A node wishing to transmit traffic determines the number of slots required to carry the traffic, selects a first set of slots from among those identified in its maps as free, and transmits a reservation initiation message (RIM) that identifies the first set of slots. Nodes receiving the RIM determine which, if any, of the first set of slots are already reserved based on their own maps, and transmit counter reservation initiation messages (CRIMs) if any slots are reserved. The CRIMs also identify those slots that the CRIM transmitting nodes determine to be currently free.

Abstract: Outside air enters a ram air scoop on an aircraft frame, and is ducted to a ram air control valve. The air control valve outputs a desired air mass flow to a cyclone air-water separator which removes moisture and produces a dry air flow. A heater assembly heats the dry air to a desired temperature and directs the heated air into an equipment bay enclosure on the aircraft. The relative humidity of the heated air is sensed by an air moisture sensor which produces a corresponding signal. Other sensors disposed near a payload in the bay enclosure produce corresponding air temperature and air pressure signals. All the sensor signals are input to a processor or controller configured to activate the air control valve and the heater assembly according to set points for temperature and humidity that are specified for the payload in the bay enclosure.

Abstract: A secure communications system has at least one processor and a control bus. A number of ports, each having a different fixed address, are coupled to the control bus. The processor assigns each port the address of another port whose data the port is permitted to receive when placed on a system data bus by the other port. A time slot generator outputs each fixed port address sequentially during corresponding time slots in a recurring manner, and a time slot bus is coupled to the time slot generator and to each of the ports. The ports are configured so that (a) when a given port detects its fixed address on the time slot bus, it writes desired outbound data on the data bus, and (b) when the given port detects its assigned port address on the time slot bus, the given port reads data off the data bus.

Abstract: A surgical fastener system for acromioclavicular (AC) joint dislocations, includes a first fastener having an elongate body, and an inner pair of openings centered on the long axis of the body. A closed loop stitch passes through the openings, and the length of the stitch corresponds to the depth of a passage defined between the top of a first hole bored through a patient's clavicle, and the bottom of a second hole bored through the coracoid in axial alignment with the first hole. A second fastener has an elongate body arranged to slide under a portion of the loop stitch that protrudes from the top of the hole in the clavicle, after the first fastener is set beneath the coracoid and the stitch is pulled upward through the passage. In an alternate embodiment, the second fastener also has an inner pair of openings for passing and engaging the loop stitch.

Abstract: Nodes in a wireless network participate in either point-to-multipoint (PMP) or MANET/mesh communications with other nodes on one or more shared channels of the network. A first or base station node transmits a downlink signal having a time frame structure of determined duration to a number of second or subscriber nodes. Portions of the frame structure establish (i) first time periods during which messages are transmitted from the first node to the second nodes, and (ii) second time periods during which messages are transmitted from the second nodes to the first node, using the PMP protocol on one or more shared channels or subchannels of the network. Other portions of the time frame structure establish third time periods during which nodes communicate with one another using the MANET/mesh protocol on the shared channels or subchannels, while avoiding interference with messages transmitted under the PMP protocol.

Abstract: An antenna system has N antenna units stacked on a mast. Each unit has elements for responding to, e.g., GPS signals, and a phasing network that produces mutually orthogonal primary and auxiliary pattern modes at corresponding mode ports of the unit. A number of power dividers are each associated with a different mode, and each divider has N input ports coupled to the associated mode port of a corresponding antenna unit. The power divider associated with the primary pattern mode produces a reference beam and an auxiliary beam, and remaining power dividers produce different auxiliary beams. All beams have approximately both a common phase center and a common group delay center. An adaptive processor combines the reference and selected auxiliary beams to obtain a composite antenna reception pattern in which nulls are inserted at certain angles to suppress interfering signals, without degrading authentic signals arriving at other angles.

Abstract: Wireless medium access in a communication network having a number of terminals is controlled by defining protocol message units for transmission by a given terminal which units correspond to operational states of at least one of the terminal and the medium. A number of time slots are allocated for transmission of packets from each terminal, and a number of contention opportunities are defined at the beginning of each time slot. Priority and backoff mechanisms are defined and applied at each terminal during the contention opportunities in the slots. Packets are then transmitted by the terminal within the slots while (1) minimizing the occurrence of empty slots at times when packets are available for transmission, and (2) minimizing the number of slots during which two or more packets are detected on the medium simultaneously at the terminal.

Abstract: A fiber optic link for platforms with data sources including, e.g., sensors, cameras, radars and antennas. An array of optical transmitter/receiver pairs is coupled to an integrating network of the platform. Data modules are each coupled to certain ones of the data sources and include a receiver for detecting control data, and a modulator for modulating a light signal according to signals from the module's data sources. At least one optical fiber is coupled between a given transmitter/receiver pair of the array, and a corresponding data module. A laser source associated with each transmitter supplies a light signal with the control data to a corresponding data module downstream over an optical fiber. The light signal is modulated by the signals from the module's data sources, and the modulated light signal is returned to an array receiver upstream over an optical fiber.

Abstract: A hyperspectral imaging system has fore-optics including primary, secondary and tertiary fore-optics mirrors, and an imaging spectrometer including primary, secondary and tertiary spectrometer mirrors. Light from a distant object is collected by the primary fore-optics mirror, and the tertiary fore-optics mirror forms an intermediate object image at an entrance side of a spectrometer slit. The spectrometer mirrors are configured so that light from an exit side of the slit is diffracted by a grating on the secondary mirror, and an image representing spectral and spatial components of the object is formed by the tertiary spectrometer mirror on a focal plane array. The surface of each mirror of the fore-optics and the spectrometer has an associated axis of symmetry. The mirrors are aligned so that their associated axes coincide to define a common system axis, thus making the imaging system easier to assemble and align in relation to prior systems.

Abstract: A process and system for enhancing connectivity among nodes of a wireless communications network by adapting to changes in the network topology. Nodes of the network are configured to operate according to either (i) an ad hoc protocol wherein a given node assumes a role of a mesh node capable of connecting with other like-configured nodes, or (ii) a point-to-multipoint protocol wherein the given node assumes a role of either a base station, or a subscriber station being served by another node which is assuming the role of a base station. A determination is made as to whether each node should operate according to the ad hoc protocol or the point-to-multipoint protocol, in order to maintain an optimum state of connectivity among all nodes of the network. The determined operating protocol is then implemented for each node.

Abstract: Ground clutter is effectively separated from true signals echoed by a cable in the flight path of an aircraft, by encoding a transmitted pulse wave in a radar system with at least one transmit (TX) coding sequence, so that received signals echoed by the cable on which the pulse is incident and associated ground clutter are orthogonal or separable from one another. The TX coding sequence is altered into two receive (RX) coding sequences one of which corresponds to the cable and the other to the ground clutter. The two RX coding sequences are then correlated with the received signals, thereby separating the true signals echoed by the cable from the associated ground clutter.

Abstract: A method of enforcing a network security policy including mandatory access control (MAC), discretionary access control (DAC) and integrity control for a secure information network, includes operating a transport guard within a memory partition logically between a protected application running in the partition and a networking stack, and defining ports for the transport guard including (i) an application port for forwarding data to and receiving data from the application, (ii) a data port for receiving data addressed to the application from the networking stack, and for sending data originating from the application to the stack, and (iii) a control port for supplying configuration data to the transport guard. The configuration data corresponds to MAC, DAC and integrity control policies specified by the network for the protected application. The transport guard limits data flow between its protected application and the data ports accordingly.

Abstract: Domains are formed in a mobile ad hoc network by exchanging topology update messages among neighboring nodes, each message including the node coverage of the originating node. The node having an optimum coverage of its neighbors becomes a domain lead (DL) node, and nodes within hearing distance or range of the DL node form a network domain. Each domain node, including the DL, selects a set of bridge nodes (BNs) that can link the domain node to nodes in corresponding neighboring domains. All domain lead nodes in the network exchange messages to inform one another of the nodes contained in their respective domains. A node in one domain seeking a route for a message destined to a node in another domain, may send a route discovery (RDisc) message to the DL node of the inquiring node's domain. A responsive route resolution (RRes) message is returned to the inquiring node.

Abstract: A wideband, e.g., 550 nm to 940 nm, apochromatic lens system for use with an external aperture stop, includes first, second, and third optical groups having, in order, positive, negative, and positive powers. The first group includes four optical elements having, in order, negative, positive, negative, and positive powers. The second group includes one element of negative power; and the third group includes two elements each having positive power. In another embodiment for use with an internal stop, the system includes first, second, and third optical groups having, in order, positive, positive, and negative powers. The first group includes four optical elements having, in order, positive, negative, positive, and negative powers. The second group includes one element of positive power, and the third group includes one element of negative power. In either embodiment, all of the optical elements are formed from not more than three different types of glass material.

Abstract: A stabilised voltage controlled oscillator circuit comprises a closed loop circuit containing a voltage controlled oscillator (34), a local oscillator (40) and a harmonic mixer (38) that mixes a stabilised local oscillator (LO) frequency signal and a radio frequency (RF) signal from the voltage controlled oscillator (34) to obtain an intermediate frequency (IF) signal. An IF amplifier (42) is connected to a linear frequency discriminator (44) that provides an output signal to a summing amplifier (46), which is connected to the voltage controlled oscillator (34). The closed loop circuit uses the linear frequency discriminator (44) to provide a feedback signal that stabilises the voltage controlled oscillator (34).

Abstract: A mute device for a cymbal of the kind mounted on a cymbal post. The device include a strike plate assembly having a mount for engaging an upper part of a cymbal post, and at least one foot projecting from the strike plate assembly to rest on the cymbal. A cymbal mute assembly projects from the strike plate assembly to receive part of an outer circumference of the cymbal. The mute assembly includes a muting part of sound dampening material arranged to contact the cymbal in a rest position, and a strike piece arranged to strike the cymbal in response to a percussion force on the strike plate assembly.

Abstract: A clamp for clamping a workpiece comprises a base member a clamping member mounted on the base member for linear movement relative thereto and a drive member mounted on the base member for rotary movement relative thereto. First and second cam elements comprising a face cam are provided on the drive member and the base member, at least one of the cam elements including at least two portions of different pitch. The arrangement is such that rotation of the drive member relative to the base member causes linear movement of the clamping member relative to the base member.

Abstract: A mute device for use with music drums including tom-toms, snares, and the like. The device includes a drum stick strike plate, and at least one sound post projecting from the strike plate. The sound post contacts the drum skin at a location where the skin is supported on the drum shell housing, when the strike plate is mounted on the drum.

Abstract: A clamp for clamping a workpiece comprises a base member, a clamping member mounted on the base member for limited linear and rotational movement relative thereto and a drive member mounted on the base member for rotational movement relative thereto. First and second cam elements are provided on the drive member and the clamping member and arranged such that relative rotation of the drive member and the clamping member produces relative linear movement thereof. The clamp includes a lost motion mechanism whereby rotation of the drive member can produce limited rotational movement of the clamping member without causing linear movement thereof.