Abstract: A system and method for moving an aerial vehicle along a flight path includes rotatable hubs mounted on opposite sides of the vehicle. Elongated airfoils are mounted on the hubs parallel to a common hub axis for rotation about the hub axis on a blade path. Each airfoil defines a chord line and the system includes a gear assembly changeable, during hub rotation, between a first modality wherein airfoil chord lines remain tangential to the blade path (curtate flight), and a second modality wherein airfoil chord lines remain parallel to the flight path of the vehicle (prolate flight). Also, rotation of the hub can be stopped and the airfoils used for fixed wing flight.

Abstract: A passive navigation system for an airborne platform includes an on-board computer having a database that contains preprogrammed information regarding pre-existing ground-based signal emitters (e.g. cell-phone, television and radio broadcast transmitters). For each emitter, the database includes the geolocation of the emitter and identifying signal characteristic(s) of each emitter's signal such as frequency, bandwidth and strength. An antenna array and digital receiver cooperate with the computer on the platform to passively receive signals from the emitters and determine a direction of arrival (DOA) for selected signals. The computer also extracts identifying signal characteristic(s) from selected received signals and matches them against the database information to ascertain the geolocation of the emitter that corresponds to the received signal. The platform location is then calculated from the DOA(s) and emitter geolocations using a triangulation-type algorithm.

Abstract: An apparatus for inflating and deploying an aerostat having a nose section and a tail section includes a cylindrical container for housing the deflated portion of the aerostat. The cylindrical container is formed with an open end and defines a longitudinal axis. A feed hose extends from a gas source, through the container to a hose end that projects axially from the open end of the container. The deflated aerostat is initially folded to juxtapose the nose and tail of the aerostat. Next, the nose of the aerostat is attached to the feed hose end and the remaining portion of the aerostat is folded and inserted into the container. As the tail section is inflated outside of the container, aerostat cloth is drawn from the container. A mechanism is provided to control the release of cloth from the container and maintain pressure in the inflating aerostat within a predetermined range.

Abstract: A system for tracking a moveable object such as a soldier in an urban environment includes a receiver that is positioned on the movable object and a plurality of signal transmitters. The transmitters are mutually dispersed at known locations within the urban environment and each transmitter is configured to generate a low frequency electromagnetic signal capable of penetrating into buildings in the urban environment. At the receiver, phase related information and the receiver location information are extracted from received signals and used to determine the location of the receiver. Phase related ambiguities can be eliminated by a processor to find the real receiver position using an algorithm such as the maximum likelihood method (MLM) algorithm. Once the real receiver position is calculated, it can be transmitted to a central location using a low probability of intercept (LPI) waveform to prevent hostile parties from intercepting the location of the soldier.

Abstract: An apparatus for inflating and deploying an aerostat having a nose section and a tail section includes a cylindrical container for housing the deflated portion of the aerostat. The cylindrical container is formed with an open end and defines a longitudinal axis. A feed hose extends from a gas source, through the container to a hose end that projects axially from the open end of the container. The deflated aerostat is initially folded to juxtapose the nose and tail of the aerostat. Next, the nose of the aerostat is attached to the feed hose end and the remaining portion of the aerostat is folded and inserted into the container. As the tail section is inflated outside of the container, aerostat cloth is drawn from the container. A mechanism is provided to control the release of cloth from the container and maintain pressure in the inflating aerostat within a predetermined range.

Abstract: A system and method for identifying the position of an airborne platform on a flight path includes at least three radar transceivers that are directed along respective beam paths to generate return signals. Each of the return signals respectively indicate a speed and a direction of the platform relative to points on the surface of the earth. A computer uses the return signal to establish a ground speed, an altitude and a direction of flight for the platform. This information is then used to identify the position of the platform on its flight path. Additionally, the system can include a last known position, or a site-specific radar clutter model, to establish a start point for the platform. The computer can then calculate the position of the platform relative to the start point.

Abstract: A narrowband beamformer for extracting a mainbeam having a frequency, &OHgr;, that is received at a beamsteered sensor array includes a plurality of nonlinear oscillators. Each nonlinear oscillator operates on a signal from one of the beamsteered sensors to produce a nonlinear oscillator output. A summer receives and sums all of the nonlinear oscillator outputs. Each nonlinear oscillator is coupled to at least one other nonlinear oscillator to create a signal in the summer output having a frequency of approximately, &OHgr;, in response to receipt of the mainbeam signal by the sensor array. Further, the nonlinear oscillators are coupled to create a spectrum of signals in the summer output that are centered around a frequency, {overscore (&ohgr;)}, in response to receipt of a directional interference signal by the sensor array. A matched filter is used to isolate the frequency, &OHgr;, to thus extract the mainbeam from the directional interference.

Abstract: A wireless system for locating a signal emitter includes at least three base stations for receiving the emitter signal, and a central processing site for converting information from the received signals into range estimates. Specifically, an antenna array at each base station for receives the emitter signal, and a beamformer isolates the direct path component of this received signal from interference and multi-path signals using cyclic phase minimizer techniques. In operation, an extractor is used to separate a cyclostationary feature from the direct path component of the emitter signal, and the cyclostationary feature is identified in an absolute time reference. The identified cyclostationary feature is then passed to the central processing site. At the central processing site, phase delay characteristics of the cyclostationary features from all participating base stations are compared with each other to obtain phase difference measurements.