Abstract: A technique for reducing altitude error involves determining a corrected altitude for an aircraft using forecast atmospheric pressure data available, for example, from a weather forecasting service. The forecast atmospheric pressure data includes, for a number of points in time and for a number of geographic locations, a set of pressure levels and corresponding altitude values. Altitude correction data is periodically calculated from the forecast atmospheric pressure data for each of a number of geographic grid points. Upon receiving aircraft position information and an aircraft altitude measurement for an aircraft, one or more of the geographic grid points corresponding to the aircraft position are identified, and a corrected altitude of the aircraft is determined based on the altitude correction data of the one or more geographic grid points.

Abstract: Embodiments are generally directed to anti-spoofing techniques for satellite navigation systems. In general, the anti-spoofing techniques use codeless or semi-codeless tracking of encrypted satellite signals to generate measurements that can be used to perform consistency checks to received non-encrypted signals. The consistency checks will detect if the non-encrypted signal is a genuine satellite signal or a spoofing signal.

Abstract: A registration authority (RA) server registers unmanned aerial vehicles (UAVs) and their owners/operators (O/O). A UAV is maintained in a flight lock state until a flight plan request from the O/O is approved by the RA, which sends an key-signed approval to unlock the UAV's flight lock. The RA server evaluates a UAV's proposed flight plan based on the attributes of the O/O and UAV, the location and time of the requested flight plan, and a set of flight rules and exclusion zones that are developed in view of privacy assurance, security assurance, flight safety assurance, and ground safety assurance. The flight plan key-signed approval supplied to the UAV by the RA server specifies an inclusion zone that corresponds to a flight plan trajectory to be followed. Once in flight, the UAV maintains real-time knowledge of its position and time to ensure its flight remains within the approved inclusion zone.

Abstract: A receiver determines a roll rate of a spinning projectile that receives a signal from a satellite or terrestrial transmitter at a directional antenna fixed to the projectile. The receiver tracks a code phase and a rate of change thereof of the received signal relative to a local model signal corresponding to the transmitter. A roll correlator of the receiver correlates the received signal with the model signal based on (i) the tracked code phase and rate, and (ii) a roll-correlator integration time assumed to produce a predetermined number N of correlation samples per revolution of the antenna, to produce sequential correlation samples for each of successive revolutions of the antenna. The receiver determines a time difference between successive periods of observed signal reception based on the correlation samples, and determines a roll rate based on the time difference.

Abstract: Fizeau interferometers, in-flight metrology systems and methods of testing optical systems are described. Collimated or near collimated light is directed to interact with at least one diffractive focusing element of an optical system. The collimated or near collimated light is modified by the diffractive focusing element to form first diffracted light. The first diffracted light is directed to an image surface of the diffractive focusing element. A portion of light directed from the image surface is reflected by the diffractive focusing element back to the image surface as second diffracted light. The second diffracted light has a different diffraction order than the first diffracted light. The second diffracted light is detected to characterize the optical system.

Abstract: Provided is an apparatus comprising a source which emits at least one of particles or radiation. The particles or radiation are emitted towards a target. Arranged between the source and the target is a microchannel plate. Also arranged between the source and the target is a collimator.

Abstract: A computer simulates flight routes for simulated airborne transmitters across a spatial region divided into unit area tiles and over time based on actual aircraft flight plan data. The computer determines transmitter counts per tile per time interval based on the flight routes and assigns transmit parameters, including transmit message rates, to the transmitters. The computer determines transmit message rates per tile based on the transmitter counts and the transmit parameters. The computer generates, for a simulated receiver, an antenna pattern covering at least some of the tiles, and converts the transmit message rates of the covered tiles to a total effective receive message rate of interfering messages at the receiver. The computer determines a probability of successful detection of a desired message among the interfering messages at the receiver based on the effective receive message rate.

Abstract: Image navigation of an input image by edge registration proceeds by generating a reference image kernel in which edges of a reference image are embraced by borders. Image intensities of the reference image kernel internal to the borders increase with decreasing distance from the edges. A registration score is computed by cross-correlating the image intensities of the reference image kernel with image intensities in the input image. A feature exists in the input image when the registration score meets a registration criterion.

Abstract: A cover is fitted to an aperture in an enclosure. A biasing mechanism is connected to the cover to mechanically bias the cover in an open position. An adhesive member is disposed around the aperture to retain the cover in a closed position against the bias of the biasing mechanism. A release mechanism effects release of the cover from the adhesive member by diminishing adhesion thereof in response to an open command signal.

Abstract: A point cloud contains data points having coordinates that locate each data point in a coordinate system. Cell boundaries are defined in the point cloud and a unique index is assigned to each cell. The indexes of the cells are assigned to any of data point contained in a cell having the same index. The index data points can be accessed in a manner analogous to rasterized or gridded data while maintaining the arbitrary or random distribution associated with point clouds. The indexed point cloud can be further processed to achieve a scalable compression level, either losslessly by increasing redundancy in the point cloud data and/or by separating the point cloud data into relevancy bands, or by conventional lossy techniques, such as by exploiting the redundancies created in the point cloud data to represent the point cloud in a finite number of symbols.

Abstract: An apparatus is provided for underwater operation comprising a pressure regulator configured to reduce a pressure of a gas received from a gas source at a first pressure to a second, lower pressure. A multiport differential pressure regulator is provided to receive the gas at the second pressure at a first port and to provide the gas to a second port at a differential pressure relative to an ambient pressure that varies based on a depth of the apparatus, where the differential pressure is set to a pressure that is at least 0.1 PSI below ambient pressure. A check valve vent is coupled to the second port of the multiport differential pressure regulator to relieve pressure at the second port accumulated by the apparatus during operation at a higher pressure depth when the apparatus rises from the higher pressure depth to a lower pressure depth.

Abstract: Provided is an apparatus which includes a near-to-eye display, a microcontroller, a hot shoe interface with an external port configured to communicate with an external mounting device for the near-to-eye-display, a hot shoe interface line between the external port and the microcontroller, and a communication line between the external port and the microcontroller. The communication line is configured to share at least a portion of the hot shoe interface line, and is also configured to transmit and receive external communications through the external port. The microcontroller is configured to activate and inactivate transmission over the communication line in response to predetermined signals received over the communication line within a first predetermined time period of at least one of the near-to-eye display being powered-on or the mounting device transitioning from one of an active orientation or a stowed orientation to the other.

Abstract: A vision system is supported by an articulated support frame having at least one proximal frame member coupled to an attachment device and a pair of distal frame members that retain optical devices in fixed mutual parallelism between optical axes of the optical devices and mounting axes of the distal frame members. A number of joints are mechanically interposed between the frame members that define respective axes of rotation about which the frame members are relatively moveable. The joints afford motion of the distal frame members through spatial trajectories over which the mounting axes diverge from mutual parallelism. A bridge device immobilizes the distal frame members on their trajectories in a binocular viewing configuration in which the mounting axis are parallel.

Abstract: A technique for generating a three-dimensional reconstruction of a scene involves generating a high-fidelity point cloud representing a three-dimensional reconstruction of a scene from two-dimensional images generated by at least one sensor whose position and orientation are known relative to a fixed coordinate system for each of the images. The high-fidelity point cloud is generated in a relative coordinate system without regard to the position and orientation of the sensor(s). A low-fidelity point cloud is generated in the fixed coordinate system from the two-dimensional images using the position and orientation of the sensor(s) relative to the fixed coordinate system.

Abstract: A set of global navigation satellite system receivers is deployed in and moves about a region that may be occupied by a signal jammer or spoofer. The receivers collect truth data from spectral content of the broadcast satellite signal and, optionally, from a set of sensors associated with each receiver from which an independent determination of location can be derived. The truth data are compared with data acquired by the receivers and an alert is issued upon detection of an anomaly. The data from receivers in a region of influence of the jammer or spoofer are aggregated, integrated, and correlated to generate a two-dimensional representation of a region in which the offending signals are present.

Abstract: A weather control station receives from a communication network data packets transmitted wirelessly to the network by a mobile platform separated from the control station. The data packets carry images captured by an image sensor aboard the mobile platform and show one or more weather conditions local to the mobile platform. The control station recovers the images from the data packets and processes the recovered images according to one or more weather condition detection algorithms to detect the one or more weather conditions, respectively. The weather station reports the one or more detected weather conditions.

Abstract: Measuring the polarimetric response of an optical instrument includes the steps of: emitting light along an optical axis; receiving the light through first and second polarizers; and detecting the light received through the first and second polarizers, using a filter and a detector. A first set of measurements is obtained by measuring the intensity of light received through the first and second polarizers. A second set of measurements is obtained by placing an optical instrument along the optical axis in lieu of the filter and detector; and measuring the intensity of light received through the first polarizer, after the second polarizer has been removed. A third set of measurements is obtained using the optical instrument but having the second polarizer replace the first polarizer. The optical instrument may be characterized using the first, second and third sets of measurements. The characterization is completed without having to know the extinction ratios and the transmittance parameters of the polarizers.

Abstract: A method of detecting a dynamic weather event includes the steps of: (a) receiving video images of a scene from a camera; (b) dividing each of the video images into multiple regions, in which a region is defined by a range of distances from the camera to objects in the scene; (c) selecting a region; and (d) segmenting the selected region into a plurality of three-dimensional (3D) image patches, in which each 3D image patch includes a time-sequence of T patches, with each patch comprised of N×M pixels, wherein N, M and T are integer numbers. The method also includes the following steps: measuring an image intensity level in each of the 3D image patches; masking 3D image patches containing image intensity levels that are above a first threshold level, or below a second threshold level; and extracting features in each 3D image patch that is not discarded by the masking step. Based on the extracted features, the method makes a binary decision on detecting a dynamic weather event.

Abstract: A weather surveillance system includes a data ingest module for receiving weather forecasts of a region, and multiple cameras for viewing targets of interest and providing imagery of the targets of interest, wherein the targets of interest are located within the region. The data ingest module also receives the imagery from the multiple cameras. The system also includes an analytics module for selecting at least one of the multiple cameras; a data fusion module for combining the received weather forecasts of the region with received imagery of the selected camera; and an output module which provides fused data to a user for verifying the weather forecast in the target of interest. The output module includes a web-based service module for collecting, storing and disseminating the fused data to the user.

Abstract: An “on-demand” approach for a routing protocol for a wireless network that achieves balanced energy consumption among all participating nodes in the network. Synchronization messages transmitted by nodes associated with an upstream node include local node information (LNI) that a node can use to repair or bypass a lost upstream node in a real or virtual (temporary) manner depending upon the local node's battery level. Only if a repair process fails will a global re-organization (Re-Org) be initiated. The LNI also allows for nodes having lower power availability (battery level) not to transmit the LNI so that unaffiliated node(s) can select an upstream node having more power availability thereby extending network life.