Abstract: An apparatus for measuring distance to a surface is disclosed. The apparatus transmits at least one subsequent pulse of light prior to receiving a reflection of a previously sent pulse of light. Thus, multiple pulses of light are in-flight at a given time. The embodiments are applicable to terrain mapping, bathymetry, seismology, detecting faults, biomass measurement, wind speed measurement, temperature calculation, traffic speed measurement, military target identification, surface to air rangefinding, high definition survey, close range photogrammetry, atmospheric composition, meteorology, distance measurement, as well as many other applications. Examples of such apparatuses include laser ranging systems, such as light detection and ranging (LIDAR) systems, and laser scanners. Data received from the apparatus by a data processing unit can be used to create a data model, such as a point cloud, digital surface model or digital terrain model describing the surface, terrain, and/or objects.

Abstract: A method for processing received radar returns of a radiated wide-band arbitrary waveform in a wide-band radar processing system using spectral processing. The received wide-band radar returns are undersampled by using a first sampling rate to obtain an undersampled digital wide-band radar waveform. Spectral processing is performed on the power spectrum of the undersampled digital wide-band radar waveform in order to obtain a discrete ripple frequency power spectrum of the undersampled digital wide-band radar waveform. Ripple frequencies indicating radar targets are located in the discrete ripple frequency power spectrum of the undersampled digital wide-band radar waveform. A radar receiver, a digital wide-band radar processing system and a computer program product.

Abstract: Method and apparatus for validating an initial position in a satellite positioning system using range-rate measurements is described. In one example, range-rate measurements are obtained at the remote receiver with respect to a plurality of satellites. Expected range-rates are computed with respect to the plurality of satellites using the initial position. Single differences are computed using the range-rate measurements. Expected single differences are computed using the expected range-rates. Single difference residuals are computed between the single differences and the expected single differences. The single difference residuals are compared to a threshold. The initial position may be deemed valid if the absolute value of each of the single difference residuals is less than or equal to the threshold. A valid initial position may be used to fix the pseudorange integers.

Abstract: This invention relates to a three-dimensional image of ground surface and the method and system that generates the three-dimensional image. Here, a three-dimensional image is an image that has three-dimensional XYZ coordinates in a ground coordinate system for every pixel of the image and the ground surface means the bare-earth surface plus all the objects on the bare-earth surface. The scene covered and represented by such a three-dimensional image is a three-dimensional real world scene where everything visible in the three-dimensional image has three-dimensional coordinates. The three-dimensional XYZ coordinates of all the pixels of a three-dimensional image are attributed by the method and system of this invention for generating three-dimensional images with airborne oblique/vertical imagery, GPS/IMU, and LIDAR ground surface elevation or range data.

Abstract: Embodiments provide radio-frequency systems that can automatically detect, focus-on, and track objects in the environment without the need for expensive electronic scanning and phase-shifting components. Some embodiments are directed to retrodirective systems including: (1) quiescently broadcast pseudorandom-modulated radiation, such as pseudorandom bit sequences, in the absence of a target, over a field-of-view comparable to the beam solid angle of a single element in the transmit array; (2) a receive antenna element or array, in a desired spatial relationship with respect to the transmit antenna array, that receives reflected pseudorandom radiation from a target; and (3) an electronic signal-processing and feedback channel between the receive and transmit arrays that carries out cross-correlation between the received radiation and the transmitted pseudorandom signals and computes complex correlation coefficients to form a re-transmitted beam.

Abstract: Systems and methods for monitoring and classifying RF emissions in the field include storing an electronic signature map (ESM) of a selected geographic area, where the electronic signature map includes previously detected emitter closeness measures (ECMs) in the selected geographic area. The ECMs are representative of detected sources of radio frequency energy. A RF energy emission is detected, a new ECM for that RF energy emission is created, and that the new ECM is compared with the ECMs in the ESM. That comparison may help to determine whether the RF energy emission should be considered a threat.

Abstract: A near field radar imaging system looks at the distance between the several points under evaluation, and corrects image strength based upon varying distances such that a more accurate image of the object under evaluation is provided.

Abstract: There is provided a system for forming an optical screen, including a continuous wave or pulsed laser transmitter for transmitting a beam of radiation at a predetermined wavelength and forming a planar or curved surface to be traversed by a moving object, at least one receiver including an array of detectors for receiving reflected or scattered beam radiation from the object and directing it towards the detectors for producing a signal, and a detection logic receiving the signal and determining parameters selected from the group of spatial position, velocity and direction of propulsion of them moving object. A method for detecting a moving object is also provided.

Abstract: A method and apparatus for qualifying a Satellite Positioning System (SPS) location determination. A method in accordance with the present invention comprises determining a constellation of satellites used in the location determination, making a measurement set based on signals received from the constellation of satellites, comparing the measurement set and the constellation of satellites used in the location determination to a predetermined threshold, and reporting the location determination only when the threshold is not exceeded. Such a method further optionally includes the threshold being user-selectable, the threshold being adjusted or disabled based on a pre-defined scheme, the threshold being adjusted in a sequential form based on a pre-defined scheme, and the measurement set being made in a Global Positioning System (GPS) receiver.

Abstract: A system and method for determining whether a wireless device has transmitted one or more forged satellite measurements. An estimated location of a wireless device may be determined as a function of signals from a cellular network. For each one of a first set of satellites from which the wireless device receives a signal, expected frequency information may be determined as a function of the estimated location, actual frequency information may be measured, and the expected frequency information compared with the measured frequency information. One or more satellite measurements received from the wireless device may then be identified as forged if a difference between the expected and measured frequency information is greater than a predetermined threshold.

Abstract: A method and apparatus for determining time-of-day in a mobile receiver is described. In one example, expected pseudoranges to a plurality of satellites are obtained. The expected pseudoranges are based on an initial position of the mobile receiver and an initial time-of-day. Expected line-of-sight data to said plurality of satellites is also obtained. Pseudoranges from said mobile receiver to said plurality of satellites are measured. Update data for the initial time-of-day is computed using a mathematical model relating the pseudoranges, the expected pseudoranges, and the expected line-of-sight data. The expected pseudoranges and the expected line-of-sight data may be obtained from acquisition assistance data transmitted to the mobile receiver by a server. Alternatively, the expected pseudoranges may be obtained from acquisition assistance data, and the expected line-of-sight data may be computed by the mobile receiver using stored satellite trajectory data, such as almanac data.

Abstract: A method and system obtains precise survey-grade position data of target points in zones where precise GPS data cannot be obtained, due to natural or man-made objects such as foliage and buildings. The system comprises position measurement components such as a GPS receiver, together with an inertial measurement unit (IMU) and an electronic distance meter (EDM) or an image capture device all mounted on a survey pole. The system and method obtains GPS data when outside the zone and uses the other position measurement systems, such as the IMU, inside the zone to traverse to a target point. The EDM or the image capture device may be used within or without the zone to obtain data to reduce accumulated position errors.

Abstract: A method and apparatus for calculating corrections to a navigation solution based on differential GPS data includes receiving GPS ephemeris from at least three GPS satellites. A PVT solution is resolved from the GPS ephemeris. The PVT solution includes a Circular Error Probable (CEP). Differential GPS data for calculating the corrections to the PVT solution is received. A corrected PVT solution is then based upon the differential GPS data. The corrected PVT solution is compared to an area defined by the CEP. Where the corrected PVT solution is not within the area, the corrected PVT solution is rejected in favor of the PVT solution for determining an accurate navigational solution.

Abstract: A modular system is for assembling a fill-level radar antenna, a fill-level radar antenna, and o a fill level radar. The modular system comprises several modules that can be interconnected. In this way a host of different fill-level radar antennae may be produced that are optimally adapted to the corresponding conditions.

Abstract: An ultrasonic transducer cell according to the present invention includes: a substrate; a charge holding portion provided on the substrate; a lower electrode provided on the charge holding portion and used to input and output a signal; and a vibration membrane provided above the lower electrode to be separated from the lower electrode with a cavity, and configured to include at least an insulating film and an upper electrode provided on the insulating film.

Abstract: Using a radar to detect a known target likely to be positioned at approximately a predetermined height close to other targets, these other targets also being positioned at approximately the predetermined height. A first phase of detecting the known target is carried out by performing an azimuth scan. When the known target has been detected at a certain distance Di at a certain azimuth angle ?az, a second detection phase is carried out at said azimuth angle ?az and at an elevation angle ?EL corresponding to that of an object situated at said distance Di at the predetermined height. The target is said to be detected if it is detected at the elevation angle ?EL at a distance D approximately equal to the distance Di.

Abstract: A pseudorange calculation method for calculating a pseudorange in a position calculation device includes: passing a received signal received from a satellite for position calculation through a first filter; passing the received signal through a second filter having a different phase characteristic from that of the first filter; calculating a first pseudorange on the basis of a signal acquired by passing through the first filter; calculating a second pseudorange on the basis of a signal acquired by passing through the second filter; and calculating a third pseudorange to be used for position calculation, on the basis of the first pseudorange and the second pseudorange.

Abstract: A method for passive background correction during spatially or angularly resolved detection of emission that is based on the simultaneous acquisition of both the passive background spectrum and the spectrum of the target of interest.

Abstract: A real-time radar surveillance system comprises at least one land-based non-coherent radar sensor apparatus adapted for detecting maneuvering targets and targets of small or low radar cross-section. The radar sensor apparatus includes a marine radar device, a digitizer connected to the marine radar device for receiving therefrom samples of radar video echo signals, and computer programmed to implement a software-configurable radar processor generating target data including detection data and track data, the computer being connectable to a computer network including a database. The processor is figured to transmit at least a portion of the target data over the network to the database, the database being accessible via the network by at least one user application that receives target data from the database, the user application providing a user interface for at least one user of the system.

Abstract: An electromagnetic absorber assembly capable of minimizing reflectivity caused by reflected and diffracted waves within a test chamber is presented. The absorber assembly includes a plurality of first wedges and a plurality of second wedges disposed in a symmetrical arrangement so as to form a continuous and smoothly changing v-shaped pattern along one or more walls of an anechoic test chamber. Each wedge has a triangular-shaped first end and second end formed by a pair of side walls and a base wall. One second end of each first wedge contacts and covers one first end of each second wedge along a contact plane. First and second wedges are disposed at a first angle and a second angle, respectively, about the contact plane in a symmetrical arrangement. The assemblies described could be installed on a flat or shaped absorber base or wall to divert reflected and refracted fields away from a quiet zone.