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109results about "Direction finders using electromagnetic waves" patented technology

Real-time stabilization

In a first embodiment of the invention, there is provided a method for structuring digital video images in a computer system. The digital video images are capable of being displayed on a display device and contain addressable digital data that is addressable with respect to a reference point on the display device. The method may be embodied in computer code on a computer readable medium which is executed by a processor within the computer system. The computer code removes motion from a digital video image stream. By removing motion from the digital image stream, additional information and details can be observed which are spread out over multiple images when the images are displayed in sequence. The method begins by obtaining a first digital video image and a second digital video image. A subsection is defined within the first digital image at an addressable location relative to the reference point. A subsection of the second digital image is selected which has the same addressable location as the subsection from the first digital image. The subsection of the second digital video image is shifted in a predetermined direction. After the region is shifted, an error value is calculated based upon a comparison of the subsection of the first digital image and the shifted subsection of the second digital video image. If the error is below a predetermined threshold, the digital data of the second digital video image is readdressed such that the data of the newly defined subsection would overlay the subsection from the first digital video image if displayed on a display device.
Owner:INTERGRAPH SOFTWARE TECH

Method and system for discovering and tracking remote controller of illegally flying unmanned aerial vehicle

The invention relates to a method and system for discovering and tracking a remote controller of an illegally flying unmanned aerial vehicle. The system is composed of an unmanned aerial vehicle, a direction finding and positioning device, a flight control and communication module, a camera and cradle head and ground equipment, wherein the unmanned aerial vehicle is a lift-off platform of the whole system; the direction finding and positioning device performs direction finding and positioning on an unmanned aerial vehicle remote control signal; the flight control and communication module controls the whole illegally flying unmanned aerial vehicle system on the one hand, and is used for communicating with the ground equipment on the other hand; the camera and cradle head are used for searching and tracking an illegally flying unmanned aerial vehicle target; and the ground equipment is used for remotely controlling the unmanned aerial vehicle of the own side by a ground user and transmitting and receiving interactive information. The system has a searching state, a positioning state and a tracking state. The system lifts off, recognizes tracks and approaches the illegally flying unmanned aerial vehicle by using an unmanned aerial vehicle platform, and performs continuous direction finding and positioning on the ground remote control signal, thereby achieving a purpose of positioning and tracking the remote controller of the illegally flying unmanned aerial vehicle.
Owner:XIAN DAHENG TIANCHENG IT CO LTD

Method for estimating signal DOA (direction of arrival) under fewer snapshots and impulsive noise background

The invention relates to a method for estimating signal DOA (direction of arrival) under fewer snapshots and an impulsive noise background. The method comprises the following steps: collecting signal sampling data; performing impact removal pretreatment on the received signal data vector; re-sampling and building the covariance matrix of a matrix subjected to impact removal; decomposing the subspace of the re-sampled built covariance matrix, so as to obtain the noise subspace of the covariance matrix; respectively solving the covariance matrix re-sampled for B times, so as to obtain a vector matrix formed by B incident angle estimated values theta, and using a confidence space to correct the matrix and calculating the mean value (theta)i, so as to obtain the estimated value of final DOA angle (theta)i. According to the invention, the received data is preprocessed, so that the impulsive noise can be effectively suppressed; the block-bootstrap method is adopted to resample and build the data matrix, so that the signal can be effectively expanded under the fewer snapshots; the method is high in robustness and is suitable for the estimation of DOA under fewer snapshots and the impulsive noise background and a good direction measurement effect is achieved.
Owner:HARBIN ENG UNIV

Coprime matrix robust adaptive beamforming algorithm based on matrix filling

The invention provides a coprime matrix robust adaptive beamforming algorithm based on matrix filling. The coprime matrix robust adaptive beamforming algorithm based on matrix filling comprises the following steps that a sample covariance matrix of received data is calculated; the sample covariance matrix is vectorized to obtain vectors, and then elimination of redundancy and vector rearrangementare carried out on the vectors to obtain the received data vectors of a complete coprime matrix differential optimization matrix; zero is arranged between elements with discontinuous wave range difference in the received data vectors in a filling mode to obtain the vectors, and then the vectors are obtained by taking information of the positive half part of the vectors; the vectors are expanded into a Toplitz matrix; the Toplitz matrix is restored to obtain a filled covariance matrix; spectral peak search is carried out in an interference signal angle region to obtain estimation of arrival angles of each interference signal; the estimated arrival angles of interference signals, the physical array information of a coprime array and an interference and noise covariance matrix which reconstructs a coprime array physical array are utilized; weighted vectors of an adaptive beamformer is calculated by using the estimation of the interference and noise covariance matrix and expected signal steering vectors.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Spatial directional angle measuring system based on all-optical cross polarization modulation

The invention discloses a spatial directional angle measuring system based on all-optical cross polarization modulation. The spatial directional angle measuring system comprises a first mach-zehnder intensity modulator, a polarization controller, a second mach-zehnder intensity modulator, a polarization controller I, an electric coupler, a microwave phase shifter, a polarization controller II, an optical fiber online polarizer, an optical band pass filter, a photoelectric detector, an offset T and a voltmeter, wherein the first mach-zehnder intensity modulator and the polarization controller are connected with a first laser light source; the second mach-zehnder intensity modulator and the polarization controller I are connected with a second laser light source; the electric coupler and the microwave phase shifter are connected with a microwave signal source; the polarization controller III, the optical fiber online polarizer, the optical band pass filter, the photoelectric detector, the offset T and the voltmeter are sequentially connected with the optical coupler. The spatial directional angle measuring system based on all-optical cross polarization modulation can be used for solving the problem of difficulty in quickly identifying antenna signal directional position information in an optically controlled phased array radar, and can be used for realizing primary measurement of an antenna spatial directional angle based on an all-optical cross polarization modulation method.
Owner:INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI

Solid cryogen cooling system for focal plane arrays

A cryogenic cooling system (12) for cooling electromagnetic energy detectors (50). The cooling system (12) includes a first mechanism (18) that accommodates cryogen fluid in one or more spaces (58, 60). A second mechanism (16, 42) freezes the cryogen fluid in the one or more spaces (58, 60) adjacent to the electromagnetic energy detectors (50). In a specific embodiment, the electromagnetic energy detectors (50) comprise an infrared focal plane array (50). The second mechanism (16, 42) includes a heat exchanger (16) that is mounted separately from the first mechanism (18). The one or more spaces (58, 60) are fitted with three-dimensional cooling interface surfaces (62, 64). The three-dimensional cooling surfaces (62, 64) are implemented via a thermally conductive matrix (62, 64). The thermally conductive matrix (62, 64) is a copper metal matrix or carbon/graphite matrix, and the solid cryogen reservoir (18) is a beryllium reservoir (18). The solid cryogen reservoir (18) includes integrated mounting features (52, 54) for mounting the reservoir (18) to a missile housing and a surface for attaching the focal plane array (50) to the reservoir (18). The second mechanism (16, 42) includes a Joule-Thomson orifice (42) that employs the Joule-Thomson effect to cool the cryogen fluid to a solid state. The first mechanism (18) includes a selectively detachable cryogen canister that provides pressurized cryogen fluid to the heat exchanger (16). The heat exchanger (16) directs cooled pressurized cryogen fluid to the solid cryogen reservoir (18) and Joule-Thomson orifice (42) and is positioned remotely from the cryogen reservoir (18). In an illustrative embodiment, the heat exchanger (16) outputs cooled cryogen gas to plural solid cryogen reservoirs (18) to cool plural corresponding infrared focal plane arrays (50). A line cutter selectively detaches the gas canister and/or the heat exchanger (16) from the missile in response control signal from a computer. The computer generates the control signal after a predetermined amount of the cryogen fluid is present in the cryogen reservoir (18) or after a predetermined time interval.
Owner:RAYTHEON CO

System and method for locating and positioning an ultrasonic signal generator for testing purposes

The invention is directed to an ultrasonic testing system. The system tests a manufactured part for various physical attributes, including specific flaws, defects, or composition of materials. The part can be housed in a gantry system that holds the part stable. An energy generator illuminates the part within energy and the part emanates energy from that illumination. Based on the emanations from the part, the system can determined precisely where the part is in free space. The energy illumination device and the receptor have a predetermined relationship in free space. This means the location of the illumination mechanism and the reception mechanism is known. Additionally, the coordinates of the actual testing device also have a predetermined relationship to the illumination device, the reception device, or both. Thus, when one fixes the points in free space where the part is relative to either of the illumination device or the reception device, one can fix the point and / or orientation of the testing device to that part as well. It should be noted that the results of the point and / or orientation detection may also be used in an actuator and control system. If the position of the testing device needs to be altered with respect to the tested object, the control system and actuator may use the results of this determination to move the testing device relative to the tested object.
Owner:LOCKHEED MARTIN CORP

Compressed sensing theory-based four-dimensional antenna array DOA estimation method

The invention discloses a compressed sensing theory-based four-dimensional antenna array DOA estimation method. According to the method, a sparse signal model for four-dimensional antenna array DOA estimation is established to find that time sequences have important influences on sparse signal recovery, and an improper time sequence is possible to change time modulated noise into color noise so asto seriously worsen the sparse signal recover ability. Therefore, matrix dependency and a noise covariance matrix are introduced to quantitatively analyze the influences, on sparse signal recovery and noises, of different time sequences; and on such basis, a differential evolution algorithm is utilized to establish a time sequence-oriented optimization model. An I1 norm singular value decomposition-based sparse signal recovery algorithm applied to traditional arrays is extended into four-dimensional antenna arrays and the optimized time sequences are combined to carry out four-dimensional antenna array DOA estimation. Numerical simulation results prove that the method has large advantages in the aspects of resolution characteristic and accuracy characteristic when being compared with other four-dimensional array DOA estimation methods, particularly under the conditions of low signal to noise ratio and small snapshot number.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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