13results about "Direction finders using electromagnetic waves" patented technology

The application is a lightning positioning optimization method and system and a medium for correcting the influence of terrain and geological parameters on lightning electromagnetic wave propagation. The method grids the area around the lightning detection station involved in lightning positioning. Using the ground and ionosphere electromagnetic wave propagation model, the time delay correction value and parameter correction coefficient of lightning electromagnetic wave propagation from the preliminary lightning position to the lightning detection station are calculated without considering terrain and geological parameters and considering terrain and geological parameters. When the closest grid point is found as the lightning point in the time delay correction table and parameter correction coefficient table corresponding to the lightning detection station involved in positioning, the time delay correction value and parameter correction coefficient corresponding to each lightning detection station are used to correct the lightning detection station, and the corrected waveform arrival time and corrected characteristic parameters corresponding to each lightning detection station are obtained. The accurate lightning position and accurate lightning characteristic parameters are calculated.

The invention discloses a single Rydberg atom receiver multi-target direction of arrival estimation method based on spatial resolution fluorescence spectrum analysis. According to the method, a modulation pattern formed by interference of a plurality of radio frequency signals and a local oscillation field in the steam chamber is obtained through spatial resolution fluorescence imaging, traditional lumped power measurement is replaced, and therefore multi-target spatial information is completely reserved. On the basis, complex spatial modulation caused by a plurality of signals is linearized into superposition of sine waves with different spatial frequencies by utilizing a strong local oscillation condition, so that a multi-target direction-of-arrival estimation problem is converted into a classical frequency spectrum estimation problem. And finally, through spectrum analysis, extracting each spatial frequency and calculating a corresponding direction of arrival. According to the method, through the core steps of spatial resolution imaging, linear modeling and spectral analysis, the limitation that a single Rydberg atom receiver can only estimate a single target is fundamentally broken through, and simultaneous estimation of the directions of arrival of a plurality of signal sources by using a single receiver is realized.

A missile warning system comprises: a primary sensor (110) for detecting a potential missile (50) in a first spectral range; a secondary sensor (120) for detecting the potential missile (50) in a second spectral range; and an evaluation unit (130). The evaluation unit (130) is configured: to receive first detection signals (115) from the primary sensor (110) and compare them with a threshold value (S1), and, if the threshold value (S1) is exceeded, to generate a warning signal for the potential missile (50); to continuously receive second detection signals (125) from the secondary sensor (120) and store them for a predetermined period; and, if the warning signal is present, to perform a verification of the potential missile (50) based on a traceback, wherein the traceback includes an analysis of the stored sensor signals of the secondary sensor (120).

Method for characterizing the motion of an object, computer, system and associated carrier. The present invention relates to a method for characterizing the motion of an object comprising the steps of: - obtaining measurements of two angular orientations of the object with respect to a sensor, - applying an estimator to each pair of measured orientations, the estimator assuming motion for the object, to obtain estimated state vectors, - determining a set of possible values ​​for the coordinates of each state vector by applying a constraint to the estimated state vectors, a constraint being a constraint according to which the motion of the object is the motion assumed by the estimator, and - detecting the nature of the motion of the object, the detected motion being the motion assumed when each estimated state vector belongs to the set determined for the considered estimated state vector.The detected movement being different from the movement that would otherwise be assumed. Figure for the abbreviation: figure 3.

This invention relates to the field of radio frequency signal measurement technology, and proposes a microwave photonic system and method for nanosecond-level measurement of frequency and angle of arrival. The system includes: an optical frequency comb generation module, in which a narrow-linewidth laser generated by a tunable laser is amplified by an erbium-doped fiber amplifier and then excited by the Kerr nonlinear effect to generate a coherent optical frequency comb; an antenna receiving module, which receives a first radio frequency signal and a second radio frequency signal; an electro-optic modulation module, in which the first radio frequency signal and the second radio frequency signal are respectively input to a first sub-modulator and a second sub-modulator, and a third sub-modulator is used to combine the first and second modulated lights and introduce a preset phase difference to obtain a target optical pulse signal; and a frequency-time mapping and detection module, in which the target optical pulse signal is frequency-time mapped via a dispersive fiber, a photodetector converts the mapped optical signal into an electrical pulse train, and an oscilloscope is used to observe the time interval between adjacent peaks and the pulse amplitude information of the electrical pulse train to obtain the characteristic parameters of the radio frequency signal.

A method for providing a differential code bias, in particular a primary differential code bias and a secondary differential code bias, in a global navigation satellite system using satellites communicating by using at least a first signal and an additional first signal both having a first carrier frequency and a second signal and an additional second signal both having a second carrier frequency, where a primary differential code bias for the first signal and the second signal is determined and wherein the primary differential code bias is used for determining, and in particular providing, a secondary differential code bias for the additional first signal and the additional second signal.

According to the MSCKF visual odometer method based on the course constraint, the problem that the estimation precision is reduced due to inconsistent course observability is solved through course constraint information, the system robustness is improved, and the MSCKF visual odometer method based on the course constraint has wide application prospects in multiple fields in the future. The problem that the estimation precision is reduced due to inconsistent course observability is solved, and the robustness of long-time operation of the MSCKF system is enhanced.

The invention relates to a position detection system, having at least one position detection device (1) and at least one light source device (20 to 2N), which differs from the position detection device (1). Every light source device (20 to 20N) is designed to generate a light point at a distance from the at least one position detection device (1). The at least one position detection device (1) comprises at least two line scan image sensors (11, 11'), wherein directions of extent of sensor surfaces (12, 12') of the two line scan image sensors (11, 11') together enclose an angle greater than 0° and preferably 90°. Above each line scan image sensor (11, 11'), a slot aperture (13, 13') is provided such that the slot aperture (13, 13') and the associated sensor surface (12, 12') enclose an angle greater than 0° and preferably 90°. The at least one position detection device (1) and the at least one light source device (20 to 2N) each have interfaces for wireless communication via which the at least one position detection device (1) and the at least one light source device (20 to 2N) are temporally synchronised in order to enable the position of a light point generated by a respective light source device (20 to 2N) to be detected by a time-multiplex method during the emission of light by the at least one light source device (20 to 2N).

The application discloses a kind of robust DOA estimation methods based on sparse bayesian learning, belong to array signal processing field, the method of this application first introduces position error parameter, and determines the prior distribution of grid error and element position error, secondly with the aid of sparse bayesian learning model, establish joint probability density distribution function, finally with the aid of maximum expectation algorithm to each unknown parameter is iterated, obtains spatial spectrum diagram, estimates the direction of incident signal.This application method can better azimuth estimation accuracy and azimuth resolution, still have good performance under the condition of less snapshot, low signal-to-noise ratio, and the application method has good robustness to the array system that exists element position error, has greater engineering application value.

Method for determining the positioning of a device (10) worn by a vehicle occupant, in particular data glasses (11), in a vehicle interior (12), wherein light emitted by at least one light source (13) arranged in the vehicle interior (12) is modulated by a control device (14) with a predetermined frequency not perceptible to the vehicle occupant, recordings of at least one area of ​​the vehicle interior (12) are made by means of a camera (15) of the wearable device (10) and received by an evaluation unit (16, 16'), and the frequency of the modulated light is determined by the evaluation unit (16,16') is recognized in several of the recordings and assigned to the light source (13) and the positioning of the portable device (10) in the vehicle interior (12) is determined based on a previously known spatial position of the light source (13) in the vehicle interior (12) and a position of the modulated light assigned to the light source (13) in the recordings; such system (20), vehicle (30) and portable device (10).,

The invention discloses an angle-measurement-only multi-sensor multi-target tracking method based on joint probability data association, solves the problem that the multi-target tracking precision of an angle-measurement-only multi-sensor system is reduced when targets are dense or mutually shielded, and belongs to the technical field of multi-target tracking. According to the method, the condition of merging measurement is described by establishing the merged graph model, and the probability of the merged graph is calculated. Then, the measurement merging situation is included into the association hypothesis, so that the association hypothesis is more complete; then, the probability of the joint association event is calculated, and the probability comprises the probability of the combined graph; and fusing the probability of each joint association event to obtain the association probability of the sensor measurement value and the target. And finally, according to the association probability of the measured value of the sensor and the target, weighting and updating the state of each target to realize multi-target tracking.

A device (800) for protecting an aircraft against missiles, includes a Short-Wave InfraRed based (SWIR-based) Missile Tracking Unit, having a SWIR-based optical imager that associated with an optical SWIR band filter. The device (800) further includes a SWIR signals processor; it analyzes the captured SWIR optical signals; and it performs a SWIR-based missile acquisition process, which is also based on raw angular position data of a missile as received from a Missile Approach Warning System (MAWS); and it performs a SWIR-based missile tracking process, which continuously and dynamically determines a precise angular position of the missile based on the captured SWIR optical signals. The device (800) includes a laser-based missile-jamming unit, having an internal laser emitter; and optionally also being operably associated with an external high-power laser emitter; to disrupt the missile, or to disrupt a guiding station of the missile.

Various embodiments of the present invention may comprise a biometric sensor (220), an IR sensor (225), a communication module (240), a memory (245) storing instructions, and a processor (230). The instructions, when executed by the processor, may cause the wearable device to: acquire first sensing data from the IR sensor as the wearable device is worn on a user's finger; determine the wearing direction of the wearable device on the basis of the acquired first sensing data; guide the wearing direction of the wearable device according to the result of the determination; and redetermine the wearing direction of the wearable device on the basis of second sensing data acquired from the IR sensor after guiding the wearing direction. Various embodiments are possible.