216 results about "Coherent processing" patented technology

Radar for detecting and tracking short range airborne targets using a non-scanning beam to illuminate the entire search space, and processing the return signals from a plurality of spaced apart receive antennas. Target angle in one plane may be determined by coherent processing of the returns from the plurality of receive antennas. Spacing the receive antennas apart in three dimensions allows determining of two angles, such as azimuth and elevation. Processing of the returns may be coherent or noncoherent, or returns may be processed both coherently and noncoherently. Programmability of the processing algorithms and parameters provide flexibility in applications, as well as flexibility based on such things as the target type and its range. Exemplary applications are disclosed.

Described embodiments provide coherent processing of hash operations of a network processor having a plurality of processing modules. A hash processor of the network processor receives hash operation requests from the plurality of processing modules. A hash table identifier and bucket index corresponding to the received hash operation request are determined. An active index list is maintained for active hash operations for each hash table identifier and bucket index. If the hash table identifier and bucket index of the received hash operation request are in the active index list, the received hash operation request is deferred until the hash table identifier and bucket index corresponding to the received hash operation request clear from the active index list. Otherwise, the active index list is updated with the hash table identifier and bucket index of the received hash operation request and the received hash operation request is processed.

A LADAR system for coherently imaging a target within a volume has a modulated laser transmitter at a frequency and a receiver. The receiver has a plurality of lenses, each with its own detector. Each detector is supplied by a centrally located local oscillator tuned to the frequency. The paths from the local oscillator to each detector, as well as the delay within each lens / detector combination are measured during a calibration. A calibrating reflector reflects a test signal during the calibration at many frequencies, temperatures and accelerations. Measurements of paths and delays obtained during the calibration are stored, and used to phase compensate subsequent target reflections for coherent processing.

The invention belongs to the field of radar technologies, and relates to a CE-OFDM (Constant Envelope Orthogonal Frequency-Division Multiplexing) based radar communication integration system. The invention is a CE-OFDM based super-resolution radar communication integration scheme which is provided on the basis of a traditional OFDM radar communication integration scheme, compensated through communication information, and capable of improving the effective data transmission rate and solving a problem that the PAPR of OFDM signals is too high. A transmitting terminal firstly turns data to be transmitted into CE-OFDM symbol frames through QAM (Quadrature Amplitude Modulation), IFFT (Inverse Fast Fourier Transform) and phase modulation, and a single pulse in a pulse repetition period is replaced by using a CE-OFDM symbol, so that the data transmission rate is improved, and the problem that the PAPR of transmitted signals is too high is solved. At a receiving terminal, received waveform pulses are demodulated, an inverse process of the transmitting process of the CE-OFDM system is carried out on the signals, and data can be demodulated; and the transmitting waveform is known, pulse compression processing is carried out on received echo waves, and super-resolution estimation for the distance and the speed of a target can be accomplished through decorrelation processing and an MUSIC algorithm after information compensation.

Described embodiments provide coherent processing of hash operations of a network processor having a plurality of processing modules. A hash processor of the network processor receives hash operation requests from the plurality of processing modules. A hash table identifier and bucket index corresponding to the received hash operation request are determined. An active index list is maintained for active hash operations for each hash table identifier and bucket index. If the hash table identifier and bucket index of the received hash operation request are in the active index list, the received hash operation request is deferred until the hash table identifier and bucket index corresponding to the received hash operation request clear from the active index list. Otherwise, the active index list is updated with the hash table identifier and bucket index of the received hash operation request and the received hash operation request is processed.

A system and technique for calibrating a plurality of radars provides a set of simultaneous equations derived from monostatic echo returns from a plurality of targets. A solution of the simultaneous equations provides relative position calibration factors and time delay calibration factors associated with the plurality of radars. The relative position calibration factors and the time delay calibration factors allow the plurality of radars to be coherently combined with only a small amount of processing gain loss compared with an ideal coherent processing gain.

The invention discloses a compressive sensing theory-based Doppler ambiguity-resolution processing method, which comprises the following steps of: (1) performing non-uniform sampling on continuous echo pulses in a totally-coherent processing period by utilizing Q-fold pulse repetition frequency values; (2) designing the possible Doppler frequency range of a target, and ensuring the Q-fold pulse repetition frequency values do not have Doppler dead zones in the Doppler frequency range; (3) constructing a compressive sensing (CS) model by utilizing the time-domain under-sampling characteristics of sampled data in the totally-coherent processing period and the sparse characteristics of frequency spectrums of the target to be detected in the possible Doppler frequency range; and (4) resolving the CS model by utilizing an orthogonal matching pursuit (OMP) reconstruction algorithm to directly estimate the amplitude response of ambiguity-free Doppler spectrums. The method eliminates the restriction of the PRF multiplicity adopted by a radar system to the number of the targets to be detected, and simultaneously avoids the condition of false values caused by the influence of measurement errors in the conventional methods by taking the influence of noise on reconstruction results into account and performing de-noising operation when the CS model is resolved to estimate the amplitude response of the ambiguity-free Doppler spectrums by adopting the OMP reconstruction algorithm.

The present invention discloses an ancient architecture monitoring and early warning system based on an internet of things, comprising a wireless sensor network configured to monitor the ancient architecture environment, a cloud data server, and a real time monitoring platform. The wireless sensor network comprises a gateway node and a plurality of sensing nodes located everywhere about the ancient architecture, the sensing nodes include sensor modules, interface circuits, first controller modules and first wireless communication modules, and the gateway node includes a second wireless communication module, a second controller module and a network communication module. A nested and coherent processing flow comprising acquisition, transmission, fusion and display of information is formed through tight cooperation, therefore the continuity of the time and the efficiency of the spatial distribution of the data of monitoring the environmental factors associated with the ancient architecture are effectively improved, and at the same time the cost of manpower and material resources is greatly reduced; and moreover, the ancient architecture monitoring and early warning system based on the internet of things may make timely early warning in response to unexpected disasters and is capable of performing intelligent analysis and determination of monitoring data.

Method and apparatus for improving the detection and discrimination of slow moving or stationary range-Doppler spread objects on or in close proximity to the ground (or sea surface). Invention detects, discriminates and separates radar returns from interference including ground clutter discretes via a coherent process for separating target returns from the myriad of received signals. Thus the method and apparatus improves the probability of detecting and declaring the presence or absence of an object at the same time that the probability of false declaration decreases. The method and apparatus may be applied to the processing of any over resolved object, including airborne radar.

The invention discloses a radar target detection method based on the sparse Fourier transform. The detection method comprises 8 steps and 13 detection processes of firstly carrying out Fourier transform on emission signals and echo signals; separating positions of targets with near frequency by use of the sequence rearrangement method; carrying out target separation by use of a filter; by use of Fourier transform results of segmentation signals, determining delay positions and frequency of the targets and carrying out target detection by use of the Fourier transform. The detection method is advantageous in that a problem of huge operand during coherent processing of broadband signals or long-time accumulated signals is overcome; meanwhile, due to rational selection of threshold values and segmentation lengths of the signals, detection probability and calculation speed in the low signal to noise ratio of the targets can be achieved and improved in a project; and he detection method has a quite high actual application value and worthy of adoption and promotion.

The invention provides a detection device of an optical time domain detection signal (OTDR, Optical Time Domain Reflectometry) and a related coherent detection method of the optical time domain detection signal. The method comprises the following steps of: modulating detection light according to a related code pattern sequence to generate a pulse sequence optical signal, and inputting the pulse sequence optical signal into a detected optical fiber; receiving back scattering light from the detected optical fiber, carrying out coherent processing on the back scattering light and local oscillator light, and converting an optical signal obtained after the coherent processing into a digital signal; and carrying out digital related processing on the digital signal and the related code pattern sequence to obtain and output an optical time domain detection signal. According to the scheme of the invention, the advantages of related and coherent OTDR are integrated, the defects of the related and coherent OTDR are made up, and high dynamic range and high resolution OTDR detection is realized.

The invention discloses a GPS (global positioning system) multi-path mitigation method based on a robust beam forming algorithm, which comprises the following steps: step I, modeling a GPS multipath channel by adopting a uniform linear array; step II, performing decorrelation on received signals by adopting the forward-backward spatial-smoothing technology, so as to obtain a new data covariance matrix and the optimal weight of a Capon beam former; step III, on the basis of the step II, establishing a cost function of the worst-case performance optimization robust beam forming algorithm, so as to solve the optimal weight under steering vector mismatch; step IV, on the basis of the step III, exerting uncertainty constraint on other array response errors, so as to obtain an improved model for the worst-case performance optimization robust beam forming algorithm; and step V, according to the model determined in the step IV, calculating to obtain the optimal weight vector of the Capon beam former, and determining the loading capacity by utilizing the Newton iteration method.

The invention discloses an automatic pipe bundling and bagging machine which comprises a machine frame. A turnover frame and a supporting and pressing mechanism are arranged on the machine frame. The turnover frame is located on the supporting and pressing mechanism and used for leading in outside pipes to be bundled and bagged and turning the pipes into the supporting and pressing mechanism. The supporting and pressing mechanism is used for controlling the pipes to roll in sequence. A pushing mechanism, a bundling mechanism and a bagging mechanism are sequentially arranged behind the supporting and pressing mechanism from right to left and located on the same horizontal axis. The pipes are pushed by the pushing mechanism to be firstly bundled by the bundling mechanism and then bagged by the bagging mechanism. The bagged pipes can be discharged into an outside storage rack through a lifting discharging mechanism. The automatic pipe bundling and bagging machine is high in automation degree, and coherent processing of bundling and bagging on the same axis is achieved; besides, the whole machine is small in occupied space so that a large batch of machines can carry out pipe packaging in a concentrated mode.

A method and system for finding the position of a mobile unit with respect to the satellites of a satellite network such as the Global Positioning System and with respect to the base stations of a wireless communications network. Each satellite transmits a signal that consists of a series of frames of a pseudonoise sequence. The frames of a signal received from the satellite network by the mobile unit are arranged as columns of a matrix and are processed coherently to provide estimated pseudoranges and estimated rates of change of pseudoranges for in view satellites. The coherent processing includes performing an orthogonal transform on the rows of the matrix, multiplying the elements of the matrix by Doppler compensation factors, and then, for each satellite in view, convolving the columns of the matrix with the pseudonoise sequence of that satellite. Other pseudoranges are inferred from synchronization burst sequences received by the mobile unit from one or more base stations. If the base stations are not mutually synchronized, reference units are provided to determine the time offsets between the base station clocks and the satellite network clock and to transmit these time offsets to the mobile unit, so that all the pseudoranges include the same bias relative to the satellite network clock. The pseudoranges are processed and reconciled by a dynamic estimator that includes a linear optimal estimator such as a Kalman filter, to produce successive estimates of the location of the mobile unit as the mobile unit moves.

A novel method and apparatus is described for reducing the number of CDMA codes for a constellation of multiple trasponder platforms serving a number of subscribers in the same service area. A coherent processing technique synchronizes the phase of CDMA signals arriving at a subscriber from multiple trasponder platforms to increase the code capacity and thus the number of possible subscribers for most of the multiple transponder platform systems in current use.

A system and technique for calibrating a plurality of radars provides a set of simultaneous equations derived from monostatic echo returns from a plurality of targets. A solution of the simultaneous equations provides relative position calibration factors and time delay calibration factors associated with the plurality of radars. The relative position calibration factors and the time delay calibration factors allow the plurality of radars to be coherently combined with only a small amount of processing gain loss compared with an ideal coherent processing gain.

A method and apparatus is operative for multiple target detection in a radar system which employs a radar waveform of two or more frequency diverse subpulses. The apparatus adds coherent processing of the subpulse echo signals to determine the presence of multiple scattering centers within the radar resolution cell. The subpulses are coherently combined and one can then estimate the number of scattering centers by forming a sample covariance matrix between the subpulse frequency channels and then performing an Eigenvalue decomposition. The resulting Eigenvalues represent the signal strengths of the scattering centers when the associated Eigenvectors correspond to the optimal subpulse weights associated with that signal. A single strong Eigenvalue indicates a single target while two or more strong Eigenvalues or those Eigenvalues larger than the noise related Eigenvalues or a threshold, indicates the presence of multiple targets.

The present invention relates to the field of passive radars, and more particularly the field of the processing of the signals utilized by such radars. The signal processing method received according to one or more embodiments of the invention performs coherent processing, in order to purge spurious signals from the useful signal, including the reference signal and its multiple reflections, to regenerate the transmission signal and to perform a coherent integration of the signal received, by computing the cross-ambiguity between the signal received and the regenerated transmission signal. One or more embodiments of the invention also performs operations of non-coherent processing making it possible in particular to carry out extraction and Doppler distance purification operations making it possible to form blips and to eliminate the spurious blips present among the blips formed. The invention applies to passive radars operating on non-cooperating opportunity transmissions, such as FM transmissions intended for the public.

The invention discloses a radio frequency channelization method based on optical comb double modulation sidebands and an implementation device. The method comprises the following steps: generating coherent signal light and local oscillation light; the signal optical comb generation module modulating an optical comb with a comb tooth interval of FSRsignal; wherein the local oscillation optical combgeneration module modulates an optical comb with a comb tooth interval of FSRlocal, the modulation module modulating an RF signal based on the signal optical comb, the RF signal being filtered by thefilter, and performing coherent receiving processing after channel division is performed based on an output signal of the filter and the local oscillation optical comb. The device comprises a coherent light generation module, a signal optical comb generation module, a local oscillator optical comb generation module, a modulation module, a periodic filter, a channel separation module and a coherent processing module. According to the method and the device, the comb tooth interval of the local oscillation optical comb can be reduced, the requirement on the number of comb teeth of the signal optical comb is reduced, the energy utilization rate is improved, and the channelization difficulty is reduced.

The invention discloses a coherent-processing multi-target tracking method of a security monitoring radar system. Spectrum analysis is carried out on target echo signals, different spectral lines include distance information of different targets, FFT processing is carried out on spectral lines of the same distance unit in different repetition periods to obtain target Doppler information, namely speed information of the target, and tracks of the multiple targets are tracked at the same time in a target association algorithm. The method can effectively solve the problem that multiple targets tend to be pair in error, and reduce the complexity of the algorithm of a signal processing unit.

The invention relates to a multi-beam combined angle measuring angle and point trajectory fusion method of MIMO radar targets under orthogonal waveforms. The method includes the following steps that: the geometric model of radars in a Cartesian coordinate system is established, the number N of radar receiving array elements, the number L of radar received beams, and a radar power radiation space-domain range Omega are determined; a detection region corresponding to Omega is uniformly divided into K detection sub-regions, the received composite signals r<k>i(t) of a k-th detection sub-region which adopts the center pointing direction of an i-th radar received beam as a benchmark; conventional detection processing is carried out on the received composite signals r<k>i(t), so that the target detection result set Di of the i-th radar received beam is obtained; the angle measurement values of Mm target point trajectories in a target detection result set Dm of an m-th radar received beam, a target point trajectory set D<~>m containing the angle measurement values of the m-th radar received beam and the target point trajectory set sequence D containing the angle measurement values of L radar received beams are calculated sequentially; and point trajectory fusion is carried out, so that a target point trajectory set final sequence D<^> containing the angle measurement values of the L radar received beams in one coherent processing time is obtained.

The invention provides a weak signal quick capture method on basis of part correlation, which can meet the requirement of long coherent accumulation of a weak signal, and meanwhile, is suitable for the effect of wide-range Doppler change. The method comprises the following steps: generating 8-path data sequences, obtaining a duplication code, and allowing each path of the data sequence to be subjected to exclusive or operation together with the duplication code so as to obtain 8-path data auxiliary duplication codes; and allowing in-phase base band data and orthogonal base band data to be subjected to coherent accumulation operation through the auxiliary duplication codes and the duplication code, allowing the accumulation result of each path of data sequence to be subjected to FFT (Fast Fourier Transform), and then calculating the quadratic sums of the transformation results so as to judge whether the capture succeeds or not according to the maximal quadratic sum. According to the invention, the 8-path data sequences with different phase positions are adopted, a multi-path parallel coherent processing is adopted according to the processing results of the data sequences, and the coherent integration time in the signal capture process is prolonged as far as possible to an extent that the coherent integration can span several modulation data widths so as to improve the signal-to-noise ratio.

The invention belongs to the technical field of radar signal processing, relates to the technology of radar clutter processing, and discloses an airborne phased array radar two-dimensional multi-pulse cognitive clutter suppression method. The method includes the steps that (1) a ground clutter echo signal model of airborne phased array radar is built, (2) a residual clutter echo signal is obtained through calculation according to the ground clutter echo signal model, (3) by means of residual clutter echo energy of the residual clutter echo signal, a two-dimensional multi-pulse phase canceller coefficient matrix is solved, (4) by means of the two-dimensional multi-pulse phase canceller coefficient matrix, clutter suppression is carried out on one echo signal received by the airborne phased array radar within coherent processing time. The method enables clutter to be suppressed greatly, is suitable for front side looking radar and suitable for non-front-side-looking radar, and is applied to radar clutter processing scenes.

In a passive radar system a space-borne transmitter broadcasts wide-band digitally modulated signals over a region and illuminates the region. A receiver antenna is oriented to receive radiation from at least one portion of the region. The portion is an area viewed by the receiver antenna. A reference antenna is oriented toward the transmitter, the reference antenna receives a portion of the wide-band digitally modulated signal. A coherent processing time duration is selected based on: a radar cross-section of a target within the viewed area, a bandwidth of the wide-band digitally modulated signal, and the viewing angle of the receiver antenna. The received signal from the receiver antenna is coherently processed with a reference signal from the reference antenna, over a time interval greater than the coherent processing time duration.

The invention relates to a spatial ultrahigh-speed maneuvered target detection method based on RMDCFT (Radon-Modified Discrete Chirp-Fourier Transform). According to the method, firstly, modification is carried out based on the conventional Radon-Fourier transform method by using prior information of spatial target motion parameters, searching is carried out in a known target motion parameter range, and thus, target echo signals are extracted along the motion trajectory of a target; meanwhile, modification is also carried out based on the conventional MDCFT method, transform processing is carried out on the extracted target echo signals, and thus, the estimation on the frequency modulation rate of the target can be obtained; secondary phase of echoes is compensated based on the estimation, coherent accumulation is carried out on the target echo signals, and target detection is realized. The method has no need of predicting or estimating the fuzzy number of speed of the target and is applicable to the circumstances of limited CPI (Coherent Processing Time) and low signal-to-noise ratio; simulation results are compared with processing results of MTD, Radon-Fourier transform, FRFT (Fractional Fourier Transform) and RFRFT (Radon-FRFT) detection methods, experimental results show that the method provided by the invention can be used for effectively detecting the target when the CPI is limited and the signal-to-noise ratio is relatively low, and thus, the effectiveness of the method provided by the invention is proved.

The invention discloses a frequency band fusion method and device based on an adaptive iteration scheme. The method comprises that 1) a multiband radar signal fusion model is established; 2) an initial phase difference and a linear phase difference of each frequency band radar signal are estimated via an all phase fast Fourier transform (apFTT) algorithm, and coherent compensation is carried on each frequency band radar signal; and 3) and multiband signal fusion can be realized for the frequency band radar signals after coherent processing via the adaptive iteration scheme. According to the method and device, the phase differences of the frequency band radar signals are estimated via the apFTT algorithm, thereby improving the estimation precision for the phase differences, and avoiding that estimation errors of radar signal model parameters caused by noises in a routine algorithm influence the subsequent coherent compensation precision and final fuse imaging quality. At the same time, fusion is carried out on the frequency band radar signals after coherent processing directly through the adaptive iteration scheme, thereby overcoming the difficulty in data prediction for blank frequency domains as required in a routine frequency band fusion algorithm.

The invention discloses a rub-impact sound emission fault position identification method based on near field sound source focusing positioning. According to the method, sub-band decomposition of a sound emission signal acquired by a rub-impact sound emission test device is carried out to extract a characteristic signal; a subspace frequency focusing method is utilized to carry out frequency focusing of a sound emission characteristic signal, and decoherence processing on multiple coherent signals is carried out; lastly, a space spectrum estimation method is employed to carry out further precise sound source positioning. Through the method, fast fading, coherent and multi-modal problems of the broadband sound emission signal can be solved, so the rub-impact fault source position can be effectively identified. The method is advantaged in that the generation position of the rub-impact sound emission signal can be accurately identified, precision and complexity indexes are better compared with a positioning algorithm in the prior art, and the method is an effective rub-impact fault position detection method.

The present invention discloses an MIMO (Multiple-Input Multiple-Output) radar waveform modulation and demodulation method. The method comprises the following steps of: according different transmitting channels at a transmitting end, modulating periodic target detection baseband signals to form different phase codes at the Doppler dimension; converting echo signals received by each receiving signals of a receiving end to digital echo signals after the echo signals are preprocessed, and performing windowed Fourier transform of the digital echo signals according to distance dimensions; converting the digital echo signals after windowed Fourier transform to a matrix in a distance-Doppler two-dimensional form, and performing decoding of the matrix in the Doppler dimension; and performing Doppler dimension coherent processing of the decoded signals to separate each transmitting channel to obtain two-dimensional output of the distance-Doppler frequency. The waveform modulation and demodulation method generates different frequency offsets at the Doppler dimension through phase encoding so as to achieve the purpose of distinguishing different transmitting channels and solve the mutual interference problem between the channels due to increasing of the transmit-receive antennas; and moreover, the signal real-time bandwidth and the computing resource consumption are not increased.

Some embodiments of the present invention overcome I / O bottlenecks of an EDA work flow by keeping layout data distributed during handoffs among different processing stages. Specifically, some embodiments leverage a concurrent computation paradigm where data is propagated incrementally between stages, and where data processing among consecutive stages and the I / O between stages are executed concurrently. Specifically, some embodiments can generate a template database which contains the unique templates in a set of templates. During operation, an embodiment can determine a set of templates for a layout. Next, the system can determine a processing schedule based on a spatially coherent ordering of the set of templates. Next, the system can process the templates according to the spatially coherent processing schedule. Processing templates in a spatially coherent order can ensure that the downstream processes in the concurrent work flow will be able to maximize concurrency, thereby improving overall performance of the system.

The invention relates to a frequency domain coherent joint capture method of a GNSS data / pilot mixed signal, more particularly to a coherent joint capture method of a GNSS data / pilot mixed signal. According to a traditional single-channel capture method, energies of a new-system navigation signal can not fully utilized, so that capture performance is poor; however, the above-mentioned problem canbe solved according to the invention. The method comprises the following steps that: with utilization of a phase relationship between a data channel signal and a pilot channel signal, coherent processing is carried out on the signals of the two channels aiming at a GNSS data / pilot mixed signal, and then capture is completed. The invention is suitable for application in a capture process of a GNSSdata / pilot mixed signal.