65 results about "Passive radar" patented technology

The invention relates to the technical field of target detection and identification, and discloses a low-altitude target identification system and method combined with multi-band signal processing. Comprising the steps of establishing a cross-frequency implicit vector model and constraining a geometric scale, a scattering center and rotor harmonic waves through synchronous acquisition of an L-band radar, a Ku-band radar and a millimeter-wave radar, and realizing unified characterization of multi-frequency signals; receiving a global satellite navigation system reflection signal, communication channel state information or a very high frequency / ultrahigh frequency passive radar signal to form prior discrimination, and triggering high-frequency radar short-time imaging; carrying out propagation correction on millimeter wave, terahertz and infrared signals in combination with a meteorological profile and generating an environment label; determining a sampling window by using the region of interest and rotor phase prediction, and optimizing a residence strategy; harmonic waves are extracted from radar and acoustic signals, robust pairing is carried out, and a cross-domain consistency score output category is calculated. The method realizes multi-frequency multi-source cooperative processing, has environment self-adaption and closed-loop feedback capabilities, and can improve the precision and stability of low-altitude target identification.

The invention discloses a passive radar target positioning method and system based on an external radiation source, and relates to the technical field of radar positioning, and the method comprises the steps: screening an external radiation source signal set of a target monitoring region, laying a distributed receiving antenna array based on the signal set, receiving a signal in real time, and transmitting the signal to a quality evaluation unit; the quality evaluation unit adaptively screens the signal and outputs a standard radiation source signal with a radiation source type identifier; and carrying out feature parameter extraction on the standard signal to obtain a multivariate signal feature set, and carrying out multi-band signal fusion and target positioning analysis based on the feature set to generate target position information. According to the invention, the technical problems of complex signal processing, insufficient positioning precision and limited dynamic monitoring capability of the existing passive radar technology in a complex electromagnetic environment are solved, and multi-band signal fusion and adaptive signal processing are realized. And the positioning precision and the dynamic monitoring capability of the passive radar in a complex environment are improved.

A frequency estimation method based on time-delay sampling is suitable for signal processing in an engineering scene in which leaf end timing, nondestructive testing or passive radar is difficult to deploy a high-sampling-rate or multi-sampling-rate system, and comprises the following steps: uniformly sampling signals by using two channels with the same sampling period; the time delay and the sampling period of the two sampling channels are relatively prime; carrying out Hilbert transformation preprocessing on data points of the two sampling channels, and solving aliasing frequency in cooperation with an ESPRIT algorithm; changing the initial position of the analysis data to construct a plurality of delay schemes, and repeating the step S2 to obtain equivalent sampling frequencies and equivalent aliasing frequencies under different delay schemes; according to the equivalent aliasing frequency, calculating two remainder frequencies under each delay scheme; and performing traversal solution on the congruence equation set with the equivalent sampling frequency as the modulus and the remainder frequency as the remainder by using the Chinese remainder theorem, and obtaining the target frequency in combination with the consistency criterion and the minimum estimation criterion.

The application relates to an ionosphere virtual height estimation method applied to a short-wave active-passive integrated radar, which comprises the following steps: 1: an integrated detection system receives active radar detection echoes and passive radar detection echoes, and a main-passive detection channel is respectively subjected to distance, speed and azimuth sorting to obtain an active radar point track measurement set and a passive radar point track measurement set; 2: a group of points is respectively taken out from the two measurement sets, and the ionosphere virtual height is calculated by assuming the points as matched points; 3: the active radar measurement and the passive radar measurement are converted to the northeast sky coordinate system according to the calculated ionosphere virtual height; 4: a threshold method is used for global matching on the converted measurement sets to obtain a matching result, and a cost function value is calculated according to the matching result; 5: the two measurement sets are respectively traversed, and the steps 2, 3 and 4 are repeated, and the ionosphere virtual height corresponding to the minimum cost function is taken as the ionosphere virtual height in a detection environment. The application is used in the field of high-frequency over-the-horizon radar signal processing.

The invention provides a target reconstruction method and system based on passive sensing radar echo signals, and the method comprises the steps: obtaining a passive sensing radar echo signal set of a target scene, the passive sensing radar echo signal set comprising a plurality of echo signal sequences; performing signal preprocessing operation on the passive sensing radar echo signal set to obtain a preprocessed radar echo signal set; multi-level feature extraction operation is executed on the preprocessed radar echo signal set, a multi-dimensional state feature set of the target object is generated, and the multi-dimensional state feature set comprises scattering characteristic features, motion correlation features and environment interference suppression features; and calling a pre-trained target state analysis model to carry out state transition modeling processing on the multi-dimensional state feature set, generating a reconstructed state vector of the target object, and carrying out reverse mapping based on the reconstructed state vector to obtain a geometric parameter set and a motion parameter set of the target object.

The present invention discloses a method for estimating the direction of arrival of a coherent signal, belonging to the field of ship radar and communication signal processing. The method comprises: a transmitting end sends a pilot signal of a target power to a receiving end, and the receiving end obtains the multipath delay structure of the channel based on the pilot signal; the transmitting end sends a normal pilot signal to the receiving end, and calculates the cross-correlation function between the received signal and the transmitted signal; the peak values ​​of the cross-correlation function are sorted in descending order to determine the candidate possibilities of the first delay, and the cross-correlation function after the composite path is calculated to determine the shortest delay; a cost function for the delay is constructed, and the cost function is differentiated with respect to two independent variables to obtain an estimated value of the arrival time difference; the direction of arrival is calculated from the estimated value of the arrival time difference, completing the one-dimensional direction of arrival estimation of the coherent signal applied to a uniform linear array. This method can improve the detection accuracy of passive radar and sonar equipment for targets and enhance the comprehensive detection capability of surface ships.

This invention discloses an adaptive tracking method and device for anti-dropped decoys based on a multi-model approach to measurement errors, belonging to the field of radar target tracking technology. The method includes constructing motion and centroid interference models for passive radar dropped decoys to determine the impact of interference on radar measurements; constructing a set of passive radar measurement models characterizing the time-varying characteristics of measurement noise, and establishing a hybrid system with uncertain measurement noise by combining the target motion model; employing an interactive multi-model architecture combined with a capacitive Kalman filter algorithm to perform interactive and parallel filtering on each sub-model of the hybrid system; updating the posterior probability of the measurement noise in each sub-model at the current moment in real time based on the measurement residuals and information covariance; and performing weighted fusion of the state estimates of each sub-model to obtain the adaptive tracking result. This invention effectively solves the tracking divergence problem caused by weak observability and time-varying measurement errors in passive radar under dropped decoy interference, significantly improving the tracking accuracy and robustness of the system.

The invention discloses a weak cyclostationary signal detection method based on an unmanned aerial vehicle-mounted passive radar network, and the method comprises the steps: firstly building an active radar transmitting signal and unmanned aerial vehicle passive radar receiving signal model, and then building a binary hypothesis model based on cyclostationary generalized likelihood ratio detection through block cyclic matrix approximation; and constructing generalized likelihood ratio test detection statistics and obtaining local detection results of the unmanned aerial vehicles under a colored noise background by using the cyclostationary characteristic of target echoes, finally fusing the local detection results of the unmanned aerial vehicles based on a Bayesian minimum risk criterion at a fusion center, and outputting global detection judgment. And a detection process of cyclostationary generalized likelihood ratio test-Bayesian minimum risk fusion is formed. According to the method, the detection statistics are constructed by using the cyclostationary characteristics of the target echoes, the global detection accuracy and robustness can be improved under the conditions of low signal-to-noise ratio and complex colored noise, and the method is suitable for a multi-unmanned aerial vehicle cooperative passive radar detection scene.

The present invention discloses a passive networked radar target detection method based on waveform characteristics, belonging to the field of target identification technology. The method includes obtaining a collected direct wave signal and a reflected wave signal to be detected; reading a historical database containing prior information of several historical direct waves and their emission source signals; searching the historical database for the historical direct wave with the highest similarity to the direct wave signal, and using the prior information of its emission source signal as the prior information of the direct wave signal; selecting a detector based on the prior information, inputting the direct wave signal and the reflected wave signal into the detector for detection, and outputting detection information; comparing the detection information with a preset detection threshold. If the detection information is greater than the detection threshold, a target is present; if the detection information is less than the detection threshold, a target is not present. This solution solves the problem of low target detection accuracy in low signal-to-noise ratio environments in existing networked passive radar target detection methods.

The invention discloses a UWB (Ultra Wideband) positioning method, device and equipment, relates to the technical field of communication, and can utilize broadcast signal frames of a plurality of base stations and mobile equipment in an information interaction process to form a condition of a passive radar to perform supplementary positioning verification on a position obtained by positioning calculation so as to improve the accuracy of UWB positioning. The method comprises the following steps: in the process of information interaction between a plurality of base stations and mobile equipment, acquiring broadcast signal frames received among the plurality of base stations, judging whether the broadcast signal frames carry reflected signals or not, if so, determining position change information of the mobile equipment according to the change condition of the reflected signals, and performing supplementary positioning verification on the position obtained by the positioning calculation of the mobile equipment by using the position change information of the mobile equipment so as to update the position of the mobile equipment.

The application discloses a passive radar network signal cooperative complementary sorting method and system, wherein the method comprises the following steps: cooperatively complementing mixed alias radiation source pulse sequence signals received by multiple passive radar stations to obtain complemented pulse sequence signals; and sorting the complemented pulse sequence signals by using a cumulative difference histogram method to separate pulse sequences of different radiation sources. Compared with an existing single-station passive radar signal sorting method, the method solves the problem of incomplete pulse sequences caused by pulse loss, greatly improves the correctness of signal sorting, and has better sorting performance, especially when pulse loss is serious.

The invention discloses a multi-base passive radar weak target detection method based on multi-channel space-time joint accumulation, and relates to the technical field of radar communication, and the method comprises the steps: constructing a multi-base passive radar system observation model, obtaining a direct wave signal and an echo signal, and carrying out the sampling and preprocessing of the direct wave signal and the echo signal; constructing a target detector, and updating the target detector into a simplified form expressed by the target motion parameters to obtain a first target detector; processing the first target detector by adopting a signal framing processing mode to obtain a second target detector; and processing and solving the second target detector by adopting a standard discretization mapping mode so as to realize detection of the weak target and obtain an estimation parameter of the weak target. According to the method, on the premise of ensuring relatively low calculation complexity, efficient collaborative accumulation of multi-channel signals is realized, and the detection performance of the system in a low signal-to-noise ratio and high maneuvering target environment is improved.

The utility model provides a head-mounted display device, and the device comprises a passive radar which is used for measuring an electromagnetic signal in an environment, so as to generate electromagnetic environment data; the control device is in communication connection with the passive radar and is used for acquiring the electromagnetic environment data and generating an electromagnetic image according to the electromagnetic environment data; and the display device is in communication connection with the control device and is used for acquiring and displaying the electromagnetic image so as to realize visual expression of the electromagnetic environment. According to the head-mounted display device, the passive radar is arranged, so that the head-mounted display device can monitor the electromagnetic environment and visually display the electromagnetic environment, the use function of the head-mounted display device is expanded, and the attraction to consumers is improved.

The application discloses a multi-radar joint positioning method based on azimuth angle and Doppler velocity, and mainly solves the problems of poor positioning precision caused by large sensor measurement error and insufficient utilization of multi-source data. The method is aimed at a sea surface target moving at a constant speed, and uses target direction finding results of 1-2 fixed passive radars and target Doppler velocity measurement values of 1 fixed ground wave active radar. According to different numbers of radars, different filter initial values and covariance matrices are constructed, corresponding measurement equations and different filter starting times are determined, and filtering is performed on the target state according to the constant speed motion model. The filtering output is used as the positioning result of the target. The method uses the measurement of passive radars and ground wave radars of two different systems, reduces the influence of large single measurement error on the positioning result, shortens the positioning time, and improves the positioning precision.

The application provides a radiation source positioning method and device based on distributed passive radar, the method comprising: acquiring a first linear frequency modulation signal intercepted by a plurality of receiving stations distributed at different positions and a second linear frequency modulation signal intercepted by a reference receiving station; determining a coarse time difference measurement value of the receiving station relative to the reference receiving station by using a correlation method based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to the receiving station; calculating a time domain phase difference between the first linear frequency modulation signal and the second linear frequency modulation signal to determine a time difference error value of the receiving station relative to the reference receiving station; determining an accurate time difference value of the receiving station relative to the reference receiving station; and determining spatial position coordinates of the target radiation source according to the accurate time difference value corresponding to each receiving station. Through the method and device, the finally solved spatial position coordinates of the target radiation source are more accurate and stable.

This invention proposes a conformal array direction finding method and system based on hybrid resolution quantization, relating to the field of direction-of-arrival (DOA) estimation in passive radar. It aims to reduce the high resource consumption of conformal arrays in DOA estimation, thereby solving the deployment challenges of direction finding under space-constrained conditions such as UAV positioning or vehicle-mounted radar. The method involves designing the conformal array structure; constructing models of the received signal from the receiving antenna and the transmitted signal from the transmitting antenna to obtain received data; using the designed structure to receive high-precision and low-precision quantized data, and processing the low-precision quantized data according to an additive Gaussian noise model to obtain received data under hybrid resolution quantization; performing covariance decomposition on the received data under hybrid resolution quantization; and performing spectral peak search on the covariance-decomposed hybrid resolution quantized data to estimate DOA and polarization information. This invention is applicable to direction finding methods for conformal arrays.

The invention discloses an external radiation source radar range migration correction method based on star chain communication signals, and belongs to the technical field of external radiation source radars. The method comprises the following steps: performing reconstruction and pulse compression processing on a target echo signal; converting the signal to a range frequency-slow time domain; doppler fuzzy number compensation is carried out; dynamically dividing the frequency spectrum of the signal into a first processing area and a second processing area; performing interpolation correction on the signals of the first processing area by adopting a first type of interpolation Keystone transformation algorithm, and performing interpolation correction on the signals of the second processing area by adopting a second type of interpolation Keystone transformation algorithm; the corrected signals are recombined in the range frequency-slow time domain. According to the method, the interpolation strategy can be adaptively adjusted according to the energy distribution of the star chain communication signal, the calculated amount is remarkably reduced while high-precision range migration correction is ensured, and the method is suitable for high-speed target detection of the external radiation source radar of the star chain communication signal.

The application is aimed at the channel allocation problem of the passive radar when tracking the maneuvering target, and a channel allocation method based on a new maneuvering target tracking accuracy prediction function for passive radar is proposed. By analyzing the deficiency of the existing IMM algorithm in the calculation of the target tracking accuracy prediction function in the processing of the mutual information between models, the size of the variance between models is considered in the proposed tracking accuracy prediction function to balance the perception sensitivity to target maneuvering and the accuracy of tracking performance prediction, and a new IMM-based PCRLB (IMM-PCRLB) is realized as a target tracking accuracy prediction function. Further, an optimization problem (MSCA) model of minimizing the channel usage under the constraint of expected tracking accuracy is established, and a heuristic algorithm based on contribution degree is designed for solution. The simulation results show that the algorithm proposed in the application can more accurately predict the actual tracking error, achieve the expected accuracy with reasonable channel resources in the maneuvering scene, and effectively alleviate the problem that the expected tracking accuracy cannot be met due to the inaccuracy of the objective function.

This paper discloses a distributed radar fusion tracking method based on an adaptive birth model and dynamic field of view partitioning. This method, based on active and passive distributed radars, solves the problems of target loss and track interruption for active radars and difficulty initiating tracks for passive radars in active interference scenarios through the adaptive birth model and dynamic field of view partitioning track fusion method, achieving stable target fusion tracking throughout the entire process. The method first determines the radar operating state and divides the field of view space. Then, based on the feedback of the fused target state, it sets a Bernoulli birth distribution. Simultaneously, when the radar field of view space changes, it adaptively adjusts the prediction model to achieve robust target tracking throughout the entire process and improve the target track integrity.

The present invention provides a handover control method and system for simulating an active and passive radar detection device, comprising the following steps: a detection step for detecting target information and changing the operating state based on the target information; a parsing step for collecting the operating state information and parsing it to obtain flag information and control instructions; and a response step for responding to the flag information and control instructions. The present invention's handover control method for simulating an X / W active and passive radar detection device achieves stable control of the transition of the target's field of view center from the X-band to the W-band, enhancing the wide-band, high-precision simulation capabilities of the hardware-in-the-loop simulation system.

The invention discloses a group target joint tracking and classification method based on active and passive radar interactive fusion, which belongs to the field of multi-sensor fusion, and comprises the following steps of: modeling active and passive radar measurement by using a double-layer random set, so that the active and passive radar measurement can be filtered under a unified Bayesian theory framework; passive measurement is processed through a fuzzy measurement filtering method, and the position and category information of the passive radar about the target is obtained; establishing a joint likelihood function of active and passive radar heterogeneous measurement by using a random set so as to construct a coupling relationship between target tracking and classification; on the basis of a centralized fusion method, active and passive radars are organically combined, filtering of heterogeneous measurement information is completed, position and category joint posterior distribution is obtained, and target tracking and classification integration is achieved. The method has the characteristics of low calculation complexity, high tracking and classification precision, strong algorithm robustness and the like.

The invention relates to a frequency selective passive radar echo intensifier, and relates to the radar field, the frequency selective passive radar echo intensifier comprises a Luneberg ball, a reflection layer attached on one side of the Luneberg ball far away from the electromagnetic wave incidence direction, and a spherical shell-shaped skin layer wrapping the Luneberg ball and the reflection layer, the reflection layer comprises a substrate layer and an FSS layer, the multiple cross-shaped FSS layers are embedded between the two substrate layers at intervals so as to control the resonant frequency, and selective reflection is carried out on the frequency of part of radar waves. Meanwhile, the reflection intensity of radar waves with frequencies not specified by users can be reduced, so that the reflection intensity of the radar waves with the frequencies specified by the users can reach the highest intensity in common radar wavebands, or the specific requirements of the users can be met by implementing inverse-law echo enhancement on the radar waves with specific frequency bands; and the application range of the passive radar echo intensifier in the field of characteristic simulation systems is expanded.

This invention discloses an adaptive differential evolution algorithm for optimizing passive radar station deployment, comprising the following steps: establishing a passive time difference station deployment simulation scenario; step 2: population initialization; step 3: fitness value calculation; step 4: genetic operation. On the one hand, this invention addresses the problem of numerous variable parameters and complex parameter settings in particle swarm optimization (PSO) algorithms by incorporating iteration counts, fitness values, and weights into parameter generation, making the algorithm's search and convergence more reasonable. On the other hand, this invention considers the impact of station location error, time difference error, and communication distance between observation stations on the deployment results during experimental simulation, making the modeling process more realistic.

The application discloses a kind of passive radar multi-shot DOA estimation method and device based on sparse convex optimization, method includes obtaining the array receiving signal corresponding to the original input signal of multi-shot;Based on compressed sensing method, the problem of original input signal angle of arrival estimation is converted into l 2,th Sparse recovery convex optimization problem; 2,th Sparse recovery convex optimization problem by using hyperbolic tangent function instead of l 2,0 Mixed norm sparse recovery optimization problem in the l0 norm model is obtained;l 2,th Sparse recovery convex optimization problem in the l 2,th Mixed norm model is optimization goal, with the product of dictionary matrix and original input signal equal to array receiving signal as constraint condition;Iterative solution l 2,th Sparse recovery convex optimization problem obtains original input signal;And according to original input signal and dictionary matrix, the angle of arrival estimation value corresponding to original input signal is obtained, so as to improve the estimation accuracy and estimation efficiency of angle of arrival by effectively using multi-shot data.

The utility model relates to radar technical field, proposes a kind of passive radar conformal antenna array, comprising: outer panel, the one side of outer panel is fixedly installed with foam layer, the one side of foam layer is fixedly installed with function layer, the one side of function layer is fixed with bottom panel, the inside of foam layer, function layer is provided with helical antenna, the one side of helical antenna is fixedly installed with antenna receiving surface, the outside of helical antenna is fixedly installed with signal amplifier, the one side of antenna receiving surface is fixedly installed with heat dissipation shell, the inside of heat dissipation shell is fixedly installed with TR component. The shape of outer panel, foam layer, function layer and bottom panel is all set as arc panel, which can facilitate the installation of passive radar conformal antenna array on aircraft, thereby ensuring the aerodynamic performance of aircraft. The conformal antenna is designed integrally with the carrier surface, which can effectively reduce the radar reflection area RCS, thereby improving the stealth performance.

This invention discloses a passive radar moving target detection method based on low-Earth orbit (LEO) internet satellite radiation sources. Applied to the field of passive radar moving target detection, it addresses the problem of difficulty in acquiring satellite signals due to non-cooperation when using LEO internet satellites as radiation sources. This invention first acquires the direct wave and echo signals from the LEO internet satellite; then, it performs synchronization preprocessing on the direct wave signal to obtain the synchronization sequence; next, it demodulates both the direct wave signal and the target echo signal into the OFDM symbol domain; within this symbol domain, it calculates the correlation between the direct wave and target echo signal matrices; then, through signal processing of the correlation calculation results, it extracts the target bistatic distance and Doppler information from the correlation results; finally, it completes target detection based on this information.

A passive radar system and method of detection of low-profile low altitude targets based on the application of Low Earth Orbit (LEO) and Very Low Earth Orbit (VLEO) satellite signals. The staring array of directional antennas covers the entire sky and provides continuous illumination (receiving reflected satellite signals) from multiple targets for fast detection, recognition, and target tracking and increasing detection range. The coupling of each directional antenna with a separate receiver channel allows the fast continuous process of information from all targets simultaneously. Monopulse processing of signals from reference sub-set of antennas with overlap antenna patterns provides the highest directing accuracy and better clutter / noise and media influence suppression. A directional antenna array does not need a beam-forming module. The system has a small weight, and size may be portable or mounted on a light vehicle or small drone because small size and weight.

A ground based air defence system comprising, a detection system 12, a tracking system 14 to identify, locate and track the detected target 19, a soft kill system 16 considered to perform a countermeasure against the target, the detection system comprising an active detection device 22 and a at least one passive detection device 20, 21. The active detection system preferably being a radar and the passive system preferably being a passive radar. The passive detection device may be a broadband radio antenna detecting the targets transmissions. The tracking system preferably including an electro-optical sensor 24 or camera capturing images of the target and may include a laser rangefinder 26 aligned with the camera boresight. The system preferably including an identification system 28 to identify the target from images taken by the camera and the detected range. The soft kill system 16 preferably being an electronic warfare system 30 configured to jam the targets radar system, deny or spoof the targets communications 32 or GNSS system 34. The system preferably passing targeting information to a linked hard kill system 18 configured to disrupt or destroy the target.

One example includes a passive radar receiver system including an RF receiver front-end to receive a wireless source signal and a reflected signal. An antenna switch of the front-end switches a first antenna to a receiver chain during a first time to generate first radar signal data based on a combined wireless signal comprising wireless source signal and the reflected signal, and switches a second antenna to the receiver chain during a second time to generate second radar signal data based on the combined wireless signal. A signal processor generates source signal data associated with the wireless source signal based on the first and second radar signal data and generates reflected signal data associated with the reflected signal based on the first and second radar signal data, and generates target radar data associated with a target based on the source and reflected radar signal data.

The utility model provides a passive radar protection device, and relates to the technical field of radar protection structures, the passive radar protection device comprises a conical protection frame, a conical protection cylinder and a pressing piece, the conical protection frame comprises two semi-conical frame bodies, one ends of the two semi-conical frame bodies are hinged to each other, and the other ends of the two semi-conical frame bodies are detachably connected through a connecting piece; the conical protective cylinder covers the outer part of the conical protective frame and is detachably connected with the conical protective frame; the pressing piece comprises two pressing seats arranged on the radar base in a covering mode, semicircular notches are formed in the two pressing seats, the two pressing seats are located on the two sides of the two semi-conical frame bodies respectively, and a tensioning piece is arranged between the two pressing seats; a semi-annular protruding part is arranged at the bottom of the semi-conical frame body, and a pressing step used for pressing the semi-annular protruding part is arranged on the bottom face of the pressing base. The radar mounting rod can be conveniently protected, and deviation or collapse of the radar mounting rod caused by collision of rolling stones or accumulation of debris flow is avoided.