12 results about "Direction finding algorithms" patented technology

This invention discloses a design method and apparatus for a high-resolution direction-finding IP core for broadband signals based on HLS, relating to the field of signal processing technology. By constructing a comprehensive evaluation standard for sub-frequency wavelength and half-wavelength matching and sub-frequency energy—that is, a sub-frequency comprehensive evaluation function—this invention optimizes reference and candidate sub-frequency points that contribute significantly to algorithm performance. This effectively reduces the complexity of broadband signal focusing operations while ensuring algorithm performance. Furthermore, it integrates the high-resolution direction-finding algorithm for broadband coherent signals with a high-level synthesis implementation method, forming a high-resolution direction-finding IP core for broadband coherent signals that can be directly called by FPGAs, possessing strong versatility and reusability.

This invention relates to a direction-finding method based on matrix decomposition, belonging to the field of array signal processing technology. The invention first calculates the covariance matrix of the received data, then performs matrix decomposition and reconstruction based on the covariance matrix, and finally constructs a solution function by combining the spatial relationship between the reconstructed matrix and the array steering vector. The direction of arrival of the signal source is obtained from the mapping relationship between the peak value of the solution function and the signal incident angle. This invention utilizes the orthogonality between noise vectors to reduce the impact of noise on the direction of arrival (DOA), which can further improve the stability of the direction-finding algorithm.

This application provides a radio detection method and system for unmanned aerial vehicles (UAVs), belonging to the field of UAV technology. The method includes: dividing the airspace to be detected into multiple scanning areas based on the refresh rate requirements of the airspace; receiving full-band radio frequency (RF) signals from the multiple scanning areas using an antenna array to obtain raw RF signals; cyclically switching the raw RF signals using an RF switch array to obtain a time-sequentially processed signal; preprocessing and extracting frequency domain features from the time-sequentially processed signal to obtain target RF features; adjusting the cyclic switching period and gain parameters of the RF switch array based on the target RF features using an intelligent switching strategy constructed based on signal strength feedback, and calculating the direction of arrival and distance of the detected target based on an amplitude ratio direction-finding algorithm; and determining the position and trajectory of the detected target by analyzing the target RF features over a preset continuous period. This application improves the accuracy of UAV detection.

The application relates to a single-pole cross-ring antenna signal direction finding method combining amplitude comparison and variable step size MUSIC, which mainly comprises the following steps: obtaining an initial estimated angle through an amplitude comparison algorithm; if the angle is located in a cross-angle domain of a ring antenna, the high-precision characteristic of the amplitude comparison algorithm in the angle domain is utilized to directly take the angle as a final result, so that the direction finding performance of the angle domain is improved; if the angle is not located in the cross-angle domain, the initial estimated result is further utilized to reduce the spectral peak search range of a MUSIC algorithm, and a variable step size mode is adopted to search a spatial spectrum function, so that the direction finding resolution of the MUSIC algorithm is improved, and the calculation complexity is reduced. The application utilizes two direction finding algorithms of amplitude comparison and MUSIC, realizes high-precision direction finding in the cross-angle domain of the ring antenna, shows higher resolution success rate, effectively improves direction finding efficiency, and has important application value in the fields of high-frequency radar sea current detection and short-wave communication.

The application provides a DOA estimation method based on a hybrid analog-digital array architecture design, which comprises the following steps: a hybrid analog-digital array is arranged at a receiving end architecture; the hybrid analog-digital array adopts a low-complexity HAD array architecture; the hybrid analog-digital array architecture is used to receive an incident signal and model; an initial value of an analog phase shifter network is designed; a difference virtual array of the low-complexity HAD array architecture is calculated; an initial angle estimation value is obtained from the difference virtual array receiving signal by using a classical direction finding algorithm; after the initial angle estimation value is obtained, the phase shifter network weight is redesigned, and then a difference virtual array output signal is obtained; and a DOA estimation result is obtained from the classical direction finding algorithm; the method can effectively avoid the problems of phase ambiguity and beam scanning, can reduce the cost and complexity, and can effectively approach the estimation performance of a full-digital array architecture.

The application relates to a Bayesian DOA estimation method of an array distortion passive synthetic aperture sonar and belongs to the technical field of signal processing. The method comprises the following steps: performing layered probability modeling on array observation data, the model is used for applying a binary prior distribution to a signal vector to contain sparse induction characteristics; a variational Bayesian method is used to iteratively maximize the lower bound of the marginal likelihood function of array distortion parameters and hidden variables; unknown parameters are iteratively updated according to the estimated posterior distribution; and a spatial spectrum diagram is drawn according to the optimal estimation result, and each DOA is determined according to a peak value. The method solves the problems that a traditional passive synthetic aperture direction finding algorithm cannot estimate the direction of a random source and is sensitive to array distortion.

The invention relates to a monopole cross loop antenna signal direction finding method combining amplitude comparison and variable step size MUSIC, and the method mainly comprises the steps: obtaining an initial estimation angle through an amplitude comparison algorithm, if the angle is located in a loop antenna cross angle domain, directly taking the angle as a final result through the high-precision characteristic of the amplitude comparison algorithm in the angle domain, and carrying out the direction finding of the monopole cross loop antenna signal. The direction finding performance of the angular domain is improved; and if the spatial spectrum function is not located in the cross angle domain, the spectral peak search range of the MUSIC algorithm is further narrowed by using the initial estimation result, and the spatial spectrum function is searched by adopting a variable step size mode, so that the direction finding resolution of the MUSIC algorithm is improved, and the calculation complexity is reduced at the same time. According to the method, two direction finding algorithms of amplitude comparison and MUSIC are utilized, high-precision direction finding in a loop antenna cross angle domain is realized, a higher resolution success rate is shown, the direction finding efficiency is effectively improved, and the method has important application value in the fields of high-frequency radar ocean current detection, short-wave communication and the like.

The application discloses a noise vector direct estimation method for a receiver multiplexing single-target direction finding system of a BLE AoA / AoD type direction finding system, and belongs to the technical field of measurement and testing. The method estimates the autocorrelation coefficients of each antenna and a reference antenna by calculating the sum of the single-time acquisition data of each antenna in an antenna array and the single-time acquisition data of the reference antenna and then taking the average, and constructs an estimation matrix of a noise space feature vector from the estimated autocorrelation coefficients of each antenna and the reference antenna, without needing to perform matrix autocorrelation, eigenvalue decomposition, eigenvalue sorting and other operations. With the noise space feature vector provided by the application and a traditional direction finding algorithm, such as Root-MUSIC, high-precision direction finding effects can be obtained with lower computing resources, and the application is suitable for Internet of Things devices with limited computing resources.

The present application belongs to the technical field of electromagnetic signal interference troubleshooting, and particularly relates to a multi-rotor electromagnetic signal interference troubleshooting system and a direction finding positioning method. The system comprises an aerial part and a ground control part; the aerial part comprises a multi-rotor unmanned aerial vehicle platform and a monitoring direction finding load, a task computer, a load link aerial end and a power management module mounted on the multi-rotor unmanned aerial vehicle platform; the monitoring direction finding load is used for receiving electromagnetic signals, discovering electromagnetic targets and measuring the target direction; the monitoring direction finding load comprises a direction finding device and a monitoring direction finding receiver. The troubleshooting system provided by the present application can realize continuous direction finding of the unmanned aerial vehicle in flight, realize target positioning based on a direction finding algorithm, and realize optimal track optimization based on the positioning result, and has the beneficial effects of accelerating the convergence speed of target positioning, improving the positioning accuracy and improving the efficiency of electromagnetic signal interference troubleshooting.

The invention discloses a battlefield interference source discovering and positioning method based on an unmanned aerial vehicle platform, and the method comprises the steps: arranging a direction-finding positioning system, and enabling the direction-finding positioning system to be mounted on the unmanned aerial vehicle platform; the antenna is compact in structure, is suitable for being mounted on an unmanned aerial vehicle platform, and provides omnibearing radiation source detection capability. Setting a flight trajectory, so that the unmanned aerial vehicle flies around a predetermined trajectory within a certain range to ensure that the target area is covered; obtaining azimuth information of a radiation source based on a Music five-element circular array direction finding algorithm; positioning the position of the radiation source by adopting an iterative algorithm based on least square method estimation in combination with azimuth information of the radiation source obtained by the moving unmanned aerial vehicle at different moments and GNSS information of the unmanned aerial vehicle, and quickly converging to a true value through multiple iterations; the positions of the unmanned aerial vehicle platform and the radiation source are displayed in real time through the display terminal so as to facilitate real-time monitoring and analysis of operators, and the system has the technical characteristics of high-precision positioning, low cost, simple and convenient operation, high flexibility and the like.

The invention relates to the field of interferometer direction finding, and provides an interferometer ambiguity-resolving direction finding method and device based on flexible virtual antenna array elements, equipment and a medium, and the method comprises the steps: estimating a signal frequency, and obtaining an array manifold vector at a target azimuth; based on the obtained array manifold vector, mapping a physical array to a virtual array by using an array manifold mapping method; and applying the virtual array to an interferometer direction finding algorithm to realize ambiguity-resolving interferometer direction finding. According to the method, the physical array is mapped to the virtual array, the virtual array is used for interferometer direction finding, the ambiguity resolution accuracy and stability can be improved, and a single target only obtains a unique target orientation estimation result.

The invention belongs to the field of field electromagnetic radiation disturbance test and optimization of medical electrical equipment, and particularly relates to a field electromagnetic radiation disturbance test method of large medical electrical equipment. Large medical electrical equipment can be tested in an on-site environment according to radiation emission test requirements specified by a medical electrical electromagnetic compatibility standard, and under the fusion of various algorithms such as a radio direction finding algorithm, a background noise filtering algorithm and a signal identification algorithm, the radiation emission test efficiency is improved. Compared with a test curve in an electromagnetic compatibility darkroom test environment, the test curve obtained by the method has the same distribution trend and is almost the same in numerical value difference, and electromagnetic radiation disturbance characteristics of large-scale medical electrical equipment in a field installation environment can be accurately evaluated; and a basis is provided for electromagnetic radiation disturbance optimization design of large medical electrical equipment. The method has the advantages of simple and rapid test, accurate and credible test result and the like.