17 results about "Skywave" patented technology

This invention discloses a method for adjusting the active port, calculating the interruption probability, and calculating the interruption rate of shortwave communication based on a manifold antenna system in the field of wireless communication technology. The method includes: obtaining the architectural parameters of the target manifold antenna system, which include N ports uniformly distributed along a linear dimension W, each port sharing a common radio frequency link; calculating the instantaneous channel gain of each port; and selecting the port with the maximum instantaneous channel gain as the active port for shortwave communication. By introducing a manifold antenna, this invention achieves dynamic spatial adaptability within a limited area. Unlike traditional arrays with static elements, the FAS utilizes spatial diversity through real-time reconfiguration of antenna positions, eliminating the need for multiple radio frequency links. It also utilizes ionospheric reflection to establish beyond-line-of-sight connections. The FAS dynamically adjusts its active port to optimize reception from different refraction points, mitigating the inherent fading and signal attenuation of high-frequency skywave channels.

The present invention discloses a method for evaluating the tracking effect of a skywave radar. The method evaluates the tracking effect of a skywave radar based on a three-stage cascade evaluation process of "detection path modeling - echo data preprocessing - target tracking processing." By separately evaluating various influencing factors at each stage and thereby obtaining the effect of each stage, and ultimately obtaining an overall evaluation based on the evaluation effect of each stage, the effect of skywave radar target tracking can be evaluated more comprehensively and effectively. The present invention evaluates the effect of each process of skywave radar target tracking separately, and comprehensively evaluates the evaluation results of the three stages. This not only ensures the comprehensiveness and accuracy of the evaluation results, but also further determines the specific stage where the error in the target tracking result originates, thereby further facilitating the improvement of skywave radar target tracking.

The present invention provides a shortwave signal direction-finding method and device for an irregular sparse array, belonging to the technical field of shortwave communication direction-finding. Addressing the direction-finding ambiguity problem in irregular sparse arrays, the present invention employs an array arrangement of antenna elements with different horizontal and vertical positions, simultaneously eliminating angular ambiguity in both azimuth and elevation. A dual-polarized antenna is used to receive incoming signals for direction-finding, fully utilizing the two polarization components of the shortwave skywave signal to improve direction-finding capability. Peak correlation between the current phase difference vector and expected phase difference vectors in different azimuths is used to determine the direction-finding azimuth angle range, reducing the computational complexity of DOA estimation. Azimuth consistency judgment and DOA spectrum peak size comparison methods are used to fuse the direction-finding results to obtain a correct direction-finding result. This method can effectively resolve the direction-finding ambiguity problem in irregular sparse arrays, improve the direction-finding capability for incoming signals with composite polarization patterns, and achieve both accuracy and real-time performance.

A multi-station collaborative skywave massive MIMO secure communication system and method includes a description module, a setup module, a precoding module, a base station selection module, and a data acquisition module. The description module describes the roles and relationships of the various elements in the multi-station collaborative skywave secure communication method. The setup module establishes a mathematical model for user location-based precoding schemes, base station selection, and achievable rate distribution. The precoding module solves the precoding problem for each base station. The base station selection module selects the appropriate base station based on the user's location. This method effectively improves the poor security issues inherent in traditional shortwave communications, which suffer from low user rates and wide coverage.

This invention proposes a range estimation method for skywave over-the-horizon radar based on a sparse Bayesian algorithm. The implementation steps are as follows: beamforming is performed on the data received by the skywave over-the-horizon radar antenna array; pulse compression and moving target detection are performed on the echo data from the target's azimuth to obtain the range-Doppler matrix; two-dimensional constant false alarm rate (CFAR) detection is performed on the range-Doppler matrix; and the target's range information is obtained by sparse recovery of the echo data from the Doppler channel using the sparse Bayesian algorithm. This invention can improve the range resolution and range estimation accuracy of skywave over-the-horizon radar; it reduces the computational load and system complexity of the algorithm, making it more suitable for engineering applications.

This invention proposes a frequency selection method and system for massive MIMO skywave communication based on ionospheric maps, addressing the problems of limited channel capacity, low signal-to-noise ratio, and the strong frequency selectivity of the ionosphere, which makes it difficult to support multi-user access in skywave communication. The method includes: acquiring historical ionospheric observation data to construct an ionospheric map; calculating the azimuth and elevation angles between the base station and each user based on the geographical location information of the base station and each user; determining the location of the ionospheric reflection point based on the elevation angle and obtaining the critical frequency by querying the ionospheric map, thereby determining the carrier frequency range corresponding to the user's elevation angle; within the carrier frequency range, establishing a joint optimization model of the carrier frequency and precoding vector, and solving for the optimal carrier frequency and the corresponding precoding scheme. This invention can effectively improve the multi-user transmission rate and spectrum utilization efficiency of massive MIMO skywave communication systems and is suitable for high-reliability long-distance communication scenarios in complex ionospheric environments.

This invention relates to radar target detection and tracking technology. To address the limitations of traditional particle filtering over long-term accumulation, it provides a pre-detection tracking method for skywave over-the-horizon radar. This method divides virtual frames and velocity intervals using motion constraints to obtain multiple parallel processing channels, thereby narrowing the coherent pulse number estimation interval and performing coherent processing. Simultaneously, before particle filtering, the constant false alarm rate (CA-CFAR) method ensures that particles are randomly generated only in range-Doppler cells exceeding a threshold, further reducing the particle number. This invention reduces computational load while improving the detection and tracking capabilities of OTH radar for weak targets. This invention combines echo data preprocessing with coherent and non-coherent processing techniques, improving the detection and tracking performance of weak targets in skywave over-the-horizon radar while reducing computational complexity through multi-channel and low-threshold methods.

This invention relates to the field of shortwave antenna communication channel testing and modeling technology, specifically to a method for measuring the angular power spectrum of an antenna in a shortwave skywave scenario. The method includes: the receiver performing a two-dimensional equally spaced angular scan within a preset azimuth and elevation range; establishing an angular power spectrum measurement equation based on the received signal power, antenna pattern, and noise power channel, using the scattering function; convolving this equation with the pattern to obtain the angular power spectrum within a single path; discretizing the single-path received power matrix and antenna pattern matrix in two dimensions, and then performing zero-plugging expansion on each; converting the discretized single-path received power matrix and antenna pattern matrix into two-dimensional frequency domain matrices, and determining the frequency domain ratio between the received power matrix and the antenna pattern matrix mapped to the angular domain using time-delay Doppler domain parameters. This invention improves the accuracy of angular power spectrum measurement in shortwave skywave channels while reducing the dependence of traditional empirical modeling methods on a single propagation assumption.

The present invention discloses a method and system for precoding transmission of a Tianbo massive MIMO-OFDM channel with a smooth beam structure. The Tianbo massive MIMO-OFDM base station utilizes a beam-based channel model to design a beam structure precoder for each user in conjunction with a group of subcarriers on the basis of constraining the smoothness of the equivalent channel at each user's receiving end, and utilizes the channel smooth beam structure precoder to precode the signal sent to each user to achieve downlink transmission. First, the base station utilizes a beam domain precoder on each subcarrier to precode the data signal and pilot signal sent to each user, and then maps the beam domain precoded signal of each user to a complete beam domain transmission signal based on the spatial beam set of each user, and finally transforms the sum of the beam domain transmission signals of each user into a spatial domain transmission signal. The present invention can effectively improve the equivalent channel estimation performance and significantly improve the signal detection performance while ensuring the downlink precoding transmission performance of Tianbo massive MIMO-OFDM.

A method for detection of a skywave symbol, the method may include receiving, by a skywave propagation receiver, received signals that are within a skywave frequency range that comprises legal subcarriers and illegal subcarriers; and detecting a reception of the skywave symbol based on at least one energy parameter related to at least two out of (a) received signals at the illegal subcarriers, (b) received signals at the legal subcarriers, (c) received signals at any of the subcarriers.

A method for detecting a skywave symbol, the method may include (i) receiving, by a skywave receiver, signals of different subcarriers that are within a skywave frequency range that comprises legal subcarriers and illegal subcarriers; (ii) performing sorting iterations to provide a sorted list of signals intensities; and (iii) providing a detection result indicative of a reception of the skywave symbol based on at least some members of the sorted list.

The invention relates to a sky wave over-the-horizon radar high-speed parallel coordinate registration method based on reference source assistance, and the method comprises the steps: constructing and estimating the posterior distribution of ionosphere activity parameters under a Bayesian framework based on the prior information of the ionosphere activity parameters and reference source data; secondly, according to posterior distribution of the ionosphere activity parameters, based on a near-end gradient descent method and an average field variational method, solving estimated values of the ionosphere activity parameters of all dimensions in parallel, and then substituting the estimated values of the ionosphere activity parameters of all dimensions into an international reference ionosphere model to obtain a posterior ionosphere; and finally, calculating an electromagnetic wave propagation path in the posterior ionosphere by using a three-dimensional ray tracing method to obtain a coordinate registration result of the to-be-positioned target. According to the method, timeliness can be improved while the accuracy of sky wave radar target positioning is ensured.

Disclosed by the present disclosure is a skywave massive MIMO-OFDM triple beam-based channel modeling as well as related methods and systems for channel information acquisition. Established by the present disclosure is a skywave massive MIMO-OFDM triple beam-based statistical channel model, where a spatial-frequency-time domain channel vector is expressed as a product of a triple beam matrix and a triple beam domain channel vector; the triple beam matrix is composed of sampled triple steering vectors corresponding to one set of sampling points of a direction cosine, a time delay, and a Doppler frequency that are selected by a base station; where each of the sampled triple steering vectors is called as a triple beam. Based on the triple beam-based statistical channel model, the base station groups each of the users and allocates pilot sequences by utilizing the statistical channel information; the base station obtains an estimated triple beam domain channel vector by using the received pilot signal, and obtains the spatial-frequency-time domain channel vector for the pilot band and the data band according to the triple beam-based statistical channel model. The present disclosure performs a more accurate channel modeling, which can reduce pilot overhead and computational complexity.

The invention discloses a method, a device and equipment for tracking sky wave radars before networking detection, and a storage medium. The method comprises the following steps: acquiring radar measurement information and gate result information of a target object detected by each sky wave radar in a sky wave radar networking system at each moment and each frame according to a preset sliding window length; associating radar measurement information and gate result information of each frame of sky wave radar detection at each moment, and establishing a data association event space; according to each associated event, calculating a posterior probability cumulative value of each associated event and estimating state prediction information of each associated event; and determining the track of the target object according to the posterior probability cumulative value of each associated event and the state prediction information of each associated event, thereby solving the technical problem that the target track is difficult to track due to low target measurement detection probability and high false alarm probability under the condition of low target signal-to-noise, and improving the target track tracking efficiency. And tracking of the target track is realized.

The invention discloses a Doppler frequency shift calculation method based on a short-wave signal path. The Doppler frequency shift calculation method comprises the following steps: step 1, ray path calculation; step 2, refractive index calculation; 3, calculating a geomagnetic field; 4, solving a ray tracing equation; and step 5, Doppler frequency shift calculation. Simulation analysis of Doppler frequency shift in the prior art stays at a theoretical level, and no specific calculation method exists. According to the method disclosed by the invention, the problem is solved, the Doppler frequency shift of any short wave channel can be calculated in real time according to the real-time ionosphere condition, and the Doppler frequency shift comprises a ground-to-air link, a ground-to-ground sky wave link and an air-to-air link.

The application relates to the technical field of short-wave radio, in particular to a short-wave sky wave signal angle-of-arrival-polarization information estimation method and device, wherein the method comprises the following steps: receiving a short-wave sky wave signal by using a preset short-wave three-component polarization receiving antenna array; based on a rank-deficient MUSIC algorithm and a multi-core parallel operation optimization strategy, performing corresponding array signal processing, signal source number estimation and multi-stage spectrum peak search operation in a preset DSP processor to obtain short-wave sky wave signal angle-of-arrival estimation information and polarization angle estimation information. According to the electromagnetic vector receiving antenna array and the DSP processing method, the sky wave signal angle-of-arrival and polarization information are estimated at the same time, so that the sky wave signal accurate direction finding, the signal quality improvement and the ionospheric wave propagation environment research are provided with the basis.

The present invention discloses a method for constructing a semi-supervised classification model for skywave radar ground and sea clutter using an improved generative adversarial network. This method uses the intermediate layer network of the discriminator in the semi-supervised generative adversarial network to filter out features in a multi-layer network, and weights the feature matching losses of each layer to obtain a joint feature matching loss. Furthermore, the standard adversarial loss and the joint feature matching loss are linearly weighted to obtain a weighted loss. Based on the standard adversarial loss, the joint feature loss, and the weighted loss, a ground and sea clutter classification model WL-SSGAN based on an improved generative adversarial network is designed. This method solves the technical problem of how to avoid manually adding labels and improve the classification performance of the model, achieving the technical effect of saving the cost of adding labels and improving classification efficiency.