37 results about "Subspace algorithms" patented technology

The invention discloses an impact positioning method for a composite material plate based on a rotation invariant subspace, comprising the following steps: collecting the impact signal of the composite material plate; The rotation invariant subspace algorithm is used to estimate the wave direction of the shock source; the distance to the shock source is estimated by combining the local mean decomposition and Lamb wave propagation characteristics, and the wave direction of the shock source is used to locate the shock source. The present invention has the following advantages and effects: the method of the present invention is simple and reliable, and the direction of arrival is directly estimated by calculating the rotation invariant factor, without the need to search for spectral peaks in the monitoring area, which greatly saves calculation time and realizes the impact on the composite material plate Online monitoring, strong real-time performance.

The invention discloses a single-snapshot data-based coherent signal DOA estimating method and relates to the technical field of array antenna systems or methods capable of indicating different signal directions. The method comprises rearranging the single-snapshot received data of an array to obtain two pseudo-covariance matrixes, and then through two pseudo-covariance matrixes, expanding the covariance matrix of a subspace restructuring algorithm; performing singular value decomposition on the new pseudo-covariance matrixes to obtain a signal subspace and a noise subspace, and performing DOA estimation on incoming coherent wave signals through a MUSIC spectrum estimating method. The single-snapshot data-based coherent signal DOA estimating method can eliminate coherence among source signals under single-snapshot conditions and meanwhile further improve the DOA estimating precision. The single-snapshot data-based coherent signal DOA estimating method is mainly applied to rapid estimation of incoming directions of coherent signals under the single-snapshot conditions.

The invention belongs to the array signal processing field and relates to a hexagonal array-based coherent signal two-dimensional DOA (Direction of Arrival) estimation method, in particular to a high-precision, de-coherence, two-dimensional signal DOA subspace estimation method. According to the estimation method of the invention, an array is virtualized and extended through performing conjugate matrix solution on array receiving data, so that a hexagonal array including three sub arrays are obtained, and then, a correlation matrix of a subspace algorithm is extended and reconstructed according to an autocorrelation matrix and a cross correlation matrix of the three sub arrays, and therefore, de-coherence can be realized; and singular value decomposition is performed on the new correlation matrix, so that a signal subspace and a noise subspace can be obtained, and then, DOA estimation is performed on coherent receiving signals through utilizing a two-dimensional MUSIC (Multiple Signal Classification) estimation method. With the estimation method of the invention adopted, coherence between source signals can be eliminated, and the estimation accuracy of two-dimensional DOA can be further improved. The estimation method is mainly applied to two-dimensional high-precision DOA estimation of coherent signals.

The invention proposes a UAV detection method based on a time modulation array, which belongs to the technical field of UAV detection. Including: after periodic modulation of each antenna unit, the received multiple signals are combined into one; the combined signal is down-converted to an intermediate frequency analog signal, and the corresponding digital signal sequence s(n) is obtained by sampling through the ADC module ); the digital signal is separated and reorganized into multiple groups of digital signals, and then the harmonic components of each group of signals are obtained; each group of frequency components is combined into a new array signal harmonic vector, and its autocorrelation matrix is ​​obtained; according to DOA estimation The subspace algorithm is used to obtain the estimated DOA angle of the signal; according to the estimated DOA of the UAV flight control image transmission signal, the orientation of the UAV is calculated. The present invention splits the originally single-channel signal into the baseband digital signal and performs time-frequency conversion respectively, thereby improving the direction finding precision, and eliminating false spectrum peaks by improving the antenna response vector.

The invention discloses a transmission tower modal parameter identification method based on an improved subspace algorithm and used for completing the modal parameter identification of a large span transmission tower structure through individually utilizing response data under the excitation of a field environment. According to the identification process, multi-group packet response data are integrated into synchronous pulse response data based on a random subspace identification principle; the integrated data avoid fitting errors caused by the packet identification, so the synchronous integrated identification of the data is realized; and a stable graph is constructed by utilizing modal parameter identification results under different system orders, so a modal parameter identification order determination problem under the environment excitation is solved, modal omission and repetition phenomena of traditional methods of a peak value method and the like are avoided, the obtained identification result is accurate and stable, and bases are established for subsequent structure damage detection and life estimation.

The invention discloses an L-shaped antenna array low computation complexity two-dimensional DOA (Direction of Arrival) estimation method, mainly solving the problems of high computation complexity and poor estimation performance under a low signal to noise ratio and small snapshots of a present L-shaped antenna array low computation complexity two-dimensional DOA estimation method. The method comprises the steps of: (1) receiving signals; (2) constructing a cross-correlation matrix; (3) constructing an orientation augmentation matrix; (4) constructing a pitching augmentation matrix; (5) estimating an azimuth; (6) estimating a pitch angle; and (7) paring two-dimensional angles. The method utilizes an ESPRIT (estimation of signal parameters via rotation invariant technique) algorithm and a diagonal Toeplitz matrix to decompose characteristic values, realizes L-shaped antenna array DOA estimation with low computation complexity, a low signal to noise ratio and small snapshots, and can be used for radar and communication target location.