7results about How to "Reduce sidelobe level" patented technology

The invention discloses an airborne radar moving target detection method based on space-time image feature learning, and the method comprises the following steps: constructing an airborne phased array radar echo signal model, and carrying out the simulation generation of a large amount of space-time echo data containing different target signals, clutter signals and noise signals; performing range pulse compression processing on the space-time echo data to obtain a space-time echo signal vector; performing sparse recovery processing on the space-time echo signal vector by using a sparse Bayesian algorithm to obtain a space-time image corresponding to each piece of space-time echo signal data; according to different feature distribution of targets and clutters on the space-time images, performing target labeling on each space-time image to obtain a labeling data set; training the deep learning network to obtain a deep learning target detection network capable of extracting target space-time image features; according to the method, the target and the clutter are distinguished on the space-time image based on the deep learning technology, so that airborne phased array radar moving target detection is realized.

The invention provides a detection method based on weighted Fourier integral method, which adopts double triangular window, double cosine window and double Kaiser window multi-group windowing mode to shift left and right and select small value for beam diagram of weighted Fourier integral method. Since beam diagrams of three weighting modes have differences in sidelobe level, the invention can reduce the sidelobe level of beam diagram by selecting small value for blending, reduce the background level of target estimation result, improve the detection performance of weak target, accurately estimate the position of weak target, and overcome the problem that weak target is difficult to detect under high background caused by high sidelobe level of beam diagram when single window function is weighted; the invention obtains narrower main lobe of beam by using the method of shifting left and right of beam diagram, overcomes the problem that main lobe of beam diagram is wide under single window function, and improves the display effect of target in azimuth estimation result.

The invention discloses a high-gain dual-polarized directional antenna, which comprises an antenna body and an antenna mounting bracket used for rolling the antenna body and adjusting the pitch angle of the antenna body, the antenna body comprises a feed network board, and a first antenna array and a second antenna array which are arranged in parallel are mounted on the feed network board; each of the first antenna array and the second antenna array comprises three rows of longitudinal arrays which are parallel to each other, and radiation units in two adjacent rows of longitudinal arrays are arranged in a staggered manner so as to be spaced by a first wavelength distance in a vertical plane direction; it can be understood that the antenna provided by the invention can effectively reduce the sidelobe level of the horizontal plane through the staggered arrangement of the radiation units in the double-antenna array so as to reduce the cross-zone interference, so that the trains running in opposite directions at high speed can receive the main beam signal coverage more accurately, and the accurate scheduling is realized.

The invention discloses a uniform area array constant beam width linear constraint minimum variance beam forming method and device, and the method comprises the steps: respectively and independently designing two stages of sub-arrays through employing the property that a planar array weight matrix can be represented as a two-dimensional convolution form of a two-stage sub-array weight matrix; the method has the advantages of high fixed beam robustness, low complexity and strong adaptive beam interference noise suppression capability, meets the requirements of constant beam width in an expected direction and formation of wide null suppression in an interference direction, is simple in design and low in complexity, and can support application with high real-time requirement. According to the invention, a two-dimensional Chebyshev windowing constant beam width fixed beam method is adopted, and window parameters adjusted along with frequency are utilized, so that not only is the beam width constant maintained, but also the sidelobe level can be effectively controlled.

The application provides a radar communication system and receiver joint filter design method and system, the method comprises the following steps: constructing the filter of the working scene of the integrated radar communication system and the JRC-CWG-RF model; when the target and the integrated system move relative to each other in the working scene, the sidelobe performance design optimization criterion is designed according to the filter output of the radar receiving end of the integrated radar communication system; the optimization problem is constructed according to the optimization criterion; the optimization problem is solved by using the AO-KKT-MM algorithm, the constraint parameters of the JRC-CWG-RF model are adjusted, and the filter of the adaptive JRC-CWG-RF model is obtained. The system is based on the above method. By constructing the working scene and the JRC-CWG-RF model, the filter output of the JRC-CWG-RF model has a low sidelobe level, the parameter value of the filter is adjusted according to the constraint, the PAPR of a radar communication system transmission waveform can be effectively limited, the application also realizes radar detection while realizing communication function, and the performance of the integrated system is improved through joint optimization.

The application discloses an air moving target positioning method and device based on a ground-based distributed passive detection system, a medium and a product, and relates to the field of target positioning. The method comprises the following steps: optimizing the layout of receiving stations in the ground-based distributed passive detection system by using a genetic algorithm to obtain an optimal non-uniform receiving station deployment structure; determining a spatial Doppler signal history based on signals radiated by an air moving target and received by each receiving station in the optimal non-uniform receiving station deployment structure; dividing a space to be measured into spatial grids according to slant range, azimuth angle and pitch angle, calculating the theoretical propagation distance of a grid point to a receiving station, and constructing a corresponding theoretical Doppler signal history; performing coherent accumulation on the theoretical Doppler signal history and the spatial Doppler signal history, constructing a spatial positioning cost function, searching for the peak position of the spatial positioning cost function, and determining the position of the air moving target. The application can realize high-precision and high-robustness positioning of the air moving target under the condition of a single fast shot.

The present invention discloses a low sidelobe broadband low cross-polarization planar dipole antenna array, comprising a multilayer dielectric substrate; a first metal surface; a second metal surface; a feed network; a dipole antenna array; each dipole antenna unit comprises a top dipole arm, a middle dipole arm, and a bottom dipole arm; the first metal surface is connected to one end of the top dipole arm; the second metal surface is connected to one end of the bottom dipole arm; the feed network comprises a signal conducting strip and a metallized through hole; the signal conducting strip at the output end of the feed network is directly connected to the signal input end of each dipole antenna unit; the antenna array etches a pair of slits at appropriate positions, so that the dipole works in a half-wavelength mode and a 1.5 times wavelength mode at the same time, greatly improving the impedance bandwidth of the dipole antenna. The antenna array adopts a SICL structure for feeding, which can effectively suppress the cross polarization of the dipole antenna, and the SICL structure works in a quasi-TEM mode without a cutoff frequency.