7 results about "Azimuth compression" patented technology

This application relates to the field of space imaging technology and provides a method for decoupling translational and rotational motion in space-based microwave imaging of space targets based on parameter estimation. The method first uses adjacent cross-correlation and self-focusing methods to perform preliminary compensation for the translational motion components of the microwave imaging echo data. Then, using the first-order translational motion parameters fitted by the former as initial values ​​and minimizing the image entropy of the echo data as the cost function, it combines Keystone transform to optimize and compensate for the translational linear phase components. Next, it uses Keystone transform to compensate for the spatially varied range cell migration caused by the rotational motion components. Finally, it performs a second compensation for the residual translational motion components, obtaining echo data after almost complete compensation of the translational and rotational MTRC. By performing spatially varied phase error compensation and azimuth compression on this data, the imaging result of the space target can be obtained. This method achieves a balance between the efficiency and accuracy of parameter estimation, effectively improving imaging quality.

This invention relates to the field of radar imaging technology, and proposes a system and method for detecting local surface defects in field equipment based on a robotic arm. The system includes: a robotic arm unit with a SAR transceiver antenna mounted at its end, which transmits electromagnetic signals to the surface of the field equipment to be inspected and receives echo signals; a motion controller connected to the robotic arm unit, which controls the movement trajectory of the robotic arm; and an industrial control computer, which has a built-in SAR imaging data processing module and a path optimization module. The industrial control computer is electrically connected to the motion controller and the SAR transceiver antenna, respectively, driving the robotic arm unit to move according to the planned sampling trajectory, and simultaneously controlling the signal transmission and reception timing of the SAR transceiver antenna; the SAR imaging data processing module performs range compression, azimuth compression, and two-dimensional inverse Fourier transform processing on the received echo signals to generate SAR images characterizing the surface and internal defects of the equipment. This invention achieves full automation of the field equipment defect detection process.

The application provides a terahertz SAR high-efficiency self-focusing imaging method and system based on RB-PCA, comprising: obtaining original echo signal data and performing pretreatment; performing distance block in the distance direction on the pretreated echo signal data to obtain a plurality of distance blocks, performing sub-aperture segmentation in the distance block for each distance block to obtain a plurality of sub-aperture signal data; performing desquamation processing on each sub-aperture signal data to obtain desquamation signal data; performing PCA processing on the desquamation signal data and selecting a characteristic vector with the largest characteristic value as a target characteristic vector; obtaining each sub-aperture phase error gradient estimation value through adaptive PGA estimation on the target characteristic vector; obtaining two-dimensional space-varying phase errors of each distance block through global splicing and fusion on each sub-aperture phase error gradient estimation value; and performing phase compensation and azimuth compression on the pretreated echo signal data based on the two-dimensional space-varying phase errors to obtain focused imaging results.

The application discloses a kind of small SAR data processing method and system based on PCIe RDMA, it is related to radar signal and information processing technical field, comprising the following steps: S1, data preprocessing: the original echo data received by radar is preprocessed;S2, range compression: the original echo data after preprocessing is compressed in range;S3, azimuth compression: the original echo data compressed in range is compressed in azimuth, and the SAR image of target area is obtained;S4, image post-processing: SAR image is post-processed, and post-processing includes geometric correction, radiation correction and image enhancement.The application adopts the above-mentioned small SAR data processing method and system based on PCIe RDMA, eliminates the data copy overhead of CPU participation in traditional communication model, realizes the direct access of cross-node memory after the interconnection of multiple hosts through PCIe, significantly reduces data transmission delay, and improves system bandwidth.

The application discloses a kind of based on physical consistency modeling multiple scattering SAR imaging simulation method, system, equipment and medium, including the following steps: constructing the three-dimensional electromagnetic model of target;Geometric model under the condition of transmitting-receiving co-located SAR operating mode is constructed by light ray tracing;Using high-frequency electromagnetic scattering algorithm based on ray tracing, considering first-order, second-order and higher order multiple scattering path, the superposition and amplitude modulation of each order scattering contribution are carried out, the scattering field distribution of target under far-field condition is calculated, and the far-field scattering field is obtained;Total far-field scattering field is mapped by space propagation, and the far-field scattering result is mapped as radar platform near-field echo signal;Echo signal amplitude is corrected, and two-dimensional SAR near-field echo matrix is obtained;SAR imaging processing is carried out, and SAR imaging processing includes range compression, range migration correction RCM and azimuth compression.The application improves the fidelity and accuracy of SAR imaging simulation under complex target scene.

The application relates to the technical field of remote sensing and radar imaging, and relates to a space target ISAR imaging and scaling integrated method based on a translation-rotation parameter joint estimation.The application is used to solve the problem that the existing space target ISAR imaging is affected by motion compensation, and the scattering points of a space target are prone to moving across distance units in a long-time accumulation.The application performs distance compression on echo obtained by a ground-based radar, performs generalized Radon Fourier transformation on a one-dimensional distance image sequence, and further estimates phase coefficients of the echo signal; the effective rotation angular velocity module value of a space uniform rotation target and a compensation signal are calculated by using the estimated value; the echo signal is subjected to translation compensation by using the compensation signal, the compensated echo signal is converted from a Cartesian coordinate system to a polar coordinate system by using the effective rotation angular velocity, and interpolation is performed; the imaging result is obtained by performing distance and azimuth compression on the interpolation result, scaling is completed according to the effective rotation angular velocity, and the space target ISAR imaging and scaling integration are realized.

The application relates to an airborne SAR moving target imaging method based on Doppler parameter estimation, and aims to solve the problem that a traditional RD algorithm is not applicable to airborne SAR moving target imaging. The process is as follows: 1. the Doppler center frequency and the Doppler frequency modulation slope of a target are derived; 2. a distance frequency domain signal is obtained; 3. a distance compression function is constructed to obtain distance compressed echo data; 4. an azimuth compression function is constructed to obtain azimuth compressed data; 5. a particle swarm optimization algorithm is adopted to obtain the target Doppler center frequency and the Doppler frequency modulation slope corresponding to the minimum entropy value; 6. a distance migration correction function is constructed to obtain two-dimensional frequency domain data after distance migration correction; 7. a distance matching function is constructed to obtain distance compressed azimuth frequency domain data; 8. an azimuth matching function is constructed to obtain two-dimensional time domain data, and imaging is completed. The application is used in the field of airborne SAR moving target imaging.