20 results about "Slant range" patented technology

The application provides a kind of InSAR deformation monitoring point high-precision geometric positioning method combined with three-dimensional model data, belongs to synthetic aperture radar technical field, comprising: converting three-dimensional model data into space rectangular coordinates, combined with satellite orbit parameter iteration to solve row and column coordinates in SAR image, calculate the slant range projection distance of satellite-observation vector, screen and eliminate invalid data in shadow area;With the screening result as a mask, obtain a subset of three-dimensional model data, calculate the row and column coordinates of the InSAR deformation monitoring point of the subset of three-dimensional model data, and search for candidate points based on plane geometric constraints, match the accurate elevation of the monitoring point by height system deviation;Based on the determined accurate elevation, construct the RD positioning model of distance constraint, Doppler frequency constraint and ellipsoid constraint, and solve the high-precision geometric position of InSAR deformation monitoring point. It can realize the high-precision geometric positioning of infrastructure InSAR deformation monitoring point, and improve the applicability in infrastructure fine deformation monitoring.

The application relates to a space target joint imaging and attitude inversion method based on a spaceborne platform, and relates to the field of inverse synthetic aperture radar imaging, in particular to a space target joint imaging and attitude inversion method based on a spaceborne platform. The application aims to solve the problems that in the existing space target imaging process of a spaceborne platform, three-dimensional high-order space-variable range migration and phase errors caused by complex relative motion between the target and the platform are difficult to realize high-precision imaging, and the existing attitude estimation algorithm needs to be completely compensated for the rectangular component segmentation and orbit error before the attitude inversion can be realized. The process is as follows: one, a narrowband tracking system of a radar obtains target slant range and a radar line-of-sight unit vector; two, a wedge-shaped transformed signal is obtained; three, spatial Doppler parameter distribution of a special point is obtained; four, an imaging result is obtained; and five, accurate estimation of target attitude parameters is completed through plane coefficient fitting.

This invention discloses a method and system for de-flattening preprocessing, belonging to the field of radar imaging. The method includes: acquiring a main radar image and a secondary radar image, each containing several main image scattering points and several secondary image scattering points; calculating the secondary image scattering points corresponding to the main image scattering points to form several scattering point pairs; performing a flat-ground phase acquisition action to obtain an ideal flat-ground phase, thereby forming an ideal flat-ground phase map and completing the de-flattening preprocessing process. The flat-ground phase acquisition action includes: calculating the main image Doppler history and the secondary image Doppler history of the scattering point pairs; determining the main image focusing time that meets a preset time threshold to calculate the main image slant range, thereby determining the secondary image focusing time that meets the preset time threshold, and calculating the secondary image slant range based on the secondary image focusing time; and obtaining the ideal flat-ground phase of the scattering point pairs based on the main image slant range and the secondary image slant range. The de-flattening preprocessing method disclosed in this invention can effectively reduce the processing error of de-flattening preprocessing methods.

The application discloses a spiral trajectory glider synthetic aperture radar imaging method and device, and the method comprises the following steps: sequentially performing time domain and frequency domain compensation processing on echo signals through a time domain compensation function and a frequency domain compensation function to obtain two-dimensional frequency domain signals; wherein the time domain compensation function and the frequency domain compensation function are constructed according to the relationship between high-precision instantaneous slant range of any point in an imaging scene and instantaneous slant range of a reference point, and the instantaneous slant range is determined based on a spiral trajectory geometric model with rapid acceleration and speed change; and performing non-uniform fast Fourier transform on the two-dimensional frequency domain signals to obtain transformed two-dimensional frequency domain signals. The application can improve imaging precision.

The application relates to an equatorial ionospheric irregularity automatic detection method and system, and belongs to the field of artificial intelligence. The method comprises the following steps: downloading GOLD satellite data, pre-processing and labeling, and constructing an original data set; inputting the original data set into a deep learning network model for training to obtain a trained deep learning network model; calculating the performance index of the trained deep learning network model, and outputting an equatorial ionospheric irregularity identification result. The application solves the problem of low accuracy in identifying and detecting equatorial ionospheric irregularities caused by the influence of factors such as slant range, background airglow intensity, instrument characteristics and threshold.

A vortex electromagnetic wave near field azimuth identification method is provided. Four kinds of vortex electromagnetic waves with different modes are set to detect a target, four groups of echo data are obtained, two-by-two interference processing is performed on the four groups of echo data, the phase generated by the target slant range is eliminated, six groups of echo phases after interference are extracted, six groups of theoretical phases are constructed, and a search algorithm is used to obtain a high-precision target azimuth angle which makes the sum of absolute values of errors between the echo phases after interference and the theoretical phases minimum. The present application can complete azimuth identification only by using four modes under the condition of ensuring measurement accuracy, is more efficient, and is more in line with the demand of rapid direction finding of near field detector.

The application discloses a strip mode spaceborne SAR multi-dimensional parameter joint self-focusing imaging method. First, spaceborne SAR original echo complex data and related parameters are acquired and preprocessed, and then baseband Doppler center frequency is estimated through azimuth direction delay conjugate multiplication and two-dimensional integration. Subsequently, Doppler ambiguity is solved based on an image sharpness maximization criterion, and the absolute Doppler center frequency is obtained in combination with the baseband frequency. Finally, initial Doppler frequency modulation is acquired through contrast maximization coarse search and sub-aperture cross-correlation fine search, a multi-dimensional parameter joint self-focusing optimization model based on a minimum entropy criterion is further constructed, three variables of Doppler center frequency, Doppler frequency modulation and center slant range are cooperatively optimized by using a simplex method, and full-automatic high-precision high-resolution imaging is realized. The method can complete parameter inversion and self-focusing imaging under the condition of extreme blind processing without ephemeris, and has excellent robustness and engineering practical value while reducing the calculation cost.

The adaptive distance detection method, system and medium based on the TOF sensor include obtaining an original slant range measurement value and an original attitude angle measurement value; correcting the original slant range measurement value to obtain an effective slant range value; performing attitude solving processing on the original attitude angle measurement value to obtain an attitude angle component; performing time alignment processing based on the effective slant range value and the attitude angle component to obtain a correlated data tuple; calculating a calibrated straight-line distance based on the data tuple and a preset formula; performing effectiveness verification on the calibrated straight-line distance to obtain an effective straight-line distance; calculating a time sequence statistic based on a plurality of continuous effective straight-line distances, and calculating a time sequence change based on a plurality of continuous attitude angle components; comparing the time sequence statistic with a first static threshold value, and comparing the time sequence change with a second static threshold value; and adjusting a ranging frequency of the TOF sensor according to a comparison result.

This invention discloses a mid-orbit curve SAR frequency domain imaging method based on spatially varied azimuth preprocessing. This invention relates to an imaging algorithm that, under long synthetic aperture time and slant-look observation geometry conditions, suppresses the two-dimensional spatial variation of range cell migration (RCM) through improved azimuth resampling technology, thereby achieving high-precision focusing. This invention is achieved through the following technical solution: Step 1, constructing a two-dimensional spatially varied model of the higher-order slant range history and its parameters for MEO SAR. Step 2, establishing an improved azimuth resampling model based on range gate dependence. Step 3, solving for the optimal azimuth resampling coefficients. Step 4, performing improved azimuth resampling and imaging focusing processing.

The application provides a kind of based on weighted linear iteration's spaceborne multi-base radar system three-dimensional positioning method and system, comprising: obtaining the radar echo data of multiple receivers and effectively detecting target, search the elevation angle and spatial cone angle of target signal by two-dimensional adaptive filtering technology, obtain the two-dimensional angle estimation information of target under different base different visual angle;According to the two-dimensional angle information and slant range information of target under different visual angle, construct nonlinear equation group, and carry out first-order Taylor expansion to it, obtain corresponding linear overdetermined equation group;According to the measurement accuracy known to radar system, form accuracy matrix to the linear overdetermined equation and carry out normalization operation and iterative calculation, and calculate the three-dimensional coordinates of target in the earth-centered earth-fixed coordinate system, and then obtain the longitude and latitude and height information of target, realize the high-precision three-dimensional positioning of multi-base radar system.

The application relates to an underwater ranging method and device based on motion state compensation, equipment and a storage medium. The method comprises the following steps: determining the position information of a transponder based on a pre-constructed motion state equation and an observation equation of the transponder; compensating the original slant range between the transponder and a base station to obtain a compensated slant range according to the position information of the transponder and the movement vector of the base station; extracting the sound speed gradient and the signal-to-noise ratio parameter; calculating the environmental confidence factor based on the sound speed gradient and the signal-to-noise ratio; calculating the first horizontal distance and the second horizontal distance between the transponder and the base station by using the depth difference and the vertical angle respectively; determining the first weight corresponding to the first horizontal distance and the second weight corresponding to the second horizontal distance according to the environmental confidence factor; and calculating the target horizontal distance between the transponder and the base station according to the first horizontal distance, the first weight, the second horizontal distance and the second weight.

The application relates to the technical field of geographic positioning, and provides a target positioning method, device and electronic equipment. The method comprises the following steps: acquiring a UAV aerial image and flight attitude parameters; determining an offset angle of a target pixel point in an imaging plane according to the aerial image, and determining a unit direction vector of the target pixel point in a world coordinate system according to the offset angle and the flight attitude parameters; determining northward displacement and eastward displacement of the target relative to the UAV in a north-east coordinate system according to the vertical relative height and slant range of the UAV and the target, the unit direction vector, the flight attitude parameters and the offset angle; and positioning the target according to the latitude and longitude of the UAV, the northward displacement and the eastward displacement. The application can improve the accuracy of target positioning when the UAV performs large-angle maneuvering, so as to meet actual positioning requirements.

The application discloses a kind of stereoscopic SAR geometric calibration methods based on alternating direction multiplier method, comprising: obtaining multiple SAR images covering the same area, extracting satellite ephemeris parameters, observation slant range and Doppler center frequency, and obtaining elevation model data as prior elevation information;Based on the range-Doppler model, the range equation and Doppler equation containing the estimated parameter vector are established;Joint adjustment global optimization objective function with L2 regularization constraint is constructed;Auxiliary variables are introduced to convert the objective function into an equality constrained optimization problem, and an augmented Lagrangian function is constructed;Iterative solution is carried out using alternating direction multiplier method, and the estimated parameter vector, auxiliary variable and dual variable are updated alternately;After meeting the convergence condition, the optimal estimate of ground point three-dimensional coordinates and slant range system error is output.The application can realize high-precision and high-stability three-dimensional geometric calibration without ground control points.

The application relates to a navigation system calibration method and device, electronic equipment and a storage medium. The method comprises the following steps: starting a multi-source navigation positioning device to collect multi-source original data; screening an effective measurement point set meeting a slant range difference constraint condition; if a current track in the effective measurement point set is in a slant range constraint invalidation scene, a measurement vector and an observation equation are constructed by using the effective measurement point set; if not, attention weights of each measurement dimension are calculated by using an attention weight function, and the observation equation is constructed by weighting; a K-means clustering initialization algorithm based on deep reinforcement learning optimization is run to update a state in a filtering iteration; if the state converges, installation error parameters are output, and system installation errors are compensated; if the state does not converge, a time synchronization and interpolation completion link of the multi-source original data is returned to continue iteration until a calibration process is completed. The application can improve underwater navigation anti-interference capability, realize high-precision calibration, widen an adaptation range, and achieve a high-quality navigation calibration target.

This invention proposes a bistatic forward-looking SAR target localization method, the implementation steps of which are: initializing the bistatic forward-looking SAR target localization scene; calculating the slant range between the receiver and the scene center, as well as the precise position of the scene center; and obtaining the target localization result. This invention decouples the bistatic slant range by establishing a system of equations based on the triangle formed by the receiver's slant range relative to the scene center at adjacent synthetic aperture center times and the flight trajectory within the synthetic aperture time interval, and the triangle formed by the transmitter's slant range relative to the scene center at the previous synthetic aperture center time, its projection, and the transmitter's height. This allows for the acquisition of the receiver's slant range relative to the scene center at the next synthetic aperture center time, avoiding the defect of amplified beamline angle error due to sine calculations, thus improving localization accuracy. Furthermore, the data used to calculate the transmitter's slant range relative to the scene center can be directly obtained from the constructed localization scene, without the need for beamline angle calculations, thus possessing universality and broadening the application scope.

This invention discloses a method and system for generating three-dimensional cloud field profiles based on the Earth's spherical baseline, belonging to the field of meteorological radar data processing technology. By establishing the coordinate transformation relationship between the planar radar polar coordinate system based on the Earth's spherical surface and the computer screen rectangular coordinate system, the minor arc baseline of the great circle of the Earth, determined by any two points on the Earth's spherical surface, is analyzed and calculated. Furthermore, by calculating the elevation angle, azimuth angle, and slant range of grid points in the vertical profile rectangular coordinate system of the radar reflectivity factor in the radar polar coordinate system, the radar reflectivity factor analysis value of these grid points is obtained using a vertical linear interpolation method. By replacing the traditional planar baseline with the minor arc of the great circle of the Earth's spherical surface, spatial position distortion under long-distance observation is effectively overcome, significantly improving the calculation accuracy and geometric realism of the three-dimensional cloud field profile. This method is suitable for refined meteorological monitoring and dynamic tracking and analysis of strong convective cloud systems.

The application discloses a kind of aerial work lift platform collision detection and early warning method, device, electronic equipment, the method includes the following steps: the data of 360 ° laser radar in its scanning range is screened, only the data in effective scanning interval is retained, wherein, effective scanning interval is determined by the size structure of the upper surface of current aerial work lift platform;All real-time slant ranges Dis 实时 The projection DisY in vertical Y direction is calculated, and the minimum projection MinY is obtained;The minimum projection MinY is compared with the set safety threshold Min 阈值 If MinY>Min 阈值 , it is determined that the current is safe state, if MinY≤Min 阈值 , it is determined that the current is collision state and triggers alarm.The application improves the timeliness, reliability, accuracy of aerial work lift platform safety protection, reduces the number of safety personnel, reduces labor intensity, reduces operation cost.

The application provides a SAR constellation area effective coverage evaluation method and system, the method comprises the following steps: S1, a constellation comprising a plurality of satellites is constructed to periodically cover a target area; S2, for the target area, the blind area state of each ground point under single satellite transit is calculated based on a digital elevation model and satellite orbit parameters, and a binary blind area matrix is output; S3, the single effective coverage is calculated based on the binary blind area matrix; S4, the cumulative effective coverage is further calculated and output according to the calculation result of the single effective coverage. The application combines the digital elevation model and the slant range monotonicity analysis, solves the technical problem that the complex terrain area overlap / shadow blind area is difficult to accurately quantify, realizes a sub-pixel level terrain blind area detection system, and significantly improves the modeling accuracy of SAR observation in a complex deformation environment.

The application discloses a kind of evaluation methods, systems, electronic equipment and storage medium of spaceborne SAR uncontrolled positioning accuracy, it is related to microwave remote sensing SAR satellite technical field, alleviateed the problem that existing spaceborne SAR uncontrolled positioning accuracy evaluation technology cannot be accurately evaluated and decomposed inaccuracy.A kind of evaluation method, the position and speed of the satellite to be evaluated at initial time and the imaging position of target point are obtained;The position and speed of the satellite to be evaluated at beam crossing time are obtained, the slant range between the satellite to be evaluated and target point and doppler center frequency;The predicted imaging position of the target point is obtained by SAR geometric model;Based on imaging position and predicted imaging position, obtain a plurality of error proportion factors;Further, the total positioning error is obtained as the evaluation of spaceborne SAR uncontrolled positioning accuracy.The application is suitable for the field of spaceborne SAR overall design.