18 results about "Angular distance" patented technology

The invention discloses a star map registration method based on a remote optical image, relates to the technical field of image processing, and solves the problems that the existing method is multi-oriented to a single telescope, most of the single telescope is aligned at a star point level, and the robustness is insufficient when parallax, distortion, optical difference and background pollution exist in remote multi-station imaging. The method comprises the following steps: acquiring a remote star map and extracting a star point centroid; angular distance calculation and triangle construction; registering the centroids of the star points in the whole image; performing similarity transformation and homography estimation; and carrying out sub-pixel refinement and full image registration. According to the invention, dual registration of star point centroids and pixel coordinates can be realized for star maps shot by a plurality of telescopes in different places, and meanwhile, a high-quality registration reference can be provided for subsequent three-dimensional information acquisition of a space target and identification and positioning of the space target.

The invention provides an inertial navigation aided navigation positioning method and system, and the method comprises the steps: calculating the coordinate of each navigation satellite in an ECEF coordinate system according to the satellite ephemeris of a satellite navigation system; according to the navigation satellite coordinate and the inertial navigation system positioning result, the azimuth angle and the pitch angle of the navigation satellite relative to the optical detection equipment under the ENU coordinate system are solved, and the navigation satellite is tracked; acquiring star maps collected by the optical detection equipment, matching the star maps through a star map recognition algorithm, resolving a coordinate transformation matrix between two continuous frames of star maps, and recognizing fixed stars and satellites in the star maps based on the transformation matrix; converting the identified fixed star in the field of view into an ECEF coordinate system, calculating an observation angular distance between the fixed star and the satellite, and calculating a satellite observation vector in the ECEF coordinate system according to the observation angular distance; and performing error correction on the positioning result of the inertial navigation system based on the satellite observation vector. Through the scheme, the positioning precision of the inertial navigation system can be improved, and the influence of interference deception signals is reduced.

The invention discloses an optical observation correlation method based on mixed multi-hour ephemeris, and belongs to the technical field of space target monitoring. Aiming at the problem that the correlation performance is reduced when the ephemeris quality is unstable due to dependence on a single ephemeris in the prior art, the method comprises the following steps of: firstly, constructing a mixed set containing multi-source ephemeris; secondly, intelligently selecting a leading ephemeris and a lagging ephemeris which are closest in time for each observation arc section and each target; then, the two ephemeris are used for association respectively, and union sets of results are obtained, so that an initial association set is expanded; and for the generated fuzzy correlation, performing primary disambiguation based on the comprehensive confidence, and performing secondary accurate disambiguation on the residual fuzzy condition by comparing the weighted angular distance residual error root-mean-square value of the whole arc section. According to the method, the dependence on single-term and single-source ephemeris precision is effectively reduced, available information is fully utilized, and the correlation robustness and accuracy of optical observation data under the complex ephemeris condition are remarkably improved.

A celestial exploration support program is disclosed. The program can execute, on a computing device, a hopping-path providing function that generates and provides to a user a hopping-path image in which hopping information including a hopping direction and an angular distance from a guiding star to a specific celestial object is reflected on a basic star chart image.

The invention provides an autonomous visual navigation method for on-orbit remote identification and target tracking of a satellite. The method comprises the following steps: acquiring an original image observation star point position; extracting a navigation star library in a view field range according to the camera optical axis direction and the camera view field; constructing an observation triangle by using the observation star points, and calculating angular distance information between the observation star points; searching the angular distance of the navigation star triangle in the star database, matching the angular distance with the angular distance information of the observation triangle, determining an observation star point, and calculating an attitude conversion matrix between the celestial coordinate system and the camera coordinate system; according to the matrix, back-projecting star points in the star catalogue into the spacecraft image, and matching and deleting the star points; performing continuous multi-frame target detection to determine a spacecraft target; the method comprises the following steps: acquiring a mass center position of a target in a spacecraft image, solving an azimuth angle and a pitch angle of a current spacecraft in a celestial body, performing navigation positioning on the spacecraft target, realizing remote point target tracking, and performing back projection verification on the image in the tracking process.

The star map recognition method based on radial features and interstellar angular distance relates to the field of star map recognition in astronomical navigation, solves the problems that the existing star map recognition algorithm has less number of stars to be recognized at one time, and the recognition speed and robustness are difficult to be compatible, and the method comprises the following steps: a navigation star table is made, radial recognition feature library and interstellar position relationship library are constructed according to the position distribution features of each navigation star and surrounding near neighbor stars; the interstellar position relationship library is used for storing the star number and radial ring number of the surrounding near neighbor stars of each navigation star; then, initial recognition and accurate recognition are carried out. In the process of matching by using the radial feature library, an angular distance error tolerance is set, and a weight value is set for each ring number, so that the star position noise has strong robustness. After the initial recognition, the accurate recognition is carried out, the surrounding near neighbor stars of the main star are used, and the method has strong robustness to false star noise and missing stars. The method realizes the recognition of multiple stars at one time, and improves the initial attitude solution accuracy.

A kind of relative navigation reference deviation calibration method of star and pulsar information fusion is disclosed, which comprises the following steps: configuring a star angular distance measuring sensor and an X-ray detector on a spacecraft; observing stars by the star angular distance measuring sensor to extract navigation information contained in two kinds of relativistic effects, i.e., star aberration caused by the movement of the spacecraft and light deflection caused by celestial gravitational field; observing pulsars by the X-ray detector to obtain pulse arrival time difference observations; combining spacecraft and earth orbit dynamics model to predict the state; processing star angular distance and pulse arrival time difference observations by an extended Kalman filter to correct the state prediction value, and obtaining the estimation of the spacecraft position and velocity, the geocenter position and velocity, and the sensor system error parameters, so as to realize the calibration of two kinds of reference deviations, i.e., earth ephemeris error and sensor system error. The present application provides a new way to improve the performance of relativistic navigation system.

This invention relates to an on-orbit calibration method for the micro-variations of intrinsic parameters of a high-precision star sensor optical system, belonging to the field of high-precision on-orbit calibration technology for spacecraft. First, using the ground-calibrated intrinsic parameters of the optical system as initial values, the relationship between various coordinate systems and the angular distance model of the star sensor points is combined to establish the equality between the angle of the direction vector in the star sensor camera coordinate system and the angle of the navigation star in the celestial coordinate system. Then, based on this, and considering the characteristic that the angular distance between observed stars and the angular distance of the navigation star remain unchanged after environmental changes, a calibration model for the micro-variations of the intrinsic parameters of the star sensor optical system used in this invention is established. Finally, the extended Kalman filter (EKF) algorithm is used to calibrate the micro-variations of the intrinsic parameters of the optical system. After the micro-variation calibration is completed, the initial intrinsic parameter values ​​are added to obtain the intrinsic parameters of the optical system after environmental changes.

The invention relates to the technical field of remote sensing satellite ground data processing, in particular to a multi-probe star camera internal and external parameter joint calibration method, which comprises the following steps: constructing an initial light pointing model, and resolving initial attitude parameters; calculating a theoretical image space coordinate of a fixed star control point based on the initial attitude parameter, calculating an attitude parameter again by using the star point data after gross error elimination, and determining a relative installation relation initial value among the multi-probe star cameras; based on the angular distance constraint between star points in a single-frame image, constructing a single-probe internal parameter calibration model and a combined calibration model with internal parameters and relative installation relations as unknown numbers; the observation equation is weighted according to the weighting model, the internal and external parameters are updated based on the resolving result, iterative optimization is carried out until the convergence condition is met, the accurate internal and external parameters of the star camera are obtained, the influence of observation errors on parameter resolving is effectively restrained, and the calibration precision and the reliability of parameter estimation are further improved.

This invention discloses a star map recognition method, apparatus, and related equipment based on an improved K-vector. The method includes calculating the elevation angle of the current observation position relative to each star in the star catalog, filtering the stars in the catalog based on the elevation angle to establish a temporary navigation star database; taking any two stars within a preset angular distance range in the temporary navigation star database as a pair, calculating the angular distance of each pair, and constructing an angular distance table based on the cosine value of the calculated angular distance; dividing the angular distance table into equal regions, connecting the beginning and end of each region with straight lines to obtain multiple segmented straight lines; constructing a K-vector lookup table; obtaining the target angular distance between the target navigation star pairs to be identified, and calculating the matching range of the target navigation star pairs in the angular distance table based on the target angular distance, a preset measurement error, and the K-vector lookup table. This method effectively improves the star map recognition speed.

The embodiment of the present application provides a kind of deep space exploration transfer section starlight angular distance information optimization, autonomous navigation method and device, by the probe with optical sensor, method includes: through optical sensor acquisition deep space image;The deep space image includes multiple stars and at least one planet;According to the deep space image and ephemeris, select the planet closest to the probe from the at least one planet as target planet;To the deep space image collected, construct optical sensor measurement coordinate system, in the optical sensor measurement coordinate system, determine the sum of stellar vectors of each star in the multiple stars and the planet vector of the target planet;According to the sum of stellar vectors of all stars, determine target star combination in all star combinations;According to the sum of stellar vectors of three stars in the target star combination and the planet vector of the target planet, determine the optimal deep space exploration transfer section starlight angular distance information.

This invention discloses a method and apparatus for calculating the systematic difference of space-based directional observation data. The method includes: acquiring a set of stellar angular distance measurement data; processing precise ephemeris data of BeiDou satellites obtained from the MGEX system to obtain a set of true stellar angular distance values; calculating the systematic difference of the observation data using the set of stellar angular distance measurement data and the set of true stellar angular distance values; performing error calculation processing on the systematic difference of the observation data to obtain systematic difference characteristics; and evaluating the systematic difference characteristics to obtain systematic difference accuracy evaluation information. Using the technical solution provided in this application, the influence of different error sources on space-based directional observation data can be effectively separated and corrected, improving the robustness and adaptability of the calculation model.

The embodiment of the invention discloses a satellite selection method based on a multi-beam receiving antenna. The method comprises the following steps: determining spatial positions of N visible satellites according to a navigation satellite ephemeris; transmitting M receiving beams by using a multi-beam receiving antenna and uniformly dividing the space into M areas; classifying satellites with elevation angles greater than or equal to a first threshold value and carrier-to-noise ratios greater than or equal to a second threshold value in each area into a first candidate satellite set; calculating the comprehensive quality score of each satellite in each first candidate satellite set according to the elevation angle of the satellite, the carrier-to-noise ratio of the satellite and the average spherical angular distance of the satellite in the scanning beam angle; descending the comprehensive quality score of each satellite in each first candidate satellite set, and reserving W satellites corresponding to the first W comprehensive quality scores to obtain M second candidate satellite sets; l satellites are selected from the M second candidate satellite sets, precision factors of the L satellites are calculated, and the L satellites corresponding to the minimum value of the precision factors of the L satellites are selected as final satellite selection results.

The present application relates to remote sensing satellite ground data processing technical field, especially to a kind of multi-probe star camera internal and external parameter joint calibration method, the method, including constructing initial light direction model, and solving initial attitude parameter;Based on initial attitude parameter, the theoretical image coordinate of star control point is solved, and the relative installation relationship initial value between multi-probe star camera is determined after solving attitude parameter using star point data after gross error elimination;Based on the angular distance constraint between the star points in single frame image, a single-probe internal parameter calibration model and a joint calibration model with internal parameters and relative installation relationship as unknowns are constructed;According to the weighting model, the observation equation is weighted, the internal and external parameters are updated based on the solution, and the star camera accurate internal and external parameters are obtained by iterative optimization until the convergence condition is met.The present application effectively suppresses the influence of observation error on parameter solution, and further improves the calibration accuracy and the reliability of parameter estimation.

This invention discloses a space-based directional observation method and apparatus based on orbital accuracy assessment. The method includes acquiring stellar angular distance measurement data, Ka-band inter-satellite link observations, and L-band satellite-to-ground link observations from BeiDou satellites. Using this information, a multi-dimensional observation matrix is ​​constructed and processed to obtain satellite position parameters corresponding to three space-based directional observation modes. Using the MGEX precise ephemeris as a baseline, the satellite position parameters are compared to obtain the optimal observation mode. Therefore, this invention proposes three space-based directional observation modes, using orbital accuracy as the evaluation criterion, forming a highly adaptable and practical observation mode system that improves the orbital accuracy of BeiDou satellites.

The application provides a star map recognition method based on radial and ring angular distance, and the main steps include selection of a star table and construction of a navigation database, construction of an observation star radial and ring angular distance mode feature, initial matching of a radial mode, further matching of a ring angular distance mode, and link angular distance verification. The method realizes one-to-one identification of star points in a star map with large density and multiple pseudo stars, still maintains a high recognition rate when large noise interference and edge field loss are encountered, and makes the correct rate of star map recognition reach 98.7%, and has strong robustness to pseudo stars and background noise interference.

This invention discloses a simulation method for distorted star maps taken by a large field-of-view telescope based on measured star maps, solving the problem of how to simulate distorted star maps taken by a large field-of-view telescope; belonging to the field of star map simulation; including: obtaining the theoretical coordinates of stars in the star catalog according to the coordinate transformation equation; setting an angular distance threshold, and matching the actual coordinates of star points in the measured star map with the theoretical coordinates of stars in the star catalog using the cross-matching method; subtracting the actual coordinates of selected control points from the theoretical coordinates of stars, and constructing a distortion model and a normalized distortion model from the residual results; removing outliers in the normalized distortion model using the Laida criterion, and fitting the parameters of the normalized distortion model using the least squares method to obtain a fitted model; adding distortion to the theoretical coordinate positions of each star in the star catalog using the fitted model, thereby simulating distorted star maps taken by a large field-of-view telescope. This invention realistically simulates images taken by a large field-of-view telescope through the fitted model.

The invention discloses a low-orbit target association evaluation method based on optical observation, and belongs to the technical field of space target monitoring. In order to solve the problems of high false alarm rate and poor robustness caused by neglecting a distance factor in a traditional fixed angular distance correlation method, the method comprises the following steps: firstly, setting a nominal detection distance and a corresponding nominal angular distance residual error threshold; secondly, aiming at potential associated targets of different distances, dynamically calculating an exclusive associated threshold value according to a formula that an angular distance residual error threshold value = a nominal threshold value * (nominal distance / target distance), and reflecting a principle that an angular distance residual error caused by an ephemeris forecast error is inversely proportional to the distance; and finally, in order to prevent the correlation threshold of the extremely close distance target from being too wide, setting a maximum angular distance threshold for constraint. According to the method, the association confidence of different distance targets is unified through the distance self-adaptive dynamic threshold, the association false alarm rate is remarkably reduced, the tolerance to ephemeris forecast errors is improved, and the accuracy and robustness of optical observation data association are effectively improved.