216 results about "Star chart" patented technology

A computer simulation method is provided for modeling the behavioral expression of one or more agents in an environment to be simulated, then running a simulation of the modeled agent(s) against real-world information as input data reflecting changing conditions of the environment being simulated, and obtaining an output based on the modeled agent(s) response(s). The simulation method models the underlying cultural, social, and behavioral characteristics on which agent behaviors and actions are based, rather than modeling fixed rules for the agent's actions. The input data driving the simulation are constituted by real-world information reflecting the changing conditions of the environment being simulated, rather than an artificial set of predefined initial conditions which do not change over time. As a result, the simulation output of the modeled agent's responses to the input information can indicate more accurately how that type of participant in the simulated environment might respond under real-world conditions. Simulations can be run on global networks for agent types of different cultures, societies, and behaviors, with global sources of information. Simulation environments can include problems and situations in a wide range of human activity. Robust new visual tools are provided for discerning patterns and trends in the simulation data, including waveform charts, star charts, grid charts, and pole chart series.

An automatic celestial navigation system for navigating both night and day by observation of K-band or H-band infrared light from multiple stars. In a first set of preferred embodiments three relatively large aperture telescopes are rigidly mounted on a movable platform such as a ship or airplane with each telescope being directed at a substantially different portion of sky. Embodiments in this first set tend to be relatively large and heavy, such as about one cubic meter and about 60 pounds. In a second set of preferred embodiments one or more smaller aperture telescopes are pivotably mounted on a movable platform such as a ship, airplane or missile so that the telescope or telescopes can be pivoted to point toward specific regions of the sky. Embodiments of this second set are mechanically more complicated than those of the first set, but are much smaller and lighter and are especially useful for guidance of aircraft and missiles. Telescope optics focus (on to a pixel array of a sensor) H-band or K-band light from one or more stars in the field of view of each telescope. Each system also includes an inclinometer, an accurate timing device and a computer processor having access to catalogued infrared star charts. The processor for each system is programmed with special algorithms to use image data from the infrared sensors, inclination information from the inclinometer, time information from the timing device and the catalogued star charts information to determine positions of the platform. Direction information from two stars is needed for locating the platform with respect to the celestial sphere. The computer is also preferably programmed to use this celestial position information to calculate latitude and longitude which may be displayed on a display device such as a monitor or used by a guidance control system. These embodiments are jam proof and insensitive to radio frequency interference. These systems provide efficient alternatives to GPS when GPS is unavailable and can be used for periodic augmentation of inertial navigation systems.

An automatic celestial navigation system for navigating both night and day by observation of K-band or H-band infrared light from multiple stars. In a first set of preferred embodiments three relatively large aperture telescopes are rigidly mounted on a movable platform such as a ship or airplane with each telescope being directed at a substantially different portion of sky. Embodiments in this first set tend to be relatively large and heavy, such as about one cubic meter and about 60 pounds. In a second set of preferred embodiments one or more smaller aperture telescopes are pivotably mounted on a movable platform such as a ship, airplane or missile so that the telescope or telescopes can be pivoted to point toward specific regions of the sky. Embodiments of this second set are mechanically more complicated than those of the first set, but are much smaller and lighter and are especially useful for guidance of aircraft and missiles. Telescope optics focus (on to a pixel array of a sensor) H-band or K-band light from one or more stars in the field of view of each telescope. Each system also includes a GPS sensor and a computer processor having access to catalogued infrared star charts. The processor for each system is programmed with special algorithms to use image data from the infrared sensors, position and timing information from the GPS sensor, and the catalogued star charts information to determine orientation (attitude) of the platform. Direction information from two stars is needed for locating the platform with respect to the celestial sphere. The computer is also preferably programmed to calculate further information which may be used by a guidance control system. These systems provide efficient alternatives to inertial navigation systems when such systems are too expensive and can be used for periodic augmentation and calibration of inertial navigation systems.

A method and apparatus determines the shape of an orbiting or airborne object. A radar determines the general location and a telescope is directed toward the object to form an image of background stars, which will be occluded by the object. The image is compared with a memorized star map, to identify the region of the image in the map. Stars visible in the map which are not visible in the image are listed. The invisible stars are paired with next adjacent visible stars to form star pairs. The midpoints are identified of lines extending between star pairs. Segment lines are drawn between a midpoint and the next closest midpoint. The segment lines define an outline of the object.

A non-labeled identifying method of star atlas includes picking up character rector of navigation star, setting up navigation star mode library according to grille storage, picking up character vector of observed star when star atlas identification is carried out, carrying out match in navigation star mode library according to picked up character vector to confirm star to be selected, grouping stars to be selected and confirming visual filed direction according to attribution of star to be selected.

The invention relates to an autonomous navigation semi-physical simulation test system based on biconical infrared and star sensors. The biconical infrared earth sensor is used for observing a dual-string-width earth simulator, the star sensor is used for observing a dynamic fixed star simulator, and a measurement signal is sent to a navigation computer; an attitude orbit simulator is used for calculating a satellite attitude orbit and sending the satellite reference orbit attitude data to a control computer; the control computer, according to the reference attitude orbit data, generates a string-width control instruction to control the string width of the earth simulator and an inertial quaternion instruction to control a star map of the dynamic fixed star simulator to change; and the navigation computer, according to the measurement signal, performs navigation filtering calculation to obtain a satellite position estimation value and a speed estimation value, and compares the satellite position estimation value and the speed estimation value with the reference data to obtain navigation accuracy. According to the autonomous navigation semi-physical simulation test system based on the biconical infrared and star sensors provided by the invention, the semi-physical simulation verification test for real measurement data of a hardware in a loop based on the biconical infrared and star sensors is realized, and the performance of the full-autonomous navigation system for a satellite can be effectively verified on the ground.

An automatic celestial navigation system for navigating both night and day by observation of K-band or H-band infrared light from multiple stars. A preferred embodiment uses three telescopes with each of the three telescopes rigidly mounted with respect to each other and rigidly mounted on a movable platform such as a ship or airplane with each telescope being directed at a substantially different portion of sky. Telescope optics focuses, onto the pixel array of a sensor, H-band or K-band light from stars in the field of view of each telescope. The system also includes an inclinometer, an accurate timing device and a computer processor having access to cataloged infrared star charts. The processor is programmed with special algorithms to use image data from the infrared sensors, inclination information from the inclinometer, time information from the timing device and the cataloged star charts information to determine positions of the platform. At least two telescopes pointed far enough from the sun detect stars. Direction information from two stars is needed for locating the platform with respect to the celestial sphere. The computer is also preferably programmed to use this celestial position information to calculate latitude, longitude and absolute azimuth, all of which may be displayed on a display device such as a monitor. In a preferred embodiment each of the three telescopes are fixed on a moving ship and views a 0.5×0.4 degree region of the sky for H-band starlight from stars with brightness greater than 6.4 H-band magnitude. Located stars are then compared with star positions from the star catalog within a selected 5×5 degree region of the sky. A correlation of the data from the three telescopic measurements determines the position of the ship to a precision of 30 meters.

The invention relates to a data fusion method for an autonomous-calibration star vector level star sensor with multiple fields of view, which is applied to star sensors with multiple fields of view. The star sensor with multiple fields of view is provided with 2-3 optical heads, and information detected by the optical heads is used for carrying out data fusion. The data fusion method comprises the following steps: S1, carrying out autonomous all-day identification by a plurality of optical heads; S2, selecting a reference head; if an installation matrix is loaded, skipping to step S3; if the installation matrix is not loaded, executing step S4; S3, carrying out star vector fusion with a solidified installation matrix, outputting attitudes and ending; and S4, carrying out autonomous calibration on the installation matrix, carrying out star vector fusion, outputting attitudes and ending. The data fusion method has the advantages that the star vector level fusion method avoids the limit of corner dimension among the heads in a star chart fusion method, overcomes the problem that the fusion attitude precision decreases due to few single head detection stars in attitude level fusion, and effectively upgrades the attitude precision and attitude output robustness of the star sensor.

The present invention provides a method for star point extracting of a navigational star in cloud environment in daytime, and the method comprises firstly, respectively performing the following operation on each frame of star map of a plurality of frames of daytime cloud star maps which are consecutively taken: (1) using an improved morphological TopHat operator to filter an original start map to obtain a first star map; (2) using a RobinsonGuard filter to filter the first star map to obtain a second star map; (3) using an adaptive threshold method for threshold cutting of the second star map, and storing coordinates and grayscales of all pixels higher than a threshold; and (4) using a clustering method for four-connected domain star point extracting; secondly using a multiframe comparison technique to eliminate pseudo-star points in the connected domain extracted from each frame of star map; and thirdly, calculating the centre of mass of each successfully-compared connected domain to complete the star point extraction. The method can effectively eliminate the interference of daytime sky clouds and other backgrounds, meanwhile avoids mistaken extraction caused by dust and other air floating objects, and ensures the effective and stable star point extraction.

The invention relates to an electronic star simulator for an APS (Active Pixel Sensor) star sensor, which comprises a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), an RAM (Random Access Memory) and an LVDS (Low Voltage Differential Signaling) interface circuit. The DSP receives posture data of the APS star sensor, which is input from the outside, and calculates to generate a star chart; then star chart data is stored in the RAM by the FPGA; and by the LVDS interface circuit, the FPGA outputs the star chart data stored in the RAM. The electronic star simulator generates the dynamic star chart and simulates an image output by a star sensor probe to excite a star sensor circuit box. The electronic star simulator is not provided with a complex optical system, does not need to be machined under high accuracy, and also does not need to be accurately installed when in use; the electronic star chart output by the electronic star simulator has high accuracy of positions of star points; and the electronic star simulator can be used for testing a subsystem, an integral star and a target range.

The invention discloses an attitude capture method of a star sensor under the space particle interference condition. The method comprises steps as follows: when attitude capture of the star sensor is interfered by space particles, rolling strip type storage is performed on effective pixels read from an image surface of the star sensor, so that complete star map star point information is acquired; matching identification is performed by the aid of the star map star point information, position information of multiple frames of star points is compared when matching fails, the star points with larger deviations are rejected, and then matching identification is performed again; attitude calculation is performed by the aid of matching identification results, multiple frames of attitude capture results are compared and verified, and attitude capture is judged to be successful when deviations between the results meet requirements. According to the method, comparison and screening are performed according to multiple frames of complete star point position information, pseudo star points caused by space particle interference can be accurately distinguished, and the correctness of attitude capture of the star sensor in the space environment can be guaranteed.

The invention relates to an imaging system for a stellar field of computer simulated star sensors. The imaging system comprises an observation star database, a user input end and an extension module. The user input end is created in optical design software ZEMAX and is applicable to setting the direction of an optical axis of an optical module in the optical design software ZEMAX and the quantity and sizes of pixels of an image surface detector. The extension module is applicable to calling the optical design software ZEMAX and comprises an observation star extracting module, a visual field position computing module and a pixel gray scale computing module. The optical design software ZEMAX further comprises a ray tracing module, and the pixel gray scale computing module outputs a digital star chart according to the set quantity and the set sizes of the pixels of the image surface detector and a received energy value. By the imaging system, star chart data matched with the detector can be obtained, image surface data are sampled and quantified by the pixel gray scale computing module according to the sizes and the quantity of the pixels, the sizes and the quantity of the pixels are inputted by a user, the brightness of each pixel is computed, and the digital star chart matched with the detector can be outputted.

The invention discloses a real-time orbit determination method for a drift scanning geosynchronous satellite. The method comprises the following steps: firstly, processing a star map background to ensure uniform distribution of background pixels, and removing smear if a smear phenomenon occurs; detecting star points in a self-adaptive manner, segmenting an image background, highlighting star images through a feature fusion method, extracting a star image target, and calculating mass center coordinates of the star points; matching and identifying the star images through an improved triangle method, namely, extracting a star image with maximum gray value for triangle matching, performing reduction to obtain CCD negative model parameters according to the matching result, substituting all the star images into a negative model to calculate corresponding celestial coordinates, and matching the celestial coordinates with a star catalogue; and finally, performing reduction on the CCD negative model according to the matching identification result, and substituting geosynchronous satellite coordinates into the CCD negative model to calculate the optical position of the geosynchronous satellite, thereby completing orbit determination of the geosynchronous satellite. The method is high in precision and speed and good in real time property, and is free of bid data calculation and storage.

The invention discloses a method for calculating earth rotation parameters through observation data of a CCD zenith telescope. The latitude variation and universal time of an observation point are calculated by processing the fixed star maps photographed by the CCD zenith telescope in two positions with relative direction included angle of 180 degrees through the combination of the photographing moments of the two star maps and the astronomical latitude and longitude of the observation point. By means of the method, a technical basis is provided for establishing an autonomous earth rotation parameter measurement system in China through the CCD zenith telescope, and the situation that China excessively depends on the international earth rotation and reference system service organization on the aspect of earth rotation parameter measurement can be relieved.

The embodiment of the invention discloses a starry sky image processing method and device. The method comprises the following steps: acquiring a shot image; wherein the shot images are multiple framesof continuously shot images; under the condition that the reference image in the shot image is a starry sky image, obtaining a star map corresponding to the shooting time and the positioning place ofthe reference image; determining a star map area corresponding to the reference image on the star map; and adjusting the gray scale of the stars in the shot image according to the gray scale values of the stars in the star map area. By utilizing the embodiment of the invention, the problems of poor starry sky image imaging effect and difficulty in image processing can be solved.

The invention discloses a roller shutter exposure star sensor star point position correction method based on average speed, which comprises the following steps of 1) according to two continuous framesof star maps (a qth frame and a (q + 1)th frame), obtaining the star point centroid position and the average speed of the star point moving along the horizontal and vertical directions in the (q + 1)th frame of star map, 2) taking the kth row of exposure time of the (q + 1)th frame of image as a reference, and obtaining the corrected star point position in the (q + 1)th frame of star map, 3) resolving the angular distance measured value between the star points after correction, comparing the angular distance measured value with the angular distance theoretical value under a celestial coordinate system, and verifying the correctness of the star point position after correction in the step 2) according to the angular distance error, and 4) according to the corrected star point centroid coordinates solved in the step 2) and the verification conclusion in the step 3), resolving to obtain the star sensor attitude corresponding to the kth row exposure moment of the (q + 1)th frame of image.According to the method, the position correction relation is established based on the line exposure moment and the star point average movement speed in the roller shutter exposure star map, and the attitude measurement precision of the star sensor in the roller shutter exposure mode under the star point movement condition is improved.

The invention discloses a system for performing relative navigation on a spacecraft based on background astronomical information. The system comprises a target spacecraft and reference celestial body recognition unit, a star map matching recognition unit, a determining unit for relationship between a focal plane and an upper included angle, a relative orbital motion relationship unit and a Kalman filtering resolving unit. The system is kept in a processor of a navigational computer. According to the system, by means of a hardware platform of a tracing spacecraft, in reference to the information of the target astronomical background and according to the distance between the target spacecraft and the tracing spacecraft, the relative motion state of the target spacecraft under the inertial frame OCXCYCZC of the tracing spacecraft is calculated by using a filtering method, and the target spacecraft is finally traced and positioned.

The invention provides a star camera in-orbit calibration attitude determination and remote sensing image geometric positioning method and system. The method comprises steps of after star point identification is completed and control points extracted from a star map are obtained, establishing observation vectors of star points in a J2000 coordinate system, establishing a distortion model and an imaging model of a star camera, and obtaining coordinates of the star points in a star camera coordinate system under mirror distortion; establishing a single star point error equation according to theimaging model of the star camera and the coordinate observation value of the star point in the star camera coordinate system; according to the sequence star map, obtaining an error equation set for simultaneously determining calibration parameters and attitudes of the star camera; inputting the rough laboratory calibration parameters and the rough initial attitude as initial values, and simultaneously determining the calibration parameters and attitude of the star camera by using a least square method to obtain an on-orbit calibration attitude result of the star camera. Compared with the traditional method, the method provided by the invention has higher calibration attitude precision, and has good robustness and fault tolerance, and thereby the direct geometric positioning precision requirement of the current high-resolution remote sensing image is met.

The invention relates to an autonomous course and attitude determination method based on polarization-astronomical included angle information observation. The method comprises the following steps: firstly, measuring a polarization vector pb under the current attitude by utilizing a polarization sensor mounted in a carrier coordinate system b system; calculating to obtain a moon vector Lb under thecarrier coordinate system b system according to polarization vectors measured by the polarization sensors in different directions, and converting the Lb into a navigation coordinate system n system by utilizing an attitude conversion matrix outputted by the system to obtain a moon vector Ln under a geographic coordinate system n system measured by the system; measuring a starlight vector Ab underthe carrier coordinate system by using a star sensor installed on the carrier coordinate system b system, obtaining a starlight vector under an inertial coordinate system i system by combining with an astronomical calendar according to star map matching, and obtaining the starlight vector An under the n system by combining with time and position information; taking an included angle alpha betweenthe starlight vector Ab and the moon vector Lb under the carrier coordinate system b system as measurement and establishing a relationship between the included angle alpha and a platform error anglephi to obtain an attitude measurement equation.

The invention discloses a star sensor artificial star screening method based on angular distance screening. The method comprises the following steps: (1) all star points in a first frame of a star mapare recorded as initial star points; (2) starting from a second frame, corresponding relations between each star point and the initial star points are established by utilizing a star tracking method;(3) the angular distances between other frames and the initial frame are compared, the angular distances are screened according to angular distance changes, and an angular distance screening matrix is updated; (4) star pairs corresponding to the screened angular distances are used to vote for each star point, and the star points with the excessively low vote numbers are screened; and (5) each frame is output by the screened star points and is sent to a subsequent star map recognition module. The method has the following advantages: (1) the convergence success rate is high, and the convergencesuccess rate is over 98% within 600 artificial stars; (2) the convergence speed is high, and all the artificial stars can be screened by only at most 10 frames of the star map on average; (3) the adaptability to the number of the artificial satellites is high, and all the artificial stars can be screened from the star map with no less than 700 artificial stars; and (4) the screening of the artificial stars does not depend on shape information of the star points.