30 results about "Celestial coordinate system" patented technology

The invention discloses a simulation system and a simulation method for three-dimensional comprehensive situations of a space mission. The simulation system comprises a space satellite trail and posture modeling module, a satellite frame modeling module, a coverage area analysis and modeling module, a data tracking and receiving modeling module, a time management module, a coordinate system management module and a three-dimensional visualizing simulation module, wherein the time management module is used for providing simulation time and various time standards of astronomical time for simulation of the space mission; the coordinate system management module is used for providing various coordinate systems such as a celestial coordinate system, an earth fixed connection coordinate system, a moving coordinate system and the like to describe moving rules of moving objects; and the three-dimensional visualizing simulation module is used for three-dimensional visual display, playback and deduction for situation analysis and modeling results, capable of controlling acceleration, deceleration, pause and start of a simulation process according to the simulation mission or a demonstration script, and capable of providing a powerful guarantee for display of the space comprehensive situations and analysis and demonstration of a focused simulation stage.

Embodiments of the present disclosure include self-aligning telescope control systems and self-alignment methods. In an embodiment, a telescope control system orients a telescope with respect to the celestial sphere by pointing the telescope in the direction of an alignment star or alignment area of the sky. The telescope control system images a field of view in the alignment area, and processes the images to determine the celestial coordinates of a center of the filed a field of view the alignment area. The telescope control system then maps the telescope's coordinate system to the celestial coordinate system. Once mapped, the telescope control system can advantageously slew the telescope to any desired celestial object in the viewable sky based on, for example, user selection, system recommendations, combinations of the same, or the like.

A fully automated telescope system is operable in both alt-az and equatorial modes. In either configuration, the telescope system aligns and orients itself to the celestial coordinate system following a simplified initialization procedure during which the telescope tube is first pointed North and then pointed towards the horizon. A command processor, under application software control, orients the telescope system with respect to the celestial coordinate system given the initial directional inputs. The initial telescope orientation is refined by automatically inputting geographical location data and a timing parameter. A simplified tracking procedure allows tracking of celestial objects after the telescope system has had its axis positions initialized to a horizontal and a vertical index. Object tracking is subsequently performed with no additional orientation procedure required.

The invention relates to a wave water surface sky diffuse reflection light polarization field simulation method. The method has the following steps: a celestial coordinate system describing a sky light polarization field is established; sun point location and observation point location are designed in the celestial coordinate system; a sky light scattering angle is calculated in spherical geometry; degree of polarization of sky light at any point is calculated according to a semi-analytical Rayleigh scattering model; a polarization angle of sky light is calculated according to the sun point location and sky observation point coordinates via a vector mode; the polarized reflectance and the degree of polarization of wave water surface sky diffused light are calculated; and the polarization angle of water surface reflected sky light is obtained according to information of sky light degree of polarization in combination with an STOKES vector and a trigonometric function relationship so that calculation of the polarization state of water surface reflected sky light is realized. Sky light can be incident at any polarization state, and the polarization state of the reflected light of a static water surface and the wave water surface can be realized so that polarization characteristics of a natural water surface can be really described.

The invention relates to a sun vector resolving method based on an underwater polarization distribution mode. The method comprises the steps of firstly, obtaining the underwater polarization azimuth angle information in at least two arbitrary observation directions under an underwater celestial coordinate system; then, inverting the propagation direction of the atmospheric incident light in the underwater observation direction based on the law of light refraction; determining an atmospheric polarization E-vector corresponding to a polarization E-vector observed underwater by using a Fresnel refraction formula; and finally, according to a Rayleigh scattering model, obtaining a solar vector by utilizing the vertical relationship between the atmospheric polarization E-vector and the solar vector. According to the invention, the sun vector calculation basic model based on the polarization distribution mode in an underwater Snell window under the horizontal attitude is established, and themethod can be popularized and applied to the underwater application scenes of point source type and image type polarization sensors.

The invention relates to a low-earth-orbit satellite long-term orbit prediction method based on a two line element. The method comprises the following steps: performing related processing on a two line element in an orbital coordiante system at a moment t, thus obtaining a satellite orbital element initial value applicable to an orbit prediction dynamical model in a J2000.0 geocentric celestial coordinate system; and solving the orbit prediction dynamical model by adopting a numerical method, thus obtaining a satellite orbital element prediction result, wherein the related processing comprisesreduction processing performed on angular velocity of peace movement in the two line element, conversion of a mean element into an instant element in the orbital coordinate system at the moment t andconversion of the instant element in the orbital coordinate system at the moment t into an instant element in the J2000.0 geocentric celestial coordinate system. The low-earth-orbit satellite long-term orbit prediction method based on the two line element is high in prediction precision.

A method and apparatus is disclosed for aligning an optical instrument with respect to a celestial coordinate system, the optical instrument having a field of view and an optical instrument coordinate system, the celestial coordinate system having a plurality of objects each having celestial coordinates. The method includes the steps of receiving a plurality of captured optical instrument positions in the optical instrument coordinate system along with a plurality of associated capture times; calculating, for each associated capture time in the plurality of associated capture times, coordinates in the optical instrument coordinate system for the plurality of objects to create a plurality of calculated object positions for each associated capture time; and, determining, for each associated capture time, a match for each captured optical instrument position in the plurality of captured optical instrument positions with the plurality of calculated object positions to create a list of actual alignment objects.

The invention provides a whole-space information system-oriented coordinate system conversion method, and belongs to the field of geospatial information visualization. A space conversion framework ofa whole-space information system is established, and description of WKT on a space reference system is extended to enable the same to support definition of planets and coordinate systems of celestial-sphere coordinate systems, orbit coordinate systems and the like; and a space reference memory model based on a nine-degree-of-freedom space reference tree is designed, and thus maintenance of the space reference tree, calculation of relative status and plug-in realization of the coordinate system conversion method are realized. The method can effectively solve continuous whole-space-time modelingand simulation of the whole-space information system from macroscopic worlds (such as stars and planets in a solar system) to microcosmic worlds (such as indoor environments), from static status to dynamic status and from physical space-time to logical space-time, has good scalability and realization efficiency, and can be widely applied to many fields of satellite positioning and navigation, aerospace remote-sensing, smart cities, territorial planning, military application and the like.

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 provides a novel great-circle celestial coordinate system with six regions, which belongs to the field of astronomy basic theories. The building of a traditional celestial coordinate system is related to theories of earth rotation, south and north poles and parallel circles, wherein the parallel circles are small circles, and the problems that longitude in polar regions is difficult to distinguish and a celestial sphere is divided non-uniformly as a longitude plotting scale deforms along with latitude. According to the novel great-circle celestial coordinate system with the six regions, the celestial sphere is divided into six identical regions, each novel coordinate is constructed by a great circle completely, the coordinate relations between each region and an equatorial system of coordinate as well as each region and a space rectangular coordinate are deduced, and formulas of the relation are concise. The novel great-circle celestial coordinate system is defined intuitively, treats six celestial sphere regions equally, can not be influenced by the south and north poles and the parallel circles, is more uniform in region division, does not increase calculation complexity of coordinate conversion, and is suitable for popularization. With the devolvement of the south and north poles and the satellite orbit design, in particular to constant expanding of the deep space exploration filed, the novel coordinate system has potential application value.

The invention discloses a method and device for automatically searching and tracking an astronomical target by an astronomical telescope, and the method comprises the steps: S1, obtaining a preset astronomical target, obtaining the direction of the astronomical target in a celestial coordinate system from a database of a man-machine interaction device, and recording the direction of the astronomical target in the celestial coordinate system as a first direction; S2, acquiring an astronomical image in real time, performing feature extraction on the astronomical image, and identifying a feature extraction result; S3, calculating the direction of the astronomical telescope in the celestial coordinate system in real time according to the recognition result, and recording the direction of the astronomical telescope in the celestial coordinate system as a second direction; S4, comparing the first direction with the second direction; and S5, when the first direction is inconsistent with the second direction, adjusting a servo device, and repeatedly executing the steps S2-S4 until the first direction is consistent with the second direction. In this way, the astronomical target can be automatically aligned and automatically tracked.

The invention relates to a multi-view-field starry sky observation satellite target attitude planning method, which comprises the following steps of: 1, acquiring seasons or months of starry sky observation of a satellite, a satellite orbit height and a stray light suppression angle of imaging optical equipment; 2, according to the projection relation between the selectable view field and the observable sky area of the optical equipment, providing the selectable sky area of each piece of optical equipment; 3, selecting an observation point set according to the distribution of fixed stars in the selectable sky area, obtaining the direction of each optical device under the observation point under the celestial coordinate system, judging whether the optical device is in the available sky area, and deleting unavailable observation points; 4, counting the number of fixed stars in the field of view of the camera under the available observation points, and optimizing the available observation points; and 5, repeating the steps 3 and 4 until a satisfactory observation point set is found, and outputting the right ascension and declination of the optimal observation point and a satellite attitude conversion matrix. According to the invention, ideal observation sky areas and target attitudes are provided for multi-view-field star sky imaging of remote sensing satellites and astronomical observation satellites.

The invention belongs to the field of motion control of large-aperture radio telescopes, particularly relates to a scanning mode trajectory planning method and system in motion of a large-aperture radio telescope, and aims to solve the problems of discontinuous speed and low effective utilization rate of a scanning trajectory caused by frequent rapid speed change and direction change of the large-aperture radio telescope. The method comprises the following steps: initializing right ascension and declination positions and speeds of starting and ending parts of each to-be-planned scanning section based on sky area scanning parameters; extracting right ascension and declination in the celestial coordinate system, and constructing a space-time Bezier curve equation of right ascension and declination time by combining time as a to-be-planned variable; taking the minimum curve curvature as a target, integrating the normal scanning segment track, and obtaining a scanning sky right ascension and declination complete track under a celestial coordinate system; and converting to obtain a planned moving track of the feed source terminal under an east-north sky coordinate system of the earth. The OTF scanning speed is continuous, the impact on the system is small, no pause process exists in the planned track, and the effective utilization rate of the scanning track is improved.

A representation instrument of celestial coordinate systems is formed by a celestial sphere model, an earth model, a support, a first auxiliary ring, a second auxiliary ring, a third auxiliary ring first half-ring, a third auxiliary ring second half-ring and a sliding handle; the celestial sphere model is fixed on the support in a rotatable mode; the inner wall of the celestial sphere model comprises the two auxiliary rings which are perpendicular to each other; the earth model is fixed on a shaft rod which is arranged in the center of the celestial sphere model; the sliding handle is used for controlling rotation of the two auxiliary rings which are perpendicular to each other and are arranged in the celestial sphere model through a magnet; the inner diameter of a third auxiliary ring is equal to the outer diameter of the celestial sphere model; the third auxiliary ring can be fixed on the outer wall of the celestial sphere model if necessary. According to the representation instrument of the celestial coordinate systems, learners can analyze the four celestial coordinate systems, the relation between the four celestial coordinate systems and the relation between the celestial coordinate systems and a celestial sphere; the functions which can be shown through the traditional celestial globe can be achieved; the mind and hand capability of students can be increased and the intelligence of the students can be stimulated through operation on the auxiliary rings of the students.