35 results about "Star position" patented technology

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 provides an extracting method for fixed star sensitive east and west parameters of stationary satellite imaging navigation and registration. The extracting method comprises the following steps of obtaining a changing curve of a total gray value of pixels of each line along with time; obtaining a moment that a fixed star image center crosses a center line of the pixels of the line; fitting a motion law of the fixed star image center in east and west line coordinates of a satellite remote sensing detector array; obtaining a moment that the fixed star image center crosses a center line of the east-west direction of the satellite remote sensing detector array. According to the extracting method provided by the invention, high-frequency error of star positions caused by factors such as optical imaging of the detector, circuit noises, high-frequency wobble of a satellite and the like can be eliminated by multiframe data information fusion processing and curve fitting, thereby improving the identification accuracy of fixed star position parameters. The extracting method can be used for stationary satellite imaging navigation and registration, and has important significance for improving on-orbit thermal deformation precision of a remote sensing imaging system and the imaging navigation and registration processing property by acquiring parameters such accurate time and the like that the fixed star crosses the center of the detector array.

The invention discloses a modified mating method of star tracer in the astronomical navigational technological domain, which comprises the following steps: collating stars of present time and spot according to X coordinate position to generate sequence A; estimating the traced star of last time and spot in the position of present visual field; collating the traced star position to generate sequence B; proceeding mating identification for sequence A and B.

The invention discloses a high-dynamic rapid star tracking method. The method comprises 1, designing a weighted value according to multiframe attitude information output by a star sensor at the T1-Tn moment and a proximity relationship of the multiframe attitude information, forecasting attitude of the star sensor at the next T<n+1> moment, searching a star point corresponding to the attitude from a star database by the forecasted attitude, and producing a virtual forecasted large view field star image for matching by mapping, and 2, carrying out matching identification on a star position A and a star mass center position B at t+delta t moment to realize star tracking. The high-dynamic rapid star tracking method utilizes multi-frame attitude information prediction, has a fast prediction rate, improves prediction accuracy, realizes tracking and matching based on a forecasted virtual wide field star image without novel star identification and improves a star tracking algorithmic speed.

A celestial navigation device. A full-featured embodiment is useful as a sundial and planisphere and for measuring, among other things, latitude, longitude, and for time to angle conversions. The device may have one or more rings and is based on a transparent circular tube having a gravity indicator, typically a ball or bubble, in the circular tube, which locates the lowest or highest point in the tube to indicate time or angle measurements against a corresponding scale. The device may have a 24-hour time scale, a calendar scale, and/or an angle scale. One embodiment includes a split analemma with separate north and south portions. Each analemma portion is used with a corresponding gnomon of a pair of gnomons, each on opposite sides of the tubular ring. A two-ring embodiment has an inner ring and outer ring rotatably slidable relative to one another. Two additional gnomons and star position marks may be provided for star sighting observations. The device has a hollow center and may be worn as a bracelet and may be constructed with precious metals and/or gems to enhance the value of the bracelet aspect.

The invention discloses a different-orbit single-satellite time-sharing frequency measurement positioning method based on star position optimization. The method comprises the following steps: measuring the frequency of a signal sent by a ground radiation source reaching an observation satellite; establishing a different-orbit single-satellite time-sharing frequency measurement positioning model, selecting a plurality of satellites with different orbits to respectively carry out frequency measurement at different moments, and establishing a positioning equation set according to a plurality of measured different signal frequencies; deriving geometric dilution precision factors, and analyzing the influence of various factors on the positioning precision; and establishing a star position optimization model, and optimizing the selection of orbit and satellite observation moments to improve the positioning precision. According to the invention, within a limited range of visibility, single satellites flying through different orbits of a positioning visual area at different moments are used for repeatedly and independently observing the same interference source; due to the difference in the aspects of flight direction, observation position distribution and the like, compared with a single-orbit single-satellite time-sharing frequency measurement positioning scheme, the positioning effect is stable, the precision is higher, the space between satellites is larger, and the selection of measurement positions can be more flexible.

The invention belongs to the technical field of photoelectric measurement and discloses a photoelectric theodolite orientation calibration method based on a common star. Any first zero-direction reference is determined after leveling and positioning of a photoelectric theodolite, then common star position measurement is carried out to calculate a preliminary reference value, on this basis, zero-direction reference value calculation is carried out through higher star position measurement to obtain a second zero-direction reference value, and equipment orientation calibration is completed. The method is advantaged in that the zero-direction reference of the photoelectric theodolite is rapidly obtained based on the position of the common star, a problem of orientation calibration in the calibration process of the photoelectric theodolite is solved, the equipment calibration time is shortened, and calibration efficiency is improved.

The invention provides a forecasting method and system for evaluating satellite stability and pointing precision in-orbit performance. The forecasting method comprises the following steps of S1, calculating a highlight protection angle of a star sensor, S2, calculating a strong light protection angle of the optical camera, S3, calculating an effective arc section of fixed star observation, and obtaining fixed star observation opportunity information, S4, calculating the projection of the optical axis vector of the optical camera in the inertial space, and S5, selecting a fixed star of which the maneuvering angle and the brightness both meet the requirements near the optical axis direction of the camera, obtaining the position and magnitude information of the target fixed star, and obtaining forecasting result information for evaluating the satellite stability and the pointing precision in-orbit performance. The method searches the fixed star suitable for satellite observation, predicts the fixed star observation opportunity, provides accurate fixed star position and star magnitude information, and provides support for evaluation of high-precision satellite stability and pointing precision.

The invention relates to a telescope main light path star guiding device which comprises a telescope main focus detector and a star guiding detector, the telescope main focus detector is located on a telescope focal plane, the star guiding detector is installed near the telescope main focus detector, the star guiding detector and the main focus detector are located on the same focal plane, and the star guiding detector and the telescope main focus detector share the same light path. According to the invention, main light path star guiding is realized, so that position and angle errors of the star guiding detector and the main detector are eliminated, and star guiding and tracking precision of the telescope is improved. The invention further discloses a guide star offset algorithm, the guide star camera sends a formed image to a program for processing within a certain exposure time, the program finds a star in image data by using a method in the field of image processing, and XY (row and column in the image) offset is obtained according to historical records of star positions, so that the guide star offset is obtained. And the offset is returned to the movement mechanism of the telescope to make the movement mechanism perform correction movement, so that the purpose of compensation is achieved, and a more reliable closed-loop control system is formed.

The invention relates to the field of telescope axis detection, in particular to an optical detection method for polar axis type telescope polar axis shaking errors. The problems that when a star calibration method is used for detecting the polar axis shaking errors of a polar axis type telescope, the calculating process is complex, the position of a fixed star needs to be known in advance, and the method is limited by weather and places are solved. The method comprises the steps that a plane mirror is arranged on an axis head of a polar axis, meanwhile, an obliquely-arranged 0.2'' parallel collimator is adopted to be aligned to the plane mirror, and the optical axis of the 0.2'' parallel collimator is parallel to the axis of the polar axis; the polar axis is rotated once every a certain angle, meanwhile, component data in the pitching direction and the orientation direction are respectively read on the 0.2'' parallel collimator, the polar axis is continuously rotated by 360 degrees, and the process is repeated four times; data processing is carried out through a Fourier hamonic function, and the root-mean-square value of the axis of the polar axis on pitching and orientation shaking components is calculated based on the Bessel formula. According to the method, the position of the fixed star does not need to be known, the method is not limited by the weather and the places, no complex mathematical calculation process exists, implementation is easy, convenience and reliability are achieved, and measuring precision is high.

The invention discloses a star high-precision position extraction method based on pixel internal response. According to the response distribution in the pixel, the relationship between the point target position and the pixel gray level is established, and the high-precision position extraction of the star is realized. The steps of position extraction are as follows: 1, removing background and non-uniform correction of the obtained image; 2, according to the pixel filling factor, the energy distribution function of the star after passing through the optical system is obtained by selecting ten frames of images with the largest pixel gray value. 3. According to the energy distribution function and pixel filling factor, the pixel gray values of a series of star objects at different positions are obtained, and the look-up table of star positions and pixel gray values is established by interpolation. 4. Find the corresponding pixel position according to the gray value of pixel. Because of the symmetry of energy distribution and pixel response, we can get several groups of pixel positions. 5. using the centroid method, star positions are selected from the set of pixel positions obtained in step 4.

The invention relates to a GPS positioning differential base station device. The device comprises a shell, an integrated main board is arranged in the shell, a voltage-stabilized source module, a three-star positioning differential module and a serial port output module are arranged on the integrated main board, the voltage-stabilized source module is electrically connected with the three-star positioning differential module and the serial port output module, three-star multi-frequency chips are arranged on the three-star positioning differential module, the serial port output module is connected to a data output connecting tube on the front end surface of the shell, and wing plates are arranged on the two side faces of the shell. The device has high signal stability, only one base stationis needed, the installation is convenient, and the cost is reduced.