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222 results about "Starlight" patented technology

Starlight is the light emitted by stars. It typically refers to visible electromagnetic radiation from stars other than the Sun observable from Earth during the night time although a component of starlight is observable from the Earth during the daytime.

Robust infrared countermeasure system and method

A system and method for focusing electromagnetic energy on a moving target. Generally, the inventive system sends a pilot beam to a target and analyzes a return wavefront to ascertain data with respect to any distortions and other phase and/or amplitude information in the wavefront. This information is then used to pre-distort an output beam by so that it is focused on the target by the intervening distortions. In an illustrative embodiment, the pilot beam is provided by a beacon laser mounted off-axis with respect to the output beam. The reflected wavefront is received through a gimbaled telescope. Energy received by the telescope is detected and processed to ascertain wavefront aberrations therein. This data is used to predistort a deformable mirror to create an output beam which is the phase conjugate of the received wavefront. In a first alternative embodiment, a nonlinear optical phase-conjugate mirror is employed to generate the required wavefront-reversed replica of the received wavefront. The system further includes an arrangement for modulating the output beam to confuse the target. In a second alternative embodiment, the system is adapted to examine atmospheric distortions of starlight to predistort the output beam. The alternative embodiment offers a faster response time and a lower susceptibility to detection.
Owner:RAYTHEON CO

Satellite starlight refraction navigation error determination and compensation method

The invention relates to a satellite starlight refraction navigation error determination and compensation method. The method comprises the following steps: firstly, generating data of a satellite orbit by virtue of STK software; establishing a satellite attitude planning model; determining an actual observation visual field, and simulating an observation star map comprising refraction stars and non-refraction stars; calculating to obtain the tangential height h of the refraction stars; calculating to obtain the tangential height h'' of the refraction stars with errors of refraction angles and errors of an atmospheric model, wherein tangential height errors are mainly caused by the measurement precision errors of the refraction angles and the errors of the atmospheric model; calculating to obtain the position of a satellite under a geocentric inertial coordinate system; and performing filtration by an extended Kalman filtration method, and outputting a starlight refraction navigation estimated position and position errors. The method provided by the invention can realize accurate prediction of navigation precision of a satellite starlight refraction navigation system, and is comprehensive in error analysis and accurate and reliable in results.
Owner:CHINA ACADEMY OF SPACE TECHNOLOGY

Small satellite autonomous navigation system based on starlight/ geomagnetism integrated information and navigation method thereof

The invention provides a small satellite autonomous navigation system based on starlight / geomagnetism integrated information and a navigation method thereof and belongs to the technical field of integrated navigation. The autonomous navigation system comprises a star sensor measuring system, an earth magnetic field measuring system, an orbit determination system and an attitude determination system. The navigation method comprises the following steps of: the establishment of a navigation system state equation, the measurement equation establishment of the navigation system and integrated navigation system information fusion based on UKF(unscented kalman filter). According to the method, a large view filed star sensor is utilized to simultaneously observe starlight vector information of multiple navigational stars, thereby making up the defect caused by overlarge measurement noise of a magnetometer and obtaining high navigation accuracy; based on track and attitude information contained in the measured values of a magnetometer and the star sensor and in comprehensive consideration of influences of various factors, a measurement equation of the system is established, the adaptability and the stability of a filter to measurement noise are improved; therefore, the method is suitable for navigation of a low earth rail small satellite adopting a cheap small autonomous navigation system.
Owner:BEIHANG UNIV

Airborne starlight of coupling inertial position error and independent navigation method of inertial composition

InactiveCN101660914AGive full play to the role of attitude observationAvoid the need to independently maintain the attitude combination algorithm in the geographic systemInstruments for comonautical navigationAviationMathematical model
The invention discloses airborne starlight of a coupling inertial position error and an independent navigation method of inertial composition. In the method, firstly theoretical analysis is carried out on an attitude integrated observation principle in navigation under an aviation airborne geography department, an attitude observation linearization measurement equation under a geography departmentis established, inter-conversion relation between the attitudes from an inertial system to the geography department measured and output by a star sensor (star light) is analyzed, a coupling error model between the attitudes under the inertial system measured and output by the star sensor and the attitudes under the geography department calculated and output by the inertial navigation is established through introducing an inertial navigation position error conversion matrix, and finally aviation airborne starlight based on the modeling thoughts of the coupling inertial position error and a mathematical model of an inertial integrated navigation system are designed, and a KF filtering method is adopted to optimally estimate the error state of the inertial navigation. The invention has high-accuracy in navigation, and can give full play to the estimation function of the attitude measurement equation under the geography department on error state amount of the aviation airborne inertial navigation system.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

In-orbit calibration method of star sensor lens distortion and satellite attitude determination method based on starlight vector correction

InactiveCN103234556ARealize CalibrationEliminate errors in satellite attitude determinationMeasurement devicesFixed starsOptical axis
The invention relates to an in-orbit calibration method of star sensor lens distortion and a satellite attitude determination method based on starlight vector correction. The invention relates to an in-orbit calibration method of star sensor lens distortion and a satellite attitude determination method. The invention aims at solving a problem of incapability of calibrating a temperature distortion term of an existing calibration method, and a problem of low precision of an existing satellite attitude determination. The star sensor lens distortion in-orbit calibration method comprises the steps that: an included angle between fixed star incident light and a lens optical axis is obtained by calculation according to target fixed star imaging point coordinates and a star sensor lens distortion formula; a light vector direction of the target fixed light is obtained according to the included angle of the incident light and the lens optical axis; and in-orbit calibration of star sensor lens distortion is carried out according to a principle that the included angles of light vector directions of a plurality of target fixed stars are fixed. The attitude determination method comprises the steps that: a target fixed star starlight vector is obtained by calculation according to the target fixed star imaging point coordinates and the star sensor lens distortion formula obtained by calibration; and satellite attitude is determined through star map matching. The methods provided by the invention are applied in the technical field of satellite attitude determination.
Owner:HARBIN INST OF TECH

Robust infrared countermeasure system and method

A system and method for focusing electromagnetic energy on a moving target. Generally, the inventive system sends a pilot beam to a target and analyzes a return wavefront to ascertain data with respect to any distortions and other phase and / or amplitude information in the wavefront. This information is then used to pre-distort an output beam by so that it is focused on the target by the intervening distortions. In an illustrative embodiment, the pilot beam is provided by a beacon laser mounted off-axis with respect to the output beam. The reflected wavefront is received through a gimbaled telescope. Energy received by the telescope is detected and processed to ascertain wavefront aberrations therein. This data is used to predistort a deformable mirror to create an output beam which is the phase conjugate of the received wavefront. In a first alternative embodiment, a nonlinear optical phase-conjugate mirror is employed to generate the required wavefront-reversed replica of the received wavefront. The system further includes an arrangement for modulating the output beam to confuse the target. In a second alternative embodiment, the system is adapted to examine atmospheric distortions of starlight to predistort the output beam. The alternative embodiment offers a faster response time and a lower susceptibility to detection.
Owner:RAYTHEON CO

Daytime stellar imager

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.
Owner:TREX ENTERPRISES CORP

Star sensor calibration device based on external field star observation and star observation calibration method

The invention discloses a star sensor calibration device based on external field star observation and a star observation calibration method thereof. The calibration device comprises a medium-precisionturntable capable of rotating around a zenith, a star sensor arranged on the turntable, and a circuit box connected with the star sensor. The circuit box comprises a data acquisition module and a clock reference module. The calibration method comprises the following steps: step 1, replacing a single-star simulator with starlight, replacing a high-precision turntable with the earth, driving a starsensor through a turntable, simulating a laboratory calibration system, and carrying out a star observation experiment; and step 2, applying a parameter method in laboratory calibration to star observation calibration for data processing; to be specific, constructing an initial alignment error model, compensating an initial alignment error, carrying out nonlinear optimization solution, constructing a distortion correction model, and carrying out least square solution. According to the method provided by the invention, a parameter method in laboratory calibration is applied to star observationcalibration; and especially for a large-field star sensor, the calibration precision is improved.
Owner:SHANGHAI AEROSPACE CONTROL TECH INST

Adaptive satellite selection method and system with celestial body interference

InactiveCN105352500ARealize the function of adaptively selecting navigation starsNavigation by astronomical meansFixed starsTime information
The invention discloses an adaptive satellite selection method and system with celestial body interference. The method comprises: obtaining the optical axis information of a star sensor sent by a starlight analog module and formed by an orbit; selecting a optimum interval of observing the refractive starlight; establishing a starlight observation window according to the position of a spacecraft, determining the area of the fixed star observed by the star sensor; analyzing the starlight refraction celestial body interference to select and optimize the starlight observation window; determining an observing star area of the spacecraft according to the obtained starlight observation window to obtain a selectable refraction star range of the spacecraft, predicting the direction and information of the fixed star of which starlight occurs refraction according to the given position and time information of the spacecraft by using a starlight refraction navigation error minimum satellite selection method, and selecting the adaptive navigational star. The adaptive satellite selection method and system with celestial body interference can exclude the celestial body interference according to the given position and time information of the spacecraft, and can predict the direction and information of the fixed star of which starlight refracting accurately, so that the function of selecting the adaptive navigational star is realized.
Owner:BEIHANG UNIV

Starlight positioning navigation method based on artificial satellite

ActiveCN113984069AImprove autonomous navigation accuracyAchieving autonomous attitude determinationInstruments for comonautical navigationHigh level techniquesFlight vehicleEphemeris
The invention relates to a starlight positioning navigation method based on artificial satellites. Thestarlight positioning navigation method comprises the following steps: firstly, observing three satellites in a space by adopting a star sensor, obtaining position coordinates of the three observed satellites according to satellite ephemeris, and calculating a relative distance between any two satellites; measuring unit direction vectors of three satellites relative to the star sensor by adopting the star sensor, and calculating field angles of any two satellites relative to the star sensor; calculating the relative distance between the star sensor and each satellite; and calculating the position of the star sensor according to the position coordinates of the three satellites and the relative distance between the star sensor and each satellite, thereby realizing the autonomous positioning of the aircraft. According to the invention, the functions of the star sensor are expanded, on the basis of traditional autonomous attitude determination, autonomous positioning is realized, no extra equipment is added, no extra space is occupied, and the method has very high economical efficiency.
Owner:BEIJING LINJIN SPACE AIRCRAFT SYST ENG INST

Deep space probe angle measurement and time delay integrated navigation method based on on-line estimation

The invention provides a deep space probe angle measurement and time delay integrated navigation method based on on-line estimation, and the method comprises the steps: estimating the current positionand speed information of a probe and a reflection celestial body according to the orbit dynamics, and building a system state model through employing the current position and speed information as a system state quantity; obtaining starlight angular distance measurement between the detector and the reflection celestial body as well as between the detector and the background fixed star by using anangle measurement sensor, and establishing a starlight angular distance measurement model; respectively observing the direct sunlight and the reflected sunlight reflected by the reflection celestial body by using two atom frequency discriminators so as to obtain time delay measurement, and establishing a time delay measurement model; obtaining state estimation and error covariance estimation through implicit unscented Kalman filtering, correcting the actual position and speed information of the reflection celestial body, then obtaining the actual position and speed information of the detector,and achieving detector navigation. The influence of the ephemeris error of the reflection celestial body on the navigation precision is inhibited, and the autonomous navigation precision of the detector is improved.
Owner:CENT SOUTH UNIV
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