30 results about "Celestial coordinate system" patented technology

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.

Embodiments of an automated telescope system are operable in multiple modes, including alt-az and equatorial modes. The telescope system aligns and orients itself to the celestial coordinate system using, for example, data gained through tracking the drift of a celestial object. In various embodiments, an imager may be used to find and track celestial objects.

The invention belongs to the technical field of navigation measurement and satellite navigation application technology, and discloses an attitude determination method based on double short baselines of navigation satellite signals. This method first establishes the estimation model of the direction vector of the two measured short baselines in the geocentric coordinate system; secondly, calculates the estimation model of the direction vector of the two measured short baselines in the geocentric coordinate system; then calculates the two measured short baselines at Estimation of the direction vector in the local north sky east coordinate system; then calculate the target body coordinate system Y 1 The direction vector of the coordinate axis in the geocentric coordinate system and the direction vector in the local North Tiandong coordinate system; finally calculate the estimated attitude angle of the target. The invention controls the length of each measurement baseline within half a wavelength of the satellite downlink carrier signal, which solves the problem that satellite navigation signals cannot be used in the measurement of small and micro target attitudes, thereby enabling more and more navigation in space The navigation signal of the satellite is directly used in the attitude determination of the tiny target, which expands the scope of application.

The invention relates to a solar vector calculation method based on an underwater polarization distribution mode. First, obtain the underwater polarization azimuth angle information in at least two arbitrary observation directions in the underwater celestial coordinate system; then, based on the law of light refraction, invert the propagation direction of the atmospheric incident light in the underwater observation direction; then use the Fresnel refraction formula Determine the atmospheric polarization E-vector corresponding to the polarization E-vector observed underwater; finally, according to the Rayleigh scattering model, use the vertical relationship between the atmospheric polarization E-vector and the sun vector to obtain the sun vector. The invention establishes a basic sun vector calculation model based on the polarization distribution mode in the underwater Snell window under the horizontal posture, and can be popularized and applied to underwater application scenarios of point source type and image type polarization sensors.

The invention discloses a measurement reference conversion method for a celestial body sensor. A light source simulator, a three-axis turntable and a photoelectric autocollimator are set up on an optical platform, and the astronomical body sensor is arranged on the inner frame of the three-axis turntable. A. Adjust the photoelectric autocollimator so that its optical axis is parallel to the rotation axis of the inner frame; B. Rotate the middle frame and outer frame of the turntable to different angles to obtain calibration point data, and calibrate the internal and external parameters of the celestial body sensor; determine the coordinate system of the turntable to the celestial body sensor C: measure the vector relationship between the normal direction of the two reflective surfaces of the mirror cube and the optical axis of the photoelectric autocollimator, and calculate the transformation matrix from the turntable coordinate system to the mirror cube coordinate system; D: calculate the astrosensor coordinate system to the mirror surface The transformation matrix of the cube coordinates; the product of the light vector measured by the astrosensor and the transformation matrix in D is the direction of the transformed vector. The invention also discloses a sub-device for realizing the above method. The invention has simple and high precision.

A method and device for calculating target angular velocity based on a photoelectric turret, the method comprising: step 1, calculating the Euler angle of the target in the photoelectric turret coordinate system; step 2, based on the Euler angle of the target in the photoelectric turret coordinate system Angle, calculate the quaternion and attitude, and calculate the Euler angle of the target in the northeast sky coordinate system; step 3, calculate the target’s Euler angle in the northeast sky coordinate system based on the Euler angle of the target in the northeast sky coordinate system Euler angular velocity; step 4, based on the Euler angular velocity of the target in the northeast sky coordinate system, calculate the Euler angular velocity of the target in the photoelectric optical axis coordinate system; step 5, obtain the Euler angular velocity of the target in the photoelectric optical axis coordinate system The angular velocity is converted to the photoelectric turret coordinate system, so as to obtain the Euler angular velocity of the target in the photoelectric turret coordinate system. The present invention can also calculate the target angular velocity when there is no target distance information.

The invention relates to a method for calculating coordinates of an intersection point D of an optical axis and a celestial surface based on a star sensor. The method comprises the steps of establishing a space rectangular coordinate system under a celestial coordinate system, performing translation or rotation transformation on the space rectangular coordinate system to enable the space rectangular coordinate system to coincide with a star sensor coordinate system to obtain a transformation relationship between the two coordinate systems, and representing a coordinate expression of the pointD in the celestial coordinate system by using each parameter; obtaining the relationship among the coordinates according to the cosine law, and obtaining an approximate expression of the distance f from the projection center to the projection point on the star sensor light-sensitive surface by using a Taylor expansion formula; substituting the approximate expression into the coordinate expressionof the point D in the celestial coordinate system to obtain a celestial coordinate approximate value expression of the point D; performing error analysis in combination with a median theorem, and obtaining a fixed star selection standard to further improve the coordinate precision of the point D. The invention aims to establish a mathematical model, solve the coordinates of the intersection pointD of the optical axis and the celestial surface, enables coordinates of the point D to be accurate through an optimization algorithm, and improve the attitude measurement precision of the star sensor.