G01C21/025

DAYTIME AND NIGHTTIME STELLAR SENSOR WITH ACTIVE POLARIZER
20170370725 · 2017-12-28 · ·

The invention relates to a daytime and nighttime stellar sensor (1), comprising: at least one video camera (2) suitable for taking images of stars (3) in the sky; and a control unit (4), characterized in that it furthermore comprises: a polarizer (5), the control unit (4) being configured: to obtain an estimation of a direction of polarization of the polarized light received from the sky by the video camera (2); and to control the orientation of the polarizer (5) so that said polarizer (5) filters polarized light from the sky directed toward the video camera (2) and having said polarization direction.

Device and method for positioning a star tracker on a structure
09835711 · 2017-12-05 · ·

A device for positioning a functional trihedron of a star tracker in a reference trihedron tied to a structure on which the star tracker is mounted comprises: a fixing interface to connect the device to the star tracker, a set of geometric markers configured to, by means of an optical measurement instrument tied to the structure, position a marker tied to the device in the reference marker tied to the structure, an optical simulator comprising a set of optical markers to be measured by the star tracker, making it possible to position the functional trihedron of the star tracker in the trihedron tied to the device, the measurements of position of the functional trihedron in the trihedron tied to the device, and of position of the trihedron tied to the device in the reference trihedron, making it possible to position by calculation the functional trihedron in the reference trihedron.

APPARATUS AND METHOD FOR MEASURING MICRO-VIBRATION INFLUENCE OF SPATIAL ORIENTATION MEASURING INSTRUMENT

A device and a method for determining a microvibration effect on a millisecond-level space optical sensor are provided. The device includes: a light source, a star simulator, an air flotation vibration isolation platform, a suspension system/air flotation system, a zero stiffness system, a supporting system, a six-degree-of-freedom microvibration simulator, a signal driving apparatus, and a data acquisition and processing system. In the device for determining a microvibration effect on a space pointing measurement apparatus, a free boundary condition and a zero gravity environment are simulated by using a suspension system and a zero stiffness system. A light source and a star simulator simulate a star at infinity. A six-degree-of-freedom microvibration simulator simulates an on-orbit microvibration mechanical environment which is used as an input of a test. Extremely high-precision sensors collect system response data.

Navigating with star tracking sensors

One embodiment is directed towards a method of navigating a body. The method includes determining a respective measured direction of each of a plurality of celestial objects with respect to the body based on an output of one or more star tracking sensors mounted to the body. Calculating an expected direction of at least one of the plurality of celestial objects with respect to the body based on a current navigation solution for the body. Calculating an updated navigation solution for the body based on the expected direction of the at least one celestial object, the measured direction of the plurality of celestial objects, and an output of one or more inertial sensors mounted to the body.

Automatic astronomical observation system and observation method
09739996 · 2017-08-22 ·

An automatic astronomical observation system includes an astronomical telescope (1), a star finding servo motor (2) for driving the astronomical telescope (1), and a control system (4). A focusing servo motor (3) is connected to a lens regulation mechanism of the astronomical telescope (1); a CMOS sensor (5) used for obtaining a starry sky image is disposed on the astronomical telescope (1); the control system (4) includes a control chip, a gyroscope, a memory, and a WIFI communication interface; the control chip is electrically connected to the CMOS sensor (5), the gyroscope, the memory, and the WIFI communication interface; a handheld device provided with a WIFI communication interface is disposed by being fitted to the control system (4); and a GPS module is disposed in the control system (4) or the handheld device. Also provided is an automatic astronomical observation method.

Electron-bombarded active pixel sensor star camera

A star camera system that includes an optical system configured to focus radiation from a star to be imaged onto a collector. Specifically, the collector is in the form of an electron bombarded active pixel sensor (EBAPS) configured to provide high gain. The EBAPS comprising a photocathode disposed in a vacuum is configured to release electron into a vacuum when exposed to radiation focused thereon by the optical system. In addition, the EBAPS includes an active pixel sensor anode disposed distant from the photocathode in the vacuum. An electric field is generated by a voltage source to direct electrons from the photocathode to the active pixel sensor anode to thereby generate an image of the star.

SINGLE STAR-BASED ORIENTATION METHOD USING DUAL-AXIS LEVEL SENSOR

Disclosed is a single star-based orientation method using a dual-axis level sensor, which includes a calibration process and an actual calculation process.

DIRECT SUN IMAGING STAR TRACKER

Described are systems and methods for direct sun imaging by a star tracker. Disclosed in a certain example is a direct sun imaging star tracker that includes an imaging sensor and a baffle. The baffle includes a star port, a sun port, and a beam splitter. The star port is configured to image first viewing environment while the sun port is configured to image a second viewing environment that includes the sun. The beam splitter is configured to combine electromagnetic radiation from the star port and the sun port into a combined image. In various examples, the systems and techniques described herein allow a star tracker to simultaneously view both the sun and the stars.

Celestial navigation system

A celestial navigation system includes an optical device for receiving light from a celestial object, a spectrometer for measuring a spectrum of the light in sufficient detail to identify absorption and/or emission features, and a processor for processing the spectrum to match the spectrum, or a processed version thereof, against a set of reference spectra information in a database, a device for measuring the pointing direction of the optical device and a clock. The matching may be on a maximum likelihood basis. The system is thus able, on identification of a single star, and, using commonly available navigational almanacs, to calculate a geographical position. Celestial navigation takes place even when only one celestial object (that is also within the database) is visible, although improved accuracy may be obtained with multiple observations. Advantageously, the database includes stars of the K and/or M type, that have more characteristic spectral content.

Method for acquiring images having unidirectional distortion from an aerial vehicle for 3d image reconstruction

A method for capturing images of large target area using a single low FOV high resolution camera mounted on an Aerial Vehicle for 3D reconstruction is disclosed. The camera captures sets of images consisting of a nadir image a plurality of oblique images at predefined waypoints or as the Aerial Vehicle travels along a flight path. Oblique images are captured in two perpendicular directions by tilting camera about a single tilt axis at one time thereby preventing bidirectional distortion of objects in images. Further, first direction and second direction define a quadrant of area below the Aerial Vehicle. Oblique images along two perpendicular directions are captured either by using roll and pitch axes, or by using a single tilt axis and a pan axis of camera control mechanism wherein using pan axis the single tilt axis is reoriented in a perpendicular orientation to capture oblique images in perpendicular direction.