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3163results about "Spacecraft guiding apparatus" patented technology

Autonomous Space Flight System and Planetary Lander for Executing a Discrete Landing Sequence to Remove Unknown Navigation Error, Perform Hazard Avoidance and Relocate the Lander and Method

An autonomous unmanned space flight system and planetary lander executes a discrete landing sequence including performing an initial velocity braking maneuver to remove velocity at altitude, coasting during which the planet surface is imaged and correlated to reference maps to estimate cross-track and along-track navigation errors and one or more lateral braking maneuvers are performed to reduce cross-track navigation error, and performing a terminal velocity braking maneuver(s) to reduce the along-track braking maneuver and remove the remainder of the velocity just prior to landing. A bi-propellant propulsion system provides a very high T/M ratio, at least 15:1 per nozzle. Short, high T/M divert maneuvers provide the capability to remove cross-track navigation error efficiently up to the maximum resolution of the reference maps. Short, high T/M terminal velocity braking maneuver(s) provide the capability to remove along-track navigation error to a similar resolution and remove the remaining velocity in a very short time window, approximately 3-15 seconds prior to touchdown. The propulsive efficiency frees up mass which can be allocated to a fuel to remove the unknown navigation errors, perform hazard avoidance and/or relocate the lander by flying it to another site or be allocated to additional payload.
Owner:RAYTHEON CO

Space sailboard bending and turning mode vibration simulation active control device and method

The invention discloses an active control device of vibration simulation for bending and torsional modes of space sailboards and a method. The device symmetrically sticks multi-chip bending mode piezoelectric actuators on front and rear faces of a flexible plate, a bending mode sensor is arranged at the position horizontally closing to a fixed end by 320-25mm of the flexible plate and on the longitudinal center line of the flexible plate, torsional mode actuators composed of a plurality of piezoelectric ceramic chips are antisymmetrically stuck on both faces of the flexible plate, and torsional mode sensors composed of a plurality of the piezoelectric ceramic chips are stuck on both faces of the flexible plate. The method operates an active vibration control strategy according to information of the bending mode and trosional mode sensed by a piezoelectric sensor, and then drives a voltage amplifier through piezo-electricity to respectively drive the piezoelectric actuators for controlling multimode vibrations of bending and torsion, thereby realizing the purpose of actively inhibiting the vibrations. The invention employs the optimum distribution of piezoelectric sensor chips and driving chips, and realizes decoupling of bending modes and torsional modes of flexible cantilever plates in inspection and drive control.
Owner:SOUTH CHINA UNIV OF TECH

Attitude control system for space vehicle and method thereof

The invention discloses an attitude control system for space vehicle and a method thereof. The control system has only one biased momentum wheel, one set of tri-axial magnetic torquer and one attitude controller loaded with algorithm. The method comprises a step of rate damping controlling, a step of initially capturing controlling and a step of stationarity controlling. At the rate damping stage, geomagnetism change is used to control the magnetic control of three passages of a satellite by B-dot; at the initially capturing stage, the magnetic control is realized, PD control is performed by pitching and the passages are rolled and yawed to carry out nutation and precession composite control; at the stationarity controlling stage, the magnetic control is realized, PD control is performed by pitching and the passages are rolled and yawed to carry out nutation and precession composite control. The capturing stage and the stationarity controlling stage fully depend on magnetic torquer to perform positive magnetic control, thereby changing which a satellite only uses a magnetic torquer to carry out unload of the momentum wheel or auxiliary magnetic control, so as to refine system configuration to further improve reliability of the system. Momentum of a satellite is biased to rotate on the ground, so as to ensure stable separation of the satellite without performing air injection control. Therefore, the magnetic torquer can be used for realizing fast and stable initial rate damping.
Owner:SHANGHAI ENG CENT FOR MICROSATELLITES

Satellite posture all-round controlling method based on magnetic moment device and flywheel

The invention discloses a satellite posture all-round controlling method based on a magnetic moment device and a flywheel, relating to an all-round posture controlling method for completing a satellite orbit-injection phase by using the magnetic moment device and the flywheel. The invention solves the problems of low reliability and short service life of the traditional satellite posture all-round controlling technology. The satellite posture all-round controlling method comprises the following steps of: 1, setting controller parameters according to the requirement of a control system; 2, measuring a geomagnetic field intensity vector Bb, a satellite angular velocity vector Wb and a solar azimuth, and sending the measured data to a satellite controller; 3, calculating an expected control moment vector Tm and a control magnetic moment vector Mm, and sending the control magnetic moment vector Mm to the magnetic moment device; 4, acquiring an effective solar azimuth vector Alfa; 5, calculating a control input moment vector Tw and sending to the flywheel; and 6, jointly completing the satellite posture all-round control by the magnetic moment device according to the control magnetic moment vector Mm and the flywheel according to the control input moment vector Tw. The invention is suitable for the field of satellite posture control.
Owner:HARBIN INST OF TECH

Daytime stellar imager

InactiveUS20070038374A1Small and light systemAvoid star image blurCosmonautic vehiclesDigital data processing detailsDisplay deviceLongitude
An automatic celestial navigation system for navigating both night and day by observation of K-band or H-band infrared light from multiple stars. In a first set of preferred embodiments three relatively large aperture telescopes are rigidly mounted on a movable platform such as a ship or airplane with each telescope being directed at a substantially different portion of sky. Embodiments in this first set tend to be relatively large and heavy, such as about one cubic meter and about 60 pounds. In a second set of preferred embodiments one or more smaller aperture telescopes are pivotably mounted on a movable platform such as a ship, airplane or missile so that the telescope or telescopes can be pivoted to point toward specific regions of the sky. Embodiments of this second set are mechanically more complicated than those of the first set, but are much smaller and lighter and are especially useful for guidance of aircraft and missiles. Telescope optics focus (on to a pixel array of a sensor) H-band or K-band light from one or more stars in the field of view of each telescope. Each system also includes an inclinometer, an accurate timing device and a computer processor having access to catalogued infrared star charts. The processor for each system 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 catalogued star charts information to determine positions of the platform. 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 and longitude which may be displayed on a display device such as a monitor or used by a guidance control system. These embodiments are jam proof and insensitive to radio frequency interference. These systems provide efficient alternatives to GPS when GPS is unavailable and can be used for periodic augmentation of inertial navigation systems.
Owner:TREX ENTERPRISES CORP

Different-surface crossover quick-change track fixed time stable posture pointing direction tracking control method

The invention relates to a different-surface crossover quick-change track fixed time stable posture pointing direction tracking control method. The different-surface crossover quick-change track fixed time stable posture pointing direction tracking control method aims at solving the problems that the uncertainty of inertia of a spacecraft is not considered in the prior art, the convergence time can not be freely adjusted depending on the state initial value, and compensating moment generated in the singular direction of a flywheel needs to be designed artificially. The method comprises the particular steps that 1, a tracking satellite and a target satellite are supposed to be located on a different-surface crossover track, and the expected posture needs to be determined; 2, an expected posture tracking control rule is designed; 3, buffeting of the expected posture tracking control rule is eliminated; 4, the expected posture of the crossed points of the tracking satellite and the target satellite changes along with distance between the crossed points of the tracking satellite and the target satellite, a configuration scheme of an execution mechanism is determined according to the expected posture tracking control rule, and the expected posture control torque is solved. The different-surface crossover quick-change track fixed time stable posture pointing direction tracking control method is applied to the field of satellite control.
Owner:HARBIN INST OF TECH
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