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1293results 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.

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.

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.

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.

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.

Method for controlling rigid spacecraft for target attitude tracking

The invention relates to a method for controlling a rigid spacecraft for target attitude tracking, and belongs to the technical field of the high-precision and high-stability attitude tracking control of spacecrafts. The method solves the problem that when the attitude tracking spacecraft runs in a low orbit in outer space, the conventional control method cannot eliminate the inherent flutter of a sliding mode variable structure. The method comprises the following steps: 1, establishing a kinetic model and a kinematic model of the rigid spacecraft; 2, setting an attitude tracking error and anexpected attitude parameter of the rigid spacecraft, and combining the attitude tracking error and the expectation attitude parameter with the kinetic model and the kinematic model to establish a mathematical model for the attitude tracking; 3, adopting a control algorithm of a sliding mode variable structure controller to adjust a control law of the mathematical model which is established in thestep 2 and is used for the attitude tracking, and simultaneously combining an observation result of a disturbance observer to modify the control law; and 4, controlling the rigid spacecraft by using the modified control law obtained in the step 3 to realize the attitude tracking. The method is suitable for the attitude tracking of targets running in the outer space.

Flywheel based attitude maneuvering control device and method for successive approaching of satellite rounding instantaneous Euler shaft

The invention discloses flywheel based attitude maneuvering control device and method for successive approaching of a satellite rounding an instantaneous Euler shaft and relates to control device and method for satellite attitude adjustment. The invention is provided for solving the problems of great fuel consumption, short service life of a satellite, complex configuration of an air injecting control system and difficult reduction of size and weight of the satellite existing in the realization of satellite wide-angle attitude maneuvering by adopting air injecting control. The method comprises the following steps of: setting a parameter of the control device according to the system requirement of the control device and obtaining attitude deviation angular velocity according to a motion equation; and expressing a relationship of the instantaneous Euler shaft and a deviation angle of the current attitude and a target attitude of the satellite by an attitude error quaternion to obtain a control signal, calculating to obtain a flywheel control input moment vector calculated by a satellite controller, to be used as a data control command as a basis for generating moment by a back action flywheel. The invention does not consume other resources on the satellite or consume fuel, prolongs the service life of the satellite and can be widely suitable for various satellites needing attitude maneuvering.
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