The method for sensing spacecraft attitude with stellar map is analyzed in the paper. The simulation experiments were carried out under the different conditions when star was brighter than 6 m with SAO star catalogue and the corresponding identification probability is achieved.
Star sensor is a kind of high-accuracy posture sensitive measuring system, how to confirm star sensor's photo-spot of corresponding fixed star at the moment of photography, that is stellar map recognition, it is the key of posture measurement.
According as the specialty of stellar map recognition problem and the characteristic of the neural network technology, this article proposed a method of sample construction based on the method of stellar map recognition of the BP network. It can give consideration to the performance, efficiency and easy realization.
The star sensor optical system is usually aligned in a defocused position to calculate the luminance centroid of a star image in sub-pixel resolution.
The influence of the axis-inclination on the transit time can be eliminated by the observation of the star image reflected by a mercury level together with the influence of the variable collimation produced by a flexion of the axis.
A filter composed of a crossed pair of doubly refracting crystals and a polaroid, mounted at the focal plane of the telescope, divides each star image into two images of constant intensity ratio.
adaptor-link device is developed to bring a star image at the focus of a Schmidt telescope to the slit of a spectrograph located at the observing floor, as well as part of the field, to a T.V.
monitor, transfer the star image through the link to the slit of the spectrograph and guide the star during observation.
A four hydrophone array arranged in a symmetrical star pattern was used to measure the echolocation signals of four species of dolphins in the wild.
About 80% of cat-scratch disease (CSD) infections occur in children, and CSD neuroretinitis (optic neuropathy with retinal exudates in a "macular star" pattern) mostly occurs in children and young adults.
The significance of the star pattern the sulphur colloid scan in patients with obstruction is stressed, as the significance of this pattern not has been evaluated previously.
Again all elements within five units of the maximum are identified as centers of a star pattern; this time two elements are thus identified.
Each star pattern was planned to take 18 hours so that about 6 circuits were completed during each 5--day period.
In this paper,a model of “star background proportion-integ-ration guiding method” concerning the rendezvous of moving object withhigh speed out of the atmosphere.It includes CCD star image processing,guiding stars and object recognition,mathematical description of guidingmethod etc.Finally brief analysis of the simulation results is given.
This paper describes the method and procedure of guide star catalog generation for star sensor. The relationship between the FOV density of guide stars, guide star pattern uniqueness and the success ratio of star pattern recognition is also discussed in detail based upon the statistical data. At last, the requirements are made concerning the FOV size and sensitivity of star sensor.
This paper makes a through study in the method of designing and realizing whole-orbitreal-time star simulator and advances the design plan of star simulator which can meet the requirement ofhardware-in-the-loop simulation of satellite attitude control system. Several questions about selecting thestar displayer,determining the design principle of optical system of simulator,realizing the system preci-sion and correcting the system error are also discussed in this paper.