javad haghshenas

In this paper, a step-by-step laboratory procedure for performing a satellite's payload’s alignment measurement is presented. Four highly accurate theodolites are used along with two or more alignment corner cube to accurately extract the final attitude. Theodolites are arranged around the satellite in such a way that they have a clear direct view of the alignment cubes mounted on the payload and the satellite. Two theodolites should point to the payload’s alignment cube and the other two theodolites must point to the satellite’s alignment cube. Each theodolite must see at least one other theodolite, directly. Finally, by forming the coordinates systems of the payload and satellite in the theodolites coordinate system along with using the coordinate transfer matrices, the payload alignment correction matrix will be extracted in detail. The total method accuracy is within the order of few arcseconds.

In this paper, an accurate computational method is proposed to measure the relative accuracy of the star sensor, which does not require complex laboratory instruments. The proposed method uses the direct observation of the night sky along with the exact equations of motions of the Earth and stars to measure the accuracy of the star sensors in the order of 1 arcsecond. The Classical Laboratory Measurement Procedures of the star sensor’s accuracy requires at least a sky simulator along with some auxiliary tools such as a collimator, an accurate 3 DOF Rotary table, an exact alignment instruments, and so on. The classical procedure, in addition of being complex and time-consuming, is costly, and the auxiliary tools also increase the measurement error by themselves. Identifying and eliminating these errors are more difficult process. The proposed procedure is more accurate and more reliable because the sensor is tested in its actual operating environment, i.e., the sky, rather than the simulated laboratory environment.

In this paper, we are going to classify each pixel of a hyperspectral image. For this purpose, we group the spectral bands to sub-bands and try to decompose the corresponding sub-tensors to the endmember and abundance matrices. Abundance matrices obtained through tensor factorization methods contain spatial information in contrast to the ones acquired by matrix factorization. Therefore, the 2D abundance maps achieved by tensor decomposition methods, construct discriminant features for the classifier. A 3D CNN architecture is proposed for classification which utilizes the abundance maps of the individual sub-bands as input features. This way, we jointly exploit spectral and spatial information of the image. The experiments are performed on well-known hyperspectral data and reveal the effectiveness of the proposed sub-band tensor decomposition methods compared to matrix factorization approaches.

In this paper, a precise method for calculating albedo and IR heat flux applied to a satellite is presented. For obtaining albedo heat flux applied to a satellite, a point on the earth’s surface that sun flux reflected at that point and reach to the satellite is obtained, hence albedo heat flux reaches to a satellite is obtained as a function of longitude, attitude and longitude. IR heat flux is integration of emitting heat flux for points on the earth surface that in satellite’s view. Atmospheric transparency for calculating albedo and IR heat is considered for sun light and IR spectrum using MODTRAN algorithm using PcModWin software. For a generic LEO satellite, IR and albedo heat fluxes are calculated at a time period and compare with reference values. Obtained heat fluxes are used to obtain temperature variation of satellite’s components during its mission.

Iranian rural Architecture with regard to its thousands year history makes a homogeneous and appropriate form in which the functions and role of communication and multi-functional spaces in the house were always so clear that included the social as well as the economic and cultural systems of rural housing in accordance with geographic requirements. The rural housings are obvious examples of this feature. The nature and its potentials along with knowledge of many generations, along with the attitude and approach of villagers to the nature have made another feature in rural architecture which created the most desirable and efficient relationship between environmental components while observing all the simplicity of components and its generalities and well impact of the use of environment beside economics, traditions and norms which govern the rural community is evident in its spatial organization. While present situation of rural housing encountered its particular problems, studies of housing in the country have been mainly focused on urban housing or specific villages. Lacking precise and useful studies in the field and differences between urban and rural housing, have transformed the research in the field of housing characteristics in rural architecture to a very important one. Answering to numerous needs in rural housing and the need for its compatibility with the demands of rural community requires the participation and attention of all the experts in rural issues. In this paper the typology of rural housing in one of the relatively untouched rural areas – Taleghan valley - in nine selected villages of the area were investigated. Taleghan is located in southern Alborz in Savojbolagh, Tehran. The area is located along the linear path of Shahrood river. It consists of three rural districts, called Down-Taleghan (the district center is Shahrasar), Middle-Taleghan (the district center is Shahrak) and Up-Taleghan ()the district center is Jovestan)(and there are totally 77 villages in this area. In this study, selected villages have been studied in general and micro-scale system deployment, geography effect held, perspective, texture and housing. The formation of Taleghan Valley habitats, according to geography and climate factors, consists of two different types: (1) Formation based on the river path (most villages are formed by this type), and (2) Formation regardless to the river path, for security reasons. The housing typology of rural areas has been analyzed from two perspectives: (A) Evaluation of spatial- functional patterns; and (B) Assessment of climate patterns. The most important features of indigenous architecture in this region can be summarized as follows: the harmony between the texture and the earth, and formation of the texture based upon the earth shape, the various spaces of rural housing according to the livelihoods of the households, climatic factors, and sociocultural status. Prospects resulting from this study can be summarized in cases such as: 1. Documenting these habitats may result in creating useful documents for protecting these villages in future. 2. Rural architectural details and their generalities which have been considered in this study can address the future constructions in a sustainable as well as harmonious architecture.