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Attitude Estimation and Control of Satellite Using Noisy Measurements
,
M.Sc. Thesis
Sharif University of Technology
;
Namvar, Mehrzad
(Supervisor)
Abstract
Satellite attitude determination means specifying its rotation relative to a known reference. To determine satellite attitude, gyroscope is used to measure angular velocity and attitude sensors such as sun sensor, magnetometer, star tracker and earth horizon scanner are used in order to obtain vector measurements. In kinematic control, satellite angular velocity is determined in a way that its attitude converges to desired attitude. Usually, gyroscope and attitude sensors measurements are contaminated by noise which leads to errors in satellite attitude estimation and control. In the literature, gyroscope and at least two vector meaurements are used to estimate and control the...
Analysis of gyro noise in non-linear attitude estimation using a single vector measurement
, Article IET Control Theory and Applications ; Volume 6, Issue 14 , 2012 , Pages 2226-2234 ; 17518644 (ISSN) ; Namvar, M ; Sharif University of Technology
IET
2012
Abstract
This study investigates the effect of noisy measurements of the angular rate in a non-linear attitude estimator for satellites. The attitude estimator uses measurement of a single attitude sensor such as Sun, Earth-horizon, star tracker or magnetometer together with a rate gyro, and guarantees exponential convergence of the attitude estimation error to zero under a no-noise condition. In view of a realistic situation where the presence of noise in gyro measurement is not negligible, this study presents stochastic and deterministic upper bounds for the attitude estimation error resulting from noisy angular rate measurement. A realistic simulation is presented to illustrate the results
Noise analysis in satellite attitude estimation using angular rate and a single vector measurement
, Article Proceedings of the IEEE Conference on Decision and Control, 12 December 2011 through 15 December 2011 ; December , 2011 , Pages 7476-7481 ; 01912216 (ISSN) ; 9781612848006 (ISBN) ; Namvar, M ; Sharif University of Technology
2011
Abstract
This paper investigates the effect of noisy measurements of the angular rate in a nonlinear attitude estimator for satellites. The attitude estimator uses measurement of a single attitude sensor such as sun, earth horizon, star tracker or magnetometer together with a rate gyro, and guarantees exponential convergence of the attitude estimation error to zero under no noise condition. This paper presents stochastic and deterministic upper bounds for the attitude estimation error affected by the noise in gyro. A realistic simulation is presented to illustrate the results
Effect of E-Commerce on Automobile After Sales Service Business Model
, M.Sc. Thesis Sharif University of Technology ; Isaee, Mohammad Taghi (Supervisor)
Abstract
In this era of competitive markets, firms and organizations can survive that have a competitive advantage through their business models. Having a competitive business model and its frequently evaluation is one of the secrets of success. Another, especially of these days, is digitalization of many businesses. Every day in our business environment new digital businesses are establishing. Conversely emergence of the Internet affected many of current businesses, then this question be arose that, what and how this phenomena can affect the current business models? Abstract (Max. 300 words for M.S and 500 words for Ph.D. theses) In this research we will check this affect on the automobile after...
The effect of micro and nano particle sizes of H-ZSM-5 on the selectivity of MTP reaction
, Article Catalysis Communications ; Volume 10, Issue 12 , 2009 , Pages 1582-1585 ; 15667367 (ISSN) ; Baghalha, M ; Asadi, M ; Sharif University of Technology
2009
Abstract
The effect of particle size on the catalytic activity of H-ZSM-5 zeolite in the methanol to propylene (MTP) reaction was investigated in a fixed-bed flow reactor under the operating conditions of T = 460 °C, P = 1 atm, and WHSV = 1 h-1. Nano and micro size H-ZSM-5 were prepared by reflux and hydrothermal crystallization methods, respectively. The nano and micro H-ZSM-5 were characterized using XRD, NH3-TPD, BET area, SEM and ICP-AES analytical techniques. Nano size H-ZSM-5 showed higher activity and stability compared to the micro size H-ZSM-5. Nano H-ZSM-5 was also found to have higher selectivity to propylene than the micro size H-ZSM-5. © 2009 Elsevier B.V. All rights reserved
Synthesis of Nano H-ZSM-5 for Methanol Conversion to Propylene
, M.Sc. Thesis Sharif University of Technology ; Baghghalha, Morteza (Supervisor) ; Asadi, Mousa (Co-Advisor)
Abstract
Nano and microsize H-ZSM-5 were synthesized by hydrothermal crystallization method with same batch composition to investigate the effect of crystallite size of H-ZSM-5 in the methanol conversion to propylene (MTP) process. The average particle size of nano and microsize H-ZSM-5 were obtained in the range of 0.15- 0.2 and 1- 2 µm, respectively. Also, optimized catalyst of Petrochemical Research and Technology Company was synthesized using terapropylammonium bromide as template. Nowadays, terapropylammonium bromide (TPABr) is cheeper than terapropylammonium hydroxide (TPAOH); therefore we used it as tamplate. Activity tests were conducted at operating conditions of T= 460˚C, P=1 atm and WHSV...
Experimental Investigation on the Effect of Porous Media Wettability on Trapping and Hysteresis in Water/Oil Two Phase Flow System
,
M.Sc. Thesis
Sharif University of Technology
;
Fatemi, Mobeen
(Supervisor)
;
Ghazanfari, Mohammad Hossein
(Supervisor)
Abstract
Wettability of reservoir rock is one of the effective parameters in determining the mechanisms of production and consequently the amount of residual oil inside the porous media. In addition, the salinity of injected water is important factor in the recovery of reservoir oil in waterflooding.On the other hand, the role of the hysteresis on the residual oil saturation as well as the flow functions such as relative permeability curves is very important. In this project, the effects of reservoir wettability and injected water salinity on the hysteresis and residual oil saturation in two-phase water-oil flow systems are studied. Core-scale experiments were carried out using sandpacks and were...