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Control of a Camera Mounted on Satellite for High Resolution Photography

Moshaver, Paria | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 48258 (58)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Salarieh, Hassan; Khayyat, Ali Akbar
  7. Abstract:
  8. The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetric,Remote Sensing and GIS communities. High resolution data increases the need for higher accuracy of data modeling.The satellite orbit, position, attitude angles and interior orientation parameters have to be adjusted in the geometrical model to achieve optimal accuracy with the use of a minimum number of Ground Control Points (GCPs). In order to obtain high resolution and definition imaging for many applications including surveillance, target tracking, and missile Optical imaging sensors, such as television or infrared cameras, collect information about targets or target regions, it is thus necessary to control the sensor’s line-of-sight (LOS) to achieve accurate pointing.Maintaining sensor orientation toward a target is particularly challenging when the imaging sensor is carried on a mobile vehicle such as satellite or when the target is highly dynamic. To meet these challenges in this thesis we implement controlling an optical sensor LOS with an inertially stabilized platform (ISP). An ISP is a mechanism, typically involving gimbals’ assemblies, for controlling the inertial orientation of its payload. This research is an attempt to use ISPs for a target tracker imaging satellite. When an optical sensor is installed within an ISP, the sensor’s LOS is manipulated relative to the host vehicle. However, in long-range applications, such as satellites or exoatmospheric vehicles, the optical sensor may be strapped down, that is, rigidly fixed, so that the entire vehicle must be stabilized to achieve sensor pointing. Since the satellite moves along the orbit, to estimate the real conditions of the satellite system, as well as deriving the kinematic equations of the system, the orbit is modeled. Then the satellite was assumed to operate in the orbit conditions. In the modeling phase, the satellite along with the double gimbal system installed upon it are modeled both kinematical and kinetically using Newton’s second law. It is assumed that there are 3 reaction wheels acting on the satellite in order to control the satellite angular motion. In this Research 2 approaches have been applied to control the ISP and Satellite motion. First an AFSMC method has been employed on a coupled model of the ISP and Satellite to drive the system states converging to the desired trajectories. Then an Optimal SDRE scheme considered the system as a decoupled one. In this approach the controller on The ISP and Satellite are separated. Satellite dynamics acts as an external input to the ISP system. The system model and the controllers are simulated numerically using Matlab .Simulation results indicate that both procedures are acceptable and powerful
  9. Keywords:
  10. Cameras ; Satellites ; Nonlinear Control ; Control ; State Dependent Riccati Equation ; Fuzzy Control

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