Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 15 of 15 for “"Pointing error"”.
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Airborne protected military satellite communications : analysis of open-loop pointing and closed-loop tracking with noisy platform attitude information
… the closed-loop tracking options to eliminate pointing error in the open-loop pointing solution. In an airborne environment, aircraft disturbances and noisy attitude information affect the open-loop pointing performance. This thesis analyzes the open-loop pointing and closed-loop tracking …
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Maneuver analysis for spinning thrusting spacecraft and spinning tethered spacecraft
… body-fixed torques, which in turn cause velocity pointing errors, can be reduced by ramping up (and then ramping down) the thruster. The first topic discussed in this thesis derives closed-form solutions for the angular velocity, Euler angles, inertial velocity, and inertial displacement solutions …
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On-Orbit Pointing Risk Mitigation for the Agile MicroSat (AMS) CubeSat Laser Guidestar Payload
… mirrors, to utilize only open-loop body-pointing and generic CubeSat attitude control software. This thesis presents the pre-launch work, the radiometric link analysis, and a novel on-orbit scanning procedure to reduce mission risk due to a static pointing error and if necessary, recover …
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Evaluating the Use of TROPICS Pathfinder Observations for Lunar Calibration
… temperature and scan geometry, and accounts for pointing error. We compare the lunar brightness temperature estimates and measured antenna temperatures to the lunar radiative transfer model developed by Yang and Burgdorf [21]. We test our lunar calibration model on TROPICS Pathfinder lunar …
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Development of Optical Communication Terminals for Increasing Connectivity on Small Satellites
… fine steering mirror (FSM), used for precision pointing of the space terminal. This mirror, used within a novel optical design, enabled the terminal to correct for an average blind spacecraft pointing error of 8.494 mrad and maintain a total RMS pointing error of 0.164 mrad, equal to-0.194 dB of …
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High-precision pointing and attitude estimation and control algorithms for hardware-constrained spacecraft
… is to develop algorithms for high-precision pointing and attitude estimation and control on hardware-constrained spacecraft. This includes small spacecraft, where tight mass, volume, power, and cost constraints exist, as well as spacecraft where certain hardware has failed. As a case study, …
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Orbital Determination Feasibility of LEO Nanosatellites Using Small Aperture Telescopes
… time of observation. The determined differential errors from the well-defined TLEs acquired via online database were used to verify the feasibility of the accuracy which can be obtained from independent observations. Through minimization of error caused from imaging noise, pointing error, and …
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A Monte-Carlo performance analysis of Kalman filter and targeting algorithms for autonomous orbital rendezvous
… total change in velocity required, navigation errors, target pointing errors. In addition, other aspects of the algorithms will be studied including: technology readiness level (TRL) data uplink requirements, and complexity and computational burden for the onboard algorithms. Monte-Carlo …
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System Design of an Integrated Terrestrial-Satellite Communications Network for Disaster Recovery
… interference, rain attenuation, antenna pointing error, noise temperature, and modulation and multiple access selection, were addressed.
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Microwave Radiometer (MWR) Evaluation of Multi-Beam Satellite Antenna Boresight Pointing Using Land-Water Crossings, for the Aquarius/SAC-D Mission
… an on-orbit validation of the MWR antenna beam pointing, using calculated MWR instantaneous field of view (IFOV) centers, provided in the CONAE L-1B science data product. This procedure compares L-1B MWR IFOV centers at land/water crossings against high-resolution coastline maps. MWR IFOV …
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Improving attitude determination and control of resource-constrained CubeSats using unscented Kalman filtering
… of magnitude from about 1-5* attitude knowledge error down to 0.050 or better. This improvement benefits applications that require precise pointing, such as imaging and active tracking of specific targets, laser communications, and coordinated activity and observations among multiple CubeSats. We …
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Pointing acquisition and tracking design and analysis for CubeSat Laser communication
… weight, and power (SWaP) laser communication pointing, acquisition, and tracking (PAT) design for CubeSats in low earth orbit (LEO). As data production on-orbit continues to grow due to sensor miniaturization and the increased prevalence of satellites in LEO, current RF communication systems …
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Pointing system performance analysis for optical inter-satellite communication on CubeSats
… However, lasercom requires much more accurate pointing because of its narrower beam width. Accurate pointing is not trivial for most CubeSat platforms due to their resource constraints. A typical 3U CubeSat is 34 cm x 10 cm x 10 cm with less than 5 kg mass and about 10 W of available …
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International Space Station Remote Sensing Pointing Analysis
… analysis investigates the contribution of the error effects to the quality of data collected by the instrument. The analysis begins with the discussion of the coordinate systems involved and then conversion from the target coordinate system to the instrument coordinate system. Next the geometry …