ACS Without an Attitude

The book (ACS without an Attitude) is an introduction to spacecraft attitude control systems. It is based on a series of lectures that Dr. Hallock presented in the early 2000s to members of the GSFC flight software branch, the target audience being flight software engineers (developers and testers), fairly new to the field that desire an introductory understanding of spacecraft attitude determination and control

EVALUATION OF THE INTERNAL PICTURE OF HEALTH IN PATIENTS WITH ACUTE CORONARY SYNDROME IN PRESENTING WITHOUT ST-SEGMENT AFTER PERCUTANEOUS CORONARY INTERVENTIONS AND IN THE PROCESS OF REHABILITATION

Ischemic heart disease remains an actual problem of modern clinical and rehabilitation medicine. One of the forms of ischemic heart disease (IHD) is an acute coronary syndrome (ACS) in patients presenting without persistent ST-segment, the treatment of which involves the use of conservative treatment and reperfusion techniques. An integral part of the management of patients after acute coronary syndrome is rehabilitation and restoration with the search for methods of changing the attitude of the patient to his health. To improve the rehabilitation of patients it is important to assess the internal picture of health with the formation of the correct attitude of the patient to his health. Aim. To study the peculiarities of the components of the internal picture of health in patients with acute coronary syndrome in patients presenting without persistent ST-segment in the process of treatment and rehabilitation. Materials and methods. There were examined 135 patients with ACS presenting without persistent ST-segment, who were divided into the groups depending on the treatment performed; 60 patients with conservative treatment tactics and 75 patients with the performed PCI. The analysis of the internal picture of health was carried out with the help of methods: hospital scale for the detection of anxiety and depression (HADS); patient health questionnaire (PHQ-9); scale for measuring the level of reactive (situational) and personality anxiety of Spielberg-Hanin; SF-36; indicators of the Seattle Quality of Life Questionnaire for Patients with Angine Pectoris (Seattle Angina Questionnaire - SAQ). Results. The study of the internal picture of health in patients with ACS presenting without persistent ST-segment showed low levels of emotional, sensory, cognitive, value-motivational, behavioral components on the appropriate scales, which also depend on the method of treatment used. The revealed peculiarities of patients with ACS presenting without persistent ST-segment need to increase the knowledge of the patient about the disease and the importance of rehabilitation measures. Conclusions. In assessment of the internal picture of health in patients with ACS presenting without persistent ST-segment after transcutaneous coronary intervention and in the process of rehabilitation, it has been determined that the course of ischemic heart disease in patients with ACS presenting without persistent ST-segment, both during conservative treatment and in the course of PCI at the stages of rehabilitation, is accompanied by significant changes of the internal picture of health (IPH); the most significant changes in patients with ACS presenting without persistent ST-segment is the value-motivational and behavioral components of the internal picture of health. In order to increase the effectiveness of rehabilitation after ACS, it is advisable to apply programs that will significantly affect the positive changes in the rehabilitation of patients with ACS

EVALUATION OF THE INTERNAL PICTURE OF HEALTH IN PATIENTS WITH ACUTE CORONARY SYNDROME IN PRESENTING WITHOUT ST-SEGMENT AFTER PERCUTANEOUS CORONARY INTERVENTIONS AND IN THE PROCESS OF REHABILITATION

Ischemic heart disease remains an actual problem of modern clinical and rehabilitation medicine. One of the forms of ischemic heart disease (IHD) is an acute coronary syndrome (ACS) in patients presenting without persistent ST-segment, the treatment of which involves the use of conservative treatment and reperfusion techniques. An integral part of the management of patients after acute coronary syndrome is rehabilitation and restoration with the search for methods of changing the attitude of the patient to his health. To improve the rehabilitation of patients it is important to assess the internal picture of health with the formation of the correct attitude of the patient to his health. Aim. To study the peculiarities of the components of the internal picture of health in patients with acute coronary syndrome in patients presenting without persistent ST-segment in the process of treatment and rehabilitation. Materials and methods. There were examined 135 patients with ACS presenting without persistent ST-segment, who were divided into the groups depending on the treatment performed; 60 patients with conservative treatment tactics and 75 patients with the performed PCI. The analysis of the internal picture of health was carried out with the help of methods: hospital scale for the detection of anxiety and depression (HADS); patient health questionnaire (PHQ-9); scale for measuring the level of reactive (situational) and personality anxiety of Spielberg-Hanin; SF-36; indicators of the Seattle Quality of Life Questionnaire for Patients with Angine Pectoris (Seattle Angina Questionnaire - SAQ). Results. The study of the internal picture of health in patients with ACS presenting without persistent ST-segment showed low levels of emotional, sensory, cognitive, value-motivational, behavioral components on the appropriate scales, which also depend on the method of treatment used. The revealed peculiarities of patients with ACS presenting without persistent ST-segment need to increase the knowledge of the patient about the disease and the importance of rehabilitation measures. Conclusions. In assessment of the internal picture of health in patients with ACS presenting without persistent ST-segment after transcutaneous coronary intervention and in the process of rehabilitation, it has been determined that the course of ischemic heart disease in patients with ACS presenting without persistent ST-segment, both during conservative treatment and in the course of PCI at the stages of rehabilitation, is accompanied by significant changes of the internal picture of health (IPH); the most significant changes in patients with ACS presenting without persistent ST-segment is the value-motivational and behavioral components of the internal picture of health. In order to increase the effectiveness of rehabilitation after ACS, it is advisable to apply programs that will significantly affect the positive changes in the rehabilitation of patients with ACS

An Active Force Control (Afc) Based Control Momen Gyros for Attitude Control of Small Satellite

Sistem giroskop kawalan momen (CMG) adalah pilihan yang sesuai untuk bagi rekabentuk sistem kawalan atitud (ACS) satelit kecil bagi misi berprestasi tinggi kerana ia memiliki amplifikasi kilasan yang tinggi. Namun, kebolehan sistem ini adalah terhad dengan kehadiran unsur gangguan kerana limitasi pengawal atitud piawai untuk menolak gangguan tersebut secara teguh selain sistem CMG yang berdepan degan masalah sudut gimbal tersesar. Dalam kajian ini, kawalan daya aktif (AFC) dicadangkan dan diintegrasikan bersama pengawal berkadaran-terbitan bagi mengarah sistem CMG menjana kilasan kawalan bagi misi yang ditetapkan manakala sistem pampasan sudut gimbal kilasan magnetik (MTGAC) diintegrasikan ke dalam ACS untuk memampas gimbal tersesar sudut. Kesemua model matematik dibina dan dilaksanakan dalam perisian Matlab®-SimulinkTM. Berdasarkan simulasi, skema AFC yang dicadangkan sangat mempengaruhi prestasi manuver atitud dan tudingan atitud satelit. Dengan memilih parameter AFC yang sesuai, manuver atitud yang dikehendaki dapat dicapai dan ralat atitud dapat dikurangkan dengan ketara lebih dari 60%. Manakala, sistem MTGAC berjaya mengekalkan gimbal-gimbal GKM pada sudut yang dikehendaki lantas meletakkan sistem CMG jauh dari ketunggalan. Tambahan itu, sistem MTGAC juga memberi darjah kebebasan tambahan kepada kawalan tudingan atitud apabila ia menambahbaik ketepatan atitud sebanyak 75% tanpa mempengaruhi prestasi mavuver atitud satelite. Penemuan kajian ini telah pertama kalinya mendemonstrasikan keandalan skema AFC and MTGAC bagi satelit kecil dengan sistem CMG yang sebelum ini belum pernah dikaji. ________________________________________________________________________________________________________________________ A control moment gyroscope (CMG) system is the best option for attitude control system (ACS) design of small satellite for high performance missions due to its high torque amplification. However, the capability of the CMG system with the present of disturbance elements is limited due to the limitation of standard attitude controller to robustly reject these elements whereas the CMG system faces gimbal angle offset problem. In this research, active force control (AFC) is proposed and integrated with the proportional-derivative (PD) controller to command the CMG system to generate suitable control torque for a defined mission whereas magnetic torque gimbal angle compensation (MTGAC) system is integrated into the ACS to compensate gimbal angle offset. All mathematical models were established and implemented in Matlab®-SimulinkTM software. Based on the simulations, the proposed AFC scheme greatly influenced the attitude manoeuvre and attitude pointing performance of the satellite. By selecting suitable AFC parameters, a desirable attitude manoeuvre was achieved and the attitude errors were significantly reduced by more than 60%. Meanwhile, the MTGAC system successfully maintained the CMG gimbals at preferable angle. Moreover, the MGAC system also added an extra degree of freedom to the attitude pointing control when it improved the attitude accuracy as much as 75% without affecting the attitude manoeuvre performance of the satellite. The research findings have been the first that demonstrate the viability of AFC and MTGAC scheme for ACS of small satellite with CMG system which has never been studied before

Pointing Enhancement for an Optical Laser Downlink Using Automated Image Processing

The small satellite Flying Laptop, launched in July 2017, was developed and built by graduate and undergraduate students at the Institute of Space Systems of the University of Stuttgart with support by space industry and research institutions. The mission goals are technology demonstration, earth observation, and serving as an educational satellite. At a mass of 110 kg, it features three-axis stabilized attitude control and several payloads, including an AIS receiver, a multi spectral camera system, a wide angle camera, and an optical communication terminal. The pointing requirement for the optical communication is an accuracy of less than 150 arcseconds during a target overflight. To fulfill this requirement, several measures are needed. A major part of them is the characterization of the attitude control system (ACS). Since there is no optical receiver onboard, it is not possible to perform closed loop tracking of the satellite attitude. Therefore, the absolute performance and the characteristic noise levels of the attitude control system, can only be determined with other payloads. In this case the multi-spectral camera system was used, providing a ground resolution of 25 m. To use the images from the satellite to improve the ACS, three steps have to be taken. As a first action, the images have to be georeferenced to know the position of each pixel in the WGS84 coordinate system. With this information, the deviation of the image center from the desired target is measured. This second step includes the calculation of the deviation matrix. To avoid a corruption of the attitude control of the satellite, the matrix is checked for unrealistic values in a third and final step. These three actions can be repeated as needed without human interaction. By updating the ACS model onboard the satellite, the results of the image processing are used to correct the off-pointing. This deviation is time invariant and is caused by an insufficient alignment of the satellite axes and the cameras on ground. In contrast to that, characterizing noise as a time variant factor, the ACS is tested over a long period of time. This is achieved by analyzing images from one, as well as from multiple target overflights. This conquers the issue of a very low image rate while observing high frequency attitude changes. Using this mechanism, the proposed process can be used to continuously monitor the pointing quality. As a first approach the described processing is done manually by comparing the target position on Earth with the center of the taken image. The method successfully showed an improvement of the pointing in the pictures, paving the way for their automation. This paper gives an overview of the needed image processing and tools to automatically use cameras on board the satellite to validate and improve the ACS periodically. First results of the long term characteristics and pointing improvements are shown

Adaptive and Supertwisting Adaptive Spacecraft Orbit Control Around Asteroids

This paper addresses the development of control systems for the orbit control of spacecraft around irregularly shaped rotating asteroids with uncertain parameters. The objective is to steer the spacecraft along prescribed orbits. First, a nonlinear adaptive law for orbit control was designed. This was followed by the design of a supertwisting adaptive (STWA) control system. In the closed-loop system, which includes the adaptive law or the STWA law, all the signals remain bounded, and the trajectory tracking error asymptotically converges to zero for any initial condition. Finally, under the assumption of boundedness of the derivative of the uncertain functions of the model in a region of the state space, a supertwisting control (STW) law for finite-time convergence of the trajectory was obtained. Based on the Lyapunov theory, stability properties of the closed-loop systems were analyzed. Simulation results for 433 Eros and Ida asteroids were presented for illustration. The results showed that control of spacecraft along closed orbits or to a fixed point is accomplished using each of these controllers, despite uncertainties in the parameters of the asteroid models

Study of an attitude control system for the astronaut maneuvering unit final report, dec. 1963 - jul. 1964

Attitude control system for astronaut maneuvering unit

Development of an Assessment of Student Conception of the Nature of Science

This article describes a study in which a series of general education and introductory science courses were assessed using a Likert-scale instrument. As universities across the country have begun to make changes in their science curricula, especially with regards to non-science majors, assessment of courses and curricula has lagged behind implementation. The Likert-scale instrument, Attitudes and Conceptions in Science (ACS), provides a means by which faculty can determine the partial effectiveness of introductory and general education science courses. The established validity and reliability of this test suggests that its use in a variety of courses could allow identification of specific teaching methods, content, or other course characteristics that promote scientific literacy. Educational levels: Graduate or professional

FPGA-based operational concept and payload data processing for the Flying Laptop satellite

Flying Laptop is the first small satellite developed by the Institute of Space Systems at the Universität Stuttgart. It is a test bed for an on-board computer with a reconfigurable, redundant and self-controlling high computational ability based on the field pro- grammable gate arrays (FPGAs). This Technical Note presents the operational concept and the on-board payload data processing of the satellite. The designed operational concept of Flying Laptop enables the achievement of mission goals such as technical demonstration, scientific Earth observation, and the payload data processing methods. All these capabilities expand its scientific usage and enable new possibilities for real-time applications. Its hierarchical architecture of the operational modes of subsys- tems and modules are developed in a state-machine diagram and tested by means of MathWorks Simulink-/Stateflow Toolbox. Furthermore, the concept of the on-board payload data processing and its implementation and possible applications are described