scholarly journals Design and Simulation of a High-Speed Star Tracker for Direct Optical Feedback Control in ADCS

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2388
Author(s):  
Mikaël Marin ◽  
Hyochoong Bang
Keyword(s):  
Control Systems ◽  
High Speed ◽  
Attitude Determination ◽  
Optical Feedback ◽  
Total Delay ◽  
Star Identification ◽  
Field Programmable ◽  
Space Star ◽  
Update Rate ◽  
And Control

Star Trackers are often the most accurate instrument in an Attitude Determination and Control Systems, but often present a slow update rate, requiring additional sensor and sensor fusion algorithms to provide a smoother and faster output. However, the available rate gyros are either noisy, or expensive and heavy. The proposed work investigates the feasibility of high-speed star trackers with modern optics, sensors, and computing systems. Firstly, we investigate the sensitivity of an optoelectrical acquisition system stimulated by dim stars, secondly, we propose and evaluate an algorithm designed to operate at high speed and to be compatible with an Field-Programmable Gate Array implementation, before evaluating the performance of the implementation on FPGA. Finally, we debate the usability of such a system, both in terms of compatibility with a mission and CubeSat ecosystems, and in terms of performance. As a result, aside from removing the need for a rate gyro, Attitude Determination and Control Systems overall pointing performances can be increased. The proposed attitude determination system achieved a 0.001° accuracy, with a 99.1% sky coverage and an ability to reject false-positive while performing a single-frame lost-in-space star identification at a 50 Hz update rate with a total delay of 19 ms, including 13 ms.

Attitude determination and control systems

2021 ◽  
pp. 263-281
Author(s):  
Mikhail Ovchinnikov ◽  
James Barrington-Brown
Keyword(s):  
Control Systems ◽  
Attitude Determination ◽  
And Control

scholarly journals Efficient Star Identification Using a Neural Network

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3684
Author(s):  
David Rijlaarsdam ◽  
Hamza Yous ◽  
Jonathan Byrne ◽  
Davide Oddenino ◽  
Gianluca Furano ◽  
...  
Keyword(s):  
Neural Network ◽  
Attitude Determination ◽  
Lightweight Design ◽  
A Priori ◽  
Search Time ◽  
Identification Algorithm ◽  
Star Sensor ◽  
Feature Extraction Method ◽  
Star Identification ◽  
Space Star

The required precision for attitude determination in spacecraft is increasing, providing a need for more accurate attitude determination sensors. The star sensor or star tracker provides unmatched arc-second precision and with the rise of micro satellites these sensors are becoming smaller, faster and more efficient. The most critical component in the star sensor system is the lost-in-space star identification algorithm which identifies stars in a scene without a priori attitude information. In this paper, we present an efficient lost-in-space star identification algorithm using a neural network and a robust and novel feature extraction method. Since a neural network implicitly stores the patterns associated with a guide star, a database lookup is eliminated from the matching process. The search time is therefore not influenced by the number of patterns stored in the network, making it constant (O(1)). This search time is unrivalled by other star identification algorithms. The presented algorithm provides excellent performance in a simple and lightweight design, making neural networks the preferred choice for star identification algorithms.

Failure mode taxonomy for assessing the reliability of Field Programmable Gate Array based Instrumentation and Control systems

2017 ◽  
Vol 108 ◽  
pp. 198-228 ◽  
Author(s):  
Phillip McNelles ◽  
Zhao Chang Zeng ◽  
Guna Renganathan ◽  
Marius Chirila ◽  
Lixuan Lu
Keyword(s):  
Control Systems ◽  
Failure Mode ◽  
Field Programmable Gate Array ◽  
Field Programmable ◽  
Gate Array ◽  
And Control

Paper 12: Gas Turbine Fuel and Control Systems

1968 ◽  
Vol 183 (14) ◽  
pp. 121-127 ◽  
Author(s):  
E. H. Warne
Keyword(s):  
Control Systems ◽  
Gas Turbine ◽  
High Speed ◽  
Type Systems ◽  
Point Of View ◽  
Turbine Engines ◽  
Advantages And Disadvantages ◽  
Aircraft Type ◽  
Main Engine ◽  
And Control

Following a preliminary introduction on the necessity for fuel and control systems, it is proposed to deal in some detail with the requirements of modern gas turbine engines from the point of view of both pumping of fuel and the control. In general the paper deals with aircraft type systems. Over the last 20 years specifications have been increasing in size and the need for the additional requirements will be discussed in relation to the various types of engines. Considerations of control for two- and three-shaft engines for both civil (subsonic and supersonic) and military use are covered, as also are the somewhat different requirements for helicopters. In addition to main engine control, the effects of reheat, supersonic nozzles and variable engine geometry will be discussed. Reference is also made to the increasing severity of environment on high speed aircraft. Following this, the problems of pumping are considered and a review of the types of pumps available is made comparing their relative advantages and disadvantages in relation to the application, and indicating the general trends in this field. On control systems the types of control available will be discussed including hydromechanical, electric and fluidic, and the basis on which the optimum choice can be made for any particular engine will be dealt with. The requirements for control, both for steady running and limiting will be explained, and once again a typical example of a control system is briefly described.

Cybersecurity Case for FPGA-Based NPP Instrumentation and Control Systems

2016 ◽  
Author(s):  
Oleg A. Illiashenko ◽  
Yevheniia V. Broshevan ◽  
Vyacheslav S. Kharchenko
Keyword(s):  
Control Systems ◽  
Nuclear Power ◽  
Power Plants ◽  
Subjective Assessment ◽  
Security Requirements ◽  
Critical Systems ◽  
International Regulations ◽  
Field Programmable ◽  
High Level ◽  
And Control

Modern industrial instrumentation and control systems (I&Cs) used in nuclear power plants (NPP) are facing more with cybersecurity threats and vulnerabilities, which were neglected before. Cybersecurity incidents are a subject to grow into more complex attacks with worse consequences than before. The use of field programmable gate arrays (FPGA) in such critical systems causes specific risks for ensuring of safety, as the master-property of such kind of systems, and security as a subordinate property primarily to the NPP reactor trip systems (RTS). Cybersecurity assessment results of industrial I&Cs are mainly based on subjective assessment of the expert judgment and they do not take into account all features of propagating FPGA technology. Nowadays there is a big gap in understanding how to assess and assure the security of FPGA-based NPP I&Cs (FNI&Cs). Conformance of FNI&Cs to security requirements, their verification to high-level standards often is subjective and depends on particular expert. Regulatory and certification bodies, developers and end-users of FNI&Cs are missing the understandable methodology for security assurance of such kind of systems taking into account specific context of the operating environment which allows decreasing time-to-market and thus providing benefits for all interested parties. The paper describes cybersecurity assurance technique of multi-version FNI&Cs. Requirements profile is formulated using the best practices from the following international regulations. The goal of the paper is presentation of the case-based methodology and tool of FNI&Cs cybersecurity assurance based on international regulations. Proposed methodology provides comparable and repeatable process of assurance.

scholarly journals Ultra-high Speed and Dual-Channel Data Acquisition Card with 1GSPS Based on PXI Bus

2018 ◽  
Vol 2 (1) ◽  
pp. 22
Author(s):  
Pengyun Zhang ◽  
Henan Guo
Keyword(s):  
Data Acquisition ◽  
High Speed ◽  
Sampling Rate ◽  
Random Access ◽  
Dual Channel ◽  
Ultra High Speed ◽  
Field Programmable ◽  
Data Acquisition Card ◽  
And Control ◽  
Test Result

This paper discusses the chief techniques and design principles of an ultra-high speed and dual-channel data acquisition card based on PXI bus, using FPGA (Field Programmable Gate Array) as logic controller cell. The instrument consists of pre-process circuit, A/D converter, SDRAM (Synchronous Dynamic random access memory), and control circuit integrated in FPGA. It can achieve allowing up to 1000MHz real-time sampling rate. The test result indicates that the system works normally and the system design is successful.

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