scholarly journals Universal Verification Platform and Star Simulator for Fast Star Tracker Design

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 907
Author(s):  
Victor Hugo Schulz ◽  
Gabriel Mariano Marcelino ◽  
Laio Oriel Seman ◽  
Jeferson Santos Barros ◽  
Sangkyun Kim ◽  
...  
Keyword(s):  
Star Tracker ◽  
Open Problems ◽  
Chip Design ◽  
Small Satellites ◽  
Regression Test ◽  
Box Structure ◽  
Speed Up ◽  
Object Oriented Approach ◽  
Verification Methodology ◽  
Star Images

Developing star trackers quickly is non-trivial. Achieving reproducible results and comparing different algorithms are also open problems. In this sense, this work proposes the use of synthetic star images (a simulated sky), allied with the standardized structure of the Universal Verification Methodology as the base of a design approach. The aim is to organize the project, speed up the development time by providing a standard verification methodology. Future rework is reduced through two methods: a verification platform that us shared under a free software licence; and the layout of Universal Verification Methodology enforces reusability of code through an object-oriented approach. We propose a black-box structure for the verification platform with standard interfaces, and provide examples showing how this approach can be applied to the development of a star tracker for small satellites, targeting a system-on-a-chip design. The same test benches were applied to both early conceptual software-only implementations, and later optimized software-hardware hybrid systems, in a hardware-in-the-loop configuration. This test bench reuse strategy was interesting also to show the regression test capability of the developed platform. Furthermore, the simulator was used to inject specific noise, in order to evaluate the system under some real-world conditions.

scholarly journals Bee-Inspired Algorithms Applied to Vehicle Routing Problems: A Survey and a Proposal

2017 ◽  
Vol 2017 ◽  
pp. 1-20 ◽  
Author(s):  
Thiago A. S. Masutti ◽  
Leandro N. de Castro
Keyword(s):  
Vehicle Routing ◽  
Collective Intelligence ◽  
Travelling Salesman Problem ◽  
Optimal Solution ◽  
Vehicle Routing Problems ◽  
Open Problems ◽  
Chip Design ◽  
Routing Problems ◽  
New Approach ◽  
Np Hard Problem

Vehicle routing problems constitute a class of combinatorial optimization tasks that search for optimal routes (e.g., minimal cost routes) for one or more vehicles to attend a set of nodes (e.g., cities or customers). Finding the optimal solution to vehicle routing tasks is an NP-hard problem, meaning that the size of problems that can be solved by exhaustive search is limited. From a practical perspective, this class of problems has a wide and important set of applications, from the distribution of goods to the integrated chip design. Rooted on the use of collective intelligence, swarm-inspired algorithms, more specifically bee-inspired approaches, have been used with good performance to solve such problems. In this context, the present paper provides a broad review on the use of bee-inspired methods for solving vehicle routing problems, introduces a new approach to solve one of the main tasks in this area (the travelling salesman problem), and describes open problems in the field.

scholarly journals An Evaluation of Low-Cost Vision Processors for Efficient Star Identification

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6250
Author(s):  
Surabhi Agarwal ◽  
Elena Hervas-Martin ◽  
Jonathan Byrne ◽  
Aubrey Dunne ◽  
Jose Luis Espinosa-Aranda ◽  
...  
Keyword(s):  
Low Power ◽  
Attitude Determination ◽  
Low Cost ◽  
Cost Effective ◽  
Power Measurement ◽  
Star Tracker ◽  
Processing Unit ◽  
Small Satellites ◽  
Star Identification ◽  
Star Tracking

Star trackers are navigation sensors that are used for attitude determination of a satellite relative to certain stars. A star tracker is required to be accurate and also consume as little power as possible in order to be used in small satellites. While traditional approaches use lookup tables for identifying stars, the latest advances in star tracking use neural networks for automatic star identification. This manuscript evaluates two low-cost processors capable of running a star identification neural network, the Intel Movidius Myriad 2 Vision Processing Unit (VPU) and the STM32 Microcontroller. The intention of this manuscript is to compare the accuracy and power usage to evaluate the suitability of each device for use in a star tracker. The Myriad 2 VPU and the STM32 Microcontroller have been specifically chosen because of their performance on computer vision algorithms alongside being cost-effective and low power consuming devices. The experimental results showed that the Myriad 2 proved to be efficient and consumed around 1 Watt of power while maintaining 99.08% accuracy with an input including false stars. Comparatively the STM32 was able to deliver comparable accuracy (99.07%) and power measurement results. The proposed experimental setup is beneficial for small spacecraft missions that require low-cost and low power consuming star trackers.

scholarly journals COMPARISON OF OBJECT-ORIENTED PROGRAMMING AND DATA-ORIENTED DESIGN FOR IMPLEMENTING TRADING STRATEGIES BACKTESTER

2021 ◽  
Vol 2 ◽  
pp. 124-130
Author(s):  
Timur Mironov ◽  
Lilia Motaylenko ◽  
Dmitry Andreev ◽  
Igor Antonov ◽  
Mikhail Aristov
Keyword(s):  
Object Oriented ◽  
Performance Comparison ◽  
Object Oriented Programming ◽  
Trading Strategies ◽  
Multiprocessor Systems ◽  
Technical Indicators ◽  
Speed Up ◽  
Object Oriented Approach ◽  
Using Data ◽  
Oriented Approach

This research proposes a way to accelerate backtesting of trading strategies using data-oriented design (DOD). The research discusses the differences between DOD and object-oriented approach (OOP), which is the most popular at the current moment. Then, the paper proposes efficient way to parallelize a backtesting using DOD. Finally, this research provides a performance comparison between DOD and OOP backtester implementations on the example of typical technical indicators. The comparison shows that use of DOD can speed up the process of quantitative features calculation up to 33% and allows for parallelization scheme that better utilizes resources in multiprocessor systems.

scholarly journals Improving the Measurement Quality of Small Satellite Star Trackers

2021 ◽  
Author(s):  
Tom Dzamba
Keyword(s):  
High Performance ◽  
Calibration Procedure ◽  
Detection Performance ◽  
Star Tracker ◽  
Small Satellite ◽  
Small Satellites ◽  
Commercial Off The Shelf ◽  
Detector Configurations ◽  
Validation Tests

Recent demand from the small satellite community has led to the development of a new series of star trackers that are specifically designed for small satellites. These units represent substantial improvements in mass, power consumption and cost over traditional star trackers, but suffer slightly in terms of accuracy and availability performance. The primary factors inhibiting their performance are the use of significantly smaller optics, and commercial off the shelf components (COTS). This thesis presents a series of strategies for improving the performance of small satellite star trackers (SSSTs). These goals are realized through the development of offline calibration procedures, flight software, validation tests, and optical trade studies to guide future development. This thesis begins with the development of a target-based focusing procedure that enables precision control over the focus of the sensor optics. This improves the detection performance for dim stars, and ultimately increases the availability of the attitude solution. Flight software is developed to compensate for the effects of electronic rolling shutters, which reside on most COTS image detectors. Combined with a developed camera calibration procedure, these tools reduce the uncertainty with which a star tracker can measure the direction vectors to stars in view, ultimately increasing sensor accuracy. Integrated tests are performed to validate detection performance in dynamic conditions. These tests specifically examine the effect of slew rate on star tracker detection, and availability performance. Lastly, this thesis presents a series of optical trades studies that seek to identify design requirements for high performance SSSTs. The trends in availability and accuracy performance are examined as a function of different lens/detector configurations as well dual/triple-head sensor configurations. Together, these strategies represent tools that aim to improve small satellite star tracker performance and guide future sensor development.

scholarly journals ANALISIS KORELASI PEMANFAATAN HASIL PERKEMBANGAN TEKNOLOGI INFORMASI TERHADAP TINGKAT KELULUSAN MAHASISWA PADA FAKULTAS EKONOMI UNIVERSITAS PAKUAN BOGOR

2018 ◽  
Vol 2 (1) ◽  
pp. 73-87
Author(s):  
Satsangkaryon Satsangkaryon
Keyword(s):  
Information Technology ◽  
Student Learning ◽  
Graduate Student ◽  
Learning Process ◽  
Strong Correlation ◽  
Student Behavior ◽  
Economics Students ◽  
Regression Test ◽  
Speed Up ◽  
Test Result

ABSTRACTThe development of information technology (IT) is now very rapidly and their impact on student learning can be both positive and negative. From the data graduation in 2009/2010 known to students with graduation "Faster" and "On Time" as much as 32.79%, 21.12% in 2010/2011 and 2011/2012 as much as 25.54% of them with graduation " Too late "and" It's Too late "means the Faculty of Economics Unpak mostly less working hard to speed up graduation. Based on the answers of 100 respondents, namely the Faculty of Economics students in 2009/2010 and 2010/2011 Unpak known as much as 74% stated "quite agree" that they have made use of IT results in the learning process to obtain answers to the exam or the plagiarism and those included in the forecast graduation category of "late" (27%) and "very late" (7%). Those who expressed "quite agree" to abuse the results of IT and categorized behave "moderate" (81%) so that it can be concluded that the abuse of IT results and student behavior are correlated to the level of graduation. Based on the results obtained correlation rs = .242 and P_ value of 0:15 or less than 0.05 and based on regression test result R = 37.9% (R square = 14.4%) so it can be concluded that the rate of Conduct and Level IT misuse has relatively strong correlation to the level of graduation.Keywords: Estimated Graduate Student, Behavior, Information Technology Misuse results

scholarly journals Improving the Measurement Quality of Small Satellite Star Trackers

2021 ◽  
Author(s):  
Tom Dzamba
Keyword(s):  
High Performance ◽  
Calibration Procedure ◽  
Detection Performance ◽  
Star Tracker ◽  
Small Satellite ◽  
Small Satellites ◽  
Commercial Off The Shelf ◽  
Detector Configurations ◽  
Validation Tests

Recent demand from the small satellite community has led to the development of a new series of star trackers that are specifically designed for small satellites. These units represent substantial improvements in mass, power consumption and cost over traditional star trackers, but suffer slightly in terms of accuracy and availability performance. The primary factors inhibiting their performance are the use of significantly smaller optics, and commercial off the shelf components (COTS). This thesis presents a series of strategies for improving the performance of small satellite star trackers (SSSTs). These goals are realized through the development of offline calibration procedures, flight software, validation tests, and optical trade studies to guide future development. This thesis begins with the development of a target-based focusing procedure that enables precision control over the focus of the sensor optics. This improves the detection performance for dim stars, and ultimately increases the availability of the attitude solution. Flight software is developed to compensate for the effects of electronic rolling shutters, which reside on most COTS image detectors. Combined with a developed camera calibration procedure, these tools reduce the uncertainty with which a star tracker can measure the direction vectors to stars in view, ultimately increasing sensor accuracy. Integrated tests are performed to validate detection performance in dynamic conditions. These tests specifically examine the effect of slew rate on star tracker detection, and availability performance. Lastly, this thesis presents a series of optical trades studies that seek to identify design requirements for high performance SSSTs. The trends in availability and accuracy performance are examined as a function of different lens/detector configurations as well dual/triple-head sensor configurations. Together, these strategies represent tools that aim to improve small satellite star tracker performance and guide future sensor development.

scholarly journals Star Tracker Geometric Calibration Through Full-State Estimation Including Attitude

2022 ◽  
Author(s):  
Hyosang Yoon ◽  
Kiwook Baeck ◽  
Junsung Wi
Keyword(s):  
Least Squares ◽  
State Estimation ◽  
Attitude Determination ◽  
Calibration Method ◽  
Recursive Estimation ◽  
Star Tracker ◽  
Geometric Calibration ◽  
Full State ◽  
Star Images ◽  
Tracker Calibration

AbstractA star tracker calibration method using star images is presented in this paper. Unlike previous works, the proposed method estimates all parameters and the attitudes at once in a single least-squares formulation for the optimal calibration, which can be easily converted to a recursive estimation form. In addition, this paper presents a method to estimate the overall star tracker performance for attitude determination from the calibration results. Since the proposed method uses star images only, it can be applied to both on-orbit and ground star tracker calibration. The simulations show improvements in calibration performance about four times compared to the previous calibration method. The calibration experiments with actual star images are conducted to test its application.

Spectroscopic Observations of Visual Double Stars

1965 ◽  
Vol 5 ◽  
pp. 109-111
Author(s):  
Frederick R. West
Keyword(s):  
Radial Velocity ◽  
High Dispersion ◽  
Velocity Difference ◽  
Spectrograph Slit ◽  
Spectroscopic Observations ◽  
Double Stars ◽  
Visual Double Stars ◽  
Relative Orbit ◽  
Two Component ◽  
Star Images

There are certain visual double stars which, when close to a node of their relative orbit, should have enough radial velocity difference (10-20 km/s) that the spectra of the two component stars will appear resolved on high-dispersion spectrograms (5 Å/mm or less) obtainable by use of modern coudé and solar spectrographs on bright stars. Both star images are then recorded simultaneously on the spectrograph slit, so that two stellar components will appear on each spectrogram.

Scanning x-ray fluorescence microscopy and principal component analysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1752-1753
Author(s):  
Brian Cross
Keyword(s):  
Principal Component Analysis ◽  
Fluorescence Microscopy ◽  
Spatial Resolution ◽  
High Speed ◽  
Image Acquisition ◽  
Principal Component ◽  
Fluorescence Microscope ◽  
Acquisition Rate ◽  
X Ray ◽  
Speed Up

A relatively new entry, in the field of microscopy, is the Scanning X-Ray Fluorescence Microscope (SXRFM). Using this type of instrument (e.g. Kevex Omicron X-ray Microprobe), one can obtain multiple elemental x-ray images, from the analysis of materials which show heterogeneity. The SXRFM obtains images by collimating an x-ray beam (e.g. 100 μm diameter), and then scanning the sample with a high-speed x-y stage. To speed up the image acquisition, data is acquired "on-the-fly" by slew-scanning the stage along the x-axis, like a TV or SEM scan. To reduce the overhead from "fly-back," the images can be acquired by bi-directional scanning of the x-axis. This results in very little overhead with the re-positioning of the sample stage. The image acquisition rate is dominated by the x-ray acquisition rate. Therefore, the total x-ray image acquisition rate, using the SXRFM, is very comparable to an SEM. Although the x-ray spatial resolution of the SXRFM is worse than an SEM (say 100 vs. 2 μm), there are several other advantages.

Direct measurement of electron-diffraction-pattern intensities using an energy loss spectrometer

1989 ◽  
Vol 47 ◽  
pp. 668-669
Author(s):  
A. G. Jackson ◽  
M. Rowe
Keyword(s):  
Thermal Effects ◽  
Dynamic Range ◽  
Scattering Amplitude ◽  
Dynamical Theory ◽  
Site Symmetry ◽  
Proof Of Concept ◽  
Parallel Acquisition ◽  
Kinematic Approximation ◽  
Speed Up ◽  
Structure Calculations

Diffraction intensities from intermetallic compounds are, in the kinematic approximation, proportional to the scattering amplitude from the element doing the scattering. More detailed calculations have shown that site symmetry and occupation by various atom species also affects the intensity in a diffracted beam. [1] Hence, by measuring the intensities of beams, or their ratios, the occupancy can be estimated. Measurement of the intensity values also allows structure calculations to be made to determine the spatial distribution of the potentials doing the scattering. Thermal effects are also present as a background contribution. Inelastic effects such as loss or absorption/excitation complicate the intensity behavior, and dynamical theory is required to estimate the intensity value.The dynamic range of currents in diffracted beams can be 104or 105:1. Hence, detection of such information requires a means for collecting the intensity over a signal-to-noise range beyond that obtainable with a single film plate, which has a S/N of about 103:1. Although such a collection system is not available currently, a simple system consisting of instrumentation on an existing STEM can be used as a proof of concept which has a S/N of about 255:1, limited by the 8 bit pixel attributes used in the electronics. Use of 24 bit pixel attributes would easily allowthe desired noise range to be attained in the processing instrumentation. The S/N of the scintillator used by the photoelectron sensor is about 106 to 1, well beyond the S/N goal. The trade-off that must be made is the time for acquiring the signal, since the pattern can be obtained in seconds using film plates, compared to 10 to 20 minutes for a pattern to be acquired using the digital scan. Parallel acquisition would, of course, speed up this process immensely.

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