Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187253
Keun Soo YIM, V. Sidea, Z. Kalbarczyk, Deming Chen, R. Iyer
This paper presents a fault-tolerant, programmable voter architecture for software-implemented N-tuple modular redundant (NMR) computer systems. Software NMR is a cost-efficient solution for high-performance, mission-critical computer systems because this can be built on top of commercial off-the-shelf (COTS) devices. Due to the large volume and randomness of voting data, software NMR system requires a programmable voter. Our experiment shows that voting software that executes on a processor has the time-of-check-to-time-of-use (TOCTTOU) vulnerabilities and is unable to tolerate long duration faults. In order to address these two problems, we present a special-purpose voter processor and its embedded software architecture. The processor has a set of new instructions and hardware modules that are used by the software in order to accelerate the voting software execution and address the identified two reliability problems. We have implemented the presented system on an FPGA platform. Our evaluation result shows that using the presented system reduces the execution time of error detection codes (commonly used in voting software) by 14% and their code size by 56%. Our fault injection experiments validate that the presented system removes the TOCTTOU vulnerabilities and recovers under both transient and long duration faults. This is achieved by using 0.7% extra hardware in a baseline processor.
{"title":"A fault-tolerant programmable voter for software-based N-modular redundancy","authors":"Keun Soo YIM, V. Sidea, Z. Kalbarczyk, Deming Chen, R. Iyer","doi":"10.1109/AERO.2012.6187253","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187253","url":null,"abstract":"This paper presents a fault-tolerant, programmable voter architecture for software-implemented N-tuple modular redundant (NMR) computer systems. Software NMR is a cost-efficient solution for high-performance, mission-critical computer systems because this can be built on top of commercial off-the-shelf (COTS) devices. Due to the large volume and randomness of voting data, software NMR system requires a programmable voter. Our experiment shows that voting software that executes on a processor has the time-of-check-to-time-of-use (TOCTTOU) vulnerabilities and is unable to tolerate long duration faults. In order to address these two problems, we present a special-purpose voter processor and its embedded software architecture. The processor has a set of new instructions and hardware modules that are used by the software in order to accelerate the voting software execution and address the identified two reliability problems. We have implemented the presented system on an FPGA platform. Our evaluation result shows that using the presented system reduces the execution time of error detection codes (commonly used in voting software) by 14% and their code size by 56%. Our fault injection experiments validate that the presented system removes the TOCTTOU vulnerabilities and recovers under both transient and long duration faults. This is achieved by using 0.7% extra hardware in a baseline processor.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"29 1","pages":"1-20"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81012245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187392
S. Barrow, V. Balzano
This paper provides an overview of the event-driven architecture that will be used onboard the James Webb Space Telescope (JWST) to carry out the series of exposures, maneuvers, and engineering activities that were selected beforehand by the JWST planning and scheduling subsystem. Each week during one of the ground communication intervals one observation plan segment that contains an ordered list of tasks for JWST will be uploaded to the telescope. A set of JavaScripts running onboard JWST will be responsible for implementing the series of tasks listed in the weekly observation plan segments as sequences of flight software commands. The JavaScripts will execute the observation plan segments in an event-driven manner, in which the JavaScripts query JWST telemetry to determine when to execute the flight software commands needed to carry out the observation plan. The onboard JavaScripts consult command and telemetry dictionaries to construct command requests and CCSDS telemetry queries. This paper will demonstrate how creating flight software commands as they are needed onboard simplifies the ground to flight interface, and allows onboard events to be taken into consideration during operations.
{"title":"Commanding the James Webb Space Telescope using event-driven operations software","authors":"S. Barrow, V. Balzano","doi":"10.1109/AERO.2012.6187392","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187392","url":null,"abstract":"This paper provides an overview of the event-driven architecture that will be used onboard the James Webb Space Telescope (JWST) to carry out the series of exposures, maneuvers, and engineering activities that were selected beforehand by the JWST planning and scheduling subsystem. Each week during one of the ground communication intervals one observation plan segment that contains an ordered list of tasks for JWST will be uploaded to the telescope. A set of JavaScripts running onboard JWST will be responsible for implementing the series of tasks listed in the weekly observation plan segments as sequences of flight software commands. The JavaScripts will execute the observation plan segments in an event-driven manner, in which the JavaScripts query JWST telemetry to determine when to execute the flight software commands needed to carry out the observation plan. The onboard JavaScripts consult command and telemetry dictionaries to construct command requests and CCSDS telemetry queries. This paper will demonstrate how creating flight software commands as they are needed onboard simplifies the ground to flight interface, and allows onboard events to be taken into consideration during operations.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"62 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84052808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187439
Daniel Selva, E. Crawley
A decision support tool is presented that is especially tailored for architecting Earth observing missions and programs. The tool features both a cost model and a performance model. This paper focuses on the description of the performance model. Indeed, while considerable effort has been put into the development of cost estimating models, comparably much less effort has been put into the development of quantitative methods to assess how well Earth Observing Mission satisfy scientific and societal needs. A literature review revealed that existing methods include a commercial approach, a value-of-information approach, end-to-end simulation, assimilation in Observing System Simulation Experiments, and simple expert judgment. Limitations of these methods include limited applicability, computational complexity, low modeling fidelity (e.g. abstraction of synergies between measurements), and subjectivity. Our method uses a knowledge-based system to store and manage large quantities of expert knowledge in the form of rules-of-thumb that replace expensive computations. Scientific and societal measurement requirements and instrument capabilities are expressed in the form of logical rules and data structures. An efficient pattern matching algorithm performs the comparison of the measurement requirements and the measurement capabilities on the basis of 64 different measurement attributes. The system is demonstrated on the Earth Science Decadal Survey. While the system is still under development, it shows great potential to enhance traceability in the modeling of scientific and societal value of Earth observing missions. Furthermore, the recursive nature of rule-based systems shows potential to model synergies between instruments and measurements, at a sufficient level of fidelity for architectural trade studies, especially for the ones conducted in committees with experts such as Decadal Surveys.
{"title":"A rule-based decision support tool for architecting Earth observing missions","authors":"Daniel Selva, E. Crawley","doi":"10.1109/AERO.2012.6187439","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187439","url":null,"abstract":"A decision support tool is presented that is especially tailored for architecting Earth observing missions and programs. The tool features both a cost model and a performance model. This paper focuses on the description of the performance model. Indeed, while considerable effort has been put into the development of cost estimating models, comparably much less effort has been put into the development of quantitative methods to assess how well Earth Observing Mission satisfy scientific and societal needs. A literature review revealed that existing methods include a commercial approach, a value-of-information approach, end-to-end simulation, assimilation in Observing System Simulation Experiments, and simple expert judgment. Limitations of these methods include limited applicability, computational complexity, low modeling fidelity (e.g. abstraction of synergies between measurements), and subjectivity. Our method uses a knowledge-based system to store and manage large quantities of expert knowledge in the form of rules-of-thumb that replace expensive computations. Scientific and societal measurement requirements and instrument capabilities are expressed in the form of logical rules and data structures. An efficient pattern matching algorithm performs the comparison of the measurement requirements and the measurement capabilities on the basis of 64 different measurement attributes. The system is demonstrated on the Earth Science Decadal Survey. While the system is still under development, it shows great potential to enhance traceability in the modeling of scientific and societal value of Earth observing missions. Furthermore, the recursive nature of rule-based systems shows potential to model synergies between instruments and measurements, at a sufficient level of fidelity for architectural trade studies, especially for the ones conducted in committees with experts such as Decadal Surveys.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"88 20 1","pages":"1-20"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84070333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187157
A. Preston, J. Thorpe, L. Miner
Next generation space telescopes and interferometric missions will require stringent position and stability tolerances. To do this, these missions will require materials and bonding techniques with ever-increasing stability in order to make their measurements. As an example, the Laser Interferometer Space Antenna (LISA) will detect and observe gravitational waves in the 0.1 mHz to 1 Hz frequency range with strain sensitivities on the order of 10-21 at its most sensitive frequency. To make these measurements, critical components such as the optical bench or telescope support structure will need to have path-length stabilities of better than 1 pm/√Hz. The baseline construction method for the LISA optical bench is to affix fused silica components to a Zerodur baseplate using hydroxide-catalysis bonding (HCB). HCB is a recently developed technique that allows the bonding of glasses, some metals, and silicon carbide with significant strength and stability with a bond thickness of less than a few micrometers. In addition, a wide range of surface profiles can be bonded using only a small amount of hydroxide solution. These characteristics make HCB ideal for adhering components in complex optical systems. In addition to being used to construct the LISA optical bench, the HCB technique shows great promise for constructing other structures such as hollow retroreflectors to be used for lunar laser ranging, or a visible nulling coronograph to be used for exoplanet detection. Here we present construction techniques that could be used to make an optical bench, hollow retroreflector, nulling coronograph, or other quasi-monolithic structures using HCB. In addition, we present dimensional stability results of an optical bench that was made using HCB, as well as HCB strength measurements.
{"title":"Quasi-monolithic structures for spaceflight using hydroxide-catalysis bonding","authors":"A. Preston, J. Thorpe, L. Miner","doi":"10.1109/AERO.2012.6187157","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187157","url":null,"abstract":"Next generation space telescopes and interferometric missions will require stringent position and stability tolerances. To do this, these missions will require materials and bonding techniques with ever-increasing stability in order to make their measurements. As an example, the Laser Interferometer Space Antenna (LISA) will detect and observe gravitational waves in the 0.1 mHz to 1 Hz frequency range with strain sensitivities on the order of 10-21 at its most sensitive frequency. To make these measurements, critical components such as the optical bench or telescope support structure will need to have path-length stabilities of better than 1 pm/√Hz. The baseline construction method for the LISA optical bench is to affix fused silica components to a Zerodur baseplate using hydroxide-catalysis bonding (HCB). HCB is a recently developed technique that allows the bonding of glasses, some metals, and silicon carbide with significant strength and stability with a bond thickness of less than a few micrometers. In addition, a wide range of surface profiles can be bonded using only a small amount of hydroxide solution. These characteristics make HCB ideal for adhering components in complex optical systems. In addition to being used to construct the LISA optical bench, the HCB technique shows great promise for constructing other structures such as hollow retroreflectors to be used for lunar laser ranging, or a visible nulling coronograph to be used for exoplanet detection. Here we present construction techniques that could be used to make an optical bench, hollow retroreflector, nulling coronograph, or other quasi-monolithic structures using HCB. In addition, we present dimensional stability results of an optical bench that was made using HCB, as well as HCB strength measurements.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"1 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84165272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187024
H. Eisen, B. Jai, P. Rosen, L. Veilleux, P. Xaypraseuth
The high value of Radar and Lidar data for understanding climate change and earth dynamics led to the prioritization of the Deformation, Ecosystem Structure and Dynamics of Ice (DESDynI) mission as Tier One in the last National Academy of Sciences' Earth Science Decadal Survey. A mission concept that matched those desired objectives underwent pre-Project development and passed several layers of review in late 2010 and early 2011 with the target of a 2017 launch. However, cuts in the proposed FY2012 budget forced a reset of the Radar mission and eliminated the Lidar sciencecraft. The proposed DESDynI-Radar mission may now fulfill a more limited set of objectives with a more modest budget on a longer development timescale. A multitude of options have been studied with varying levels of cost, risk and science value. Flight and Ground system implementations have a direct bearing on many of these factors and will also be addressed. The methodology and status of evaluating these options will be discussed. A key distinguishing characteristic of the projected DESDynI-Radar measurement would be large scale coverage and frequent revisit at fine resolution. This would be enabled via a new Radar technique called SweepSAR. Efforts to develop and field test SweepSAR will also be discussed, as well as other technology developments underway that are associated with this mission.
{"title":"Conceptual development of the DESDynI mission","authors":"H. Eisen, B. Jai, P. Rosen, L. Veilleux, P. Xaypraseuth","doi":"10.1109/AERO.2012.6187024","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187024","url":null,"abstract":"The high value of Radar and Lidar data for understanding climate change and earth dynamics led to the prioritization of the Deformation, Ecosystem Structure and Dynamics of Ice (DESDynI) mission as Tier One in the last National Academy of Sciences' Earth Science Decadal Survey. A mission concept that matched those desired objectives underwent pre-Project development and passed several layers of review in late 2010 and early 2011 with the target of a 2017 launch. However, cuts in the proposed FY2012 budget forced a reset of the Radar mission and eliminated the Lidar sciencecraft. The proposed DESDynI-Radar mission may now fulfill a more limited set of objectives with a more modest budget on a longer development timescale. A multitude of options have been studied with varying levels of cost, risk and science value. Flight and Ground system implementations have a direct bearing on many of these factors and will also be addressed. The methodology and status of evaluating these options will be discussed. A key distinguishing characteristic of the projected DESDynI-Radar measurement would be large scale coverage and frequent revisit at fine resolution. This would be enabled via a new Radar technique called SweepSAR. Efforts to develop and field test SweepSAR will also be discussed, as well as other technology developments underway that are associated with this mission.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"61 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77764422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187388
I. Ali, A. Ginart, J. Goldin, P. Kalgren, M. Roemer, S. Poll
This paper presents a new sensing application to diagnose power semiconductor aging in power drive systems. It has been shown previously that device parasitic characteristics change during the aging process which results in detectable changes in their frequency response. This change is manifested in the current signal at very high frequencies. Therefore, using a wideband AC current sensor, high frequency components of the current can be acquired, providing a way to detect device aging.
{"title":"New sensing application to diagnose power semiconductor aging in actuator power drive systems","authors":"I. Ali, A. Ginart, J. Goldin, P. Kalgren, M. Roemer, S. Poll","doi":"10.1109/AERO.2012.6187388","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187388","url":null,"abstract":"This paper presents a new sensing application to diagnose power semiconductor aging in power drive systems. It has been shown previously that device parasitic characteristics change during the aging process which results in detectable changes in their frequency response. This change is manifested in the current signal at very high frequencies. Therefore, using a wideband AC current sensor, high frequency components of the current can be acquired, providing a way to detect device aging.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"5 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72839938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187368
C. Sankavaram, B. Pattipati, K. Pattipati, Yilu Zhang, Mark N Howell, M. Salman
Regenerative braking is one of the most promising and environmentally friendly technologies used in electric and hybrid electric vehicles to improve energy efficiency and vehicle stability. In this paper, we discuss a systematic data-driven process for detecting and diagnosing faults in the regenerative braking system of hybrid electric vehicles. The process involves data reduction techniques, exemplified by multi-way partial least squares, multi-way principal component analysis, for implementation in memory-constrained electronic control units and well-known fault classification techniques based on reduced data, such as support vector machines, k-nearest neighbor, partial least squares, principal component analysis and probabilistic neural network, to isolate faults in the braking system. The results demonstrate that highly accurate fault diagnosis is possible with the pattern recognition-based techniques. The process can be employed for fault analysis in a wide variety of systems, ranging from automobiles to buildings to aerospace systems.
{"title":"Data-driven fault diagnosis in a hybrid electric vehicle regenerative braking system","authors":"C. Sankavaram, B. Pattipati, K. Pattipati, Yilu Zhang, Mark N Howell, M. Salman","doi":"10.1109/AERO.2012.6187368","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187368","url":null,"abstract":"Regenerative braking is one of the most promising and environmentally friendly technologies used in electric and hybrid electric vehicles to improve energy efficiency and vehicle stability. In this paper, we discuss a systematic data-driven process for detecting and diagnosing faults in the regenerative braking system of hybrid electric vehicles. The process involves data reduction techniques, exemplified by multi-way partial least squares, multi-way principal component analysis, for implementation in memory-constrained electronic control units and well-known fault classification techniques based on reduced data, such as support vector machines, k-nearest neighbor, partial least squares, principal component analysis and probabilistic neural network, to isolate faults in the braking system. The results demonstrate that highly accurate fault diagnosis is possible with the pattern recognition-based techniques. The process can be employed for fault analysis in a wide variety of systems, ranging from automobiles to buildings to aerospace systems.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"105 1","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73388243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187213
Cagatay Tanil
In this paper, improved heuristic and evolutionary methods are presented for pre-launch trajectory optimization of a tactical missile. Computation time and trajectory length are minimized as objectives whereas maneuverability of the missile, total amount of fuel, obstacles, no-fly zones, islands, shorelines are considered to be constraints. There are two main methods developed for this purpose. One method is based on heuristic search by adaptive-based A* algorithm. In this method, sub-optimal path is obtained by constructing a network in which node distance (leg length) and node intensity can be changed adaptively with respect to mission environment in the search time. This enhancement in conventional A* method leads to closer optimal trajectories in less computation load especially in complex mission scenarios such as shorelines having narrow pass, too many unintended targets or friends etc. The other proposed path planning method is improved genetic algorithm. This algorithm has a variable-length chromosome and a real-valued encoding as well as an intelligent population creation method that produces feasible individuals only. By means of starting with a feasible population, it is observed that convergence time is far less than using random creation of initial population. Furthermore, for rapid analysis and comparison of the two proposed methods in different environments, a generic graphical user interface (MPT-The Mission Planning Tool) is developed.
{"title":"Improved heuristic and evolutionary methods for tactical missile mission planning","authors":"Cagatay Tanil","doi":"10.1109/AERO.2012.6187213","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187213","url":null,"abstract":"In this paper, improved heuristic and evolutionary methods are presented for pre-launch trajectory optimization of a tactical missile. Computation time and trajectory length are minimized as objectives whereas maneuverability of the missile, total amount of fuel, obstacles, no-fly zones, islands, shorelines are considered to be constraints. There are two main methods developed for this purpose. One method is based on heuristic search by adaptive-based A* algorithm. In this method, sub-optimal path is obtained by constructing a network in which node distance (leg length) and node intensity can be changed adaptively with respect to mission environment in the search time. This enhancement in conventional A* method leads to closer optimal trajectories in less computation load especially in complex mission scenarios such as shorelines having narrow pass, too many unintended targets or friends etc. The other proposed path planning method is improved genetic algorithm. This algorithm has a variable-length chromosome and a real-valued encoding as well as an intelligent population creation method that produces feasible individuals only. By means of starting with a feasible population, it is observed that convergence time is far less than using random creation of initial population. Furthermore, for rapid analysis and comparison of the two proposed methods in different environments, a generic graphical user interface (MPT-The Mission Planning Tool) is developed.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"8 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79886623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187244
B. Reese, B. Mcpherson, M. Schupbach, A. Lostetter
This paper presents the development of a high efficiency, rad-hard 3.8 kW silicon carbide (SiC) based power processing unit (PPU) power supply for the High Voltage Hall Accelerator (HiVHAC) Hall effect thruster. The power converter utilizes SiC JFET power switches which have on-resistance an order of magnitude smaller than equivalent 600V rad-hard silicon MOSFETs. A prototype PPU power converter was developed which was able to achieve up to 700 V output voltage, 1.3 kW output power, 2.55 kW/kg gravimetric power density, and up to 92% efficiency. The converter operates on 80-160 V input and can dynamically control the output voltage between 200-700 V.
{"title":"Silicon carbide power processing unit for Hall effect thrusters","authors":"B. Reese, B. Mcpherson, M. Schupbach, A. Lostetter","doi":"10.1109/AERO.2012.6187244","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187244","url":null,"abstract":"This paper presents the development of a high efficiency, rad-hard 3.8 kW silicon carbide (SiC) based power processing unit (PPU) power supply for the High Voltage Hall Accelerator (HiVHAC) Hall effect thruster. The power converter utilizes SiC JFET power switches which have on-resistance an order of magnitude smaller than equivalent 600V rad-hard silicon MOSFETs. A prototype PPU power converter was developed which was able to achieve up to 700 V output voltage, 1.3 kW output power, 2.55 kW/kg gravimetric power density, and up to 92% efficiency. The converter operates on 80-160 V input and can dynamically control the output voltage between 200-700 V.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"1 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80358990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-03DOI: 10.1109/AERO.2012.6187178
S. Li, H. Riris, K. Numata, S. Wu, D. Poulios, A. Ramanathan, J. Abshire, M. Krainak
A high efficiency, narrow linewidth tunable laser source is developed for greenhouse trace gas remote sensing. It features broad, continuous tuning range at 1570-1655 nm and 3291 nm with narrow linewidth (500 MHz) and high spectral purity. This laser is based on seeded optical parametric generator (OPG) technology. Several trace gas species were continuously detected for 72 hours in an open path environment. We also present our recent airborne experiment result based on this laser technology.
{"title":"Tunable narrow linewidth laser source for a methane lidar","authors":"S. Li, H. Riris, K. Numata, S. Wu, D. Poulios, A. Ramanathan, J. Abshire, M. Krainak","doi":"10.1109/AERO.2012.6187178","DOIUrl":"https://doi.org/10.1109/AERO.2012.6187178","url":null,"abstract":"A high efficiency, narrow linewidth tunable laser source is developed for greenhouse trace gas remote sensing. It features broad, continuous tuning range at 1570-1655 nm and 3291 nm with narrow linewidth (500 MHz) and high spectral purity. This laser is based on seeded optical parametric generator (OPG) technology. Several trace gas species were continuously detected for 72 hours in an open path environment. We also present our recent airborne experiment result based on this laser technology.","PeriodicalId":6421,"journal":{"name":"2012 IEEE Aerospace Conference","volume":"4 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2012-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78876037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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