Summary form only given. A vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV) called Spyglass is discussed. The mechanisms and method of control of the UAV are described, from remote or autonomous operation through final rotor blade adjustments to achieve the desired vehicle attitude and position. The Spyglass UAV missions require autonomous operations and an adaptive electronics package which will allow installation of a variety of mission payloads without modification of hardware and software. This can be achieved by an architecture which consists of a core guidance/control subsystem, a low bandwidth tactical data link, a high bandwidth sensor data link, and a modular mission payload subsystem.<>
{"title":"Teleoperation of the Spyglass UAV","authors":"M. V. Hoagland, R.P. Scilipoti","doi":"10.1109/NTC.1992.267908","DOIUrl":"https://doi.org/10.1109/NTC.1992.267908","url":null,"abstract":"Summary form only given. A vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV) called Spyglass is discussed. The mechanisms and method of control of the UAV are described, from remote or autonomous operation through final rotor blade adjustments to achieve the desired vehicle attitude and position. The Spyglass UAV missions require autonomous operations and an adaptive electronics package which will allow installation of a variety of mission payloads without modification of hardware and software. This can be achieved by an architecture which consists of a core guidance/control subsystem, a low bandwidth tactical data link, a high bandwidth sensor data link, and a modular mission payload subsystem.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124265043","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}
Coverage results are shown for an inclined, elliptic low-altitude 36-satellite system (KRYPTON). This concept would be competitive with other low-altitude satellite concepts in the high-density North Atlantic and North Pacific communication routes, but at lower cost. It may be expanded to a 72-satellite system which offers excellent coverage in the Northern Hemisphere, and competitive coverage from Tierra del Fuego to Greenland. A brief comparison to the Globalstar proposal is also presented. Interim segments of 18 KRYPTON satellites are seen to be useful.<>
{"title":"KRYPTON: a low cost satellite communication concept","authors":"P. Christopher, W.W. Wu","doi":"10.1109/NTC.1992.267917","DOIUrl":"https://doi.org/10.1109/NTC.1992.267917","url":null,"abstract":"Coverage results are shown for an inclined, elliptic low-altitude 36-satellite system (KRYPTON). This concept would be competitive with other low-altitude satellite concepts in the high-density North Atlantic and North Pacific communication routes, but at lower cost. It may be expanded to a 72-satellite system which offers excellent coverage in the Northern Hemisphere, and competitive coverage from Tierra del Fuego to Greenland. A brief comparison to the Globalstar proposal is also presented. Interim segments of 18 KRYPTON satellites are seen to be useful.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127033524","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}
V. Marmarelis, D. Sheby, E. Kisenwether, T. A. Erdley
Results obtained by two high-order signal processing methods applied to ultrawideband (UWB) radar data in the UHF band are described. The UWB radar data were collected in a specially designed bistatic test range. Four types of UWB signals were used to test a metal (reference) plate, five different commercially available radar absorbing material samples with metal backing, and five natural material (clutter) samples. The objective was to assess the potential of the authors' UWB signal modalities and associated signal processing techniques in extracting reliable and distinct characterizations of different target materials. Pseudorandom UWB radar waveforms were used, and the collected data were analyzed using two high-order spectral processing (HOSP) methods: bispectral analysis and Kernel analysis. The radar problem was cast in a black-box system identification context, allowing the interpretation of the obtained results as a system/target identifiers and the use of the HOSP techniques in this context. The preliminary results demonstrate the feasibility of this radar technology and processing methodology and provide intriguing possibilities in utilizing this approach for target/material characterizations.<>
{"title":"Target material characterization using high-order signal processing of ultra-wideband radar data","authors":"V. Marmarelis, D. Sheby, E. Kisenwether, T. A. Erdley","doi":"10.1109/NTC.1992.267898","DOIUrl":"https://doi.org/10.1109/NTC.1992.267898","url":null,"abstract":"Results obtained by two high-order signal processing methods applied to ultrawideband (UWB) radar data in the UHF band are described. The UWB radar data were collected in a specially designed bistatic test range. Four types of UWB signals were used to test a metal (reference) plate, five different commercially available radar absorbing material samples with metal backing, and five natural material (clutter) samples. The objective was to assess the potential of the authors' UWB signal modalities and associated signal processing techniques in extracting reliable and distinct characterizations of different target materials. Pseudorandom UWB radar waveforms were used, and the collected data were analyzed using two high-order spectral processing (HOSP) methods: bispectral analysis and Kernel analysis. The radar problem was cast in a black-box system identification context, allowing the interpretation of the obtained results as a system/target identifiers and the use of the HOSP techniques in this context. The preliminary results demonstrate the feasibility of this radar technology and processing methodology and provide intriguing possibilities in utilizing this approach for target/material characterizations.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128970141","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}
Range relative Doppler processing (RRDP) is implemented to simulate the effect of target height on SAR (synthetic aperture radar) performance, for both side-looking and forward-looking modes. For this purpose, a four-dimensional third-order Taylor series expansion about incremental time, azimuth and elevation angles, and target height is performed. Examples through computer simulation show that targets with nonzero height are detected with incorrect range and Doppler and that the severity of this degradation worsens as the forward-looking angle increases. The results presented provide designers of SAR and millimeter-wave seekers with a perception of the range/Doppler versus target height relationship.<>
{"title":"The effect of target height on SAR performance, side-looking and forward-looking modes","authors":"B. Mahafza, T. Black","doi":"10.1109/NTC.1992.267899","DOIUrl":"https://doi.org/10.1109/NTC.1992.267899","url":null,"abstract":"Range relative Doppler processing (RRDP) is implemented to simulate the effect of target height on SAR (synthetic aperture radar) performance, for both side-looking and forward-looking modes. For this purpose, a four-dimensional third-order Taylor series expansion about incremental time, azimuth and elevation angles, and target height is performed. Examples through computer simulation show that targets with nonzero height are detected with incorrect range and Doppler and that the severity of this degradation worsens as the forward-looking angle increases. The results presented provide designers of SAR and millimeter-wave seekers with a perception of the range/Doppler versus target height relationship.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132550953","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}
NASA and the US Army are jointly developing a teleoperated unmanned rotorcraft research platform at the National Aeronautics and Space Administration (NASA) Langley Research Center. This effort is intended to provide the rotorcraft research community an intermediate step between wind tunnel rotorcraft studies and full-scale flight testing. The research vehicle is scaled such that it can be operated in the NASA Langley 14- by 22-foot subsonic tunnel or be flown freely at an outside test range. The authors briefly describe the system's requirements and the techniques used to combine the various technologies present in the system to meet these requirements. They also discuss the status of the development effort.<>
{"title":"A teleoperated unmanned rotorcraft flight test technique","authors":"G. W. Walker, A.E. Phelips, W. Hodges","doi":"10.1109/NTC.1992.267909","DOIUrl":"https://doi.org/10.1109/NTC.1992.267909","url":null,"abstract":"NASA and the US Army are jointly developing a teleoperated unmanned rotorcraft research platform at the National Aeronautics and Space Administration (NASA) Langley Research Center. This effort is intended to provide the rotorcraft research community an intermediate step between wind tunnel rotorcraft studies and full-scale flight testing. The research vehicle is scaled such that it can be operated in the NASA Langley 14- by 22-foot subsonic tunnel or be flown freely at an outside test range. The authors briefly describe the system's requirements and the techniques used to combine the various technologies present in the system to meet these requirements. They also discuss the status of the development effort.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131046539","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}
A model for traffic arrival in a computer network is analyzed. This model is based on a train arrival process in which the traffic between each node pair consists of a certain number of trains, each having a random number of packets. With this scheme, the number of overhead bits per packet is reduced. The processing time at each node is reduced, because each node needs to make only one routing decision per train and does not need to make a separate routing decision for each packet. The scheme described can cope with the ever increasing amount of data being transferred over computer networks by decreasing processing times while maintaining maximum packet size restrictions. The model accurately describes the dependence suggested by observed correlation between successive arrivals of a train. The aggregate arrival process that results from multiplexing N sources to a multiplexer is characterized in detail. The relation of the proposed model to delay congestion and buffer sizes is described.<>
{"title":"Delay analysis for packet trains over computer communication networks","authors":"I.A. Joudeh, E. B. Hall","doi":"10.1109/NTC.1992.267871","DOIUrl":"https://doi.org/10.1109/NTC.1992.267871","url":null,"abstract":"A model for traffic arrival in a computer network is analyzed. This model is based on a train arrival process in which the traffic between each node pair consists of a certain number of trains, each having a random number of packets. With this scheme, the number of overhead bits per packet is reduced. The processing time at each node is reduced, because each node needs to make only one routing decision per train and does not need to make a separate routing decision for each packet. The scheme described can cope with the ever increasing amount of data being transferred over computer networks by decreasing processing times while maintaining maximum packet size restrictions. The model accurately describes the dependence suggested by observed correlation between successive arrivals of a train. The aggregate arrival process that results from multiplexing N sources to a multiplexer is characterized in detail. The relation of the proposed model to delay congestion and buffer sizes is described.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115922042","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}
The objective of using high-temperature superconductor (HTSC) interconnects in multichip module (MCM) substrates is to increase the functional performance to volume ratio above that of conventional MCMs. Functional performance is increased through the use of superconductive interconnect traces which allow ultra-high-speed transmissions between devices. Determining the exact operational characteristics of both the HTSC interconnect and the CMOS devices in a cryogenic environment is the initial requirement in building a HTSC MCM. Once they have been established, demonstration prototypes of the HTSC MCMs can begin to be built and tested. HTSC material requires an extremely cold (less than -150 degrees C) cryogenic environment to become operational. This produces a unique challenge for the package design. The package must allow the flow of a cryogen through it, address electrical I/O, testability, and reliability, and survive many radically large temperature changes. Special attention to the coefficient of thermal expansion of the constituent materials is required to produce a consistently reliable design.<>
{"title":"High temperature superconductor packaging technology","authors":"J. Wigand","doi":"10.1109/NTC.1992.267913","DOIUrl":"https://doi.org/10.1109/NTC.1992.267913","url":null,"abstract":"The objective of using high-temperature superconductor (HTSC) interconnects in multichip module (MCM) substrates is to increase the functional performance to volume ratio above that of conventional MCMs. Functional performance is increased through the use of superconductive interconnect traces which allow ultra-high-speed transmissions between devices. Determining the exact operational characteristics of both the HTSC interconnect and the CMOS devices in a cryogenic environment is the initial requirement in building a HTSC MCM. Once they have been established, demonstration prototypes of the HTSC MCMs can begin to be built and tested. HTSC material requires an extremely cold (less than -150 degrees C) cryogenic environment to become operational. This produces a unique challenge for the package design. The package must allow the flow of a cryogen through it, address electrical I/O, testability, and reliability, and survive many radically large temperature changes. Special attention to the coefficient of thermal expansion of the constituent materials is required to produce a consistently reliable design.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114344500","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}
S. Wu, T.P. Yunck, S. Lichten, B. Haines, R. Malla
Various GPS (Global Positioning System)-based tracking strategies for Earth orbiting satellites are reviewed. Three different categories of user satellites are studied: low circular orbits with altitudes between a few hundred and a few thousand kilometers, highly elliptical orbits with perigees as low as a few hundred and apogees as high as tens of thousands of kilometers, and high circular orbits up to the geosynchronous altitude. Results of covariance analyses which assess the orbit determination performance in all three categories are presented. Low circular orbits can be determined to subdecimeter or even a few-centimeters accuracy using up-looking differential GPS. Highly elliptical orbits, because of wide altitude range, require both up-looking and down-looking observing scenarios for optimum tracking. Among high circular orbits, geosynchronous satellites present the most difficult tracking challenge: the information content of ground-based observations is weak due to lack of temporal change in geometry; and the users are well beyond the GPS altitude and can hardly receive GPS signals. Inverted differential GPS, which requires the user to transmit signal ground GPS receivers can observe, appears ideal for tracking geosynchronous satellites.<>
{"title":"GPS-based precise tracking of Earth satellites from very low to geosynchronous orbits","authors":"S. Wu, T.P. Yunck, S. Lichten, B. Haines, R. Malla","doi":"10.1109/NTC.1992.267890","DOIUrl":"https://doi.org/10.1109/NTC.1992.267890","url":null,"abstract":"Various GPS (Global Positioning System)-based tracking strategies for Earth orbiting satellites are reviewed. Three different categories of user satellites are studied: low circular orbits with altitudes between a few hundred and a few thousand kilometers, highly elliptical orbits with perigees as low as a few hundred and apogees as high as tens of thousands of kilometers, and high circular orbits up to the geosynchronous altitude. Results of covariance analyses which assess the orbit determination performance in all three categories are presented. Low circular orbits can be determined to subdecimeter or even a few-centimeters accuracy using up-looking differential GPS. Highly elliptical orbits, because of wide altitude range, require both up-looking and down-looking observing scenarios for optimum tracking. Among high circular orbits, geosynchronous satellites present the most difficult tracking challenge: the information content of ground-based observations is weak due to lack of temporal change in geometry; and the users are well beyond the GPS altitude and can hardly receive GPS signals. Inverted differential GPS, which requires the user to transmit signal ground GPS receivers can observe, appears ideal for tracking geosynchronous satellites.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114923068","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}
Stanford Telecommunications has developed the Three-Dimensional Event-Driven Graphics Environment (3D-EDGE) for the NASA Goddard Space Flight Center's Communications Link Analysis and Simulation System (CLASS). 3D-EDGE consists of a library of object-oriented subroutines, which allows engineers with little or no computer graphics experience to programmatically manipulate, render, animate and access complex three-dimensional objects. An example program is described, and results pertaining to a model of the Compton Gamma Ray Observatory satellite are discussed.<>
{"title":"The Three-Dimensional Event-Driven Graphics Environment (3D-EDGE)","authors":"J. Freedman, R. Hahn, D. M. Schwartz","doi":"10.1109/NTC.1992.267886","DOIUrl":"https://doi.org/10.1109/NTC.1992.267886","url":null,"abstract":"Stanford Telecommunications has developed the Three-Dimensional Event-Driven Graphics Environment (3D-EDGE) for the NASA Goddard Space Flight Center's Communications Link Analysis and Simulation System (CLASS). 3D-EDGE consists of a library of object-oriented subroutines, which allows engineers with little or no computer graphics experience to programmatically manipulate, render, animate and access complex three-dimensional objects. An example program is described, and results pertaining to a model of the Compton Gamma Ray Observatory satellite are discussed.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115992122","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}
It is noted that the testing of fully autonomous air vehicles usually begins under the control of an expert teleoperator. Design and testing progress by transferring control from the expert to the onboard intelligence which will ultimately provide self-governing control for the air vehicle. The transfer process is best performed when ever-increasing authority is granted to the onboard intelligence by expanding a limited range of full authority for given flight parameters. As onboard control is proven reliable within the allotted range, that range is expanded until the onboard intelligence is able to function over the entire flight envelope with at least the proficiency of the expert teleoperator. Examples of fully autonomous air vehicles are presented, and methodologies used at the University of Texas at Arlington are described.<>
{"title":"Telerobotic testing of autonomous air vehicles","authors":"R. Michelson","doi":"10.1109/NTC.1992.267907","DOIUrl":"https://doi.org/10.1109/NTC.1992.267907","url":null,"abstract":"It is noted that the testing of fully autonomous air vehicles usually begins under the control of an expert teleoperator. Design and testing progress by transferring control from the expert to the onboard intelligence which will ultimately provide self-governing control for the air vehicle. The transfer process is best performed when ever-increasing authority is granted to the onboard intelligence by expanding a limited range of full authority for given flight parameters. As onboard control is proven reliable within the allotted range, that range is expanded until the onboard intelligence is able to function over the entire flight envelope with at least the proficiency of the expert teleoperator. Examples of fully autonomous air vehicles are presented, and methodologies used at the University of Texas at Arlington are described.<<ETX>>","PeriodicalId":448154,"journal":{"name":"[Proceedings] NTC-92: National Telesystems Conference","volume":"212 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116371423","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：