2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)最新文献_第5页

The wide-field imaging interferometry testbed 宽视场成像干涉测量试验台

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931375

X. Zhang, L. Feinberg, D. Leisawitz, D. Leviton, A. Martino, J. Mather

{"title":"The wide-field imaging interferometry testbed","authors":"X. Zhang, L. Feinberg, D. Leisawitz, D. Leviton, A. Martino, J. Mather","doi":"10.1109/AERO.2001.931375","DOIUrl":"https://doi.org/10.1109/AERO.2001.931375","url":null,"abstract":"We are developing a Wide-Field Imaging Interferometry Testbed (WIIT) in support of design studies for NASA's future space interferometry missions, in particular the SPIRIT and SPECS far-infrared/submillimeter interferometers. WIIT operates at optical wavelengths and uses Michelson beam combination to achieve both wide-field imaging and high-resolution spectroscopy. It will be used chiefly to test the feasibility of using a large-format detector array at the image plane of the sky to obtain wide-field interferometry images through mosaicing techniques. In this setup each detector pixel records interferograms corresponding to averaging a particular pointing range on the sky as the optical path length is scanned and as the baseline separation and orientation is varied. The final image is constructed through spatial and spectral Fourier transforms of the recorded interferograms for each pixel, followed by a mosaic/joint-deconvolution procedure of all the pixels. In this manner the image within the pointing range of each detector pixel is further resolved to an angular resolution corresponding to the maximum baseline separation for fringe measurements. We present the motivation for building the testbed, show the optical, mechanical, control and data system design, and describe the image processing requirements and algorithms. WITT is presently under construction at NASA's Goddard Space Flight Center.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114815356","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}

引用次数: 16

HUMS-the benefits-past, present and future 利益——过去、现在和未来

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931326

J. E. Land

{"title":"HUMS-the benefits-past, present and future","authors":"J. E. Land","doi":"10.1109/AERO.2001.931326","DOIUrl":"https://doi.org/10.1109/AERO.2001.931326","url":null,"abstract":"This paper presents a comprehensive model of how military and commercial operators achieve benefits in Health and Usage Monitoring Systems (HUMS) equipped helicopters. The model uncovers the substantial set of the potential benefits and presents a framework that each operator can use as a tool to analyze particular benefits that are tuned to the operating environment for which HUMS is being used or being considered. The model presents real-life cases to show the benefits that can be achieved from operational HUMS systems and actual operational data and analysis. The paper examines HUMS as it affects potential roles and missions of helicopters, including commercial and military. Consideration is given to such issues as fleet readiness, management of spares assets, cost of M&O staff, and effects of aircraft downtime. The model includes all sources of costs for the HUMS, including the costs of equipment, installation costs, downtimes for installation, cost of support of the HUMS, etc. The model also looks into the perceived future operational environment, where the operator and the aircraft manufacturer are integrated into a real-time team to get the best performance from the deployed fleet. A major emphasis of the paper is the use of practical, real-life experience as a feedback into the HUMS system. The system includes equipment, operating procedures and personnel, integrated into a cohesive force.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114828793","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}

引用次数: 33

Development of linear phase modulator for spacecraft transponding modem 航天器应答调制解调器用线性相位调制器的研制

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931353

S. Kayalar, N. Mysoor, C. Andricos

引用次数: 1

Commercial and Internet trends and the NASA spaceflight ground network 商业和互联网趋势以及NASA航天地面网络

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931282

M.C. Spinolo

引用次数: 2

Efficacy analysis of the power-law detector for non-Rayleigh distributed reverberation in active sonar systems 主动声呐系统中非瑞利分布混响幂律探测器的有效性分析

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931482

D. Abraham

{"title":"Efficacy analysis of the power-law detector for non-Rayleigh distributed reverberation in active sonar systems","authors":"D. Abraham","doi":"10.1109/AERO.2001.931482","DOIUrl":"https://doi.org/10.1109/AERO.2001.931482","url":null,"abstract":"Non-Rayleigh reverberation in active sonar systems causes an increase in the number of false alarms when detection algorithms are designed under the assumption that the reverberation is actually Rayleigh distributed. Many models have been used to represent non-Rayleigh reverberation and then build appropriate detectors including the Rayleigh mixture model, K-distribution, and McDaniel's model. The detectors for these models de-emphasize the tails of the distribution. Thus, a natural non-parametric alternative would be to use a power-law non-linearity with a power less than one. In this paper the efficacy is used to evaluate the power-law detector for the above reverberation models with a non-fluctuating target. For the K-distribution and McDaniel's model, it was seen that the power-law can achieve the same efficacy as the locally optimal non-linearity with a simpler implementation. However, choosing the optimal power-law requires modeling the reverberation with McDaniel's model and a numerical optimization, the former of which can result in mismatch errors if there is not a good fit with the observed reverberation. Thus, a different technique is considered in which the power is chosen so that the transformed data have the same higher order moment measure (skewness, kurtosis, or scintillation index) as the Rayleigh distribution. It wag seen that matching kurtosis resulted in the best average performance, but also the highest variability when the higher order moments must be estimated from auxiliary data. Matching the scintillation index provided the worst average performance, but the least variability, and matching the skewness was in between these extremes in terms of both average performance and variability.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124121272","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}

引用次数: 4

Applications of microsystems and signal processing for wiring integrity monitoring 微系统和信号处理在线路完整性监测中的应用

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931401

K. Blemel, C. Furse

引用次数: 7

Non-linear preprocessing of heavy tailed reverberation 重尾混响的非线性预处理

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931493

D. W. Ricker, A.J. Cutezo

引用次数: 0

DDP-a tool for life-cycle risk management ddp——生命周期风险管理工具

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931736

S. Cornford, M. Feather, K. Hicks

引用次数: 32

Electro-optic modulator coupling loss improvement by tapering waveguides and fibers 采用锥形波导和光纤改善电光调制器耦合损耗

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931378

A. Yacoubian, W. Lin, D. Olson, Y. Shi, J. Bechtel

引用次数: 6

Cryogenic, X-band and Ka-band InP HEMT based LNAs for the Deep Space Network 用于深空网络的低温、x波段和ka波段InP HEMT LNAs

2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542) Pub Date : 2001-03-10 DOI: 10.1109/AERO.2001.931264

J. Bautista, J. Bowen, N.E. Fernandez, Z. Fujiwara, J. Loreman, S. Petty, J. L. Prater, R. Grunbacher, R. Lai, M. Nishimoto, M. R. Murti, J. Laskar

{"title":"Cryogenic, X-band and Ka-band InP HEMT based LNAs for the Deep Space Network","authors":"J. Bautista, J. Bowen, N.E. Fernandez, Z. Fujiwara, J. Loreman, S. Petty, J. L. Prater, R. Grunbacher, R. Lai, M. Nishimoto, M. R. Murti, J. Laskar","doi":"10.1109/AERO.2001.931264","DOIUrl":"https://doi.org/10.1109/AERO.2001.931264","url":null,"abstract":"Exploration of the Solar System with automated spacecraft that are more than ten astronomical units from Earth requires very large antennae employing extremely sensitive receivers. A key figure of merit in the specification of the spacecraft-to-earth telecommunications link is the ratio of the antenna gain to operational noise temperature (G/Top) of the system. The Deep Space Network (DSN) receivers are cryogenic, low-noise amplifiers (LNAs). InP HEMT LNA modules are demonstrating noise temperatures less than ten times the quantum noise limit (10 hf/k) from 1 to 100 GHz. To date, the lowest noise LNA modules developed for the DSN have demonstrated noise temperatures of under 4 K at 8.4 GHz and 11 K at 32 GHz. The development and demonstration of cryogenic, InP HEMT based front-end amplifiers for the DSN requires accurate component and module characterization, and modeling from 1 to 100 GHz at physical temperatures down to and below 12 K, because of the broad band frequency response of InP HEMTs. The characterization and modeling begins with the HEMT chip, proceeds to the multi-stage HEMT LNA module, and culminates with the complete front-end cryogenic receiver package for the antenna. This paper presents an overview of this development process with emphasis on comparison between modeled and measured results at 8.4 GHz. Results are shown for devices, LNA modules, front-end receiver packages employing these modules, and antennae employing these packages.","PeriodicalId":329225,"journal":{"name":"2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130166940","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}

引用次数: 33