Journal of Astronomical Instrumentation最新文献_第9页

Novel RFI Mitigation Methods in the Square Kilometre Array 1 Mid Correlator Beamformer 平方公里阵列1中相关波束形成器中射频干扰抑制新方法

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-01 DOI: 10.1142/S2251171719400117

T. Gunaratne, B. Carlson, G. Comoretto

引用次数: 5

Statistical Discrimination of RFI and Astronomical Transients in 2-bit Digitized Time Domain Signals 2位数字化时域信号中RFI和天文瞬变的统计判别

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-01 DOI: 10.1142/S2251171719400087

G. Nita, A. Keimpema, Z. Paragi

引用次数: 6

Mitigation of Non-Narrowband Radio Frequency Interference Incorporating Array Imperfections 包含阵列缺陷的非窄带射频干扰的抑制

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-01 DOI: 10.1142/S2251171719400130

Jan-Willem W. Steeb, D. Davidson, S. Wijnholds

{"title":"Mitigation of Non-Narrowband Radio Frequency Interference Incorporating Array Imperfections","authors":"Jan-Willem W. Steeb, D. Davidson, S. Wijnholds","doi":"10.1142/S2251171719400130","DOIUrl":"https://doi.org/10.1142/S2251171719400130","url":null,"abstract":"In a recent paper, we presented a non-narrowband spatial radio frequency interference (RFI) mitigation algorithm for radio astronomy arrays. The algorithm constructs a 2nd-order filter by combining a 1st-order subspace subtraction method with a non-narrowband signal model. The model is based on the assumption that the frequency response is approximately flat and that the array is calibrated. In this paper, we consider the effects of array imperfections such as unknown complex gains and mutual coupling, incorporate these into the non-narrowband signal model and extend the RFI mitigation algorithm to include a calibration step. With a calibration step and no mutual coupling, the proposed algorithm was able to process twice the bandwidth per channel when compared to conventional narrowband techniques. This performance declines to 1.6 times greater bandwidth when the effect of mutual coupling is included. The evaluation of the algorithm was done using the layout of a Low Frequency Array (LOFAR) High Band Antenna (HBA) station and a digital audio broadcast recorded with a software defined radio.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171719400130","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48858730","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: 1

Robust Astronomical Imaging in the Presence of Radio Frequency Interference 存在射频干扰时的稳健天文成像

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-01 DOI: 10.1142/S2251171719400129

Shuimei Zhang, Yujie Gu, Yimin D. Zhang

引用次数: 6

Compatibility Between Wind Turbines and the Radio Astronomy Service 风力涡轮机和射电天文服务的兼容性

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2018-12-11 DOI: 10.1142/S2251171719400026

B. Winkel, A. Jessner

{"title":"Compatibility Between Wind Turbines and the Radio Astronomy Service","authors":"B. Winkel, A. Jessner","doi":"10.1142/S2251171719400026","DOIUrl":"https://doi.org/10.1142/S2251171719400026","url":null,"abstract":"Modern radio astronomical facilities are able to detect extremely weak electromagnetic signals not only from the universe but also from man-made radio frequency interference of various origins. These range from wanted signals to unwanted out-of-band emission of radio services and applications to electromagnetic interference produced by all kinds of electronic and electric devices. Energy harvesting wind turbines are not only equipped with electric power conversion hardware but also copious amounts of electronics to control and monitor the turbines. A wind turbine in the vicinity of a radio telescope could therefore lead to harmful interference, corrupting the measured astronomical data. Many observatories seek to coordinate placement of new wind farms with wind turbine manufacturers and operators, as well as with the local planning authorities, to avoid such a situation. In our study, we provide examples as well as guidelines for the determination of the separation distances between wind turbines and radio observatories, to enable a benign co-existence for both. The proposed calculations entail three basic steps. At first, the anticipated maximum emitted power level based on the European EN 550011 ( CISPR, 2015 ) standard, which applies to industrial devices, is determined. Then secondly, the propagation loss along the path to the radio receiver is computed via a model provided by the international telecommunication union. Finally, the received power is compared to the permitted power limit that pertains in the protected radio astronomical observing band under consideration. This procedure may be carried out for each location around a telescope site, in order to obtain a map of potentially problematic wind turbine positions.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171719400026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48969021","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: 1

An Overview of the Stratospheric Observatory for Infrared Astronomy Since Full Operation Capability 平流层红外天文观测站全面运行以来概况

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2018-12-01 DOI: 10.1142/S2251171718400123

K. Ennico, E. Becklin, Jeanette H. Le, N. Rangwala, W. Reach, Alan Rhodes, T. Roellig, George L. Sarver, P. Temi, H. Yorke, E. Zavala

{"title":"An Overview of the Stratospheric Observatory for Infrared Astronomy Since Full Operation Capability","authors":"K. Ennico, E. Becklin, Jeanette H. Le, N. Rangwala, W. Reach, Alan Rhodes, T. Roellig, George L. Sarver, P. Temi, H. Yorke, E. Zavala","doi":"10.1142/S2251171718400123","DOIUrl":"https://doi.org/10.1142/S2251171718400123","url":null,"abstract":"The Stratospheric Observatory for Infrared Astronomy (SOFIA), a joint project between NASA and the German Aerospace Center DLR, provides access to observations of the infrared and sub-millimeter universe. As its development timeline is unique compared to all other NASA astrophysics missions, a milestone called the Full Operation Capability (FOC) was defined to identify the start of science operations. SOFIA reached this in February 2014. With a wide range of imagers, spectrometers and a new polarimeter, SOFIA provides unique scientific results that cannot be obtained with a ground-based facility and any spacecraft expected in the next decade. The airborne platform has continued to mature its mission systems as part of a planned spiral development approach, particularly with upgradable instrumentation that opens up new science directions for the Observatory. A third generation instrument is planned for commissioning in 2019. This paper summarizes the current state of the Observatory with emphasis on the science and instrumentation updates since FOC.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400123","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42927462","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

SOFIA Flight Planning and Execution SOFIA飞行计划和执行

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2018-12-01 DOI: 10.1142/S225117171840010X

K. Leppik, K. Bower, C. Kaminski, C. Trinh, T. Civeit, T. Kilsdonk

引用次数: 3

Image Size and Control System Developments of the Airborne Telescope SOFIA SOFIA机载望远镜图像尺寸及控制系统的研制

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2018-12-01 DOI: 10.1142/S2251171718400093

Friederike Graf, Andreas Reinacher, H. Jakob, S. Fasoulas

{"title":"Image Size and Control System Developments of the Airborne Telescope SOFIA","authors":"Friederike Graf, Andreas Reinacher, H. Jakob, S. Fasoulas","doi":"10.1142/S2251171718400093","DOIUrl":"https://doi.org/10.1142/S2251171718400093","url":null,"abstract":"The SOFIA telescope is a worldwide unique observatory that enables infrared astronomy aboard a Boeing 747SP at altitudes of up to 45[Formula: see text]kft. Contrary to any ground-based telescope, SOFIA is exposed not only to aerodynamic forces but also aircraft motion and excitation. Nevertheless, the ambitious scientific goals require a stable platform and very precise pointing. As of now, the telescope can be considered diffraction-limited in the far-infrared wavelengths beyond 50[Formula: see text][Formula: see text]m. A careful study of the different sources of blur revealed that image jitter is among the most influential. During the course of a flight, the telescope is exposed to various excitation levels, leading to deformation of its flexible structure and vibrations in a wide range of frequencies. Since SOFIA entered its operational phase, continuous efforts have been made to develop and implement upgrades in the pointing and control system. The original design was a robust and conservative structure aimed to ensure safe operations with several different science instruments and many unknown parameters. In recent years, more and more agile system components have followed to tackle the residual image motion. This paper introduces the telescope control system followed by a summary of recently installed upgrades and ends with an outlook on future developments on our way to diffraction-limited imaging beyond 25[Formula: see text][Formula: see text]m.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171718400093","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41403617","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: 7

The SOFIA Telescope in Full Operation 索菲亚望远镜全面运行

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2018-12-01 DOI: 10.1142/S225117171840007X

Andreas Reinacher, Friederike Graf, Benjamin Greiner, H. Jakob, Y. Lammen, Sarah Peter, M. Wiedemann, Oliver Zeile, H. Kaercher

{"title":"The SOFIA Telescope in Full Operation","authors":"Andreas Reinacher, Friederike Graf, Benjamin Greiner, H. Jakob, Y. Lammen, Sarah Peter, M. Wiedemann, Oliver Zeile, H. Kaercher","doi":"10.1142/S225117171840007X","DOIUrl":"https://doi.org/10.1142/S225117171840007X","url":null,"abstract":"The SOFIA telescope is a 2.5[Formula: see text]m class Cassegrain telescope with Nasmyth focus. It is the largest telescope ever integrated into an aircraft. The telescope is exposed to the stratospheric environment during the observations and the fact that the telescope’s foundation, which is a Boeing 747 SP, is vibrating and moving in all degrees of freedom (DoF) requires a highly specialized and sophisticated design. Based on the telescope of its predecessor, the Kuiper Airborne Observatory (KAO), the SOFIA telescope design had to evolve to accommodate a telescope 2.5 times the size of KAO. In several hundred successful observation flights, the telescope proved that it performs not only as specified, but is also extremely reliable. Nevertheless, the telescope’s software and hardware are continuously upgraded to optimize its performance without interfering with the observation schedules to reach even more ambitious image size and pointing jitter goals to enable additional science cases. In addition, manufacturing of the line-replaceable units is in process to ensure that the SOFIA telescope can perform without any major interruptions for the envisioned 20 year lifetime. Some of the main features of the SOFIA telescope are its suspension assembly (SUA), which decouples the telescope from SOFIA’s fuselage with air springs and a spherical oil bearing, the extremely stiff Nasmyth tube (NT), which connects cavity and cabin mounted components of the dumbbell design, and the Secondary Mirror Assembly (SMA), which is used for chopping and fast pointing corrections. This paper aims to give an overview of these and all other major telescope subsystems in operation today. In addition, some of the upgrades, either implemented recently or slated for implementation shortly, are introduced.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S225117171840007X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46911160","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: 9

SOFIA at Full Operation Capability: Technical Performance 索菲亚在全面运行能力:技术性能

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2018-12-01 DOI: 10.1142/S2251171718400111

P. Temi, D. Hoffman, K. Ennico, Jeanette H. Le

引用次数: 10