Journal of Astronomical Instrumentation最新文献_第8页

UniBoard2, A Generic Scalable High-Performance Computing Platform for Radio Astronomy 一个通用的可扩展的射电天文学高性能计算平台UniBoard2

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-05-29 DOI: 10.1142/S225117171950003X

G. Schoonderbeek, A. Szomoru, A. Gunst, L. Hiemstra, J. Hargreaves

引用次数: 5

Erratum: Preface: “Interference Mitigation Techniques in Radio Astronomy” 勘误表：前言：“无线电天文学中的干扰抑制技术”

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-05-29 DOI: 10.1142/S2251171719920016

K. Buch, A. Boonstra, G. Hellbourg, J. Kocz, U. Rau, L. Greenhill

引用次数: 0

Coherent Integration in Astronomical Interferometry: Theory and Practice 天文干涉测量中的相干积分:理论与实践

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-05-29 DOI: 10.1142/S2251171719500053

D. Mozurkewich, A. Jorgensen, G. V. van Belle

{"title":"Coherent Integration in Astronomical Interferometry: Theory and Practice","authors":"D. Mozurkewich, A. Jorgensen, G. V. van Belle","doi":"10.1142/S2251171719500053","DOIUrl":"https://doi.org/10.1142/S2251171719500053","url":null,"abstract":"Ground-based long-baseline astronomical interferometry operates in a regime where short integration exposures are demanded by working in the presence of a turbulent atmosphere. To reduce piston noise to less than one radian per aperture, these exposure times are on order 10 milliseconds or less in the visible. It has long been recognized that, in the low signal-to-noise ratio (SNR) regime, the visibility SNR is improved by co-adding frames, each rotated by an estimate of its phase. However, implementation of this technique is challenging. Where it is most needed, on low SNR baselines and when combining multiple phases to estimate the phase for a lower SNR baseline, phase errors reduce the amplitude by a large amount and in a way that has proven difficult to calibrate. In this paper, an improved coherent integration algorithm is presented. A parameterized model for the phase as a function of time and wavelength is fit to the entire data set. This framework is used to build a performance model which can be used in two ways. First, it can be used to test the algorithm; by comparing its performance to theory, one can test how well the parameter fitting has worked. Also, when designing future systems, this model provides a simple way to predict performance and compare it to alternative techniques such as hierarchical fringe tracking. This technique has been applied to both simulated and stellar data.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171719500053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47824922","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: 3

Measuring Data Loss Resulting from Interference 测量干扰造成的数据丢失

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-04-18 DOI: 10.1142/S2251171719400075

W. Baan, A. Jessner, Jaap Steenge

引用次数: 0

Real-Time Implementation of MAD-Based RFI Excision on FPGA 基于mad的RFI切割在FPGA上的实时实现

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-04-18 DOI: 10.1142/S2251171719400063

K. Buch, K. Naik, Swapnil Nalawade, Shruti Bhatporia, Y. Gupta, B. Ajithkumar

{"title":"Real-Time Implementation of MAD-Based RFI Excision on FPGA","authors":"K. Buch, K. Naik, Swapnil Nalawade, Shruti Bhatporia, Y. Gupta, B. Ajithkumar","doi":"10.1142/S2251171719400063","DOIUrl":"https://doi.org/10.1142/S2251171719400063","url":null,"abstract":"Radio Frequency Interference (RFI) excision in wideband radio telescope receivers is gaining significance due to increasing levels of manmade RFI and operation outside the protected radio astronomy bands. The effect of RFI on astronomical data can be significantly reduced through real-time excision. In this paper, Median Absolute Deviation (MAD) is used for excising signals corrupted by strong impulsive interference. MAD estimation requires recursive median calculation which is a computationally challenging problem for real-time excision. This challenge is addressed by implementation of a histogram-based technique for MAD computation. The architecture is developed and optimized for Field Programmable Gate Array (FPGA) implementation. The design of a more robust variant of MAD called Median-of-MAD (MoM) is described. The architecture of MAD and MoM techniques and subsequent optimization allows for four RFI excision blocks on a single Xilinx Virtex-5 FPGA. These techniques have been tested on the GMRT wideband backend (GWB) processing a maximum of 400[Formula: see text]MHz bandwidth and the results show significant improvement in the signal-to-noise ratio (SNR).","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171719400063","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41850278","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: 2

Observing Exoplanets in the Near-Infrared from a High Altitude Balloon Platform 高空气球平台近红外观测系外行星

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-22 DOI: 10.1142/S2251171719500119

P. Nagler, B. Edwards, B. Kilpatrick, N. Lewis, P. Maxted, C. Netterfield, V. Parmentier, E. Pascale, Subhajit Sarkar, G. Tucker, I. Waldmann

{"title":"Observing Exoplanets in the Near-Infrared from a High Altitude Balloon Platform","authors":"P. Nagler, B. Edwards, B. Kilpatrick, N. Lewis, P. Maxted, C. Netterfield, V. Parmentier, E. Pascale, Subhajit Sarkar, G. Tucker, I. Waldmann","doi":"10.1142/S2251171719500119","DOIUrl":"https://doi.org/10.1142/S2251171719500119","url":null,"abstract":"Although there exists a large sample of known exoplanets, little data exists that can be used to study their global atmospheric properties. This deficiency can be addressed by performing phase-resolved spectroscopy — continuous spectroscopic observations of a planet’s entire orbit about its host star — of transiting exoplanets. Planets with characteristics suitable for atmospheric characterization have orbits of several days, thus phase curve observations are highly resource intensive, especially for shared use facilities. In this work, we show that an infrared spectrograph operating from a high altitude balloon platform can perform phase-resolved spectroscopy of hot Jupiter-type exoplanets with performance comparable to a space-based telescope. Using the EXoplanet Climate Infrared TElescope (EXCITE) experiment as an example, we quantify the impact of the most important systematic effects that we expect to encounter from a balloon platform. We show an instrument like EXCITE will have the stability and sensitivity to significantly advance our understanding of exoplanet atmospheres. Such an instrument will both complement and serve as a critical bridge between current and future space-based near-infrared spectroscopic instruments.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171719500119","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49178364","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: 6

Deep, Broad Null Formation for Canceling Moving RFI in Radio Astronomical Arrays 用于消除射电天文阵列中移动射频信号的深宽零阵

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-01 DOI: 10.1142/S2251171719400038

R. Black, B. Jeffs, K. Warnick

{"title":"Deep, Broad Null Formation for Canceling Moving RFI in Radio Astronomical Arrays","authors":"R. Black, B. Jeffs, K. Warnick","doi":"10.1142/S2251171719400038","DOIUrl":"https://doi.org/10.1142/S2251171719400038","url":null,"abstract":"Radio frequency interference (RFI) is rapidly becoming a major issue for many applications. It is especially problematic for radio astronomy, where signal-to-noise ratios (SNRs) are less than unity. Antenna array systems such as phased array feeds (PAFs) and interferometric imaging arrays are able to cancel RFI through adaptive projection-based spatial notch filtering techniques. Current methods for formulating these projection operators suffer from an unfortunate trade-off. They must sacrifice integration time when calculating the sample spatial correlation matrix in order to track RFI motion, but this consequently increases sample estimation error and reduces null depth. In this work, we propose a new way to process spatial correlation matrices to form a broad null that reliably cancels moving RFI without increasing sample estimation error due to insufficient integration. Additionally, when assisted by an RFI-tracking auxiliary antenna, this approach also reduces the total data rate coming out of a spatial correlator, thus making broad-null-based RFI cancelation more computationally efficient and practical for real-time active array-based RFI mitigation systems.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171719400038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41491952","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

Preface: “Interference Mitigation Techniques in Radio Astronomy” 前言：“无线电天文学中的干扰抑制技术”

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-01 DOI: 10.1142/s225117171902001x

K. Buch, A. Boonstra, G. Hellbourg, J. Kocz, U. Rau, L. Greenhill

引用次数: 0

Implementing RFI Mitigation in Radio Science 在无线电科学中实施RFI缓解

IF 1.3

Journal of Astronomical Instrumentation Pub Date : 2019-03-01 DOI: 10.1142/S2251171719400105

W. Baan

引用次数: 9

Iridium Satellite Signals: A Case Study in Interference Characterization and Mitigation for Radio Astronomy Observations 铱卫星信号:射电天文观测干扰表征和减缓的案例研究