A real-time, all-sky, high time resolution, direct imager for the long wavelength array
A real-time, all-sky, high time resolution, direct imager for the long wavelength array
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DOI：
10.1093/mnras/stz1206
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发表时间：
2019-04
影响因子：
4.8
通讯作者：
J. Kent;J. Dowell;A. Beardsley;N. Thyagarajan;G. Taylor;J. Bowman
中科院分区：
文献类型：
--
作者：
J. Kent;J. Dowell;A. Beardsley;N. Thyagarajan;G. Taylor;J. Bowman
射电天文学的未来将需要具有更高灵敏度的大收集区域，更快调查速度的宽视场以及相对于当前能力的有效计算和数据速率的仪器。我们描述了第一次成功部署的电场并行成像相关器（EPIC）的LWA站在塞维利亚，新墨西哥州，美国（LWA-SV）。EPIC是大型干涉仪计算问题的解决方案。通过实时网格化和空间傅立叶变换来自天线的信道化电场，EPIC去除了所有天线电压对的显式交叉相乘以合成孔径，将计算缩放从$\mathcal{O}（n_a^2）$减少到$\mathcal{O}（n_g\log_2 n_g）$，其中$n_a$是天线的数量，$n_g$是网格点的数量。这不仅节省了密集阵列的计算成本，而且它在真实的时间内产生非常高的时间分辨率图像。基于GPU的实现使用现有的LWA-SV硬件和高性能流框架Bifrost。我们研究的EPIC部署的实际细节和验证的成像性能，通过检测流星对大气层的影响，使用连续的全天空成像在50毫秒的时间分辨率。
The future of radio astronomy will require instruments with large collecting areas for higher sensitivity, wide fields of view for faster survey speeds, and efficient computing and data rates relative to current capabilities. We describe the first successful deployment of the E-field Parallel Imaging Correlator (EPIC) on the LWA station in Sevilleta, New Mexico, USA (LWA-SV). EPIC is a solution to the computational problem of large interferometers. By gridding and spatially Fourier transforming channelised electric fields from the antennas in real-time, EPIC removes the explicit cross multiplication of all pairs of antenna voltages to synthesize an aperture, reducing the computational scaling from $\mathcal{O}(n_a^2)$ to $\mathcal{O}(n_g \log_2 n_g)$, where $n_a$ is the number of antennas and $n_g$ is the number of grid points. Not only does this save computational costs for dense arrays but it produces very high time resolution images in real time. The GPU-based implementation uses existing LWA-SV hardware and the high performance streaming framework, Bifrost. We examine the practical details of the EPIC deployment and verify the imaging performance by detecting a meteor impact on the atmosphere using continuous all-sky imaging at 50 ms time resolution.