SWIFT-SAT: Unlimited Radio Interferometry: A Hardware-Algorithm Co-Design Approach to RAS-Satellite Coexistence

SWIFT-SAT：无限无线电干涉测量：RAS 卫星共存的硬件算法协同设计方法

• 批准号: 2332534
• 负责人: Hongbin Li
• 金额: $ 70万
• 依托单位: Stevens Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-04-15 至 2027-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2332534&HistoricalAwards=false
• 关键词: SWIFT; SAT; Unlimited; Radio; Interferometry; SWIFT; SAT; Unlimited; Radio; Interferometry

Radio astronomy has transformed the perception of the universe, providing valuable insights into the properties and behaviors of galaxies, stars, and other cosmic events. An essential requirement of radio astronomy service (RAS) is access to a spectrum devoid of radio frequency interference (RFI) from other sources. RFI can obscure faint astronomical objects, create false signals, reduce the sensitivity of radio telescopes, and lead to significant loss of data and bandwidth limitation. Traditionally, RAS operates in secluded regions, using the surrounding terrain to shield it from populated areas, or inside a radio quiet zone that enforces strict regulations on human-generated RFI. While these measures are effective in mitigating terrestrial RFI, such as TV/radio stations, mobile phones, and WiFi networks, they are unable to protect RAS against RFI originating from satellites in space. With an increasing number of mega-constellation satellites being launched into space by companies like SpaceX, satellite RFI presents a grave threat to RAS. On the one hand, it is imperative for satellite operators to cooperate, avoiding illuminating ground RAS receivers and minimizing the RFI. On the other, the RAS will have to strengthen its ability to operate amidst strong unavoidable RFI. By leveraging a novel modulo sampling approach, this project aims to develop cutting-edge circuit designs and signal processing algorithms that will bolster the resilience of radio telescopes against RFI. It holds great potential for optimizing the collection and processing of RAS data, while also fostering the coexistence of satellite communications and scientific research in the radio spectrum. The primary goal of this project is to enhance the operational capabilities of radio astronomy service (RAS) in the presence of strong radio frequency interference (RFI) arising from satellite transmitters that cannot be avoided geographically. To protect RAS systems electronically, a crucial step is to ensure the linearity of RAS receivers. Nonlinearity or saturation in receivers generates intermodulation products that can wipe out the entire observing band. It is costly to use conventional technologies, e.g., high-dynamic range (HDR) low-noise amplifiers and high-resolution analog-to-digital converters (ADCs) for amplification and digitization, to enhance the linearity of RAS receivers. This is because such enhancements can result in an avalanche of RAS data, which is known for its very large size. The proposed research takes a modulo sampling-based approach to operate radio interferometry robustly against RFI. Specifically, modulo sampling folds the out-of-range input signal to within the dynamic range before taking samples using a regular-resolution ADC. This allows the recovery of HDR information from low-dynamic range (LDR) measurements. Building on the modulo sampling approach, the proposed research encompasses three thrusts: (1) a signal processing framework for robust and super-resolution radio interferometry, which enables the receiver to operate without being limited by a fixed dynamic range; (2) scalable modulo ADC design for demonstration of unlimited interferometry capability in the presence of RFI; and (3) experimentation incorporating the modulo ADCs for comprehensive testing and evaluation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

射电天文学改变了对宇宙的看法，为星系，恒星和其他宇宙事件的特性和行为提供了宝贵的见解。射电天文学服务（RAS）的基本要求是从其他来源访问没有射频干扰（RFI）的光谱。 RFI可以掩盖微弱的天文对象，产生错误的信号，降低射电望远镜的灵敏度，并导致数据和带宽限制的显着丢失。传统上，RAS在僻静的地区运营，使用周围的地形将其避免被人口稠密的地区或无线电安静的区域屏蔽，该区域在广播的安静区域内实施了严格的人类生成的RFI法规。尽管这些措施可有效缓解陆地RFI，例如电视/广播电台，手机和WiFi网络，但它们无法保护RAS免受来自太空中卫星的RFI。随着SpaceX等公司将越来越多的巨型施工卫星发射到太空中，RFI卫星对RAS构成了严重的威胁。一方面，卫星操作员必须合作，避免启发地面RAS接收器并最大程度地减少RFI。另一方面，RAS将不得不加强其在不可避免的RFI中运行的能力。通过利用一种新型的模量抽样方法，该项目旨在开发最先进的电路设计和信号处理算法，以增强射电望远镜对RFI的弹性。它具有优化RAS数据的收集和处理的巨大潜力，同时还促进了无线电频谱中卫星通信和科学研究的共存。该项目的主要目标是在存在强大的射频干扰（RFI）的情况下增强射电天文学服务（RAS）的运行能力，而卫星发射器无法在地理上避免。为了以电子方式保护RAS系统，关键步骤是确保RAS接收器的线性。接收器中的非线性或饱和度会产生可以消灭整个观测带的交换产物。使用常规技术，例如，高动力范围（HDR）低噪声放大器和高分辨率类似物对数字转换器（ADC）进行扩增和数字化以增强RAS接收器的线性。这是因为这样的增强功能可以导致大量的RAS数据，该数据以其较大的尺寸而闻名。拟议的研究采用了一种基于模量抽样的方法来对RFI进行牢固操作无线电干涉法。具体而言，Modulo采样在使用常规分辨率ADC取样之前将偏僻的输入信号折叠到动态范围内。这允许从低动力范围（LDR）测量中恢复HDR信息。拟议的研究以模型采样方法为基础，涵盖了三个推力：（1）可靠和超分辨率无线电干涉指标的信号处理框架，这使得接收器能够在不受固定动态范围限制的情况下操作； （2）在RFI存在下进行无限干涉能力的可伸缩模量ADC设计； （3）将Modulo ADC纳入全面测试和评估的实验。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准通过评估来支持的。