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

Project: Research project

Project Details

Description

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.
StatusActive
Effective start/end date15/04/2431/03/27

Funding

  • National Science Foundation

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