A5054954856- Radio Astronomy Observations and Technology
- Antenna Design and Optimization
- Astrophysics and Cosmic Phenomena
- GNSS positioning and interference
- Electromagnetic Compatibility and Measurements
- Astronomical Observations and Instrumentation
- Radio Wave Propagation Studies
- Parallel Computing and Optimization Techniques
- Scientific Research and Discoveries
- Pulsars and Gravitational Waves Research
- Advanced Wireless Communication Techniques
- Green IT and Sustainability
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Impact of Light on Environment and Health
- Numerical Methods and Algorithms
- Polynomial and algebraic computation
- Advanced Image Processing Techniques
- Microwave and Dielectric Measurement Techniques
- Satellite Communication Systems
- Advanced Adaptive Filtering Techniques
- Scientific Measurement and Uncertainty Evaluation
- Ultrasonics and Acoustic Wave Propagation
- Bluetooth and Wireless Communication Technologies
National Centre for Radio Astrophysics
2011-2024
Tata Institute of Fundamental Research
2011-2019
The Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) has been working a decade to reduce the time cost of designing, building deploying new digital radio-astronomy instruments. Today, CASPER open-source technology powers over 45 scientific instruments worldwide, is used by scientists engineers at dozens academic institutions. In this paper, we catalog current offerings collaboration, past present built users developers. We describe ongoing state software...
Abstract We present the first detailed analysis of ultra-steep spectrum radio halo in merging galaxy cluster A521, based on upgraded Giant Metrewave Radio telescope observations. The combination observations (300–850 MHz) and archival X-ray data provides a new window into complex physics occurring this system. When compared to all previous analyses, our sensitive images detected centrally located emission greater extent ∼1.3 Mpc. A faint extension southeastern relic has been discovered....
Contemporary real-time RFI mitigation is carried out at different stages primarily using regulatory and technical approaches. Regulatory approaches include spectrum management, radio quiet zones, ensuring protection from self-generated RFI. The in the analog RF frontend systems, digital signal processing offline systems. As known, received by a telescope combination of contributions astronomical system sky background noise. has an additive effect on telescope. key distinguishing properties...
Radio Frequency Interference (RFI) is a growing concern for the highly sensitive radio receivers of ground based telescopes. RFI reduces sensitivity telescope and produces artifacts in observed data. Over years, several techniques have been proposed implemented mitigating RFI, either by controlling eliminating sources around or its removal at different locations receiver chain. This paper examines regulatory management efforts as well technological approaches employed frequency interference...
Radio Frequency Interference (RFI) is a growing concern for contemporary radio telescopes. This paper describes techniques real-time threshold-based detection and filtering of broadband narrowband RFI the correlator beamformer chains telescope back-end, with specific applications to upgraded Giant Meterwave Telescope (uGMRT). The Median Absolute Deviation (MAD) estimator used robust estimation dispersion received signal in temporal spectral domains. Results from tests carried out GMRT...
Electromagnetic radiation from human activities, known as man-made Radio Frequency Interference (RFI), adversely affects radio astronomy observations. In the vicinity of Upgraded Giant Metrewave Telescope (uGMRT) array, sparking on power lines is major cause interference at observing frequencies less than 800[Formula: see text]MHz. A real-time broadband RFI detection and filtering system implemented part uGMRT wideband signal processing backend to mitigate effect RFI. Performance analysis...
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 astronomy bands. The effect on astronomical data can be significantly reduced through real-time excision. In this paper, Median Absolute Deviation (MAD) used for excising signals corrupted by strong impulsive interference. MAD estimation requires recursive median calculation which a computationally challenging...
With 30 antennas and a maximum baseline length of 25 km, the Giant Metrewave Radio Telescope (GMRT) is premier low-frequency radio interferometer today. We have carried out study possible expansions GMRT, via adding new installing focal plane arrays (FPAs), to improve its point-source sensitivity, surface brightness angular resolution, field view, U-V coverage. array configuration studies, aimed at minimizing number GMRT required obtain well-behaved synthesized beam over wide range...
Decision based non-linear filtering is widely used for the removal of impulsive noise. Various robust statistical estimators scale are in use determining threshold process. Real-time requires this estimation to be computationally efficient and realizable within system constraints. This paper proposes Interquartile range (IQR) noise from signals possessing Gaussian distribution. The efficiency using IQR has been described through simulation varying levels An iterative introduced improve...
The Giant Metrewave Radio Telescope (GMRT) is being upgraded to increase the receiver sensitivity. This makes more susceptible man-made Frequency Interference (RFI). To improve performance in presence of RFI, real-time RFI excision (filtering) incorporated GMRT wideband backend (GWB). filtering system implemented on FPGA (Field Programmable Gate Array) and CPU (Central Processing Unit)–GPU (Graphics Unit) platforms detect remove broadband narrowband respectively. detected using a...
Contemporary wideband radio telescope backends are generally developed on Field Programmable Gate Arrays (FPGA) or hybrid (FPGA+GPU) platforms. One of the challenges faced while developing such instruments is functional verification signal processing backend at various stages development. In case an interferometer pulsar backend, typical requirement for one independent noise source per input, with provision a common, correlated component across all inputs, controllable level correlation....
Real-time RFI excision is developed for the GMRT wideband correlator as part of upgraded (uGMRT) project. The technique uses robust statistical estimation and a nonlinear filter to excise broadband narrowband RFI. This paper provides an overview its real-time implementation. results showing improvement in signal-to-noise ratio cross-correlation performance are also provided.
The GMRT Backend Group is in the process of developing wide-band digital backends as part a major upgrade GMRT. main requirements are for processing 400 MHz bandwidth signals from 30 antennas interferometry and array mode operations, along with additional features like narrow band modes RFI cancellation schemes. Both FPGA GPU based designs have been explored this paper presents design implementation details results testing prototype units. A comparison resources needed performance achieved...
Modern day radio-telescopes need extremely sensitive receivers combined with powerful signal processing capabilities. Rapid urbanization and proliferation of communication devices has made these telescopes vulnerable to increasingly high levels Radio Frequency Interference (RFI). This necessitated development algorithms for the mitigation effects RFI either in real time or during post processing. The performance different can be verified using emulator. paper proposes a programmable...
Radio telescopes are sensitive radiometers for detecting signals in very low signal-to-noise ratio (SNR) conditions. This passive detection gets affected by man-made Frequency Interference (RFI) from various sources radiating within the observing band or adjacent frequency bands. RFI has detrimental effects on radio observations. Several and excision techniques have been developed reducing its effects. paper summarizes of Excision class, useful removing strong RFI. implemented different...
The Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) has been working a decade to reduce the time cost of designing, building deploying new digital radio-astronomy instruments. Today, CASPER open-source technology powers over 45 scientific instruments worldwide, is used by scientists engineers at dozens academic institutions. In this paper we catalog current offerings collaboration, past present built users developers. We describe ongoing state software...