Real-time RFI excision for the GMRT wideband correlator

Buch, Kaushal D.; Gupta, Yashwant; Bhatporia, Shruti; Nalawade, Swapnil; Naik, Kishor; Ajithkumar, B.

doi:10.1109/rfint.2016.7833523

Cited by 2 publications

(2 citation statements)

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“…Thus, the typical duration of RFI and rate at which the signal is sampled determine the size of the data window for MAD estimation. Since real-time MAD computation over large window sizes is impractical to develop due to hardware resource requirements, an alternate technique called Median of MAD (MoM) [6] is introduced in the GWB. Instead of depending on one window for estimating the MAD value, MoM(M m ) uses median(M ) of the k MAD values…”

Section: Rfi Excision Techniquementioning

confidence: 99%

“…The RFI excision technique used for uGMRT determines the filtering threshold through robust statistical estimate of dispersion using Median Absolute Deviation (MAD). The samples outside this threshold are replaced by a constant value or threshold or digital noise [6]. Early work in RFI mitigation at the Westerbork Synthesis Radio Telescope describes FPGA implementation of the algorithm and its effects on the cross-correlation power spectrum as described in [7].…”

Section: Introductionmentioning

confidence: 99%

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Implementing and Characterizing Real-Time Broadband RFI Excision System for the GMRT Wideband Backend

Buch

Naik

Nalawade

et al. 2018

IETE Technical Review

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The Giant Metrewave Radio Telescope (GMRT) is being upgraded to increase the receiver sensitivity. This makes the receiver more susceptible to man-made Radio Frequency Interference (RFI). To improve the receiver performance in presence of RFI, real-time RFI excision (filtering) is incorporated in the GMRT wideband backend (GWB). The RFI filtering system is implemented on FPGA and CPU-GPU platforms to detect and remove broadband and narrowband RFI. The RFI is detected using a threshold-based technique where the threshold is computed using Median Absolute Deviation (MAD) estimator. The filtering is carried out by replacing the RFI samples by either noise samples or constant value or threshold. This paper describes the status of the real-time broadband RFI excision system in the wideband receiver chain of the upgraded GMRT (uGMRT). The test methodology for carrying out various tests to demonstrate the performance of broadband RFI excision at the system level and on radio astronomical imaging experiments are also described.

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Section: Rfi Excision Techniquementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%