Interference mitigation using a focal plane array

Hansen, Conly L.; Warnick, Karl F.; Jeffs, Brian D.; Fisher, J. Richard; Bradley, Richard F.

doi:10.1029/2004rs003138

Cited by 23 publications

(11 citation statements)

References 33 publications

(36 reference statements)

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“…This effectively lumps both SOI gain variation and spillover noise fluctuation into the beamformer noise response. Output noise values that are significantly larger than the quiescent system noise temperature correspond to STI windows in which the array response to the interferer is similar enough to the SOI response that the adaptive beamformer must sacrifice SOI power in order to suppress the interfering signal [ Hansen et al , 2005].…”

Section: Experimental Setup and Resultsmentioning

confidence: 99%

“…To achieve greater control over beam patterns, feed arrays of electrically small elements have also been considered for use in radio astronomy applications [ Fisher and Bradley , 2000]. Numerical simulations have been used to determine the sensitivity and noise performance of seven and nineteen‐element dipole arrays in the presence of RFI [ Hansen et al , 2005; Warnick and Jensen , 2005].…”

Section: Introductionmentioning

confidence: 99%

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Experimental verification of radio frequency interference mitigation with a focal plane array feed

et al. 2007

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[1] We demonstrate the use of spatial filtering algorithms for radio frequency interference (RFI) mitigation in conjunction with a focal plane array of electrically small elements. The array consists of a seven-element hexagonal arrangement of thickened dipole antennas with 1600 MHz designed center frequency backed by a circular ground plane at the focal plane of a 3 m parabolic reflector. Rooftop-mounted signal sources were used to simulate a weak signal of interest at boresight and a strong, broadband interferer in the reflector sidelobes. Using an adaptive beamformer, the amplitude of the interfering signal was reduced sufficiently to recover the signal of interest. For an interference to noise ratio of 15 dB as measured at the center array element, the interferer was suppressed to the level of the fluctuations of the 10-s integrated noise floor (the minimum detectable signal level was interference-limited and no longer decreased after 10 s integration). Similar cancellation performance was demonstrated for a nonstationary interferer moving at an angular velocity of 0.1°per second. Pattern rumble due to beamformer adaptation was observed and quantified. For a moving RFI source, the degree of pattern rumble was found to be unacceptably large in terms of its effects on the maximum stable integration time and receiver sensitivity. An array feed with more elements together with specialized signal processing algorithms designed to suppress pattern rumble will likely be required in order to use adaptive spatial filtering for astronomical observations. Citation: Nagel, J. R., K. F. Warnick, B. D. Jeffs, J. R. Fisher, and R. Bradley (2007), Experimental verification of radio frequency interference mitigation with a focal plane array feed, Radio Sci., 42, RS6013,

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Section: Experimental Setup and Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental verification of radio frequency interference mitigation with a focal plane array feed

et al. 2007

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“…Spatial filtering methods can also be implemented with a focal plane array feed in conjunction with a large reflector [12]. In communications and radar applications, array feeds have been used for many years to achieve shaped pattern footprints, electronically scanned beams, and compensation for reflector surface abberations [13]- [16].…”

Section: Introductionmentioning

confidence: 99%

Effects of mutual coupling on interference mitigation with a focal plane array

Warnick

Jensen

2005

IEEE Trans. Antennas Propagat.

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“…Focal plane array (FPA) systems and multi-beam receivers provide new opportunities for spatial filtering, as each of the component feeds has an independent sky signal together with the common RFI signal [43,44,45]. In addition, one of the feeds in a multi-beam system can always be used as a reference antenna.…”

Section: Spatial Filtering and Null Steeringmentioning

confidence: 99%

RFI Mitigation in Radio Astronomy (invited)

Baan¹

2010

Proceedings of RFI Mitigation Workshop — PoS(RFI2010)

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This paper presents an overview of methods for mitigating radio frequency interference (RFI) in radio astronomy data. The primary purpose of mitigation is to assist observatories to take useful data outside frequency bands allocated to the Radio Astronomy Service (RAS): mitigation should not be needed within RAS bands. Mitigation methods may be introduced at a variety of points within the data acquisition system. These range from proactive methods to change the local RFI environment by means of regulatory manners, to pre-and post-detection methods, to various precorrelation methods, and to methods applied at correlation and post-correlation. Every method of RFI mitigation results in data loss. A forward look is presented on the implementation of methods to cope with changing interference environments at observatories. RFI mitigation workshop -RFI2010,

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Interference mitigation using a focal plane array

Cited by 23 publications

References 33 publications

Experimental verification of radio frequency interference mitigation with a focal plane array feed

Experimental verification of radio frequency interference mitigation with a focal plane array feed

Effects of mutual coupling on interference mitigation with a focal plane array

RFI Mitigation in Radio Astronomy (invited)

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