Radio Seeing Monitor Interferometer

Hiriart, D.; Váldez, Jorge; Zaca-Morán, P.; Medina, J.L

doi:10.1086/342481

Cited by 4 publications

(3 citation statements)

References 2 publications

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“…A detailed description of such a design is given by Radford et al [1996]; that instrument has been in nearly continuous use at the Atacama Large Millimeter/submillimeter Array telescope site in Chile since 1995. Other instruments using the same concept were later built for the Large Millimeter Telescope in Mexico [Hiriart and Valdez, 2002], the Australia Telescope Compact Array [Middelberg et al, 2006], and the VLA [NRAO, 2013]. All of these use narrow-bandwidth signal processing and rely on the satellite to transmit an unmodulated tone.…”

Section: The Sti Instrumentsmentioning

confidence: 99%

Tropospheric delay statistics measured by two site test interferometers at Goldstone, California

et al. 2013

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[1] Site test interferometers (STIs) have been deployed at two locations within the NASA Deep Space Network tracking complex in Goldstone, California. An STI measures the difference of atmospheric delay fluctuations over a distance comparable to the separations of microwave antennas that could be combined as phased arrays for communication and navigation. The purpose of the Goldstone STIs is to assess the suitability of Goldstone as an uplink array site and to statistically characterize atmosphere-induced phase delay fluctuations for application to future arrays. Each instrument consists of two~1 m diameter antennas and associated electronics separated by~200 m. The antennas continuously observe signals emitted by geostationary satellites and produce measurements of the phase difference between the received signals. The two locations at Goldstone are separated by 12.5 km and differ in elevation by 119 m. We find that their delay fluctuations are statistically similar but do not appear as shifted versions of each other, suggesting that the length scale for evolution of the turbulence pattern is shorter than the separation between instruments. We also find that the fluctuations are slightly weaker at the higher altitude site.

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Section: The Sti Instrumentsmentioning

confidence: 99%

Tropospheric delay statistics measured by two site test interferometers at Goldstone, California

et al. 2013

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“…In this paper, we describe the design and operation of a novel, broadband, multi-baseline atmospheric phase interferometer (API) operating at the Submillimeter Array (SMA) 1 telescope site located near the summit of Mauna Kea, Hawaii. There are many examples of previous and currently operating instruments that correlate geostationary satellite beacon signals at astronomical observatory sites (Middelberg et al 2006;Hiriart et al 2002;Radford et al 1996;Ishiguro et al 1990;Masson et al 1990) and elsewhere (Kirkland et al 2000;Shao et al 1999). In contrast, rather than using a beacon tone, our instrument correlates broadband digital television emission from satellites which contains far more power than the beacon tones, thereby enabling a high signal to noise ratio while avoiding the many drawbacks of a very narrow bandpass filter .…”

Section: Introductionmentioning

confidence: 99%

A MULTI-BASELINE 12 GHz ATMOSPHERIC PHASE INTERFEROMETER WITH ONE MICRON PATH LENGTH SENSITIVITY

Kimberk

Hunter

Leiker

et al. 2012

J. Astron. Instrum.

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We have constructed a five station 12 GHz atmospheric phase interferometer (API) for the Submillimeter Array (SMA) located near the summit of Mauna Kea, Hawaii. Operating at the base of unoccupied SMA antenna pads, each station employs a commercial low noise mixing block coupled to a 0.7 m off-axis satellite dish which receives a broadband, white noise-like signal from a geostationary satellite. The signals are processed by an analog correlator to produce the phase delays between all pairs of stations with projected baselines ranging from 33-261 m. Each baseline's amplitude and phase is measured continuously at a rate of 8 kHz, processed, averaged and output at 10 Hz. Further signal processing and data reduction is accomplished with a Linux computer, including the removal of the diurnal motion of the target satellite. The placement of the stations below ground level with an environmental shield combined with the use of low temperature coefficient, buried fiber optic cables provides excellent system stability. The sensitivity in terms of rms path length is 1.3 microns which corresponds to phase deviations of about 1 • of phase at the highest operating frequency of the SMA. The two primary data products are: (1) standard deviations of observed phase over various time scales, and (2) phase structure functions. These real-time statistical data measured by the API in the direction of the satellite provide an estimate of the phase front distortion experienced by the concurrent SMA astronomical observations. The API data also play an important role, along with the local opacity measurements and weather predictions, in helping to plan the scheduling of science observations on the telescope.

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“…A well-tested means of characterizing the phase stability above a radio observatory are two-element interferometers observing unmodulated beacons of geostationary satellites (e.g. Radford et al 1996;Hiriart et al 2002).…”

Section: Introductionmentioning

confidence: 99%

The ATCA Seeing Monitor

Middelberg¹,

Sault²,

Kesteven³

2006

Publ. Astron. Soc. Aust

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We present the design of, and a first analysis of data from, the atmospheric seeing monitor at the Australia Telescope Compact Array (ATCA). The seeing monitor has been operational almost continuously since May 2004 and every 10 min delivers a measurement of the atmospheric phase stability at the observatory. Its measurements can be used by observers to help deciding whether it is worth carrying out observations at millimetre wavelengths or whether a longer-wavelength backup project should be observed. We present a statistical analysis of the data recorded since September 2004 to characterize the annual variations in atmospheric path length fluctuations. Our analysis shows that in terms of phase stability, nights in spring, summer, and autumn are as good as, or better than, days in winter. We also find that the data imply that the turbulence in the lower few hundred metres of the atmosphere is predominantly responsible for the atmospheric seeing.

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Radio Seeing Monitor Interferometer

Cited by 4 publications

References 2 publications

Tropospheric delay statistics measured by two site test interferometers at Goldstone, California

Tropospheric delay statistics measured by two site test interferometers at Goldstone, California

A MULTI-BASELINE 12 GHz ATMOSPHERIC PHASE INTERFEROMETER WITH ONE MICRON PATH LENGTH SENSITIVITY

The ATCA Seeing Monitor

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