Journal ArticleDOI
Radiometric correction of atmospheric path length fluctuations in interferometric experiments
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TLDR
In this paper, a system consisting of dual microwave radiometers, one operating at 20.7 GHz and the other at 31.4 GHz, was developed for estimating atmospheric water vapor path delay.Abstract:
To support very long baseline interferometric experiments, a system has been developed for estimating atmospheric water vapor path delay. The system consists of dual microwave radiometers, one operating at 20.7 GHz and the other at 31.4 GHz. The measured atmospheric brightness temperatures at these two frequencies yield the estimate of the precipitable water present in both vapor and droplets. To determine the accuracy of the system, a series of observations were undertaken, comparing the outputs of two water vapor radiometers with the phase variation observed with two connected elements of the very large array (VLA). The results show that: (1) water vapor fluctuations dominate the residual VLA phase and (2) the microwave radiometers can measure and correct these effects. The rms phase error after correction is typically 15 deg at a wavelength of 6 cm, corresponding to an uncertainty in the path delay of 0.25 cm. The residual uncertainty is consistent with the stability of the microwave radiometer but is still considerably larger than the stability of the VLA. The technique is less successful under conditions of heavy cloud.read more
Citations
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Journal ArticleDOI
The very large array: Design and performance of a modern synthesis radio telescope
TL;DR: In this article, the authors discuss the design and performance of the very large array (VLA) in general, and describe the VLA in particular, under the seven headings: array geometry design, sensitivity considerations, phase stability requirements, signal transmission system, delay and correlator system, control system, and data-reduction requirments.
Journal ArticleDOI
The effect of the dynamic wet troposphere on radio interferometric measurements
Robert N. Treuhaft,G. E. Lanyi +1 more
TL;DR: In this paper, a statistical model of water vapor fluctuations is used to describe the effect of the dynamic wet troposphere on radio interferometric measurements, and water vapor induced VLBI parameter errors and correlations are determined as a function of the delay observable errors.
Journal ArticleDOI
Spacecraft Doppler tracking: Noise budget and accuracy achievable in precision radio science observations
TL;DR: In this paper, a detailed noise model for Doppler radio science experiments is presented. But the model focuses primarily on the Fourier range ≈10−4-1 Hz, but the authors briefly discuss noise in lower-frequency observations.
Journal ArticleDOI
Precision Geodesy Using the Mark-III Very-Long-Baseline Interferometer System
Thomas A. Clark,Brian E. Corey,James L. Davis,Gunnar Elgered,Thomas A. Herring,Hans F. Hinteregger,Curtis A. Knight,James I. Levine,Goran Lundqvist,Chopo Ma,Edwin F. Nesman,Robert B. Phillips,Alan E. E. Rogers,B. O. Ronnang,J. W. Ryan,Bruce R. Schupler,David B. Shaffer,Irwin I. Shapiro,N. R. Vandenberg,John C. Webber,Alan R. Whitney +20 more
TL;DR: In this paper, a very long baseline interferometry (VLBI) system for acquiring and processing VLBI data known as Mark-III is described, which has millimeter-level accuracy on short baselines.
Journal ArticleDOI
Low-Frequency Gravitational Wave Searches Using Spacecraft Doppler Tracking
TL;DR: The principles of operation of this detector (emphasizing transfer functions of gravitational wave signals and the principal noises to the Doppler time series), some data analysis techniques, experiments to date, and illustrations of sensitivity and current detector performance are discussed.
References
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Journal ArticleDOI
A new method for making maps with unstable radio interferometers
Journal ArticleDOI
The accuracy of water vapor and cloud liquid determination by dual‐frequency ground‐based microwave radiometry
TL;DR: A dual frequency ground-based radiometer operating in the 1 to 1.4 cm wavelength range can provide continuous measurements of integrated water vapor and cloud liquid water using climatological data, the accuracy of the vapor and liquid determinations is estimated as a function of cloud amount as mentioned in this paper.
Journal ArticleDOI
Measurements and interpretation of the microwave spectrum of the terrestrial atmosphere near 1‐centimeter wavelength
TL;DR: In this paper, solar extinction measurements and interpretation of terrestrial atmosphere microwave absorption spectrum near 1-cm wavelength near 1.5 cm wavelength were used to estimate the extinction probability of solar radiation.
Journal ArticleDOI
A Dual-Channel Microwave Radiometer for Measurement of Precipitable Water Vapor and Liquid
TL;DR: In this article, the design and performance of a two-channel ground-based microwave radiometer (20.6 and 31.6 GHz) for measurement of total integrated water vapor and cloud liquid in a vertical column are discussed.
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