Millimeter wave radio telescopes: Gain and pointing characteristics

Ulich, B. L.

doi:10.1007/bf01007036

Cited by 13 publications

(4 citation statements)

References 7 publications

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“…( 28) demonstrates that the bending angle correction is an approximation to the MPF delay at low elevation angles. However, it is necessary to adopt a better equation to calculate the atmospheric bending angle, such as the Ulich equation [40]. In Fig.…”

Section: Discussionmentioning

confidence: 99%

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A Novel Tropospheric Error Formula for Ground-Based GNSS Interferometric Reflectometry

Feng,

Haas,

Elgered

2023

IEEE Trans. Geosci. Remote Sensing

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We deduce a Novel Interferometric Tropospheric Error (NITE) formula for ground-based GNSS interferometric reflectometry (GNSS-IR). This formula contains two parts: a geometric displacement error that accounts for the reflection point change due to the atmosphere and the earth curvature, and a path delay derived following the definition of the mapping function (with the small curve path effect included). We validate the NITE formula together with two previously used approaches, the bending angle correction and the mapping function path delay (MPF delay) using raytracing and radiosonde data. The raytracing results show that the NITE formula is more accurate than the previous approaches. Numerically, the geometric displacement error is < 5 % of the path delay error for a GNSS antenna located 20 m above sea level. We further evaluate six tropospheric correction strategies for GNSS-IR sea level monitoring through two sets of experiments. With an elevation angle range test, we show that applying no tropospheric correction and applying the bending angle correction plus the MPF delay both introduce large elevation-dependent biases. Analyzing the time series of differences between GNSS-IR and tide gauges sea level, we show that the bending angle correction with the widely used Bennett equation introduces long-term (4 h to several months) trends in the sea-level retrievals. We identify one station where the NITE formula produces better long-term (τ > 4 h) sea-level retrievals. Finally, we show that at low elevation angles, the bending angle correction can be reformulated as an MPF delay.

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Section: Discussionmentioning

confidence: 99%

“…However, tropospheric water vapor is a major error contributor to GNSS signal propagation [36], [37], and the basis of GNSS meteorology [38], [39]. We take a similar equation given by Ulich [40], where the water vapor effect is considered. The Ulich equation is ∆e = 10 −6 N cos e T sin e T + 0.00175 tan(87.5…”

Section: B Geometric Displacement Errormentioning

confidence: 99%

A Novel Tropospheric Error Formula for Ground-Based GNSS Interferometric Reflectometry

Feng,

Haas,

Elgered

2023

IEEE Trans. Geosci. Remote Sensing

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“…So, carrying out system pointing calibration is the first step to use the telescope. There are a number of pioneers who introduced the principle and method to calibrate pointing of a telescope (Meeks et al 1968;Yuan et al 1986;Himwich 1993;Iesber 1967;Ulich 1981Ulich , 1982. Instead of the fitting method of least squares, which is widely adopted in model fitting of pointing calibration, Kong (2008) introduced a new fitting method, which is named the Generalized Extended Interpolation Correction Method.…”

Section: Pointing Calibration Of the Mrt50mentioning

confidence: 99%

Measurements of electronic properties of the Miyun 50 m Radio Telescope

Zhang

Zhu

Kong

et al. 2009

Res. Astron. Astrophys.

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Measurement results of some properties of the Miyun 50 m radio telescope (MRT50) of the National Astronomical Observatories, such as pointing calibration, antenna beams, system noise temperature, gain and gain variations with elevation are introduced. By using a new de-convolution technique developed by our group, the broadening effect on measured beams caused by the width of an extended radio source has been removed so that we obtained higher accuracy on the measurements of MRT50 beams.

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“…For telescopes with a straight optical path, the classical pointing model has been derived independently by many different authors, e.g., Graser & Hopp (1991) and Wallace & Tritton (1979). In the azimuth-altitude system, which is the natural choice for az-alt telescopes such as the GREGOR solar telescope, the earliest formulation of the classical pointing model can be found for radio antennas, e.g., Stumpff (1972) and Ulich (1981).…”

Section: Introductionmentioning

confidence: 99%

Preparing the GREGOR solar telescope for night‐time use: Deriving a pointing model

et al. 2012

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We report on the results of a dedicated campaign to derive a pointing model for the GREGOR solar telescope which took place in December 2011. Two main goals were in the focus of this campaign: first to prove the aptness of the GREGOR solar telescope for night-time, unattended operations and second to derive some qualitative measure of the amount of misalignment in the optical and mechanical parts of the telescope. In the final version, a root-mean-square deviation (RMSD) of 1.6 for the azimuth model and an RMSD of 2.3 in the elevation model could be achieved.

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Millimeter wave radio telescopes: Gain and pointing characteristics

Cited by 13 publications

References 7 publications

A Novel Tropospheric Error Formula for Ground-Based GNSS Interferometric Reflectometry

A Novel Tropospheric Error Formula for Ground-Based GNSS Interferometric Reflectometry

Measurements of electronic properties of the Miyun 50 m Radio Telescope

Preparing the GREGOR solar telescope for night‐time use: Deriving a pointing model

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