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Statistical Analysis of the 70 Meter Antenna Surface Distortions

15 Feb 1987-Vol. 88, pp 29-35
TL;DR: In this paper, a statistical analysis of surface distortions of the 70 meter NASA/JPL antenna, located at Goldstone, was performed to verify whether deviations due to gravity loading can be treated as quasi-random variables with normal distribution.
Abstract: Statistical analysis of surface distortions of the 70 meter NASA/JPL antenna, located at Goldstone, was performed. The purpose of this analysis is to verify whether deviations due to gravity loading can be treated as quasi-random variables with normal distribution. Histograms of the RF pathlength error distribution for several antenna elevation positions were generated. The results indicate that the deviations from the ideal antenna surface are not normally distributed. The observed density distribution for all antenna elevation angles is taller and narrower than the normal density, which results in large positive values of kurtosis and a significant amount of skewness. The skewness of the distribution changes from positive to negative as the antenna elevation changes from zenith to horizon.
Citations
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Proceedings ArticleDOI
23 Apr 2012
TL;DR: In this paper, a simple electro-magnetic analysis of a thin composite shell reflector capable of being rolled and stowed in a tight dual-roll or single-roll configuration and discussion of potential design concerns for consideration is presented.
Abstract: This paper presents a simple electro-magnetic analysis of a thin composite shell reflector capable of being rolled and stowed in a tight dual-roll or single-roll configuration and discussion of potential design concerns for consideration. The shell is square in shape and has a doubly-curved surface for use as a segment of a larger deployable reflective aperture. Carbon fiber reinforced polymer is used as the reflective surface for its stiffness and dimensionally stable characteristics. Electro-magnetic properties are estimated from literature and discussion is provided on how to experimentally obtain more accurate values along with current test results and limitations. COMSOL is used for preliminary analysis of the reflector to examine the impact of design errors on performance.

1 citations

References
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Book
01 Jan 1967

22,994 citations

Journal ArticleDOI

6,420 citations

Journal ArticleDOI
01 Jan 1978

6,005 citations

Journal ArticleDOI

281 citations


"Statistical Analysis of the 70 Mete..." refers background in this paper

  • ...(1) and (2) are commonly used to estimate antenna gain loss even when surface distortions are due to deterministic causes such as gravity....

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  • ...The gain loss, AG, due to reflector surface imperfections can be computed in decibels from: AG = 10 loglo r/ (1) where the efficiency 77 is approximated by Ruze's (Ref....

    [...]

Journal ArticleDOI
TL;DR: A novel mathematical model to determine efficiently the average power pattern degradations caused by random surface errors shows that as sidelobe levels decrease, their dependence on the surface rms/ \lambda becomes much stronger and, for a specified tolerance level, a considerably smaller rms is required to maintain the low sidelobes within the required bounds.
Abstract: Based on the works of Ruze and Vu, a novel mathematical model has been developed to determine efficiently the average power pattern degradations caused by random surface errors. In this model, both nonuniform root mean square (rms) surface errors and nonuniform illumination functions are employed. In addition, the model incorporates the dependence on F/D in the construction of the solution. The mathematical foundation of the model rests on the assumption that in each prescribed annular region of the antenna, the geometrical rms surface value is known. It is shown that closed-form expressions can then be derived, which result in a very efficient computational method for the average power pattern. Detailed parametric studies are performed with these expressions to determine the effects of different random errors and illumination tapers on parameters such as gain loss and sidelobe levels. The results clearly demonstrate that as sidelobe levels decrease, their dependence on the surface rms/ \lambda becomes much stronger and, for a specified tolerance level, a considerably smaller rms/ \lambda is required to maintain the low sidelobes within the required bounds.

111 citations