3 July 2000 Improved method for pointing characterization of large radio telescopes
Author Affiliations +
Proceedings Volume 4015, Radio Telescopes; (2000); doi: 10.1117/12.390430
Event: Astronomical Telescopes and Instrumentation, 2000, Munich, Germany
In order to upgrade existing large radio telescopes or develop new ones, it is necessary to employ sophisticated active controls to meet the higher requirements on surface precision and pointing accuracy. However, in order for these high- performance controllers to maintain stability, they require an accurate characterization of the telescope structure. A finite element model (FEM) is sufficient to prove controller concepts, but does not have the level of accuracy required for final controller implementation. This results in a need for experimental characterization of the structure. A significant problem is that the structural behavior of the telescope is typically measured at the encoders, while the critical performance is the actual pointing on the sky. Conventional pointing measurements are excellent for obtaining the actual pointing direction, but are insufficient for structural characterization. Conversely, conventional physical measurements are excellent for determining structural behavior, but are not suitable for high accuracy calculation of the final pointing. We describe a new method for taking pointing measurements to quantify the static and dynamic tracking errors in the telescope. This is accomplished by combining pointing measurements at a high sample rate with simultaneous data taken from sensors on the structure. In the simplest form, the method allows improvement of the telescope controller and some indication of the relative importance of static and dynamic effects. More complete implementations of the approach can provide information about the major contributors of pointing error, improvements to the FEM, and extraction of the force distribution history on the structure. Such data will be essential if future telescope upgrades and designs are to take advantage of complex control and metrology.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David R. Smith, "Improved method for pointing characterization of large radio telescopes", Proc. SPIE 4015, Radio Telescopes, (3 July 2000); doi: 10.1117/12.390430; https://doi.org/10.1117/12.390430




Autoregressive models

Radio telescopes

Computer programming

Finite element methods


Pointing with the IRAM 30-m telescope
Proceedings of SPIE (July 03 2000)
Preliminary feasibility study of a Dome C radioantenna
Proceedings of SPIE (August 05 2010)
Support systems for segmented mirrors – an overview
Proceedings of SPIE (May 30 2006)
Research of Large Telescope Control System
Proceedings of SPIE (July 19 2010)
Status of the Sardinia Radio Telescope project
Proceedings of SPIE (July 10 2008)

Back to Top