It has been argued, for a number of reasons, that the next generation radio telescope should be a multi-element interferometer with a collecting area of about 1 km2. The remaining parameters of such an instrument – frequency range, angular resolution, instantaneous bandwidth, etc. – will be science driven. The requirements for propagation studies are briefly discussed, and it is pointed out how variable-source confusion may differ from the normal variety. Finally, the Dutch project to achieve a large collecting area using adaptive arrays of active antennas is described. A systematic approach has been adopted, with the construction of arrays of increasing complexity to test design features at each state. Recently, development of a low frequency array (LOFAR) has become an additional option. It would facilitate tests of some of the larger instrument’s features, and provide real data on the influence of the ionosphere and interfering sources.

Many karst depressions with diameters of 300 m to 500 m, suitable for constructing Arecibo-style radio telescopes, were identified in the south of Guizhou Province by Remote Sensing (RS) and Geographic Information System (GIS) technologies together with field investigations. Fundamental topography and landform databases were established for 391 candidate depressions, and using GIS the 3-dimensional images of depressions, at a scale of 1:10000, were then simulated to fit a spherical antenna.

A Five hundred meter Aperture Spherical Telescope (FAST) is proposed to be built in the unique karst area of southwest China, and will act, in a sense, as a prototype for the Square Kilometer Array (SKA). It will be over twice as large as the Arecibo telescope coupled with much wider sky coverage. Some results from site surveys for such a SKA concept are briefly reported. Technically, FAST is not simply a copy of the existing Arecibo telescope but has rather a number of innovations. Firstly, the proposed main spherical reflector, by conforming to a paraboloid of revolution in real time through actuated active control, enables the realization of both wide bandwidth and full polarization capability while using standard feed design. Secondly, a feed support system which integrates optical, mechanical and electronic technologies will effectively reduce the cost of the support structure and control system. Pre-research on FAST has become a key project in the CAS.

In this paper, an analysis of the aluminum reflector mesh panels for the Five-hundred meter Aperture Spherical Telescope (FAST) is described. The study concentrates on one element of the reflector surface with the shape of a triangle. For the analysis, the panel is modelled as a mesh of cables so that it can be treated as continuous. It is demonstrated that the results so obtained are reasonable.

According to the deformation and movement requirements of the FAST reflector, a multipurpose analysis, including the load-bearing behavior, deformation, construction costs of the reflector supporting structure and its model, is presented in this paper. The advantages and disadvantages of steel and aluminum alloy structures are also discussed and compared through detailed design calculations under load-bearing capacity and normal working conditions.

An innovative design for a feed support structure for the next generation large radio telescope, based on the idea of integrating mechanical, electronic and optical technologies (Optomechatronics), is considered. Theoretical analyses and simulations are carried out. A 5 m experimental model is built to demonstrate the idea.

This paper introduces the cable car feed support configuration for China’s FAST project. Recent advances on the mechanics of the proposed supporting structure and the control of the Stewart platform for secondary feed stabilization are presented. Difficulties associated with the configuration are also discussed.

The proposed FAST project is a novel giant spherical radio telescope, with active elements which form a temporary paraboloid to track radio objects in the sky. Efforts have been made to extend the limited sky coverage that is a characteristic disadvantage of Arecibo-style radio telescopes. Three measures under investigation are introduced in this paper. The expected performance of the telescope is described, and a brief comparison is made with some of the largest existing radio telescopes.

The five hundred meter aperture spherical radio telescope is will use an active spherical reflector. When the zenith scan angle is changed, the illuminated part of the reflecting surface is made to fit a paraboloid of revolution in real time by active control. The maximum zenith scan angle | ψmax | of FAST is 30° under conditions of the geometry selected in order that the feed does not illuminate the ground. The result of this paper shows that the maximum zenith scan angle | ψmax | can be extended to 69° by offsetting the feed.

The main reflector of FAST consists of about 1800 elementary units. Each unit has three adjustable supports to fix its position, and its position is adjusted by means of mechanical actuators. According to the radio source position at any given time, all the actuators are continuously adjusted to form a proper paraboloid in real time during the course of the observation. The basic requirements of such a control system are discussed. A fieldbus control system based on LonWorks technology is suggested to control all 1800 actuators. The main advantages of this distributed control system are its reliability, flexibility, efficiency and economics.