In the literature there are several papers that provide description of
heliostat fields for solar tower plants. Two years ago, for instance, the
following paper was published in the Solar Energy international journal,
that provides information regarding how to generate heliostat fields, and
also includes references to previous articles in the subject:
"Heliostat Field Optimization: A New Computationally E cient Model and
Biomimetic Layout". Corey J. Noone (MIT), Manuel Torrilhon (RWTH) and
Alexander Mitsos (MIT,*) Department of Mechanical Engineering.
Massachusetts Institute of Technology
If you do an Internet search you may find PDF copies of such article. Also
you can get it from the Solar Energy journal. I found a copy of the
article, most likely the author's draft, at the following link:
Furthermore, you may also want to explore the simulation capabilities for
solar tower systems of NREL's Solar Advisor Model (SAM).
I hope the above information is of help.