Suppose we have unit sphere in space $R^n$ which is inscribed sphere of a hypercube. Let we have epsilon-net on the facets of hypercube. For examle, in 3-D this epsilon-net is given as the set of points with coordinates:
$(-1,\hspace{2mm} -1+i*h,\hspace{2mm} -1+j*h)$
$(1,\hspace{2mm} -1+i*h,\hspace{2mm} -1+j*h)$
$(-1+i*h, \hspace{2mm} -1,\hspace{2mm} -1+j*h)$
$(-1+i*h, \hspace{2mm} 1,\hspace{2mm} -1+j*h)$
$(-1+i*h, \hspace{2mm} -1+j*h,\hspace{2mm} -1)$
$(-1+i*h, \hspace{2mm} -1+j*h,\hspace{2mm} 1)$
In R^n we form the set of points analogically.
Then we join every point from this set with the origin ( in 3-D - $(0,0,0)$) by straight line. This lines intersect with our unit sphere in some kind of points. So we have a set of points at sphere which ic called 'base of covering'.
It's need to find by analitycal way the radius of covering (or try to get up and low appreciations).