If you have already computed the spatial median plug it in here.
Value
The spatial sign covariance matrix.
Details
The spatial median is at first computed (if not supplied) and then the covariance matrix. This is used in the function comp.den.
References
A Durre, D Vogel, DE Tyler (2014). The spatial sign covariance matrix with unknown location. Journal of Multivariate Analysis, 130: 107-117.
http://arxiv.org/pdf/1307.5706v2.pdf