  This paper presents a new approach to combine cross-correlation functions.
The combination is based on a maximum-likelihood approach and uses a non-linear
combination scheme. It can be effective for radial-velocity analysis of
multi-order spectra, or for analysis of multiple exposures of the same object.
Simulations are presented to show the potential of the suggested combination
scheme. The technique has already been used to detect a very faint companion of
HD41004.
