  We present a method to estimate and remove the baseline drift affecting the
data produced by the two infrared imaging photometers onboard the ESA Herschel
satellite, namely PACS and SPIRE. The method exploits a Least Square approach
which is performed after that the signal component has been removed from the
data by means of a projection into an appropriate subspace. We present the
method, discuss its performance and implementation details and show that it is
perfectly suited for Herschel data, for which it can ideally guarantee a
complete drift removal.
