  We present the experimental realization of a laser system for ground to
satellite optical Doppler ranging at the atmospheric turbulence limit. Such a
system needs to display good frequency stability (a few parts in 10^{-14})
whilst allowing large and well controlled frequency sweeps of +/- 12 GHz at
rates exceeding 100 MHz/s. Furthermore it needs to be sufficiently compact and
robust for transportation to different astronomical observation sites where it
is to be interfaced with satellite ranging telescopes. We demonstrate that our
system fulfills those requirements and should therefore allow operation of
ground to low Earth orbit satellite coherent optical links limited only by
atmospheric turbulence.
