  LSI+61303 is one of the few GeV- and TeV-emitting X-ray binaries with a
prominent, well-studied modulated radio and gamma-ray emission. Changes in its
radio morphology suggested in the past the hypothesis of a precessing
microquasar. In 2006, a set of VLBA observations performed all around the orbit
were not used to study the precession because the souce was explained in the
context of the pulsar model, the alternative model for this system. However, a
successive radio spectral index analysis has confirmed the predictions of the
microquasar scenario in LSI+61303. At the light of these results we reanalysed
the set of VLBA observations that constitutes a unique tool to determine the
precession period and render a better understanding of the physical mechanism
behind the precession. We improved the dynamic range of the images by a factor
of four using self-calibration, and the self-calibrated maps reveal, in six out
of ten images, a double-sided structure. The double-sided structure has
variable position angle and switches at some epochs to a one-sided structure.
These variations indicate a scenario where the precessing jet, inducing
variable Doppler boosting, points close to our line of sight - a microblazar,
the galactic version of the extra-galactic blazars. High energy observations of
LSI+61303 are consistent with the microblazar nature of this object. Moreover,
we suggest in LSI+61303 the first case of core shift effect observed in a
microquasar. Because of this effect, well known in AGN, the cm-core of the jet
is rather displaced from the system center. In LSI+61303, the cm-core of the
jet traces a large ellipse, 7 times larger than the orbit, in a period of about
28 d. Our hypothesis is that this ellipse is the cross-section of the
precession cone of the jet at the distance of the 3.6 cm-core, and its period
is the precession period.
