  A simulated binary star catalogue is created that represents the full sky
distribution of stars, excluding those with galactic latitude $|b|<10\degr$,
down to $m_v < 15$. The catalogue is compatible with observed magnitude and
number distributions of the HST Guide Star Catalog. The simulated catalogue is
analyzed for observational properties of visual binary stars, both in a general
context without taking any observational constraints into account, and using
different observability criteria that model the observational capability of the
astrometric DIVA satellite. It is shown that several observational bias effects
should be taken into account when final output catalogues are analyzed. The
results indicate that $\Delta m_v$ distribution peaks at $\Delta m_v \approx 7$
and to maximize the number of binary detections with large mass ratios, the
magnitude threshold should be set as high as possible. This is especially
important if low mass $M<0.2 M_{\sun}$ secondaries are studied. The predicted
number of optical pairs is calculated and for large magnitude differences close
to the galactic plane and toward the galactic center it may be difficult to
discriminate between a red companion and a low-mass foreground/background star
for distant double stars for which no parallax measurements are available.
Using optimal detection procedures for optical double stars it is estimated
that, depending on the assumed double star distributions, 60%-70% of all the
visual binary stars in the catalogue with separations
$0.0625\arcsec<\theta<3.5\arcsec$, $m_{v}(\mathrm{secondary})<22$, and $\Delta
m<10$ could be observed during the DIVA or similar missions.
