  The mass and spin properties of binary black holes (BBHs) inferred from their
gravitational-wave signatures reveal important clues about how these systems
form. BBHs originating from isolated binary evolution are expected to have
spins preferentially aligned with their orbital angular momentum, whereas there
is no such preference in binaries formed via dynamical assembly. The fidelity
with which near-future gravitational-wave detectors can measure off-axis spins
will have implications for the study of BBH formation channels. In this work,
we examine the degree to which the Advanced LIGO Plus (A+) and Advanced Virgo
Plus (AdV+) interferometric detectors can measure both aligned and misaligned
spins. We compare spin resolution between the LIGO-Virgo network operating at
either A+/AdV+ ("Plus") sensitivity or Advanced-era design ("Design")
sensitivity using simulated BBH gravitational-wave signals injected into
synthetic detector noise. The signals are distributed over the mass-spin
parameter space of likely BBH systems, accounting for the effects of precession
and higher-order modes. We find that the Plus upgrades yield significant
improvements in spin estimation for systems with unequal masses and moderate or
large spins. Using simulated signals modelled after different types of
hierarchical BBH mergers, we also conclude that the Plus detector network will
yield substantially improved spin estimates for 1G+2G binaries compared to the
Design network.
