  During the final stages of a compact object merger, if at least one of the
binary components is a magnetized neutron star (NS), then its orbital motion
substantially expands the NS's open magnetic flux -- and hence increases its
wind luminosity -- relative to that of an isolated pulsar. As the binary orbit
shrinks due to gravitational radiation, the power and speed of this
binary-induced inspiral wind may (depending on pair loading) secularly
increase, leading to self-interaction and internal shocks in the outflow beyond
the binary orbit. The magnetized forward shock can generate coherent radio
emission via the synchrotron maser process, resulting in an observable radio
precursor to binary NS merger. We perform 1D relativistic hydrodynamical
simulations of shock interaction in the accelerating binary NS wind, assuming
that the inspiral wind efficiently converts its Poynting flux into bulk kinetic
energy prior to the shock radius. This is combined with the shock maser
spectrum from particle-in-cell simulations, to generate synthetic radio light
curves. The precursor burst with a fluence of $\sim1$ Jy$\cdot$ms at $\sim$GHz
frequencies lasts $\sim 1-500$ ms following the merger for a source at $\sim3$
Gpc ($B_{\rm d}/10^{12}$ G)$^{8/9}$, where $B_{\rm d}$ is the dipole field
strength of the more strongly-magnetized star. Given an outflow geometry
concentrated along the binary equatorial, the signal may be preferentially
observable for high-inclination systems, i.e. those least likely to produce a
detectable gamma-ray burst.
