  Background estimation is important for determining the statistical
significance of a gravitational-wave event. Currently, the background model is
constructed numerically from the strain data using estimation techniques that
insulate the strain data from any potential signals. However, as the
observation of gravitational-wave signals become frequent, the effectiveness of
such insulation will decrease. Contamination occurs when signals leak into the
background model. In this work, we demonstrate an improved background
estimation technique for the searches of gravitational waves (GWs) from binary
neutron star coalescences by time-reversing the modeled GW waveforms. We found
that the new method can robustly avoid signal contamination at a signal rate of
about one per 20 seconds and retain a clean background model in the presence of
signals.
