  A valuable target for advanced gravitational-wave detectors is the stochastic
gravitational-wave background. The stochastic background imparts a weak
correlated signal into networks of gravitational-wave detectors, and so
standard searches for the gravitational-wave background rely on measuring
cross-correlations between pairs of widely-separated detectors. Stochastic
searches, however, can be affected by any other correlated effects which may
also be present, including correlated frequency combs and magnetic Schumann
resonances. As stochastic searches become sensitive to ever-weaker signals, it
is increasingly important to develop methods to separate a true astrophysical
signal from other spurious and/or terrestrial signals. Here, we describe a
novel method to achieve this goal -- gravitational-wave geodesy. Just as radio
geodesy allows for the localization of radio telescopes, so too can
observations of the gravitational-wave background be used to infer the
positions and orientations of gravitational-wave detectors. By demanding that a
true observation of the gravitational-wave background yield constraints
consistent with the baseline's known geometry, we demonstrate that we can
successfully validate true observations of the gravitational-wave background
while rejecting spurious signals due to correlated terrestrial effects.
