  In this Letter, we propose to detect the interaction of a hypothetical
coherently evolving cosmological scalar field with an orbital network of
quantum sensors, focusing on the GPS satellite network as a test example.
Cosmological scenarios, such as a scalar-tensor theory for dark energy or the
axi-Higgs model, suggest that such a field may exist. As this field would be
(approximately) at rest in the CMB frame, it would exhibit a dipole as a result
of the movement of our terrestrial observers relative to the CMB. While the
current sensitivity of the GPS network is insufficient to detect a cosmological
dipole, future networks of quantum sensors on heliocentric orbits, using
state-of-the-art atomic clocks, can reach and exceed this requirement.
