  We investigate the utility of a constellation of four satellites in
heliocentric orbit, equipped with accurate means to measure intersatellite
ranges, round-trip times and phases of signals coherently retransmitted between
members of the constellation. Our goal is to reconstruct the measured trace of
the gravitational gradient tensor as accurately as possible. Intersatellite
ranges alone are not sufficient for its determination, as they do not account
for any rotation of the satellite constellation, which introduces fictitious
forces and accelerations. However, measuring signal round-trip time differences
among the satellites supplies the necessary observables to estimate, and
subtract, the effects of rotation. Utilizing, in addition, the approximate
distance and direction from the Sun, it is possible to approach an accuracy of
$10^{-24}~{\rm s}^{-2}$ for a constellation with typical intersatellite
distances of 1,000 km in an orbit with a 1 astronomical unit semi-major axis.
This is deemed sufficient to detect the presence of a galileonic modification
of the solar gravitational field.
