  This paper discusses three matter-of-principle methods for measuring the
general relativity correction to the Newtonian values of the position of
collinear Lagrangian points L1 and L2 of the Sun-Earth-satellite system. All
approaches are based on time measurements. The first approach exploits a pulsar
emitting signals and two receiving antennas located at L1 and L2, respectively.
The second method is based on a relativistic positioning system based on the
Lagrangian points themselves. These first two methods depend crucially on the
synchronization of clocks at L1 and L2. The third method combines a pulsar and
an artificial emitter at the stable points L4 or L5 forming a basis for the
positioning of the collinear points L1 and L2. Further possibilities are
mentioned and the feasibility of the measurements is considered.
