  The propagation time of a signal, emitted by a moving along an elliptical
orbit satellite from the GPS (or GLONASS) satellite confi gurations is a very
important ingredient of the theory, based on the formalism of the null cone and
accounting for the effects of the General Relativity Theory. For the case of
satellites, orbiting along a plane elliptic orbit, it has been proved that the
propagation time for the signal between the satellites is given by a
combination of elliptic integrals of the first, second and third kind. For the
more general case of satellites on a space-distributed elliptic orbit, the
propagation time is expressed by higher (fourth) order elliptic integrals,
which according to the standard theory can be expressed recurrently by means of
lower-order elliptic integrals. In the concrete case, the elliptic integrals of
the second and the fourth order are expressed by means of a combination of
irrational functions and the zero-order elliptic integral in the Legendre form.
It has been proved that for the investigated case, second-order elliptic
integrals can be expressed by elementary functions.
