by position I and I guess anybody who has delved even a little into the subject would think of ephemeris, which by definition is position of a satellite along its ecliptic and that is corroborated by the excerpt I posted from oxford ATPL.
Wrong. You obviously have not delved deep enough! The ephemeris of a satellite consists of a series of variables which when combined with the satellite time signal is input into an equation in the RECEIVER which enables the receiver to CALCULATE the satellites estimated position. I am afraid that this is not the only error within Oxford's ATPL notes about GPS!
Also, there appears to be some confusion between empheris and almanac. From the European Space Agency's Navipedia:
"Every satellite receives from the ground antennas the navigation data which is sent back to the users through the navigation message. The Navigation Message provides all the necessary information to allow the user to perform the positioning service. It includes the Ephemeris parameters, needed to compute the satellite coordinates with enough accuracy, the Time parameters and Clock Corrections, to compute satellite clock offsets and time conversions, the Service Parameters with satellite health information (used to identify the navigation data set), Ionospheric parameters model needed for single frequency receivers, and the Almanacs, allowing the computation of the position of ”all satellites in the constellation”, with a reduced accuracy (1 - 2 km of 1-sigma error), which is needed for the acquisition of the signal by the receiver. The ephemeris and clocks parameters are usually updated every two hours, while the almanac is updated at least every six days."
And from the "horse's mouth",
WWW.GPS.GOV
"Navigation (NAV) Message Data. The data provided to a GPS receiver via each satellite's SIS containing the satellite's predicted clock correction polynomial ("clock"), the satellite's predicted orbital elements ("ephemeris"), a reduced-precision subset of the clock and ephemeris data for all operational satellites in the constellation ("almanac"), pseudorange correction data, parameters relating GPS time to UTC, single-frequency ionospheric correction model parameters, and satellite status information."
I think it is fair to say that the European Space Agency and the US Government know a bit more about GPS than Oxford!