Though the geophysical data records for the three satellites generally
account for the precise timing of the altimeter measurements within a
small fraction of a millisecond, we still see significant errors
(Fig. 3b vs Fig. 3c)
in this estimate for Geosat, less so for Ers1, and almost undetectable
from altimetry for T/P.
A constant time-tag bias 
(lagging or leading the
stated time in the ephemeris) has a characteristic twice per revolution
signature in the altimeter height due mostly to the dominant oblateness of the
sea surface (but also from the oblate geopotential's effect on the orbit).
We follow Wagner and Klokocnik (1994) and write for this effect on
the sea height:
noting in the fuctionality for 
only those parameters which are
different for different orbits;
where is the time-tag error (correct altimeter time -
tagged time on the data record), I,a and n are the orbit's
inclination, semimajor axis and (nodal) mean motion,
and f are the Earth's mean equatorial radius and polar flattening,
is the 2nd degree zonal geopotential coefficient (-0.001082.63),
is the geocentric latitude and
the 
applies for ascending passes and
the 
for descending.
Thus for SSCs we have:
and for the 4 DSC types:
