The Pioneer space probes was not orbiting the Sun, but rather following the sun, - The radio signals emitted was therefore in principle perfect to measure / compare any orbit or rotation time dilation anomalies, on earth, - not expected based on the prevailing paradigm..
The Pioneer radio signals received on Earth is showing seasonal radio frequency variations, which could support that the earth moves more or less perpendicular to the Dark Flow axis, and even also support more about which direction it happens, - notice we talk about true motion..
Shortly spoken we can also expect unexpected time dilation influence, that to a certain (until now) unknown extend also will cause SR time dilation during some part of the orbit of the Earth, but not when moving opposite..
If so the orbit of the Earth is getting either faster elliptical or circular as expected, this part depend on where perihelion is pointing relative to that sideward SR / RR influence..
The pioneer data can even help to solve the last pieces of the outstanding problems fully to solve ice ages.
As you should be able to understand, this is a perfect starting point to discuss orbit inclination relative to DFA, - in general, - . But It require serious scientist, - not only brainwashed saved fools.