A Natural Consequence of Curvature
Pretend the straight blue line, drawn through the sun and earth, is the sightline of an observer looking out toward the constellations. Notice the observer now has a changing orientation to distant space, and with each vernal equinox, his gaze can slightly precess (change orientation) relative to the constellations or fixed stars without any wobble of the Earth required.
Zoom in to see the “incremental change” in earth orientation that naturally occurs as the sun and solar system curves through space. One year of this change is what astronomers now call one year of precession. In other words, in the moving solar system model precession is simply angular velocity.

Kepler tells us celestial bodies in orbit around another mass move in elliptical orbits – and that these orbits increase and decrease in speed depending on whether the two objects are moving closer to or farther away from their common center of mass. This changes their angular velocity. Therefore if the precession rate appears to be increasing, then the sun is in that part of its elliptical orbit where it is moving from apoapsis to periapsis – and according to Kepler’s laws it would be speeding up. Thus the variable rate of precession (known to be speeding up ever since modern records have been kept) is no longer a mystery in the binary model. It is simply the trait of an object in an elliptical orbit. The rate of change can be reliably predicted using Kepler’s laws if the basic orbit parameters are known. In fact we have found that by using Kepler’s laws we can predict the precession rate 10 times more accurately than Simon Newcomb’s constant.