This paper introduces an algorithm for automatically tuning analytic navigation functions for sphere worlds. The tuning parameter must satisfy a lower bound to ensure collision avoidance and convergence. Until now analytic navigation functions have been manually tuned, although existence of a lower bound had been proved. A theoretical improvement on this lower bound is provided and the method is extended to unbounded manifolds. Then the required formulas are derived and algorithm described. So the lower bound is here evaluated in terms of sphere world centers and radii. Automated tuning enables completely unattended solution of any navigation problem in unknown sphere worlds and a priori known worlds which belong to the sphere world diffeomorphism class.