Let vertices be defined on the unit sphere by its longitudes $\lambda_i$ and latitudes $\phi_i$. The distance between $i$ and $j$ is defined as follows: $\arccos(\sin(\lambda_i) \sin(\lambda_j) \cos(\phi_i - \phi_j) + \cos(\lambda_i) \cos(\lambda_j))$ which is an angle measure of the shortest distance between two points on unit sphere.
So, I want solve the traveling salesman problem on this unit sphere. Unfortunately, I didn't found any information on this problem.
Are there any approximations, heuristics, etc which utilize this distance definition?