I've read a couple articles over the last few years mentioning it in various levels of detail. Here's one about a lunar GPS experiment launching next year:

https://www.space.com/gps-navigation-at-the-moon-navimoon

"The [GPS] signal [that reaches the moon] is 1,000 times weaker than on Earth," Botteron said. "On top of that, the signal only comes from one side, whereas on Earth, you are surrounded by those satellites on all sides."

Still, the engineers believe NaviMoon will be able to determine the position of a satellite orbiting the moon with the accuracy of 330 feet (100 meters), which is better than what existing technologies can achieve.

Using the NaviMoon system, engineers can virtually extend GPS coverage to the surface of the moon. First, they use the NaviMoon system on the satellite to determine the position of the satellite, then beam the signal on to the rovers and astronauts on the surface. With a constellation of four or five such satellites, Botteron said, they can achieve full coverage including the moon's dark side. "