The initial "Pokemon Go" frenzy has not yet died down, and millions of people across the world are sent into the streets to catch in-game monsters. But what was the technology behind the game? "Pokemon Go" is a location-based game that tracks players' positions using global positioning system (GPS) technology and radio waves from base stations.

With people having to physically go to places to earn points, the games can be used by municipalities and companies for local revitalization or promotion.

Pokemon characters pop up when users view a landscape through their smartphone camera. The characters come out at a certain time and several players see the same Pokemon if they are in the same place.

Using GPS radio waves improved the precision of the system, enabling it to track locations to within just a few centimeters.

The other key technology is augmented reality, which superimposes Pokemon characters on real landscapes viewed on a smartphone. But "Pokemon Go" uses one of the simplest forms of AR technology in order everyone to be able to enjoy the game, even using an older phone.

Since numerous landmarks were designated as PokeStops, where users can collect items to capture Pokemon, people can also enjoy sightseeing while playing "Pokemon Go." U.S. tech company Niantic, the game's co-developer, used data it had started collecting through its free smartphone game "Ingress", which has been available since 2013.

Ingress" allows players to register the places they visited as their own territories. The game was hugely successful and numerous territories were registered.