If you’re planning to trek out to uncharted territory and don’t like getting lost, then the answer may be within your PSP. Sony has released its GPS Receiver add-on for its handheld game system, which adds navigation functionality to the PSP.

The GPS Receiver measures 45mm x 41mm x 17mm and weighs approximately 16 grams. It sits on top of the PSP expansion socket and is bolted onto the system with a thumbscrew.

The current GPS software enables road car navigation (for Japan), walking routes, and shops directory – all much like current standalone GPS offerings. Updates to maps will be offered via Sony’s usual network channels.

With the lack of touch-screen functionality on the PSP, its GPS usability will likely lag behind those of GPS systems with easier input methods other than using the d-pad. Still, Sony’s offering represents one of the cheapest entries into GPS navigation, provided that you already own a PSP. The local price for this is 5,000 yen (US$43), but Play-Asia is selling the import unit to the U.S. for $59.90, plus $8.80 shipping.

While its use as a navigation solution may end up being quite limited, developers have already incorporated the GPS functionality into its games. In the Japanese version of the new Hot Shots Golf title, players can use the GPS-enabled PSP as a golf course map for real golf courses, letting the golfer check his or distances from the pin, traps and other things. Metal Gear: Portable Ops integrates the player’s physical location into the game to unlock new locations and characters.

The product is currently only for sale in Japan, but Sony will likely release it in North America and Europe within the near future.