Games

Applications
Title	Games
Author(s)	Rui Barradas Pereira, GMV
Level	Basic
Year of Publication	2011

The availability of consumer GNSS receivers and GNSS enabled mobile devices made possible the use of GNSS for gaming. The oldest and still the most popular GNSS game is Geocaching. Geocaching combines treasure hunt with trekking and outdoor activities.

More recent GNSS based games rely on mobile devices with multimedia interfaces and permanent internet connection. Often these games are multiplayer games that take place in urban environments. Common themes are scavenger hunts, role playing and adventure games.

Application Architecture

GNSS Games depend normally on an architecture that includes a multimedia user mobile device and a game server that collects the different users positions and implements the gameplay.

The user mobile device is usually a mobile phone or smartphone with internet access, localization capabilities and a multimedia user interface.

The process usually followed by these applications is:

• An application running in the user mobile device sends the position of the player to a game server.

• The game server gathers the positions of all the players, place them in the virtual scenario being used in the gameplay, implements the gameplay and sends to the each player its own status or view of the game.

• The player receives in the mobile device the current status sent by the game server and the game application renders on screen the users view of the gameplay. This view normally includes a map with player positions in the virtual scenario of the game.

• In some games there is the possibility of communicating between players.

Variants to this architecture are:

• Game server might not be required for single-player games where the virtual scenarios can be pre-loaded or generated.

• Connection with the game server can be done through SMS. This can include only the communication layer and the user interface is done by a local application or the user can interface directly with the game server through SMS.

• Positioning can be done with celular network based localization.

These applications are considered non-critical applications.

For gaming the precision can be considered a comodity: the higher precision the better. More precision could enhance and improve the gameplay but current games adapt the gameplay to the available precision. Given this we can say that the precision required by games is low, being the current accuracy provided by civilian GPS enough.

Geocaching

Geocaching logo

The oldest and still the most popular GNSS game is Geocaching. Geocaching combines treasure hunt with trekking and outdoor activities.

When GPS Selective Availability was disconnect on March 2^nd 2000, Dave Ulmer, GPS enthusiast, wanted to test the accuracy of GPS. To do so decided to hide a container with a stash of gifts, a log book and a pencil, in the woods near Beavercreek, Oregon, near Portland.

Dave Ulmer posted the stash coordinates in a satellite navigation newsgroup and the rules were simple: find the container, register you finding in the log book, take something from the stash and leave something else.

After some days several readers had found the stash and others followed on the idea and began hiding their own stashes.

The activity was originally called GPS Stash Hunt but rapidly was renamed to Geocaching. Rapidly information about caches around the world started to be concentrated in websites such as Geocaching.com.

Currently it is estimated that there are over 5 million geocachers and over 1 million geocaches active worldwide. Several variants were created such as multiple caches until reaching the final cache, puzzles to find the cache, moving caches and temporary caches for special events. Geocaching became an outdoor activity usually paired with camping, hiking, biking, boating.

Other Game Examples

Trail on a location-based game

The most common types of GNSS games are:

• Scavenger hunts: in these games the player or a team of players needs to collect virtual items by reaching geographically defined spots and collecting the items. Geocaching, which is the oldest and most popular of GNSS games, can be considered a form of scavenger hunt.
• Role playing games: "Dungeons & Dragons"-like games, where the players can interact when in the vicinity of each other.
• Virtual Boardgames: games that use real locations as gameboards. Player assumes the role of a character in the game and moves around the location to achieve the game objective.
• Adventure game: Adventure games combine virtual worlds with the surroundings of the player. To move around the virtual world the player needs to move in the real world scenario.

Example of notable GNSS games are:

• Tourality: is a real life scavenger hunt GPS game for smartphones
• Pac-Manhattan: uses the area in and around Washington Square Park to play a real live version of Pacman.
• The Journey (part 1 + 2): location based adventure games developed by Mopius, which run on standard Symbian OS-phones.
• Gbanga Famiglia: mixed reality, mobile phone game were players takeover as many establishments as possible as part of a Mafia Famiglia.
• Tron:LifeCycle: location-based mobile game that lets you play the Tron's light cycle game in real-life.
• Mini Get Away Stockholm: advertising campaign where people took a virtual Mini when in less than 50m from the current holder. When the time finished the virtual Mini holder would get a real Mini.