<Li> lowest possible cost, </Li> <Li> minimal impact on network and equipment . </Li> <P> Several categories of methods can be used to find the location of the subscriber . The simple and standard solution is LBS based on GPS or an alternative satellite navigation system . Sony Ericsson's "NearMe" is one such example . It is used to maintain knowledge of the exact location, however can be expensive for the end - user, as they would have to invest in a GPS - equipped handset . GPS is based on the concept of trilateration, a basic geometric principle that allows finding one location if one knows its distance from other, already known locations . </P> <P> A low cost alternative to using location technology to track the player, is to not track at all . This has been referred to as "self - reported positioning". It was used in the mixed reality game called Uncle Roy All Around You in 2003 and considered for use in the Augmented reality games in 2006 . Instead of tracking technologies, players were given a map which they could pan around and subsequently mark their location upon . With the rise of location - based networking, this is more commonly known as a user "check - in". </P>

A person searching for information on car rental services online is an example of push technology