Science and Development Network (SciDev.Net)
A Location-Based Service (LBS) cannot be realized unless solutions of the positioning problem are available at hand. For the outdoor positioning, GPS based practical solutions have been introduced. Using GPS they have developed so many commercial LBS systems. Navigation, logistics, troop management and fleet management are all examples of LBS. LBS are so useful that it should be available in doors. However, GPS signal is so weak inside buildings that users cannot determine the location of a moving object in doors with GPS only. Therefore, so many indoor positioning researches have been performed. Cricket, Active Badge and BAT are pioneers in the field of indoor positioning. They are very accurate but they require special equipments dedicated for positioning.