Seamless location based service (LBS) in train stations using GNSS and IMES

In this study, technical issues were addressed and applications incorporating positional information were developed to support the establishment of seamless indoor/outdoor positioning environments in train stations and other public spaces based on the Global Navigation Satellite System (GNSS) and the Indoor Messaging System (IMES). With regard to indoor and outdoor positioning, this paper reports a case example of spot area creation based on multipath effect minimization conducted by limiting the intensity of IMES transmitter output signals as far as possible. This in turn enables stable reception of IMES signals even in confined spaces enclosed in metallic and other barriers, such as railway cars and stations. Also reported is a case example in which an algorithm was developed to increase redundancy by sending the same positional information via two sets of transmitters in order to prolong the length of time available for positional recognition and prevent misrecognition in movement between indoor and outdoor environments, between indoor floors or across other boundaries. In cases where indoor positions are configured solely using IMES transmitters, it is necessary to install numerous such units in consideration of their usage at stations and other places, which raises initial costs. To avoid this, evaluation was performed in order to determine the effectiveness of hybrid positioning methods adopted to correct absolute positions via IMES signals through the joint use of dead reckoning and map matching, which involve the use of cellphone MEMS sensors. A guide service was created using Japan Railway Museum archives to enable comprehensive evaluation on the effectiveness of these trials. As this is an information push-style service, it is expected to be useful in basic application facilitating coordination for purposes such as communication between station guides, issuance of railway operating information (e.g., timetables and transfer information) and provision of shopping coupons, all of which can be sent to personal information terminals. As evaluation of the system indicated the service's effectiveness, plans are in place for its early practical application. To this end, progress will be made with work such as verifying methods for controlling IMES transmitters and standardizing transmitter specifications as well as the application interface.