Seamless Location Based Services (LBS) in Train Stations Using GNSS and IMES

A. Shikimura, K. Mutoh, N. Kohtake, M. Utsumi, T. Furutou, H. Tomita, M. Ishii

Abstract:	The number of people transported by the railways in Japan each year comes to approximately 900 million people in 2009 and the railways’ share of transport when it comes to transportation facilities within the country is approximately 30%, putting it first place in the world in both respects. A comparison in terms of transport share reveals that Japan’s share is about three-times that of the average for each country in the European Union (EU) and about 100-times that of the United States, making Japan a country in which the railways account for a significantly large percentage of transportation. As this indicates, there is an immensely large number of people that use the railways in Japan, and so as a result the stations are built in an extremely functional manner that emphasizes user-friendliness. As an example, multiple railway companies will pull into a single station, including subway trains, making it convenient to transfer trains. Moreover, since large numbers of people gather in the stations enormous shopping malls called “ekinaka” have been established inside of the stations’ ticket gates. These and other such examples of multifunctionality in the stations create new value for the railway companies and offer an enormous revenue stream. Yet there is a major problem in that the larger and more multifunctional the stations become the more complex and hard to understand their interiors get. As a measure to remedy this, the railway companies have developed a guide system that uses universal design guide signs with outstanding visibility, as well as digital signage. Howevr, these do not add up to effective tools because the users themselves cannot identify their current location, and so as things currently stand many station staff are posted in the stations to offer station guidance. Our goal is to resolve these issues and further increase the added value and convenience of the railways and the stations. To accomplish this, we are working to establish seamless indoor/outdoor positioning technology that uses an Indoor Messaging System (IMES) in addition to outdoor positioning via the conventional Guidance Navigation Satellite System (GNSS), as well as to develop new Location Based Service applications for personal information terminals. Since the IMES that we are using employs a modulation method and frequency that are the same as those for GPS signals it can be received with existing GPS hardware, and therefore it can be easily used with GPS in a seamless manner. Another way would be to measure the signal intensity of WiFi, which is another indoor positioning technology, but the IMES method, which sends positional information in the form of a signal as is, is characterized by its superiority in terms of positional accuracy. This paper will report on an overview of and the results from a demonstration experiment conducted at the Japan Railway Museum, in which station and railway facility environments have been set in place, in order to achieve a seamless indoor/outdoor positioning environment via GNSS and IMES in stations and other public spaces. The reason that the Japan Railway Museum was utilized is because actual sized replicas of 36 railway vehicles and a 1960s-1970s station have been recreated and are on display, which makes it possible to quantitatively and continuously measure and examine factors like multipath effects that railway vehicles and station structures made of materials like steel and aluminum have on positioning signals. With regard to indoor and outdoor positioning, the paper reports a case example of creating spot areas by minimizing multipath effect by means of limiting the output signal intensity from IMES transmitters to the utmost extent possible so as to make it possible to stably receive IMES signals even in confined spaces that are surrounded by metallic and other barriers, such as railway cars and stations. It also reports 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 for positional recognition and prevent misrecognitions when moving between indoors and outdoors, or when moving between indoor floors, for example. Furthermore, in cases where the indoor position will be configured solely by an IMES transmitter it will be necessary to install numerous IMES transmitters out of consideration for their use at stations and other places, which will raise the initial costs. In order to avoid this, an evaluation was performed on the effectiveness of hybrid positioning methods that correct one’s absolute position via IMES signals through the joint use of Dead Reckoning and Map Matching, which use the MEMS sensors that are equipped on individual cell phones. A guide service was created by using the archives of the Japan Railway Museum in order to carry out a comprehensive evaluation on the effectiveness of these trials. This service is an information push-style application, and so hereafter it will be a basic application that can easily coordinate between station guides, railway operating information like timetables and transfer information, issuing shopping coupons, and more, all of which will be sent to personal information terminals. Since its effectiveness was confirmed through the creation and evaluation of this system, hereafter the plan is to aim for its early practical application by moving forward with work like verifying methods for controlling the IMES transmitters and standardizing the transmitter specifications and application interface.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	432 - 438
Cite this article:	Shikimura, A., Mutoh, K., Kohtake, N., Utsumi, M., Furutou, T., Tomita, H., Ishii, M., "Seamless Location Based Services (LBS) in Train Stations Using GNSS and IMES," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 432-438.
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