Architecture

Provide Stable Connectivity

It is not easy to connect nodes likes vehicles to the Internet. Because vehicles are made to move from one place to another, it must use wireless medias to obtaion connectivity to the Internet. However, wireless devices always brings up a problem; unstable communication.

One of the researches in our Project include building a system which providing stable connectivity to the Interet using not one but several wireless media simultaneously. For example, we use Wireless LAN near the garage or where ever capable, use celluar phone on highways, and PHS while stuck in a traffic jam. This way, it is possible to provide a stable connectivity for nodes which moves at different speed and at different places.

Also in such environment, it is better if the IP address assinged to the vehicle does not change. In our Project, we extended Mobile IP to provide Internet connectivity while switching from one media to another using one uniqe IP address. Moreover, providing Internet connectivity to millions of cars that are out in the country today, there are not enough IP addresses with IPv4. Our Project uses the next Internet protocol version, IP verion 6.

High Accuracy Positioning Detection

Global Positioning System(GPS), well known with Car navigations systems, uses artifitial satellite to measure locations. In our project, we are proposing a architecture where we can use this information not only inside of vehicles but outside as well.

Measurements using GPS can be improved by using mesurement information which are mesured at base stations with very high accuracy. We are not only doing researches on distributing the corrected information but also using it on the InternetCAR. Exsisting systems used FM frequency or bicons to distribute these informations, but because they are uni-directional medias, it was not possible to provide enough information to the users. By using the Internet makes possible to to ditribute more information to the users and seek for a higher accuracy in measurement.

With highly accurate positioning information, it is possible to detect which lanes the vehicles are in, which allows to provide new services such as giving the driver information including the lane while navigating them to their destination.

Positioning Corretion with Virtual Reference Station

This year, we made an experiment using RTK positioning with virtual reference station as a higher measurement tool. RTK positioning with vertual reference station is a technology to measure in wide area using the RTK measurement technology with corrected information from the base station. Existing RTK measurement decreases in accuracy if away from the base station for more than a few kilometers. From our experiment, we were able to see that using the RTK positioning with virtual reference station makes it possible to measure with only 5cm of difference even if away from the base station for 30 - 40 kilometers.

Measurement using the Internet can be used for not only vehicles but also for other transportations systems, navigation systems and many others. We will continue to work on this to make it a standard.