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From NUS ShuttleNet Wiki
This project, ShuttleNet, is the ongoing effort of NUS Communication and Internet Research (CIR) lab to exploit the possibility of Wi-Fi based vehicular network access. Read more about our project members here.
With the support from Office of Estate & Development (OED) and Computer Center of NUS, as well as ComfortDelgro, we have equipped 14 shuttle buses in NUS kent ridge campus with an on-board LinkSys WRT54GL router as mobile clients. These clients run on OpenWRT. Using customized scripts, they are able to roam around the APs of NUSOPEN Wi-Fi network, which jointly cover a large portion of the kent ridge campus.
Bus tracking project
We are currently developing and evaluating a bus tracking system to help OED manage their buses, and help passengers plan the trip across campus.
- Different from existing bus tracking approaches (such as the IRIS system of SBS), which use GPS for localization and GPRS for uplink, we make full use of the existing good (and free) Wi-Fi coverage in NUS campus.
- The bus uses the nearby Wi-Fi APs that it can hear to infer its current location.
- The bus uses Wi-Fi as uplink to report its location to the server, so that users can query about it from Internet.
- The system is now still in its beta version. We believe that there are many aspects of the system need to be improved. Please help us make the system better by giving us your feedback.
- You may see A1/A2 buses which are serving but not shown in our system, this is because not all buses are equipped now (for example, bus 2712, as its power outlet is down). Currently, we have only equipped 14 buses. If you find the system useful, please also give us your feedback, so that we can get more support for the project.
- Even for buses equipped with on-board router, sometimes you may find them shown to be inactive, while they are actually in service. This can happen when the Wi-Fi connection on the router is down, or its power is accidentally turned off.
- A bus may be shown to serve A1 or A2, while it is on its way leaving campus. Such a false report will time out in a few minutes, but currently we can not avoid such false report as we infer the route totally based on its previous travel path. We plan to use a camera pointing at the on-board route plate to determine the route information more accurately.
- As we can only infer the bus route based on its travel path, so in order to avoid false positive, we are quite conservative, and only put a bus into A1 / A2 state when we are relatively sure about that (its record satisfies certain constraints). We have noticed that, such a conservative approach does cause some false negative report (An A1 / A2 bus is marked as unknown). In such situation, you can use the 10-min trace playback function to determine the possible route of an "unknown" bus by yourself
- As shown in the snapshot below:
- On the left hand side of the real time tracking page, you can find the location for each active buses on the map.
- On the right hand side of our real time tracking page, you can find information for each bus in the form of: bus2712 5 sec ago @ YIH. It means that the latest report from that bus is made 5 second ago at some place near the bus stop YIH.
- Sometimes, the latest report for a serving bus can be more than 1 minute ago or even longer. This is mainly because of the coverage hole in our campus Wi-Fi network, for example, there is no Wi-Fi coverage on the area between PGP and NUH. In such a situation, the bus will be plotted in the map at a location where it is last seen.
- You can hide/show bus and bus_stop by toggling the corresponding checkbox.
- Each bus is assigned a unique color. You can click on the horizontal color bar at the bus icon in the map to learn more detail about it. For example, you can play back its trace in the last 10 minutes.
- You can see the trip statistic collected by our system. The trip statistic varies quite a lot in different time of day. More detailed statistic will be available soon.
- You can query how long a bus will reach a bus stop. The answer given to you is generated based on the current location of bus, and the previous trip statistic.
You can view the real time location of our campus buses from here
- A snapshot of the system on 9 July, 2008
- Details about the project can be found below:
Other projects
We also work on several other projects to improve the file download efficiency for vehicles using the intermittently-available high-speed WiFi connections.
- A vehicle side proxy module to hide the intermittent connection from on-board passenger devices
- A road side proxy module to pre-fetch the content asked for by vehicles
We are experimenting with Meraki nodes and Soekris nodes. More information about our equipments can be found here.
