In-Vehicle Data Hub and Processor
Description/objective
On transport vehicles, the on-board computer system is the main data hub. The on-board computer is the system to which in-vehicle ITS devices and systems (e.g. automatic ticket machines, vehicle location devices, automatic passenger counters, information displays), as well as vehicle operations systems (e.g. engine control unit, automatic braking systems) can be connected. The on-board computer system manages and/or supports the operation of all the connected devices and systems, as well as performing functions which require interaction between different systems. Due to the complexity of ITS and vehicle operations, as well as the volume of data generated, on-board computers are needed to manage this data and to manage and/or support multiple systems simultaneously. These computers act as data servers which run individual systems and which provide a communication platform between the systems. This is generally performed via a CAN (Controller Area Network) bus network. The CAN bus is the processing system of the on-board computer which provides the physical integration of different systems, and performs the operational and interaction functions. Other technology solutions are also available for the same purpose as the CAN bus. As these tend to be more complex, heavier, unreliable and slower in terms of data transfer, the CAN bus processing system is the most widely used.
The CAN bus network itself consists of a system of control units connected together in a linear network (bus) with all communications signals passing through each control unit (node). Each node can receive and transmit data in the form of a message. When a message is transmitted, it is sent to each node with the intended recipient identified. As each node has a unique identity, the message is accepted only by the node for which it was intended. Each node can request access to the bus at the same time, but some nodes, such as the airbag control unit or other safety systems, have a higher level of priority. The on-board computer facilitates communications between systems within a vehicle, between the vehicle and the control centre, and between the vehicles and other vehicles or road side ITS equipment. On-board computers also commonly include an embedded wireless LAN transmitter/receiver device, which facilitates data transfer to the control centre when the vehicle is range of the wireless LAN network. Alternatively or additionally, removable memory devices or direct computer connection can be used for data transfer. Once downloaded to a central computer system, dedicated or multipurpose software applications can be used to interpret packets of data.
Applications
- Data management
- Operations management
Benefits and cautions
On-board computer systems, integrating various on-board ITS systems, provide improved ITS capabilities. The on-board computer can store various data which the various ITS devices and systems can access as required (e.g. configuration data, route and stop data, rules, (semi-) real-time information from other devices).
The on-board computer can act as the central data store for all of the other devices, thus reducing their individual memory and processing requirements (although some devices may retain this capacity in case they need to operate in stand-alone mode). They allow a transport service operator to extract more information in a useful way. For example, driver behaviour monitoring devices, such as accelerometers integrated with the navigation system through the on-board computer, allows for analysis of driver behaviour at specific sections of a route, and further integration of the radio system allows this data to be monitored in real-time at the control centre.
Case Studies
Dublin, Florence, Izmir, Zurich