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With the economy coming out of the 1997 recession and new logistic service providers entering the market, there has been a renewed interest in vehicle tracking systems. In its most basic form, fleet managers would want to know where the vehicle leaves the yard. More ambitious fleet managers would want to be able to do enroute dispatching and may even want to link the vehicle tracking system to the logistic operations back-end systems.

These renewed interests in vehicle tracking systems are causing some concern among industry professionals. The vehicle tracking industry itself has not seen too many widespread implementation on such systems, whether in logistics or in public transportation. This begs the question of why and how past lessons can be learnt so as not to make the same mistakes.

There are enough unsuccessful attempts around to do a case study and to avoid the pitfalls of the past. The unsuccessful attempts have burdened not only the transport service providers but also the consumers along the value chain. Ultimately, it is the consumers who will have to bear the brunt of such implementation in the form of additional costs and service inefficiencies.

The aim of this article is to shed some light on vehicle tracking technologies and highlight some lessons learnt in the implementation of these technologies. By taking the mystery out of the technology and identifying the critical components that make up the vehicle tracking system, the fleet managers would be able to make informed decisions on the application of this technology in their quest for productivity, safety and security.

Why Implement
In its simplest form, a vehicle tracking system allows the fleet manager to track the vehicle once the vehicle leaves the premises. Has the vehicle gone to where it should ? Did the driver drop off the cargo on time? Could the driver make more trips?

Vehicle tracking systems are implemented for the following reasons, i.e. to improve.

(a) Productivity - By knowing where the vehicle is on request, without driver interaction.
(b) Safety - By keeping check on how the vehicle is being used.
(c) Security - By raising an alarm when an unscheduled event occurs.

Vehicle tracking systems are IT systems. To derive the benefits of any IT implementation, proper care has to be given to achieve the objectives above.

As any IT project manager will tell you, it is foolish to assume that the IT system will make up for the shortfalls in the manual procedures and replaces it with technology which will make the process more efficient.

AVL Systems
Vehicle tracking systems, also known as automatic vehicle location (AVL) systems, have the ability to integrate mapping software to data coming in from the global positioning system (GPS) receiver through the wireless data modems in the moving vehicles. The AVL system can then be used, from the core of specialised systems, for such applications as taxi dispatch, emergency services, fleet management and inventory and asset tracking systems.

Because of its specialised nature, such systems are expensive, have problems tracking a large number of vehicles and displaying the vehicles on the screen. The ability of AVL systems to track the vehicle in real time and to store data for post processing is important and can vary from system to system.

A number of AVL software suppliers have gone forward to provide GPS and communications hardware to ensure total integration of their products.

The AVL vehicle tracking market has developed more slowly than expected mainly because products were initially developed by technology push rather than market pull. The market is now taking off, thanks to lower prices and increased functionality.

Positioning Technology
There are three major technologies that are used in determining the position of a moving vehicle: GPS, dead reckoning and triangulation technolgies based on timing or angle of signal transmission and reception at the receiver. Each of these technologies can be used individually or together for navigation and vehicle tracking purposes.

The GPS system pioneered by the US Defence Force uses the concept of placing 24 orbital satellites into space, which could transmit radio signals with a satellite ID to all parts of the Earth's surface. The satellites orbit at around 22,000 kilometres from Earth's surface and at any instant, we can see between six and eight satellites in view. A GPS receiver on Earth which looks for signals from satellites in view can lock on to the satellite transmission signals. With a software package that knows the physical location of each satellite, the receiver can then calculate its position on Earth by basic geometry.

Telecoms Technologies
Communication devices are the fastest-changing components of tracking and navigation systems. The choice of communications depends on the intended application and user requirements such as reporting rate, throughput capacity, geographic coverage and cost.

The transmission of data through wireless communication network is a crucial component in knowing the location of the moving vehicle in real time. Wireless communications networks, either radio or cellular, is most commonly used for voice communication. With the right modem technology, system integrators are able to pass data through these voice channels.

Digital Mapping Technology
Geographical information systems (GIS) are used to produce digital mapping for land use and transportation planning. These GIS databases store the digital maps in a vector or raster format. However, digital maps, which have been generated by GIS, have to perform navigational function before they can be used for vehicle navigation.

How It Works
The following paragraphs are intended to explain the different components of the GPS system. The GPS antenna picks up the radio transmissions from the navigational satellites and the GPS receiver processes this information into positional co-ordinates. This positional information can be displayed on a console in the vehicle, stored onboard the vehicle or relayed to a base station for the vehicle location monitoring purposes. For the data to be transmitted back to the base station, the data from the receiver will pass through a modem interface before being channeled through a wireless data transmission system.

The wireless data transmission system can take the form of radio, cellular or satellite communications. The choice of system will depend on the type of application, area of operation and amount of data being transferred.

By using the data modems from the network system suppliers (communication companies), we are able to send the data through to the base station where it is processed and displayed against a digital mapping background on a PC.

Once displayed, the vehicle's location is immediately known and identified. The system, or component, which does this processing, is referred to as an AVL system. The location of any number of vehicles can be called up and displayed, all according to the type of inquiry initiated by the user.

For this to occur, more data will have to be channelled through the wireless data network. At the base station, the AVL system will then route the additional data to fleet management systems to cope with the vehicle routing, dispatch, inventory control and biling functions. The base station and AVL system can be set up to serve dedicated applications like taxi dispatch, emergency response to police, ambulance and fire calls, roadside assistance or public transport information.

A bureau monitoring centre can be set up to monitor large vehicle fleets or serve different AVL applications for different clients on a concurrent basis and handle data requests from telephone calls and remote data terminals at the clients' premises.