April/May 2002

Tracking vehicles is a mature science, and there are a number of ways to do it. In this invaluable introduction, Sharon Clancy steps back to review the basic technologies, and in future issues of m.logistics we'll be looking more closely at individual systems and their relative costs, and considering how they can benefit your operations

Vehicle tracking has come of age. What started as primarily a theft-prevention system for high-value loads and expensive assets has now evolved into a comprehensive fleet management tool. Improved technology has helped this transformation; so have lower costs. Indeed, systems often pay for themselves simply through reduced mileage and fuel costs, let alone in terms of any increase in vehicle utilisation or improvement in driver productivity.

Vehicle tracking systems (now often called automatic vehicle location, or AVL) are at the core of any fleet management system. Basically the thinking is that you have to know where your vehicles are or have been before you can manage them properly.

It's important to understand that real-time vehicle location or positioning is not the same as live tracking ­ although for management purposes the difference may not matter much. Live tracking means knowing where your vehicles are every instant: fun to watch, but expensive and not really necessary unless vehicle security is of the utmost importance.

 

In AVL systems, on the other hand, the truck-based device will update its position periodically ­ say every 30 minutes. It may relay that information to base at pre-set times, or on demand, or when certain events occur. Each positioning "fix" costs a few pence.

A whole host of companies have developed dynamic vehicle management applications based on low-cost tracking: conservatively the number is dozens, and it could be more. Familiar names include CS Electronics, Isotrak, Minorplanet, Siemens VDO, Thales Telematics, Tracker Network and Vehicle Solutions, to name just a few. One of the latest is Roadrunner Cab-Link, which combines an existing product called Cab-Link with fleet management software from Road Tech Computer Systems.

There are three main ways of locating vehicles: by satellite, by digital cellular telephone network and by low-frequency radio networks. There is more choice when it comes to transmitting the vehicle's position back to base ­ satellite, mobile data network, GSM, Internet. Some suppliers (Vehicle Solutions and Tracker Network are among them) have cut communications costs further by offering an ISDN link.

Satellite-based tracking

Establishing a vehicle's position via satellite is still the most popular method of AVL. The two systems best-known to UK operators are the Global Positioning System (GPS) and Eutelsat.

The US Government-owned GPS system is free to users, so not surprisingly it is the one used by the majority of fleet management companies to locate or "fix" the geographical position of vehicles. The 24 GPS satellites were deployed originally in 1989 for military use, but the signals were downgraded later through something known as "selective availability" to allow access to commercial users, and there are now an estimated four million civilian users worldwide.

In theory, until recently GPS was only accurate to within 100 metres, even though in practice it often performed better than that. However, in May 2000 the US Government stopped downgrading the signals with selective availability. That means GPS is now accurate to 20 metres in theory, and sometimes as good as 5 metres in practice. For really accurate positioning you can use differential GPS, which corrects the "fix" to a 1 metre accuracy by means of a terrestrial reference signal.

Vendors of GPS-based location systems provide on-board receivers that decode two high-frequency signals emitted by the satellites, and thereby allow the vehicle to determine its longitude and latitude. The vehicle needs to read the signal from at least three satellites to determine its precise location.

To show the location graphically, the latitude and longitude readings are then usually overlaid on digital mapping software. This may be installed either in the vehicle itself, where it might form part of an on-board navigation system, or more usually at the vehicle's base, where the mapping system can be used by a controller to monitor the positions of any vehicle in the fleet.

Since GPS is free, operators don't pay for vehicle position fixes. What you do pay for is the GPS antennae and the communications equipment to transmit the data in real time back to the depot, which is done via some form of wireless data network. However, if you don't need real-time tracking, you can elect to download position data retrospectively whenever the vehicle returns to base.

Communications costs can be managed by limiting the frequency of position updates. If you're tracking vehicles for later route analysis, for example, you may only need an update at each delivery point. Some tracking systems are automatic, requiring no intervention from the driver; in others, the driver must respond to a prompt from base.

The other main satellite-based positioning system in Europe is operated by Eutelsat, which since last July has been a private company owned by various European telecommunications companies including BT. The Eutelsat satellite network is a combined positioning and communications system launched in 1990. Two Eutelsat satellites in geostationary orbit cover the whole of Western and Eastern Europe and the Middle East, and can locate the position of the vehicles to within 100 metres. Unlike the GPS network, Eutelsat does charge for satellite usage time.

The two main systems vendors using Eutelsat are French telecommunications company Alcatel Mobicom and US-based Qualcomm. Until last year, these three companies had a joint agreement in which Alcatel sold EutelTRACS, a European version of Qualcomm's OmniTRACS tracking and communications software. But Alcatel wanted to develop its own communication capabilities and Qualcomm wanted to develop a global brand, so now the two compete.

Qualcomm has however signed a five-year agreement with Eutelsat to sell EutelTRACS. Alcatel Mobicom, meanwhile, retains long-term licensing rights to the hardware and software, but is free to develop alternate communications packages.

EutelTRACS is a closed user-group system, so communication between mobile units and base are protected against unauthorised access. The EutelTRACS communications hub near Paris receives messages and requests from fleet operators (these come in by satellite, land line or cellular telephone), and controls messaging to and from vehicles.

Each vehicle is equipped with an antenna, an on-board terminal with keyboard and a liquid crystal display with three lines of 30 characters. The terminal has a capacity of 1,900 characters per message, and can transmit a message to the base station in less than 30 seconds.

A related system, TrailerTRACS, is also available to enable carriers to monitor the "connect" and "disconnect" status and position of every trailer in their fleet. Alcatel Mobicom has now renamed its trailer tracking software MTS (Monitoring and Tracking system by Satellite).

Messages and computed positions now go through Alcatel's own hub in Toulouse. Data is exchanged between the hub and the client's IT system via TCIP-based Internet access. Large logistics companies can set up Internet -based client accounts that allow individual customers to track their own vehicles via the Web. The lease cost of the MTS hardware is £22 per month, with a similar cost for airtime. Alcatel Mobicom says this can prove very economical when tracking European fleets, because there are no roaming charges.

Radio tracking networks

Besides handling data communications between vehicle and fixed base, radio and cellular mobile telephone networks can also be used in AVL systems to handle the actual positioning fixes themselves. When it comes to mobile phone technology, such use is relatively new in the UK, although it is quite familiar in the US, where the term "cell site location" is sometimes used to describe it.

The cellular approach takes advantage of the wide coverage of the GSM (and now GPRS) networks. A digital radio link is set up between the vehicle and the nearest cell mast, and the vehicle can be tracked from cell to cell using technology such as Qualcomm's CDMA (Code Division Multiple Access).

Each cell can only handle a certain amount of voice and data traffic, so there are more cells in towns than in rural areas; and that of course means the accuracy of positioning can be variable. The upside is that GSM works well on a local, regional and national basis, and can extend to any country that has a compatible system. GPRS will increase the ability of the networks to handle data traffic and speed up transmission speeds.

A further refinement of the cell-site approach would be to track the location of individual mobile phones. This information is already captured by the phone network operators as a matter of course, since their systems need to know where to direct each phone call they handle (they don't just broadcast the transmissions everywhere and hope for the best). Clearly there would be wide-ranging privacy issues if unrestricted access were given to the location of all mobiles, but the network providers are known to be working on tailored "opt-in" services using this technology (see pages 6 and 11).

An alternative approach to pinpointing location is to use a dedicated radio-frequency network. Probably the best-established in the UK is the one operated by Datatrak, a vehicle tracking system developed originally by Securicor for its cash-in-transit vehicles, but now owned by Austrian electronics and communications group Siemens.

Datatrak locates vehicles via low-frequency radio waves transmitted from 14 transmitters covering 95 per cent of the UK mainland road system. The transmitters send phase-locked signals sequentially on two radio channels, 10 per cent apart in the 130 to 170kHz band, using what are known as "time-division multiplexing" techniques. An on-board locator in the vehicle measures the range to each of the LF transmitters and computes the point of intersection of these ranges. That information is then translated into geographic coordinates.

Position and status updates are sent at pre-set intervals between 13 seconds and 28 minutes. There is also a passive event-activated tracking system, which activates when something unusual occurs, and updates every 17 seconds.

A network of dedicated UHF base stations, at 40 to 50km intervals, provides two-way mobile radio data coverage over the same area as the positioning system; so the Datatrak system handles its own positioning and tracking. Messages up to 1,960 bits can be transmitted.

To enhance Datatrak's appeal, it can now be integrated with GPS, and the combined technologies are said to offer greater accuracy than when either is used alone. The Multicomms Locator gives Datatrak users international coverage for the first time by switching automatically to GPS-GSM when vehicles leave a Datatrak radio-controlled area. Integrated roaming facilities on the GSM and Tetra networks can also be included.

There is a further version of the Datatrak system called Trakbak which incorporates a vehicle immobiliser and battery motion sensor. These automatically send a signal to the Trakbak bureau if the vehicle is moved illegally. They in turn alert the customer and liaise with the police, while tracking the vehicle's position to help them with recovery.

Internet tracking

Once you've captured the data on where a vehicle is, how do you convey it to the people who need to know? Historically, AVL systems involved setting up a dedicated link between the user-company and a remote control centre managed by the tracking organisation. This allowed the company to plot the position of vehicles on its own computers, using locally-held mapping and software.

The advent of the Internet has changed all that. While many systems still use dedicated software, increasingly the Web is used to transmit either the tracking information or the maps to plot it on, or often both. This means that in theory you can find out where your vehicles are from any computer, or even from a portable or handheld computer.

The latest Cab-Link system from Roadrunner, for instance, can even feed positioning updates in SMS text form to mobile phones; so as the company puts it, a transport manager can check up on his fleet from the golf course (if there are any managers with the luxury of enough free time to be there).

Road Tech has also integrated an Internet tracking capability with its popular Roadrunner vehicle management software, allowing hauliers to offer customers a consignment tracking facility via their own server.

Isotrak has focused strongly on delivering all its vehicle tracking and fleet management services via the Internet ­ and in fact was ahead of the general market in this respect. The actual applications (routing, for instance) are not in the transport operator's office, but on Isotrak's own server. Operators download services and information via the Web as and when needed. Thales Telematics, which is now the parent of the Orchid tracking system, operates a similar bureau service for small fleets.

Trailer tracking

Tracking trailers is easy if they are hooked up to a tractor unit, and many systems which claim to offer trailer tracking do so only via the GPS unit on the tractor. The difficulty comes when they are parked up and unattended, because the trailer needs a separate GPS/GSM unit and some method of powering it. It's also expensive ­ equipping each trailer can easily cost over £800. The Alcatel Mobicom and Qualcomm systems mentioned above both claim a lower power drain, and hence longer battery life, than GSM-based reporting systems used by rivals.

Susie-Track from TMC Innovations is one of the few systems to justifiably claim it is an independent trailer tracking system. The trailer-mounted GSM GPS system comprises a sensor that detects coupling and uncoupling, and a control unit through which all sensor and signal information is routed. The built-in tracking unit stays in "sleep" mode until it is activated ­ something prompted either by its in-built report timer, or when a status change occurs. When active it can be polled by a position-request message, or it can receive a command from base to trigger a predefined action remotely.

The sleep mode preserves the life of the 14-amp sealed lead-acid battery. Battery life is also conserved by a clever power management system. It automatically sends the trailer to sleep when it is uncoupled, for example, and because trailers are often parked overnight hitched to tractor units, it wakes up not on recoupling but on the first occasion the driver applies the brakes.

The latest version includes interfaces with door locking systems and security sealing systems such as Encrypta and a tractor identification module. A "black box" on the tractor unit allows Susie-Track to identify which tractor is pulling the trailer. If there is no tractor ID, the unit recognises that, too.

The future

So you've installed tracking devices in your vehicles. You can see where they are on a screen, and where they've been over the past couple of days. But what do you actually do with this information?

That's a whole subject in itself. Clearly the opportunities are boundless; you can match loads with empty trucks in real time, monitor delays during deliveries, divert vehicles to last-minute jobs, monitor the speeds they're driven at and the routes drivers take. Knowledge is power.

But you've got to use it judiciously, so reporting and analysis systems are often as important as the tracking technology itself. Over the coming months m.logistics Magazine will be looking at individual systems, and considering how you can benefit from them.

Watch this space.