Feb/March 2007

An RFID-based trailer tracking system from Secureseal has brought major savings to Christian Salvesen at a fraction of the price of full GPS tracking. Peter Rowlands went to see it in action

Suppose you're operating articulated vehicles in a closed-loop operation, in which movements are mostly between your own depots and those of regular customers. You already track the movements of your motive vehicles in real time, so you might wonder why there's any need to track the trailers separately.

However, the question lingered in the minds of the operational team at Christian Salvesen, the major logistics contractor, as the company rolled out its current vehicle tracking system, which was supplied by ASL.

Initially, though, the management of trailers was left to a long-standing in-house system called VCAS (Vehicle Control and Administration System).

This was devised to manage all moveable assets including trailers, drop-boxes and even company cars. It recorded full histories for every item, identifying each one by unique six-digit codes. It worked well enough, but it relied on manual input, and wasn't connected to the ASL system in any way.

It might sound a logical approach, but think of the practical implications. You're talking about 1,500 trailers at thirteen core network sites, plus another 32 key customer sites. Trailers get dropped off, left standing around, even forgotten.

To keep some semblance of control, Salvesen had to run daily checks at each of its own sites. 'Someone literally had to go and look round every yard, record every trailer in it, and upload the data by 10 am,' says Simon Woodward, the business analyst at Salvesen's IT group. Thirteen staff were tied up by this job every morning.

'It was incredibly time-consuming,' says Woodward. 'And it was prone to mistakes. People could misread a trailer number, or miss one out if the yard was very busy. The result was poor-quality data.'

The information was required for a variety of purposes. Apart from knowing which trailers were available to be allocated to work, the company also needed to monitor trailer condition and plan maintenance properly. There was also a need to maximise utilisation, and hence keep the overall trailer population to a minimum.

By the turn of the decade it had become apparent that some kind of dedicated trailer tracking system was needed. The first attempt at this was a radio-frequency system using induction loops in the surface of depots to register each trailer as it passed. 'But it wasn't reliable enough, and the loops under the roadway got damaged,' Woodward says. 'Eventually it fell into disuse.'

However, it gave the company an appetite for a system that really would automate trailer monitoring, and the IT team kept a watching brief on the trailer tracking market. 'We were aware that new systems were coming available, using technologies like GPS and RFID, and in due course we trialled a couple of these.'

Best solution

Armed with that experience, the company decided the best solution was one from Secureseal, a supplier that had made its name in digital seals for container and trailer doors, and then branched out into tracking. Its SecureLocator system has been rolled out to all Salvesen's dry-freight trailers, and the company is now also trialling a version for its temperature-controlled fleet.

The Secureseal solution is elegantly simple; each trailer is fitted with an active RFID tag which uniquely identifies it, and the tags are read automatically every time the trailer arrives at a depot or leaves it. There's no complicated induction loop - just a relatively simple reader device at each site, which communicates with Salvesen's computer system via a GPRS data wireless data network.

'Some people said 'Surely you want to know where trailers are when they're out on the road?',' Woodward says. 'The answer is no. We already track the vehicles, and we know from our operational data which trailer each one is pulling, so if we want to, we can monitor them that way.' In any case, he says, the trailer tracking system has a different purpose: it's to monitor the trailers when they're not attached to tractor units - to have an overview of where they all are at any given time.

Installing the SecureLocator system was a learning experience. For instance, originally the RFID tags were mounted inside the trailers, but it was soon found that they tended to get damaged or knocked off by roll cages during loading and unloading - particularly on curtain-sided bodies, where loading is done through the sides.

'So with Secureseal we developed a weatherproof tag assembly for external mounting.' This includes a sealed enclosure with a special mounting plate and four self-tapping screws. The device is now fixed on the outside of the trailer bulkhead, about two thirds of the way up.

At Salvesen depots the basic communication unit is mounted on a wall at some suitable point, and wired into the depot's mains electricity system. It's called a secure housing unit, although unofficially it tends to be referred to a 'shoe box'. Inside are an RFID/data logger unit, an uninterrupable power supply unit and a small heater (to fend off the effects of British winters).

The unit is linked to a main antenna, and in the bigger depots up to two additional antennas are mounted at strategic points to ensure the whole area is covered by the system. The Secureseal tags have a guaranteed range of 100 metres and a theoretical range of 150 metres, but depots can be sprawling, and may be obstructed by many buildings. However, no extra communications protocols are involved when more antennas are added; the signal is simply amplified.

The trailer tags send a status update once a minute, and the information is logged by the communication unit and transmitted back to base every ten minutes. A message is also sent when a trailer arrives at the site or leaves. The route taken by the data is first to a secure Web server run by Secureseal, then from there to Salvesen's in-house consignment and tracking system, SHARP (Shipment Handling And Reporting Program), which runs on the IBM AS/400 platform. This part of the transmission is made using FTP (file transfer protocol) standards.

To prove that the control unit is always working, a 'master tag' is fitted inside it, and broadcasts its presence as if it were a trailer. So even if there is no real trailer in the depot, a reference signal will be captured and reported for checking purposes in the normal way.

One of the challenges faced by the developers was the fact that most of the locations served by the trailers were customer premises, not Salvesen depots. 'Understandably, customers can be reluctant to host any computer equipment belonging to third parties,' Woodward says, 'so we couldn't expect them to install our standard 'shoe boxes'.'

Instead, Secureseal developed a special version of the communications unit for customer sites, which simply plugs into an ordinary 13-amp three-pin mains socket and can sit unobtrusively at the back of a desk or in a corner. 'So we were able to overcome customer any reticence that way.'

Elimination of risk

The system is already proving its value. Benefits cited by Salvesen include more effective and timely servicing of trailers; virtual elimination of the risk that trailers might fall foul of servicing and annual testing requirements; and improvement in trailer utilisation. Indeed, the company says it has actually been able to reduce the overall size of the trailer pool, or take on more work with the equipment already in use.

And there's more. Currently the company is investigating the opportunities for tracking its temperature-controlled trailers as well - and monitoring temperature as part of the system. In this case the tags need to be installed inside the trailers - especially as there is sometimes more than one compartment, and each will need monitoring separately.

'But we don't face the same risk of damage,' Simon Woodward explains, 'since the loads aren't stacked so high, and loading is only done through the back doors.' The tags will therefore be installed near the refrigeration unit evaporator outflow vents, where they can simply be cable-tied in place.

A different form of RFID tag is needed for this application, with provision for input from a temperature sensor. It's described as a mini-data logger.

Uploading temperature data

The aspect that makes this approach compelling is the opportunity to link the output from the RFID tag wirelessly to the telematics 'black box' in the truck cab, and hence to upload temperature data back to base as part of the existing tracking system in near-real time. 'Previously we were capturing positions every ten minutes, but in this application we'll need to do it at five-minute intervals,' Woodward says.

Ben Grant, the managing director of Secureseal, has gone on record as saying his company will never offer its own ubiquitous vehicle tracking system. However, lately it has announced closer ties with ASL, which supplied the Salvesen system, so in effect the two companies can now offer a joint product which incorporates both vehicle and trailer tracking.

The ASL system in the Salvesen fleet provides a range of standard vehicle tracking and location functions. A device called a CID (for CANbus Integrated Development) gathers data such as mileage, speed, fuel consumption and tachograph status from the vehicle's inbuilt CANbus data spine.

There is also an operational element, which is provided by the use of Symbol handheld computers. These run an application called miSHARP (it stands for Mobile Integrated SHARP), which feeds data wirelessly into the main SHARP system.

Drivers can use the handhelds for scanning loads off the vehicle, as well as for photographing disputed items and for ordinary telephone contact. 'The scanning comes into its own when drivers are delivering overnight to secure unattended premises,' Simon Woodward says. 'They scan a fixed wall-mounted barcode to confirm their presence at the location.'

The handhelds are linked to the tracking system via an in-cab docking station, which has a serial connection to the CID unit. This means that when mounted in the cradle the device can be used to give feedback such as messages to the driver. It can also be used for satellite navigation, and currently the company is starting to trial the TomTom system.

'We're also aiming to incorporate low bridge data to prevent bridge-bashing accidents,' Simon Woodward says. 'We've bought a low-bridge dataset, and we're setting up the low bridge information as 'points of interest'.'

significant potential

The final piece in the whole jigsaw puzzle, he says, will be tracking of roll cages, which again can be handled via the CID units in the truck cabs. There are various issues to resolve first - not least the fact that some cages are owned by Salvesen, while others belong to customers. However, once the basic infrastructure is in place, it should be much easier to weave this function into it. The potential for preventing cage loss and misallocation is significant.

There could even be a customer involvement in some of this data. While the SHARP system is basically an in-house product used by Salvesen itself, there is also a customer-facing element called SHARPNet, which introduces the opportunity for customer-related data to be made available selectively over the Internet.

Meanwhile, the system has proved itself already in financial terms. Annual savings in the order of over £200,000 have been mentioned - and this with a system that is said to have cost only a quarter the price of a fully-fledged GPS tracking product.

Once the additional features are in place, the savings should be even greater.