There is a great demand to track millions of containers as they travel throughout the world, but no solution is perfect: the technology is simply not there. Let’s have a look at the options available and their shortcomings:
RFID – RFID tags are cheap and can be fitted relatively easily as they are very small. These tags identify themselves a few times per day and the data is read by a local reader. From there each container on site is known, but the problem comes when it leaves. Yes, the reader will detect that the tag has not reported in and, unless there is a problem with the tag, the assumption can be made that the container has left site. So it is no longer on site, but where is it? We basically know where it is not, but it has left site on its way somewhere. In a controlled environment and making use of a known number of trucks, we can put RFID readers on each truck and have a RFID reader at each site and then, by using a central computer system connected to all of the readers, we will always know where the container is. This is unfortunately not the way most containers are used, so the long and short of RFID tags is that it will, for all intents and purposes, mostly tell us where the container is not, as opposed to our requirement to know where it is.
GSM/ 3G trackers: these are more expensive and also require more power, something which can be overcome by making use of solar GPS tracking devices. These devices would have SIM cards in them which add to their ongoing costs, but if the containers were to stay within phone coverage they would be very effective and accurate. Container stacking would also not be a problem as GSM/ 3G does not require line-of-sight.
Things however change where containers are shipped overseas, as there would be no phone coverage for most of the time. There is also the issue of using SIM cards overseas due to the costs of roaming, although international SIM cards are now available, something which should help minimise the cost. So, the main problem with these 3G GPS units is that they lose contact outside phone coverage – less of a problem in places like Europe, but certainly a problem is countries like Australia and for containers that cross the ocean.
It should be noted that if using a GSM solution, that the container’s potential destinations need to be discussed prior to the deployment of the device, as being able to choose the best carrier for the departure and arrival destinations is an essential part of this solution – you want it to talk efficiently when it gets to the other side!
Satellite trackers: these devices would be the best solution for containers that travel between countries, but they also have their limitations. They are larger as they need internal batteries, so the chance of damaging them is greater. Satellite communication is also more expensive and very limited in bandwidth and it would not be uncommon to have to pay satellite fees of more than $30 per month per unit. This form of communication also requires line-of-sight, so where containers are stacked there is a real risk that the units would not be able to send back their position.
It is Digicore’s view that, as of 2015, there is no ideal, universal solution that will solve the container tracking problem. Depending on where and how the containers are used, a combination of one of the above and more conventional record keeping is as good as it gets at this stage, but the solution is not perfect and only time will tell if a cost-effective, reliable method is found.