Reusable Plastic Container Tracking – The right solutions for the right problem
By Wirepas
PUBLISHED 11 Apr 2023
A wide range of technologies is available to track, identify, or count goods or assets, as described in the white paper on Asset Technologies published by RPA in 2019. These include Barcode, RFID, GPS, Cellular or LPWAN, BLE or Wifi and, and more modern technologies such as low power mesh (e.g., Wirepas) or AoA and UWB. Each of these technologies has specific characteristics which make them suitable for given use cases. And combining some of the technologies often proves to be pertinent in many applications.
Before diving into the technologies, let us look at a typical supply chain and review the type of visibility required at any point of the chain and what value it can bring to the various stakeholders in the chain.
Example of RPC cycle:
An example of RPC flow is given in the diagram below. Of course, in practice, the flow can be simpler or more complex, involving a lower or a higher number of stakeholders; nevertheless, going through this example gives an idea of the visibility challenges (and opportunities) at each process step.
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The pooling company receives an order for a given number of RPCs
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The order is prepared and folded RPCs are shipped to the producer.
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The producer fills the RPCs with goods and ships them to the retailer distribution center.
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The goods are temporarily stored in the distribution center, waiting to be dispatched.
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The goods are then dispatched to the relevant retail stores, where they are arranged for sale.
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The empty RPCs are sent from the stores to a retailer distribution center.
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The empty RPCs are collected by the pooling company from the distribution center and sent to the service center for cleaning (and repair if needed).
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They are then stored in the warehouses of the pooling company for later dispatching for order fulfillment.
Controlled places and capability to deploy tracking infrastructure:
Steps 1, 2, 7, and 8 are usually under the control of the pooling company, while in steps 3, 4, 5, and 6, the RPCs are on premises operated by the producer, the transporter, or the retailer, which are outside the control of the pooling company.
This means that if there is a need to install specific infrastructure for the tracking (i.e. RFID gates, BLE readers, or WIFI routers), the visibility will be restricted to the sites where the infrastructure can be deployed.
Tracking the RPCs within the controlled premises vs. tracking and monitoring the goods anywhere in the supply chain:
Within its controlled premises, the pooling (or RPC) company can benefit from the following:
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Tracking the RPCs in real-time at the service centers and warehouses of the pooling company, including those in cleaning or in stock.
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In case RTLS (real-time location system) tracking in the premises is active, the pooling company can deduct at which stage of the process the RPCs are (by getting their zone location within the service center)
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The company can also determine the number of RPCs that are in use in the supply chain and generate alerts in case some of the RPCs have not been returned within a reasonable cycle time.
On the other hand, if the RPCs can be tracked (and monitored) at any point of the
supply chain, this enables a larger panel of digital services such as:
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Automatic handovers: remove the need for producers and retailers to declare the handover of RPCs from one stakeholder to the next in the supply chain.
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Direct access to the RPC inventory levels at the producer and the retailer (collect data on trips, areas of RPC congestion, and dwell time), allowing to refill the stock if too low or accelerate the recollection if too high.
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Provide supply chain visibility to the producer or to the retailers so they can reduce losses, damages, and waste of their goods.
This last item can have significant value for the retailers or the producers (and therefore, a good opportunity for monetization by the service provider) as it can enable them to extend the shelf time of fresh goods or identify root causes for waste in their supply chain.
This requires the tracker tags to be equipped with the relevant sensors (temperature, shock detection, etc.). It also requires an automatic pairing mechanism to associate the goods transported with the RPC ID.
Decision Tree: Requirements vs. technology fit
The main questions to clarify before deploying an asset visibility system are, therefore:
1. Is asset visibility in the RPC owner’s service centers sufficient?
In other words, is the value generated by knowing which RPCs have been returned in the service center high enough? I.e., is there high enough value to reduce inefficiencies in the supply chain or any costs directly associated with the RPC handling? Note that tracking the service centers only will not enable tracking (or locating) RPCs that are lost or stolen, but may give an early warning that certain RPCs have been missing for a certain time. If yes, then specific inventory (or location) infrastructure – such as RFID gates, BLE scanners, or mesh anchors – can be deployed within the service center or storage areas. Then 2 levels of service can be deployed:
1a. Goods-in / goods-out / fixed point inventory service:
In this case, the lowest cost / best technology option is RFID. This requires equipping the facility with RFID gates at the inventory area and placing an RFID tag on each RPC to collect a regular automatic inventory of the RPCs at the service centers.
1b. Room or Zone visibility in service centers.
Zone visibility can help provide a detailed understanding of the internal RPC handling process and WIP status.
It can be easily implemented using BLE tags on the RPCs. From an infrastructure
standpoint, the simplest and cheapest solution is to choose a system with battery-operated locators (or anchors) enabled by some last-generation low-power mesh networks.
These systems can be rapidly installed and are suitable for any facility. The position accuracy provided is in the range of 5m or room accuracy. These solutions are available from a large panel of system integrators and can connect to the pooling company’s IT systems.
Note that in the case of low-power mesh, the inventory detection rate, density, and speed are very high, thanks to the interaction between the tags and the anchors (routers).
2. Is visibility required during transportation? Or at the producer? or at the retailer distribution center?
The main technical challenge to tracking RPCs during transportation or at premises not controlled by the RPC owner is the connection to the internet. Depending on whether the premises (trucks, trailers, producer or retailer premises) can be equipped with an internet gateway or not, this leads to different types of systems:
2a. It is possible to install a gateway on the premises:
In some cases where there is a close business relationship between the RPC owner and the transporter, the producer, and the retailer, it may be possible for the RPC owner to install a gateway (fixed or mobile) that can scan BLE beacons (or collect mesh messages).
In this case, BLE (or mesh) tags placed on the RPCs will communicate with the neighboring gateways, and regular inventory can be collected and communicated by the gateways to the IT systems.
The advantage of Mesh over BLE is the bi-directional communication allowing the tags to adapt their behavior to their environment. A mesh system can also scan a higher density of devices and provide a higher/faster detection rate.
2b. It is not possible or not practical to install a mobile gateway on the premises:
This is the most likely scenario. The RPC owner may use several transporters, and convincing each of them to carry a gateway in their trailers is a challenge. The producer or retailer often uses several RPC vendors or has no incentive to install specific infrastructure. This makes it difficult for the RPC owner to get approvals to install dedicated gateways at their customer premises.
In this case, the internet connectivity must be embedded in the RPCs. Mobile trackers now embed cellular communication (LTE-M or NB-IOT), GPS, and BLE scanning or mesh connectivity.
If each RPC is equipped with a cellular tracker, each RPC can be individually tracked anywhere (with cellular coverage) and provide maximum supply chain visibility. This looks like the best solution. Unfortunately, although the technology is progressing, there are still limitations to the mass deployments of such a system:
Cost: The cost of a cellular tracker is still prohibitive to use on each RPC.
Battery life: Although the battery life of cellular trackers is improving, they usually need to be recharged every 80 – 100 days. Doing this at scale on a fleet of 100k-1M RPCs is a serious operational challenge.
Density: When there is a large number of cellular trackers in the same location (i.e., in a distribution or service center), this usually creates network congestion and reliability loss as the cellular systems were not designed for very high local density
The alternative is to combine the use of cellular trackers with less expensive BLE or mesh trackers:
One of the RPCs is equipped with a cellular tracker and acts as an internet gateway to the other RPCs, which are equipped with BLE or mesh tag.
The main benefits of this approach are:
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A much lower system cost since BLE or Mesh tags can be a tenth of the price of cellular trackers.
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A much-reduced fleet of RPCs to recharge:
This system can divide the number of cellular trackers by 50 or more. This means the number of devices to be recharged dramatically reduced. BLE or Mesh tags have autonomy of several years on a small battery (e.g., coin cell). These tags can be replaced after 4 or 5 years. (instead of being recharged).
Longer cycle time between recharges: The power consumption of the cellular trackers can be further optimized using Low power Mesh. Low power Mesh allows to reduce the number of active cellular trackers in a given space: if, for example, there are 20 cellular trackers in an area (a trailer, a warehouse…), and these trackers support Mesh, they can automatically form a Mesh and only 1 out of 20 needs to establish a cellular communication. This can translate into a 10x (or more) increase in battery life.
3. Condition monitoring – temperature (cold chain), shock detection:
Knowing whether goods have evolved within the right temperature range or have received any shocks during the various stages of the supply chain can deliver valuable insight to improve specific parts of the supply chain or specific handling conditions. For example, a fresh food company has managed to extend the shelf time of their fruits by ~15% by combining supply chain optimizations and corrections to the transport conditions and handling.
Various low-cost sensors can be added to BLE or Mesh tags or even to cellular trackers to monitor the conditions of goods during the supply chain.
Considering the reasonable cost adder of sensors and the potential value of the information they provide, it is recommended that tags and trackers are equipped with at least a temperature sensor and an accelerometer (to detect shocks).
Note that sensors cannot be added to passive RFID tags.
4. Provide visibility on goods being tracked (not only the RPC): supply chain visibility to the end user:
Knowing where goods are in a supply chain can be extremely valuable for perishable goods, for example, as mentioned above. To identify which goods are in which RPC, there needs to be a pairing between the RPC and the type of goods they carry when the RPC is filled.
This pairing can be done manually by scanning the bar code of RPC and associating it with the bar code of the goods carried. But there are also means to implement the pairing automatically if the tags on the RPC can interact with the infrastructure and receive messages helping them to identify automatically the ID of the goods they carry.
Once this pairing is done, the system can directly track the goods and provide more valuable insights to the end customer.
