The importance of real-time asset tracking beyond transportation management
Real time tracking of assets creates transparency about the status of assets and their location. For this reason, nowadays the ability to track assets in a broad geographic area using GPS has become key in logistics to timely identify potential delays and reduce the risk of loss. This can trigger a prompt reaction to find the best possible solution in light of unexpected delivery changes and allow more accurate scheduling as well as reduce the risk of bottlenecks.
But what happens to these assets, when over-the-road tracking ends and assets are yet to be at the end of their journey? Manual processes are typically used to track assets such as trailers and tractors, which leaves room to human error and a lack of real-time updates. And this is just the tip of the iceberg.
On-site premises are often quite large, and include large fleets of vehicles such as forklifts, materials, containers and carts which are moved frequently within the yard. Manually tracking the movement of these assets can quickly become unmanageable.
An On-Site Real-Time Locating System (RTLS) eliminates the need for manual checks and brings close to zero both search times and human errors, resulting in greater efficiency. However, is GPS always the right solution?
Is GPS always the right solution for real-time tracking?
There is a tendency to believe that what works for asset tracking in broad geographic areas would work well for smaller areas such as on-site, too.
However, GPS alone does not work well on limited areas. It requires ad-hoc adaptations and integrations which means extra work to fit the technology to the specific solution. As a matter of fact, since GPS is typically only accurate within several meters, a GPS signal is not able to give the accuracy needed in contexts such as yard management (e. g. to know the parking slot assigned to a certain vehicle).
Moreover, GPS does not work indoors, inside the warehouse, for example, and its performance can drop significantly even outdoors when buildings or other obstacles limit the sky visibility of the GPS antenna.
With the introduction of the Bluetooth Direction Finding feature in the Bluetooth 5.1 Core specification, Bluetooth Low Energy (BLE) represents a more convenient solution than GPS for real time on-site asset tracking.
How Bluetooth Direction Finding works
Bluetooth Direction Finding is designed to improve location services compared to previous versions of BLE which used solely the strength of the received signal (RSSI) to estimate the distance between tags (items to track) and locators (terminals receiving the beacon signals sent from tags). However, RSSI is not a reliable parameter, since it can be influenced by environment-dependent interferences, reflections and attenuations.
In contrast, Bluetooth Direction Finding improves the accuracy of BLE-based tracking and can be used to detect locations not only in 2D but also in 3D depending on the complexity of its implementation. The key underlying concept of Bluetooth Direction Finding is called Angle of Arrival (AoA). In AoA, the position of an asset is calculated from the angular phase-shifts that occur between the antennas receiving special Bluetooth signals sent by BLE tags.
AoA allows for the use of very simple low cost tags to act as the source device of which it is desired to determine the location. By measuring the direction of the radio signal transmitted by a tag as seen by one or more locators, the exact location of assets can be calculated using triangulation and trilateration algorithms. Based on the position data, services such as geofenced zones, heat maps, alarms and notification services can be built.
More than location tracking: IoT Gateway
BLE can provide better accuracy than GPS, which is crucial for on-site real-time asset tracking. But there is more. BLE is one of the leading wireless technologies in IoT, since it provides the means to transmit sensor data up to hundreds of meters far, with a reduced and efficient power consumption.
Therefore, in addition to location tracking, the same infrastructure can be used to monitor the condition of assets (e. g. temperature, pressure, vibrations) both when they move and when they are stored.
In other words, in their additional role as IoT gateways, locators can collect the data from IoT sensors connected to the tag and forward this information contextualized by a timestamp and a location point to the asset management software.
Initial and Operational Costs
One might think that all these benefits come at an increase in cost when comparing BLE with GPS. However, the cost of a BLE-based solution scales better than GPS as the number of assets to track increases.
If the number of assets to track is small, GPS is economically more convenient because of the possibility to transmit location data using the mobile network or a similar solution not requiring an on-site infrastructure and thus having a lower initial cost (supposing the mobile signal coverage is good enough across the entire site, which is not always the case).
On the other hand, BLE-based tracking requires the installation of locators throughout the area to be monitored. However, as the number of assets to track increases beyond several tens of units, the BLE infrastructure cost is paid back by the smaller cost per tag compared to a tag needing a GPS module, a mobile module, and a data plan to transmit the data, which in the long run impacts the operational costs in a linear manner as the number of used tags increases.
Last but not least, Bluetooth tags are as small as a fingerprint and can run on a single button cell battery for up to 20 years, thus requiring very low maintenance compared to the battery requirements of a standalone GPS+mobile terminal that can run, in the best case with bulk batteries, for few days.
Real-time tracking via GPS vs. BLE: comparing security
Previously, it has been outlined that asset tracking data (and eventually additional IoT data) is sent through a public mobile network when GPS in combination with a cellular data service is used. The alternative would be to build a WiFi or similar private infrastructure to avoid that data is exposed to the public Internet with all the related risks that could follow in case of a breach of data privacy.
With BLE instead, the locators are by design part of a private network and can forward gathered information to a local position engine in order to parse the assets’ location. In addition, the same data can be filtered, down–sampled or masked at the edge according to users’ needs before they are sent to the cloud. This allows to protect sensitive data that should never leave the premises of the company.
Conclusion
Real-time tracking of on-site assets is available now and some companies are already implementing it today. However, it is important to rely on experts to make sure the best possible technology for a certain application scenario is used.
The ideal technology should be inexpensive, accurate, secure, work over long distances, and have a substantial battery life. BLE with direction finding is the closest to encompass all these requirements for most of the on-site business scenarios.
The use of BLE for on-site asset tracking allows the use of a holistic technology for yard and warehouse management. This is convenient for those assets that frequently pass from one context to the other and thus need an integrated outdoors and indoors tracking solution.
In addition, corporations around the world are acknowledging the importance of the Internet of Things (IoT) and the need for a solution that has the ability not only to identify and track assets’ locations but also their status by means of smart sensors.
Make sure you use the latest and suitable technologies to implement your business cases more quickly and with the best possible results. We’d be happy to support you in your asset tracking project.
For questions about this or other topics in the blog, contact blog@leogistics.com.
Alessio Meloni
IoT Solution Architect
