Real Time Location Systems (RTLS) for The Fourth Industrial Revolution

The Fourth Industrial Revolution, also known as 4IR and Industry 4.0, improves manufacturing through the use of technology. The end-aims are to significantly improve productivity, reduce production delays and, for example, avoid penalties or future lost orders due to delayed work.

A key part of The Fourth Industrial Revolution is asset tracking that provides faster and more accurate stock control, item picking, job tracking, capacity measurement, demand analysis and product protection through sensing and automatic auditing.

It’s important that asset tracking is continuous because merely scanning things in/out using barcodes is open to human error and location is otherwise only as good as the last scan. Historical data is also important because it identifies blockages allowing processes to be refined.

When evaluating asset tracking systems consider:

  • Scalability and Performance – How many things do you need to track today and into the future?
  • Flexibility – Many of our customers initially buy an RTLS for one urgent purpose but later end up use the system system for additional needs.
  • Security – Where is your data stored and where does it go?

Look for a stand-alone solution rather than SAAS for greater performance, flexibility and longevity. While SAAS based systems can be a quick way into RTLS, they soon become limiting because you are sharing a platform with other customers. SAAS platforms usually don’t scale well technically and financially and don’t have efficient, direct access to the data for efficient ad-hoc reporting. They also pose potential security and reliability risks as you don’t own your data. The ultimate limitation comes when the SAAS provider, usually a startup, eventually increases costs, get’s bought out by its largest customer or goes out of business.

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Beacons in Industry and the 4th Industrial Revolution (4IR)

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Bluetooth Asset Tracking

Bluetooth tags/beacons detect the position of people and assets. Software maps jobs, valuable tools, parts, sub-assemblies and people onto your floor plans or maps.

The main uses are:

  • Searching. Knowing the location of something such as a piece of equipment, parts, stock, pallets, a job or person without ringing round. Locating expensive, shared, equipment so fewer spare assets are required to cover an area.
  • Security. Alerting when people or assets enter or leave an area.
  • Protection. Detecting quantities such as temperature and humidity for sensitive items that can spoil.
  • Process Control. Knowing where things have been. Knowing what happened at a particular location. Knowing when measured values exceeded their expected range.

Bluetooth LE is particularly suitable because it is:

  • Real Time. Better than barcode scans and NFC tags where the data is only as up to date as the last successful manual scan.
  • Compatible. Bluetooth LE works with existing devices such as smartphones, tablets, laptops and desktops.
  • Reliable. Works in electrically noisy situations such as the factory.
  • Inexpensive. Commodity hardware is more affordable than non-standard technologies such as ultra wideband (UWB).

The end result is reduced downtime, less time re-ordering or re-making things that have been lost, optimum productivity and better use of skilled staff doing their job rather than searching for assets and people.

Read about Beacons in Industry and the 4th Industrial Revolution (4IR)

Learn about Asset and Pallet Tracking for Manufacturers

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iBeacon Microlocation Accuracy

Customers often ask us the accuracy when locating beacons. In order to get the answer, its necessary to understand different ways of locating and the tradeoffs that are needed to get the different levels of accuracy.

There are two types of locating, received signal strength (RSSI) based and angle of arrival direction finding (AoA).

Locating using RSSI

There are two main scenarios. The first is a where the detector, usually a phone or gateway, is at a known location and the beacon moves. The second is where the beacons are fixed and the detector moves. Either way, the detector receives a unique beacon id and the receiving electronic circuitry provides the strength of the received signal.

The value of the RSSI can be used to infer the distance from the detector to the beacon. The main problem with RSSI is that it varies too much, over time, to be used to accurately calculate distance. The direction also isn’t known when there’s only one beacon and one detector. The varying RSSI, even when nothing is moving, is caused by the Bluetooth radio signals that are reflected, deflected by physical obstacles and interfered with by other devices using similar radio frequencies. Physical factors such as the room, the beacon not uniformly emitting across a range of 360 degrees, walls, other items or even people can affect the received signal strength. How the user holds a detecting phone can affect the effectiveness of the antenna which in turn affects the signal strength.

The varying RSSI can be smoothed by averaging or signal processing, such as Kalman filtering, to process multiple RSSI values over time. The direction not being known can be solved by using trilateration where three gateways (or beacons depending on the above mentioned scenario) are used to determine the distance from three directions and hence determine the 2D location.

Trilateration

The aforementioned physical factors that affect RSSI can be reduced by measuring the actual RSSI at specific locations and hence calibrating the system.

The change of RSSI with distance is greater when the beacon is near the detector. At the outer reaches of the beacon signal, the RSSI varies very little with distance and it’s difficult to know whether the variance is due to a change of distance or radio noise. Hence for systems that use signal processing, trilateration and calibration tend to achieve accuracies of about 1.5m within a shorter range confined space and 5m at the longer distances.

However, such systems have problems. The multiple RSSI values needed for averaging or signal processing mean that you either have to wait a while to get a location fix or have the beacons transmit more often (with a shorter period) that flattens their batteries much sooner. Trilateration requires at least three devices per zone so can be costly and require significant time to setup and maintain. Using calibration is like tuning a performance car. It works well until something small changes and it needs re-tuning. If someone adds a room partition, desk or even something as simple as lots of people in the room, the calibration values become invaid. Re-calibration takes human effort and, pertinently, it’s not always easy to know when it needs re-tuning.

An alternative to trilateration is zoning. This involves putting a detector (or beacon depending on the above mentioned scenario) in each room or zone. The system works out the nearest detector or beacon and can work on just one RSSI value to get a fix quickly. The nearest zone is often all that’s required of most implementations. With zoning, if you need more accuracy in a particular zone you add more detectors in the area to get up to the 1.5m accuracy of other methods. This will obviously be impractical if you need 1.5m accuracy everywhere over a large area.

BeaconRTLS™ area zones

Angle of Arrival Locating

An alternative to trilateration and zoning is more expensive Bluetooth hardware and more complex software that makes use of Angle of Arrival (AoA). Locator hardware with multiple antennas uses Bluetooth Direction Finding to find assets to better than 1m accuracy. Location engine software uses the difference in the time of receiving the signals at multiple antennas to calculate the position. Multiple locators can also be used to cover larger areas and/or improve the accuracy using triangulation.

Unlike RSSI systems where any beacons can be used, locators tend to be tied to using the same manufacturers’ beacons. The complex hardware and software has less throughput and supports fewer beacons. The computing hardware needs to be more powerful. Systems need careful, accurate site measurements to achieve good accuracy.

Summary

Choosing a solution just because it is more accurate, rather than needed, will cost significantly more not just in hardware but in software cost, setup effort and maintenance. Work out what accuracy you need and then seek out an appropriate solution.

Bluetooth Beacons in Factories, IoT and Industry 4.0

McKinsey has a useful chart where they assess the potential impact of the IoT by segment:

It can be seen that ‘Factory’ has the greatest potential. This links with ‘Industry 4.0‘, the current trend for more automation and data exchange in manufacturing with the aim of significantly improving efficiency. But what does this mean in practice and what are challenges? Can these be solved with Bluetooth beacons?

We have learnt that while just about every industry client has different needs, all solutions involve context and location. Context is sensing, while location is where the sensing occurs.

Requirements we have experienced range from being able to pick up documents for particular machinery through to actual sensing such as detecting vibration is within (safety) bounds for ‘aggressive’ equipment. We have also seen the requirement for matching workers with workstations and jobs as well as the tracking of workers, tools, pallets, parts and fabrications. There’s also the need for real-time overviews for short term safety and efficiency management, the same longer term data also being used for process improvement and planning.

So why beacons?

  1. Low power. Sensors need to have a long life because replacing them or their batteries requires human effort and they are sometimes placed in normally inaccessible and dangerous areas. Beacons are ideal for this because some have up to 5+ years battery life and others can be permanently powered.
  2. Sensing. Various off the shelf sensor beacons are available. Custom variants are possible to sense industry specific metrics.
  3. Connectivity. Several gateways are available to connect to WiFi. Alternatively, it’s possible to use smartphones or small single board computers as gateways. There’s a trend for ‘Fog’ or ‘Edge’ gateways that only send pertinent data on to the cloud and can provide direct alerts quicker than being dependent on the latency of the cloud.
  4. Cloud management. Software such as our BeaconRTLS platform allows for the management and visualisation of sensors.
  5. Security. Beacon devices are password protected and the gateway to cloud communication is protected using standard Internet protocols.
  6. IoT needs to be made easy. This is BeaconZone’s role. As we mentioned, with the IoT every client has different needs. We bring together ready-made hardware and software components so that they can be dovetailed to create solutions.

Read about using Beacons in Industry and the 4th Industrial Revolution (4IR)

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