Ultimate guide to Real-time Location Systems

Real-time location systems is a hotly discussed topic with manufacturing, engineering and logistic industries. There is much hot air and speculation and often little fact. This guide is designed to be a detailed, accurate and unbiased look at the technology, its pro’s and limitations.

What are Real-time Location Systems?

Real-time Location Systems, also know as RTLS, are designed to track people and assets. It manages them as they move through a manufacturing, engineering or logistic process. RTLS is a more limited version of Real-time Asset Intelligence which are now available.  Often RTLS is undertaken indoors, but this is not always the case. Some describe RTLS as indoor GPS tracking. This is because they can provide a similar level of location and movement data. They operate both in real-time as well as providing detailed tracking histories.

Three main functions of Real-time Location Systems

Broadly, there are three main applications for Real-time Location Systems;

1. Real-time tracking

2. Long-term tracking

3. Geofencing.

Real-time Tracking

Real-time tracking means that the location of an asset is seen in near real-time throughout its life within the tracked facility. 

Long-term Tracking

Longer term tracking allows the operator to assess the passage of an asset through a facility such as a warehouse or factory. This can help improve operational processes by, for example, removing un-needed steps.

Geofencing

A geofence is a virtual boundary created by Real-time Location Systems in a facility. When a tagged asset crosses one of these ‘virtual boundaries’, the system alerts a designated responder. This may be used to protect an asset or area from contamination etc.

What can RTLS be used for?

There are numerous of use cases for real-time location systems. From finding assets in a hospital, to locating and monitoring assets in a warehouse or factory. They can also be used to understanding which contractors are onsite, and how long they are there each day. RTLS is a dynamic and digital alternative to traditional record-keeping. A manual log of where equipment is kept or stored breaks down quickly because of human error. It also doesn’t support the variety of use cases that RTLS does.

Here are some example use cases;

Asset management

Real-time Location tracking is frequently an essential function provided by asset management systems.  An attached access control system authenticates users who wish to sign an asset in or out. Some storage lockers have a built-in RTLS tool called “content surveillance,” which can verify that a user returns the same high-value asset that they signed out.

Security

RTLS enabled access control systems authorise employees and visitors to move through security checkpoints. If using geofencing, they record movements across those virtual boundaries. Employees carry RTLS badges that authenticate them and provide location data to track them in real time. Emergency mustering systems can use RTLS tags carried by employees to monitor their locations during emergency evacuations.

Safety

Real-time Location Systems are also used monitoring the health and safety of people in high-security environments. An RTLS can monitor lone workers, patients in healthcare settings, or work crews in hazardous environments. If system users report an emergency or don’t meet a check-in deadline, responders are alerted.

Tool Management

Real-time tracking means that the location of an asset can be seen in near real-time throughout its life. 

WIP control

Longer term tracking allows the operator to assess the passage of an asset through a facility such as a warehouse or factory. This will often be used to improve operational processes by, for example, removing un-needed steps.

Other

A geofence is a virtual boundary created by Real-time Location Systems in an open facility. When a tagged asset crosses one of these boundaries, the system issues an alert to a designated responder. This may be used to protect an asset or area from contamination etc.

What are the elements of Real-time Location Systems?

Whilst the technical specifications will be different provider by provider, Real-time Location Systems will usually share broadly similar hardware and software components:

Tags

An RTLS tag attaches to an asset or person. It emits identification and provides location data to receivers over a wireless signal (see below). These tags are also sometimes called beacons or transponders, depending on their manufacturer and use case. They can also be incorporated into the asset, equipment or even a badge.

Detectors

RTLS detectors are positioned- strategically around the facility. They receive wireless signals from tagged assets and indicate their location. Depending on the wireless signal used, they will determine location. This will be to various levels of accuracy by either measuring the tag’s proximity to the detector or through a the angle of arrival of the signal. Locations are calculated either by assessing the time taken for the signal signals to reach the detectors. Or by triangulating the angle of arrival of the signal to three or more detectors.

Portal

The RTLS detectors will send the location data they collect via cable or wireless signal to a central management system. Here the location data can be analysed in order to manage the asset being tracked or to optimise wider processes such as bottlenecks.

Often data can also be exported from the portal via API to 3rd party systems such as ERP’s for further integration with other business data.

Technology deep dive

Real-time Locations Systems rely on a robust connection between the tag and the detector. There are a number of different technologies which are currently being used for this connectivity which have implications on the performance of the overall system;

Bluetooth

Bluetooth (BLE) is a short-range wireless communication standard popularly used to pair mobile devices, headsets, computers, and other electronics. Most smartphones, tablets, and other portable electronics already come with a Bluetooth antenna.

You can often use those existing devices as part of a Bluetooth RTLS program. Bluetooth’s short read range of fewer than 10 meters only makes it suitable for specific applications. Also, be aware that Bluetooth uses part of an unlicensed radio frequency band nicknamed the “garbage band,” which might make Bluetooth prone to interference in the future.

Ultra-wideband

UWB real-time location systems are currently some of the most precise on the market, usually locating a tag to within a meter. They use a range of frequencies, not just one like Bluetooth or IR. These signals are powerful and not prone to interference.

These benefits come at a much higher price point than the alternatives. Because UWB works across a broader range of the electromagnetic spectrum, it can also be complicated to fine-tune UWB signals in indoor environments where you use other wireless services. UWB’s precision also tends to drop off at longer ranges.

Ultra-wideband RTLSs are most suitable for indoor environments where exact asset locations are needed up to a medium range. Their cost also makes them most ideal for environments where security breaches are high risk and potentially costly.

Portal

The RTLS detectors will send the location data via cable or wireless signal they collect to a central management system. Here the location data can be analysed in order to manage the asset being tracked or to optimise wider processes such as bottlenecks.

Often data can also be exported from the portal via API to 3rd party systems such as ERP’s for further integration with other business data.

RFID

Radiofrequency identification (RFID) tags come in two varieties: passive and active. Passive tags are smaller and have no onboard battery. They receive power wirelessly when someone brings the tag within several meters of a receiver. In a trade-off for their shorter range, passive RFID tags cost much less and are more durable than other RTLS tag types.

Active RFID tags use an onboard battery but are otherwise functionally similar to their passive counterparts. They are larger, heavier, and more expensive. But in return, they have a much longer read range, sometimes up to 100 meters in ideal conditions. Like passive RFID, active RFID signals have trouble transmitting through water or metal surfaces.

Infrared

IR signals, such as those used by television remotes, can also be used in an RTLS. They’re suitable for different use cases than RFID because they require line of sight with receivers.

An IR RTLS is an excellent choice when you need low-cost, room-level location intelligence. If your goal is to identify the room in which an asset is located, it can be a cost-effective choice.

Cellular

Last but not least, cellular bands (GSM, CDMA) can also provide real-time location service. Much like Bluetooth, one of the main advantages of using cellular for location service is that many devices, such as smartphones, already come equipped with cellular antennas, which can be used as part of an RTLS detection network.

However, cellular location service relies on a connection to outdoor cellular antennas. Cell service is frequently not reliable in large indoor facilities and may require installing expensive repeater antennas to provide adequate coverage. Cellular RTLS has a very long range but is less precise than many alternatives, often only locating a target within 10 meters.

International Standards

The basic issues of RTLS are standardised by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) under the ISO/IEC 24730 series. In this series of standards, the basic standard ISO/IEC 24730-1 identifies the terms describing a form of RTLS used by a set of vendors but does not encompass the full scope of RTLS technology.

Some challenges of RTLS

Like most technology there are some issues. Whilst many solution providers have worked hard to mitigate these they must be considered by any organisation looking to source a RTLS system. These include; lack of full industry certification and radio frequency ‘noise’ causing false locations, jitter or creep.

In conclusion

As you can see, each of these standards is suited to different use cases. Maybe you only want room-level tracking, so you’ll want to choose a less expensive line of sight standard. Perhaps you want a high-precision, low-interference option and choose UWB.

Or maybe you want a cost-effective solution for a wide range of asset tracking and workplace safety jobs, and choose RFID. Regardless of which standard ends up suiting you best, you should now have a better understanding of the different available technologies so you can make the correct choice the first time

Contact us