Tracking Workers Indoors on Construction Sites

A newly published paper presents a deployable Real-Time Locating System (RTLS) for tracking workers indoors on construction sites using Bluetooth Low Energy (BLE) technology. Existing systems often face challenges with cost, wiring, reliance on smartphones, accuracy, and adaptability to the constantly changing layout of construction projects. This study introduces a fully beacon-based system that replaces traditional receivers with low-cost, battery-powered BLE beacons and employs a modular placement strategy, reducing costs and simplifying installation.


The proposed system combines a wireless hardware setup with localisation algorithms based on triangulation and filtering techniques. It addresses issues such as inconsistent signal strength and multipath interference by applying post-processing methods including Kalman filters, exponential smoothing and moving averages. Tests carried out in controlled environments showed localisation errors of around 0.56 metres for moving workers and 0.64 metres for stationary ones, which is an improvement over many previous studies. The research also examined different placements of beacons on the body, with hardhat placement giving the most reliable results.

The system balances accuracy with deployability and cost efficiency. It offers flexibility through adjustable smoothing levels, allowing it to serve both safety-critical real-time monitoring and longer-term productivity analysis.

The paper demonstrates that a beacon-only BLE RTLS can provide a scalable, low-cost, and accurate solution for indoor worker tracking in construction, with applications in safety management, productivity monitoring, and automated workspace identification

Can USB Beacons Receive Beacon Transmissions?

You might wonder whether USB beacons can be used to enable desktops/laptops or any USB device to receive beacon transmissions.

USB beacons don’t work this way and only use the USB connection for power. A few such as the Minew U1 have UART USB serial support that can be used to control the beacon but it still doesn’t detect beacons. It beacon only sends and doesn’t receive.

U1 UART Beacon

What you need is a ‘Sniffer’ such as the ABSniffer 528. It scans for Bluetooth devices and sends the data via USB to the device powering it.

ABSniffer 528

Alternatively, look for a standard Bluetooth dongle that that supports Bluetooth Low Energy (LE) and an associated programming API for ESP32, Raspberry Pi, Windows or Linux.

Do You Have Bluetooth 6.0 Beacons with Channel Sounding?

The situation with Bluetooth 6.0 is essentially the same as it was with Bluetooth 5. The adoption of Bluetooth Channel Sounding, much like earlier advancements such as Mesh, Direction Finding and Angle of Arrival (AoA), is expected to face significant delays before becoming generally available in deployable products.

Historically, the uptake of newer Bluetooth Low Energy (LE) enhancements has been slow, largely because they require not only new hardware but also updated software that makes use of the latest Software Development Kits (SDKs). This combination adds complexity to both development and deployment. In addition, compatibility constraints mean that new Bluetooth LE features typically cannot be retrofitted to existing smartphone devices, which further limits their early adoption.

At this time, the only device we are aware of that offers Bluetooth 6.0 Channel Sounding capability is the Moko L03. While we do not stock this beacon as a standard item, it can be sourced and supplied as part of our consultancy and development work.

For those who need effective distance measurement, another option is to consider beacons such as the iBS03R, which includes a dedicated Time of Flight (TOF) distance sensing hardware module.

Survey of Smartphone Datasets for Indoor Localisation

A new paper is the result of collaboration between Spanish and Italian university researchers. It surveys publicly available datasets for indoor localisation, with a focus on machine learning approaches that make use of the sensors embedded in smartphones. It reviews twenty datasets released between 2014 and 2024, noting the growing trend towards multi-sensor data collection, not only Wi-Fi and Bluetooth but also accelerometers, gyroscopes, magnetometers and other signals.

Bluetooth Low Energy (BLE), features prominently throughout the survey. It is identified alongside Wi-Fi as one of the most widely used technologies for radio frequency-based localisation, relying on received signal strength from Bluetooth beacons to triangulate or fingerprint positions. Several datasets in the survey focus on BLE signals, in the form of iBeacons deployed within controlled environments such as university buildings or libraries.

The review also discusses hybrid approaches, where BLE data is combined with other signals such as inertial measurements or geomagnetic readings, to improve robustness and accuracy. Machine learning techniques are highlighted as particularly effective in handling the noisy and fluctuating nature of Bluetooth signals in complex indoor environments. Some studies combine BLE with Wi-Fi fingerprints in unified models, enhancing resilience against signal drift.

In conclusion, the survey underscores Bluetooth’s importance as a practical, widely deployed technology in indoor localisation research, while also pointing out the limitations of current BLE datasets in terms of scale, diversity of environments, and long-term variability.

Which Beacons Have an On Off Button?

Beacons with an on/off button are popular in product and app development because they make it easier to test scenarios where a device goes into and out of range, without needing to physically move the beacon. This saves time during development and allows for more controlled testing conditions. The on/off function also provides a practical way to conserve battery life, since the beacon can be switched off when it is not needed, ensuring that power is only used during active testing.

K21 With On-Off Button

However, it is important not to rely solely on the on/off button when testing how beacons move in and out of range. You should also run tests at the edge of the detection area to understand how your app behaves as the beacon repeatedly appears and disappears. This is particularly relevant on Android, where, unlike iOS in the background, the operating system does not enforce a minimum period that a beacon must remain out of range before being considered visible again. On iOS, it is equally important to test at the edge of detection when the app is running in the background or not running at all, to ensure you capture the differences in behaviour across platforms.

Another way of hiding beacons is to use a Faraday bag:

We have a web store category for beacons with an on off button.

New iBS08T Bluetooth Sensor Beacon

INGICS have released a new product, the iBS08T Bluetooth Sensor Beacon, which combines temperature, humidity and light sensing in a compact, rugged design. With up to seven years of battery life, an operating range from -40°C to 85°C and IP67 protection, it is designed to perform reliably in demanding environments. The beacon also includes offline temperature and humidity storage, acting as a data logger with capacity for up to 6000 records.


This versatile device can be used in a wide range of applications, including monitoring refrigerators and freezers where condensation is common, safeguarding treasured items such as instruments and keepsakes, supporting cold chain management in refrigerator trucks and containers, and greenhouse monitoring.

Three features make the iBS08T stand out from other beacons. Firstly, it includes a light sensor that provides actual light levels rather than a simple on/off reading. Secondly, it is engineered to continue working even when condensation occurs, ensuring uninterrupted monitoring. Finally, it can be supplied pre-calibrated by INGICS or calibrated by the user, offering flexibility that is not usually available with other beacons.

Although we do not stock this product in our web store, it is available by special order and can also be included as part of custom projects.

Beacons for Employee Time Logging

Beacons make worker check-in and check-out fast and largely hands-free. A phone or badge simply comes within range of a doorway beacon and the event is recorded automatically, so people don’t have to queue at a terminal, find a QR code, unlock a device or remember to tap anything. That reduces friction at shift changes and cuts the small but costly delays that add up across a site.

They’re built for indoor accuracy, where GPS struggles. A beacon at each entrance, gate, or zone gives reliable, metre-level proximity so you can tell which door someone used and when, rather than relying on coarse geofences or Wi-Fi presence. That precision supports clean timesheets, correct job and cost-code allocation and a defensible audit trail for inspections and disputes.

Because beacons use Bluetooth Low Energy, the hardware is inexpensive, tiny, and battery powered. You can stick them near entrances with no cabling, and the batteries typically last years, which keeps deployment and maintenance costs down. Phones barely notice the power draw, and if there’s no signal underground or in a basement, check-ins can be stored on the device and sync automatically when connectivity returns.

Beacons are also good for safety. They support live headcounts, roll-calls, and muster reporting during evacuations because presence updates as workers move through muster points. Zone beacons can warn when someone enters a restricted area or stays too long in a high-risk zone, and they help you evidence who was on site during specific windows in the event of an incident.

They reduce time fraud and “buddy punching”. Unlike sharing a PIN or flashing a photo of a QR code, proximity requires the person’s device or assigned tag to be physically present at the right place and time.

From a privacy and compliance standpoint, beacon systems can be designed to be lighter-touch than CCTV or biometrics. You can rotate identifiers, process events on-device, and store only time, zone and worker ID needed for payroll and Working Time Regulations reporting, which helps with UK GDPR principles like data minimisation and purpose limitation. There’s no need to capture faces or fingerprints, which many staff prefer.

Accessibility and usability improve too. Hands-free check-ins work with gloves, PPE, or when carrying tools, so they’re friendlier than fingerprint readers or touchscreens. You can trigger just-in-time workflows on arrival, surface a safety brief, a permit-to-work checklist, or a reminder to clock to the correct job, because the app knows which beacon you passed and what’s relevant at that location.

Beacons scale cleanly across multi-site operations. Each site can have its own set of identifiers and rules, yet the same app works everywhere on iOS and Android. You can add temporary beacons for pop-up work areas, contractors, or events without touching existing networks. Integrations into HRIS, rostering and payroll can run automatically from the validated in/out events, reducing manual adjustments and queries.

Finally, they unlock useful analytics without extra effort. With accurate in/out and zone transitions you can see peak arrivals, overtime patterns, subcontractor utilisation, and dwell times by area. That helps with staffing plans, capacity management, and proving service levels to clients.

The first step is to choose a system such as Calamari, AllHours and PeopleHR. Almost any beacon will do, but wearable beacons will be probably best.

Custom solutions are also possible when off-the-shelf systems don’t quite match what’s needed.

Which Beacons are the Most Compatible?

We get asked a lot which beacons are the most compatible. All beacons, whether iBeacon or Eddystone, are compatible with iOS and Android. There are a few ‘tracker’ type Bluetooth devices around that don’t transmit the right Bluetooth header and can’t be seen on iOS but we don’t sell those.

Almost all beacons are slight derivations of a few standard circuit designs and firmware provided by Texas Instruments, Dialog and Nordic who produce the System On a Chip (SoC) inside beacons. Hence, they all transmit to Bluetooth standards.

Use of standard SoC Chip and firmware libraries ensures Bluetooth compatibility

The main factor that can vary between beacons is the antenna and PCB layout, which can result in different radiation patterns. This does not affect the ability to detect a beacon, but it does influence the signal strength and stability, which in turn can affect range.

Beacons generally do not differ in terms of compatibility. The main differences are physical characteristics such as battery size and waterproofing, which are listed as categories on the left-hand side of our store.

A common misconception is that problems arise from beacon compatibility, when in fact they are more often related to phone compatibility. Over time, we have found that around five per cent of customers experience issues connecting the manufacturer’s configuration app to beacons, more so on Android devices. To clarify, this only applies when apps need to connect to a beacon in order to change its settings, not when simply scanning for beacons. For most end users, once a beacon is set up, this does not present a problem.

In short, Bluetooth standards ensure that all beacons can be detected by all phones, so compatibility is not an issue. The problems we have encountered have been linked to smartphones rather than the beacons themselves and we have never had a beacon returned to us on the grounds of incompatibility.

Bluetooth Low Energy Choices

There is new research (PDF) analysing methods for indoor distance estimation using Bluetooth Low Energy (BLE), with an emphasis on practical implementation in embedded systems. It compares four main techniques, Received Signal Strength Indication (RSSI), Time of Flight (ToF), Angle of Arrival (AoA), and Channel Sounding (CS), examining their theory, hardware and software requirements, and performance. The work aims to guide designers in selecting the most appropriate method based on accuracy, power consumption, complexity and cost.

The study explains foundational localisation concepts such as trilateration, precision, accuracy, and resolution, and then explores range-based and range-free distance estimation methods. It provides a detailed breakdown of BLE architecture, including host and controller components, communication protocols, and physical layer considerations, linking these to the requirements of the four techniques.


RSSI and ToF were tested experimentally on NXP’s MCX W71x platform, showing RSSI’s simplicity but high environmental sensitivity, and ToF’s better short-range consistency but increased instability and power usage over distance. Direct testing of AoA and CS was not possible due to hardware constraints, so the analysis relies on third-party demonstrations, confirming AoA’s potential for precise angular measurement and CS’s sub-metre accuracy and robustness in complex environments.

The final comparison uses criteria such as accuracy, robustness, processing complexity, and hardware needs to recommend different methods for applications like smart buildings, asset tracking, and IoT systems. The study concludes by bridging the gap between theory and embedded implementation, offering a reference framework for future BLE-based localisation developments.

Can Beacons Store Data?

Beacons don’t generally need to store data because they are just sending out their unique id. However, sensor beacons do sense values over time that you might want to collect later via, for example, an app coming close to the beacon. Specialist devices such as social distancing beacons need to store close contacts for later collection.

It is a misconception that beacons send data directly to smartphones when they come into proximity. In reality, beacons only transmit a small identifier, not the actual content or data itself. This identifier is then matched to information stored elsewhere, either on the user’s device or on a remote server. The relevant app, or app calling a server, uses this match to retrieve and display the appropriate data to the user.

Beacons use a System on a Chip (SoC), such as the Nordic nRF51, that includes memory. Most of the memory is used for the internal functioning of the beacon. Newer versions of SoC, for example the Nordic nRF52, have more memory that allows data to be stored.

Temperature Logger Sensor
M52-SA Plus Temperature Logger Beacon

There are some sensor logger beacons that store sensor values but this tends to be restricted to temperature logging.