How can you visualize the locations of people on site? Improving safety and efficiency simultaneously

Table of contents

• Challenges in grasping worker location information on site

• Benefits of visualizing on-site personnel locations

• Main positioning technologies available for use on site

• How real-time worker location tracking works

• Points and cautions when introducing a system

• Simple surveying with LRTK

• FAQ

Challenges in grasping worker location information on site

On worksites, many workers perform tasks at their assigned stations and move according to circumstances. However, in wide work areas or complex sites, it is not easy to always know exactly “who is working where” at any given time. Supervisors spend time and effort confirming each person’s whereabouts via radio or phone or walking around the site to find needed personnel, which reduces operational efficiency.

Furthermore, the inability to know people’s locations in real time also affects safety. For example, in an emergency when everyone needs to be evacuated quickly, if you do not know where each worker is, response will be delayed and the risk to human life increases. There is also the possibility of gaps in safety management, such as not noticing immediately if someone enters a hazardous area. In particular, in indoor environments such as inside buildings or underground, GPS-based location measurement cannot be relied upon, and in practice verification by staff has been unavoidable.

Benefits of visualizing on-site personnel locations

Improved operational efficiency: By digitally visualizing workers’ location information, supervisors can immediately see on a screen who is working where. Even from the office without being on site, you can check each person’s movements and instantly determine situations such as whether workers are overly concentrated in a particular area or whether the right personnel are assigned to a task. This eliminates wasted searching and communication, enables assigning the right people to the right places, and improves productivity.

Enhanced safety: If you can grasp people’s locations in real time, the accuracy of safety management also improves. For example, when a worker enters a preconfigured hazard area, the system can automatically trigger an alarm or send a warning notification to the worker’s device. This prevents inadvertent entry into restricted areas due to human error. In the event of an accident or disaster, the system allows immediate identification of “who is where,” facilitating rapid rescue operations and evacuation guidance. You can also set zones that only authorized workers can enter and detect and warn if unauthorized persons enter, contributing to risk reduction.

Improvement through data utilization: By analyzing accumulated location data, new improvements in site operations can be identified. Reviewing each worker’s movement paths and dwell times as data reveals trends, such as which times and places tend to be congested or whether unnecessary movement is occurring. Based on these analyses, you can optimize work flow and revise layouts to continuously improve site efficiency and safety.

Main positioning technologies available for use on site

There are various technologies for automatically collecting location information. Depending on the site environment (outdoor/indoor) and the required accuracy, the following positioning methods are used.

• GPS (GNSS): A global navigation system that uses signals from satellites. In open outdoor environments, it is easy to acquire position information, but the accuracy of common standalone positioning is generally about 5〜10 m (16.4〜32.8 ft). If high accuracy is required, combining correction techniques such as RTK (described later) can improve accuracy to the centimeter level. However, satellite signals do not reach inside buildings or underground, so it cannot be used indoors.

• BLE beacons: This method utilizes Bluetooth Low Energy signals emitted by small beacon transmitters. By installing BLE beacons throughout a building and having workers’ smartphones or dedicated receiver tags pick up those signals, current positions can be detected. Accuracy is on the order of a few meters in radius, but because beacons are battery-powered and require no wiring work, installation cost is low and they are easy to introduce. Also, because beacon signals have limited range, workers who leave the site naturally fall outside detection—an advantage for keeping detection within working areas from a privacy protection standpoint.

• UWB (ultra-wideband): A radio technology that uses a wide frequency band and enables extremely high-precision positioning. Workers wear dedicated tags and position is determined by ranging between those tags and multiple fixed stations (antennas) installed on site. Time measurement precision is high, allowing precise positioning with errors of tens of centimeters or less. UWB can provide stable high accuracy indoors, but equipment and tag costs are higher than for beacons. It is attracting attention for high-precision requirements in large plants, tunnel construction, and similar projects.

• RFID: An ID recognition technology using radio waves, mainly used for asset management. By attaching active RFID (battery-powered) tags to people or items and reading them with readers placed around the site, the system can automatically record where a tag is located. Passive RFID (batteryless) is detected only when brought near a reader, but by placing readers at gates to detect passage, it can be used for entry/exit management of materials and people. However, RFID alone is not well suited for real-time positioning, so it is often used complementarily with other technologies.

• Wi‑Fi positioning: This method estimates approximate locations based on the signal strength received from Wi‑Fi access points within the site. It can take advantage of existing Wi‑Fi networks, but accuracy depends on the radio environment and can result in errors of several meters to a dozen meters or more. It is used in offices and commercial facilities, but in construction sites where metal and equipment are abundant and radio signals tend to be unstable, Wi‑Fi positioning is generally used as a supplement to other methods.

• Camera image analysis: There are technologies that track people’s movements by analyzing surveillance camera footage. With AI image recognition, you can ascertain locations without requiring workers to carry tags, but it requires installing cameras covering the entire site and faces challenges such as eliminating blind spots and ensuring privacy. It is often used in combination with other methods for limited applications like managing entry and exit to specific areas.

These technologies can be used individually or combined. For example, a hybrid system can use GPS outdoors and automatically switch to BLE beacon or UWB positioning when entering a building. In addition, accelerometers or barometric pressure sensors built into workers’ smartphones or tags can be used to detect falls or to determine floor changes indoors. It is important to select appropriate technologies according to the site environment and required accuracy.

How real-time worker location tracking works

By combining the above technologies to build a system, it becomes possible to track and display workers’ locations on site in real time. A typical setup has each worker carry or wear some kind of location-transmitting device (for example: a UWB tag built into a safety helmet, a beacon tag worn on the person, or a smartphone running a dedicated app). Signals transmitted from those devices are received by receivers (antennas or receiving beacons) installed around the site and converted into each tag’s coordinates on a cloud server.

Managers and supervisors can view that location information in real time on PCs or tablets. Each worker’s current location is displayed as an icon on floor plans or site layout maps so that who is where is visible at a glance. This makes worker movement management dramatically easier. For instance, a team leader can give accurate instructions while viewing members’ locations, and can confirm on-screen whether everyone has returned to their assigned places during breaks or at the end of the day without running around the site.

Additionally, some systems support geofencing features. By setting virtual restricted areas or zones off-limits to unauthorized personnel on the map, an alarm can sound or warning notifications can be sent to the manager and the individual if a worker mistakenly approaches such an area. The system can detect and warn when someone without the required qualifications enters an area reserved for authorized personnel, strengthening safety measures.

In the event of an on-site accident or disaster, real-time tracking systems are highly effective. For example, during evacuations for fire or earthquake, the system quickly identifies “who has not yet evacuated” and “where people are still trapped,” aiding rapid rescue and preventing secondary damage. Moreover, analyzing daily accumulated movement data provides site managers with valuable insights to review work assignments and safety guidance.

Points and cautions when introducing a system

When introducing such a location-visualization system on site, there are several important points to keep in mind.

Appropriate technology selection and design: Technically, it is important to choose a positioning method suitable for the site’s scale and structure. For example, in buildings with a lot of steel or heavy equipment, radio waves are more likely to reflect or attenuate, so you need to carefully consider antenna and beacon placement. Place a sufficient number of receivers to avoid blind spots and design the network to accurately cover the entire site. Also, be flexible in using different technologies depending on the area and purpose—for instance, adopt UWB where high precision is required and cover areas where rough location is sufficient with BLE beacons.

Seamless integration into site operations: From an operational perspective, introduce the system so that it naturally fits into the site’s work flow. If you plan to track workers via smartphones, create an environment where phones can be carried and used on site at all times (provide rugged cases, encourage the habit of carrying, etc.). If distributing dedicated tags, choose small, lightweight designs that attach to helmets or workwear without getting in the way or easily falling off. For battery-powered devices, establish a regular charging and battery-replacement routine to avoid the system failing when it’s needed most.

Small-start and phased rollout: Assessing cost and effectiveness is also important. Rather than deploying the system across the entire site at once, start with a limited proof of concept (PoC) to verify effectiveness. For example, trial location visualization on only a few floors or areas initially and collect data to see how much operational efficiency and safety improve. Once sufficient benefits are confirmed, gradually expand the scope to achieve a smooth full rollout without disrupting site operations.

Privacy and gaining site buy-in: Finally, be careful in handling collected location data. Limit data collection to what is necessary for business operations and manage it securely to protect employees’ privacy. For example, configure the system not to track detailed movements outside working hours or during breaks, and manage data-access permissions so unrelated personnel cannot view individuals’ movement histories. Communicate clearly to everyone on site that location tracking is for safety management and efficiency improvement—not for employee surveillance—so workers can use the system with confidence.

Simple surveying with LRTK

When building a position-information system for people and objects, it is important not only to install sensors and communication infrastructure but also to have accurate coordinate data for map information and reference points on site beforehand. For example, when placing beacons or UWB antennas for indoor positioning, surveying and registering the coordinates of where those devices are installed allows the system to display workers’ locations on the map more accurately. Traditionally, such surveying required specialized personnel and expensive equipment, posing a significant burden on sites.

Recently, attention has been paid to simple surveying using LRTK. LRTK is an innovative tool that achieves centimeter-level high-precision positioning (cm level accuracy (half-inch accuracy)) in conjunction with smartphones and tablets. By attaching a small dedicated GNSS receiver to a smartphone and launching an app, anyone can easily obtain accurate coordinates. For example, construction managers can walk the site holding an LRTK-equipped smartphone and quickly measure important points, digitizing floor plans and equipment locations inside buildings in a short time. Tasks that previously required outsourcing to surveying companies can now be performed by on-site staff whenever needed, speeding up preparation for system deployment.

LRTK can immediately upload measured coordinates to the cloud and share them in real time with colleagues in the office. You can confirm on the spot whether measured points match the plans, or work with remote colleagues while viewing the data, enabling smooth coordination between the site and the office. LRTK also offers a variety of functions beyond basic surveying, such as elevation measurement, automatic calculation of distances and areas, and AR-based on-site placement navigation, making it a versatile ICT tool for worksites rather than just a surveying instrument.

By leveraging simple surveying with LRTK, the work required to introduce a location-visualization system can be greatly streamlined. For example, you can measure and register the exact installation positions of indoor positioning beacons yourselves, maximizing subsequent tracking accuracy. Even in existing buildings undergoing renovation-related layout changes, LRTK lets you quickly measure and record current dimensions and placements and immediately reflect them in the system. Adopting modern simple surveying tools on site makes it possible to advance efforts to visualize people’s location information more smoothly and with higher accuracy.

FAQ

Q1. Why can’t GPS be used indoors? A. GPS is a positioning system that uses radio signals from artificial satellites, but indoors those signals are blocked by buildings and underground structures, making reception difficult. Therefore, GPS signals do not reach inside buildings or underground spaces, and positions cannot be determined. To obtain accurate indoor location information, dedicated indoor positioning technologies that do not rely on GPS must be used.

Q2. What technologies are available for tracking people and objects on site? A. Various technologies are used depending on the application and required accuracy. A common, simple method is to install Bluetooth beacons on site and have workers’ smartphones or tags receive signals to determine location. For higher accuracy, positioning using UWB tags and antennas is effective. In addition, RFID is used for asset management, GPS combined with other technologies for wide outdoor areas, and camera image analysis can track people and vehicles—often multiple technologies are combined to suit the use case.

Q3. How accurate are indoor positioning systems? A. Accuracy varies by technology. BLE beacons generally provide accuracy on the order of a few meters in radius, while UWB can be expected to achieve accuracy on the order of a few tens of centimeters. Wi‑Fi positioning depends on the environment and may have errors of several meters to a dozen meters or more; RFID accuracy depends on reader placement. Choose the appropriate technology according to the required accuracy—for example, if errors of several meters are acceptable, BLE beacons offer a low-cost solution, whereas UWB should be considered for more precise positioning.

Q4. How much does it cost to introduce a location management system? A. Implementation costs vary widely depending on the selected technology and the scale of the site. Systems using relatively simple beacons can often be started at low cost, with the expense consisting mainly of a few dozen beacon devices and software fees. Conversely, high-precision systems such as UWB require more expensive tags and antennas, and covering a wide area will demand a corresponding investment. However, with the spread of IoT technologies, equipment prices are gradually falling, and phased introduction from a small scale while verifying effectiveness is becoming increasingly feasible. It is recommended to start with a limited-area pilot to evaluate cost-effectiveness before full deployment.

Q5. How is privacy of collected location data ensured? A. When implementing a system, limit collected data to what is necessary for operations. For example, configure settings not to monitor detailed movements outside working hours or during breaks, and manage access rights so unrelated personnel cannot view individuals’ movement histories. Use location data solely for safety management and operational efficiency, and clearly communicate that monitoring is not intended for employee surveillance so that workers can use the system with peace of mind.

Q6. Is there an easy way to perform surveying and alignment? A. High-precision surveying on site typically requires specialized surveying equipment, but recently easy surveying tools using smartphones have emerged. The representative example is LRTK. With LRTK, you connect a small positioning device to a smartphone and anyone can record coordinates with centimeter-level accuracy (cm level accuracy (half-inch accuracy)). No complex operation is required—measurements can be taken with the push of a button—so people without surveying expertise can use it. This enables you to measure reference-point coordinates for indoor positioning systems yourselves or quickly lay out structures during construction, greatly contributing to improved accuracy in location information management.