Challenges and Solutions in Indoor Positioning of Security Guards

Indoor positioning is becoming increasingly important for security service providers to enhance the efficiency of supervising their security guards and to improve safety, as in most locations, the staff operates alone or isolated from their colleagues.

Indoor positioning of security guards is a technological solution that enables continuous tracking of the location and movement of security personnel within a given building or facility and allows online monitoring of their activities. 

Challenges of Indoor Positioning

Accuracy and Reliability:

Indoor positioning must be accurate and reliable to allow intervention in the security guard's duties in critical situations, such as sending immediate assistance in cases of attack, accident, or illness.

Environmental Conditions:

Buildings often contain various environmental conditions, such as corridors, stairs, walls, and doors, which complicate the indoor application of traditional satellite (GPS) positioning since it requires optical visibility. Modern technology offers several solutions to the challenges of indoor positioning for security guards, such as Wi-Fi, Bluetooth, UWB (Ultra-Wideband), and RFID technology.

1. Wi-Fi-Based Positioning:

Wi-Fi (Wireless Fidelity) networks available inside buildings can also be used for positioning. Smartphones and other devices can determine their location based on Wi-Fi signals. Wi-Fi-enabled devices typically continuously scan for Wi-Fi networks in their environment. This means that the devices can identify nearby networks and record their characteristics, such as SSID (network name), signal strength, and other information like the MAC addresses of network devices. For positioning, the system generally uses the recorded Wi-Fi network data and applies triangulation based on those. The devices attempt to determine their position relative to the fixed network points. The more Wi-Fi networks a device can detect, the more accurate the positioning can be.

1. Bluetooth Beacon-Based Positioning:

A Bluetooth Beacon is a low-power, small device that continuously broadcasts short, unique identifier signals using Bluetooth Low Energy (BLE) technology. Typically, it can be found in the form of a small box or coin, allowing discreet placement or even being worn on clothing. Beacons use communication protocols like iBeacon, Eddystone, and others to broadcast and receive identifier signals. Bluetooth Beacons form a system that helps determine the exact location of a device or person in an indoor space. The principle is that the strength and arrival time of the signals emitted by the Beacons help determine the distance of a device from the Beacons. A smartphone or other portable device with BLE support is required for this. The portable BLE device continuously searches for Beacons’ signals in its environment, and when it detects one, it records its strength along with the arrival time. If multiple Beacons are detected, the device uses this information to calculate its position.

Beacons are usually placed in predetermined positions indoors, and the system uses the signals' triangulation to determine the precise location of the BLE device. The triangulation method is effectively used in large halls or contiguous retail spaces because there, the system can be economically deployed, and communication is not affected by the building’s complexity. In highly segmented buildings composed of numerous offices, it is recommended to set up zone-based positioning. Beacons in this case are also placed in predetermined locations but in significantly fewer numbers, as they serve only to identify presence in an area, not to determine the exact position of the device. In critical areas, it is suggested to place Beacons in each room or at building exits. Zone-based positioning has the additional advantage of allowing personalized content and notifications to be sent to the device users as they enter a specific area. For example, in a museum, a security guard can receive different information and content via the BLE device from the Beacons as they enter an exhibit area. This could include a job description or even the area’s name, assisting in indoor navigation.

1. UWB-Based Positioning:

UWB (Ultra-Wideband) positioning is a technology that uses very wideband radio frequencies (RF) to enable precise positioning and location sensing of devices. UWB technology employs a very wide frequency range (typically several GHz) and transmits or detects extremely short and fast RF pulses.

Positioning:

UWB technology allows for the accurate measurement of distance between two or more UWB devices based on the timing of signal paths. Using the distances, trilateration (positioning from three points) can be performed, resulting in precise location information.

Location Sensing:

Devices equipped with UWB systems, such as smartphones or sensors, can sense their environment and determine the position and movement of nearby objects or devices. This enables, for example, indoor map navigation or specialized applications like virtual reality (VR) or augmented reality (AR).

Identity Verification:

UWB technology can identify people or devices based on their distance from each other. This can be useful in security applications to check entry and exit permissions or to restrict access.

1. RFID-Based Positioning:

RFID (Radio-Frequency Identification) technology is also suitable for tracking the location of security guards. Using RFID tags placed inside the building, the system can easily track security guards and accurately record their location. RFID technology is an automatic identification system that uses radio waves to identify and track devices and objects. The system consists of three main components: an RFID tag (or token), an RFID reader, and a central database or software application.

An RFID tag is a small device containing an antenna and a microchip. The antenna is used to receive and emit radio waves, while the microchip stores information that identifies the tag. RFID tags can be active or passive. Active tags have a built-in battery, whereas passive tags use the energy emitted by the reader to transmit data. The RFID reader is a device that can send and receive radio waves. The reader’s antenna emits radio waves at a specific frequency. RFID tags detect these waves and respond by transmitting identification and other information. The RFID reader detects the tag’s response and then sends the information to the device’s software database. The database compares the RFID tag’s identifier with stored information to determine a device, an object, a zone, or even an activity.

The main difference between active and passive RFID tags is that active tags transmit independently, while passive tags respond only when directed by an RFID reader. Consequently, active tags can operate over longer distances and at higher speeds, while passive tags need to be closer to the reader.

Summary

In summary, triangulation methods (Wi-Fi, Bluetooth Beacon, UWB) enable very precise and accurate positioning but are economical to deploy only under ideal environmental conditions. Designing such a system requires prior site assessment and extensive instrumental analysis. After the assessment, the number of system components necessary for reliable operation, as well as the installation and commissioning time and total cost, can be determined. Unfortunately, in most buildings, the triangulation positioning method cannot be economically deployed, so its area of application is much smaller.

Zone-based positioning methods (Bluetooth Beacon, RFID) allow less precise and accurate positioning. The technology does not determine the exact position of the device but identifies its presence in a given area. Therefore, this solution requires significantly fewer system components, making it much simpler, quicker to design, and more economical to deploy. The zone-based positioning method can be applied to any type of building, so its area of application is much larger. If centimeter-level indoor positioning is not necessary, the zone-based approach can be a perfect choice for almost any application area, including tracking the movement of security guards. Zone-based positioning consists of quickly and easily deployable and maintainable components, and Beacons and zones can be predefined, so they do not require complicated configuration either.

Naturally, it is also possible to combine the above-described technological solutions, allowing for much more effective control and higher security levels. Zone-based positioning can be achieved by placing Bluetooth Beacons, while RFID tags can ensure on-site documentation of task completion. The former expects passive cooperation from the security guard, i.e., continuous wearing of the BLE device. The latter requires active cooperation, which involves reading RFID tags installed in various areas from a few centimeters away.

An additional security-enhancing factor is continuous monitoring of security guards' movements and activities by a remote monitoring center using suitable remote monitoring software. If there is a deviation or omission within a predefined time interval, the system immediately alerts the dispatcher, who initiates the necessary measures. This means calling the security guard on the BLE/GSM device, then informing them about the missed task and instructing them to complete it. Alerts and actions also apply if the security guard does not wear the BLE/GSM device while working, as this makes positioning impossible. The BLE/GSM device signals the dispatcher about the device's inactivity and can also transmit impact and fall information.

For over 15 years, MOHAnet has been developing portable, GSM-based patrol monitoring devices for security guards, with the latest generation, MONICALL, equipped with BLE and RFID technology. The former continuously detects Beacons' signals and can thus determine the device’s location on a zone basis, while the latter electronically records the timely completion of repetitive tasks by reading RFID tags, supported by the MONITORINGBOOK PRO graphical remote monitoring software.

Closing Thoughts

The indoor positioning of security guards marks a significant advancement in the field of security technology because:

• Accurate Performance Documentation: It generates logged performance verification when regularly visiting assigned work sites.
• Real-Time Supervision: When complemented with remote monitoring services, it enables real-time supervision of expected but incomplete tasks, preventing damage from negligence.
• Enhanced Situational Awareness: It allows the security personnel to know precisely where they are within a building or facility.

Indoor positioning enables live security service providers to have their guards perform tasks more efficiently and accurately, thus strengthening the protection of buildings. The ability to locate security guards indoors opens new dimensions in security technology and can lead to further innovations in the future.