In 2024, the adoption of an indoor location system in a company can significantly improve operational efficiency, workplace safety and employee experience.
This article examines the main use cases, constraints and selection criteria for indoor location and tracking systems, whether for industrial sites, warehouses, office buildings or places open to the public. It then examines the technologies available and their suitability for the specific needs of different environments.
INDOOR LOCATION APPLICATIONS
Locating people and goods on industrial sites
Use cases
–Equipment and tool location: Precise location of machines and tools helps to reduce search times and optimize operations such as maintenance.
–Workplace safety: monitoring the location of employees in the event of an alarm helps prevent accidents, provide rapid assistance and ensure compliance with safety protocols.
–Optimization of production processes: real-time tracking of material flows is one way of improving production processes, parts management and logistics.
Notable constraints
–Harsh environments: the omnipresence of metal structures contributes to electromagnetic interference, and extreme conditions can be encountered, such as the presence of ATEX zones (explosive atmosphere) with particular constraints on all equipment intended to be placed or used in these zones.
–Reliability and precision: depending on the application, high precision of positioning may be a prerequisite, even a precise altitude estimation when it comes to complex infrastructures. Constant availability and reliability are generally expected.
–Equipment robustness: Equipment must be resistant to shocks, vibrations, splashes or extreme temperatures, and in some cases comply with ATEX standards.
Selection criteria
–Accuracy and reliability: the requirement for metric or even centimetric accuracy depends of course on the application, but compliance with the stated degree of accuracy will be imperative in all cases, as will non-sensitivity to possible interference.
–Robustness: the ability to operate in harsh industrial conditions, to comply with ATEX and other standards.
–Upgradability: the use of indoor location systems must be profitable in the long term, so such a system must be able to evolve with the plant’s needs and interface, for example, with new communication or supervision systems.
Locating goods or mobile assets in warehouses
Use cases
–Real-time inventory: Track goods movements for accurate inventory management.
–Optimization of logistics operations: Improve workflows to reduce processing times.
–Safety at work: Monitor hazardous areas and prevent accidents (falls, collisions, etc.).
Constraints
–Extensive environments: exhaustive tracking of materials, individual parts or batches, finished products, packages, etc. requires extensive, precise coverage with no capacity limitations.
–Mobile assets: real-time tracking of mobile assets such as forklifts and pallets coexists with that of stored or moved assets.
–Interoperability: the tracking system is only useful if it is fully integrated with the existing warehouse management system. This integration must remain effective as the WMS evolves.
Selection criteria
–Coverage and accuracy: Able to cover large areas with adequate accuracy.
–Interoperability: Compatibility with systems and equipment used in the warehouse.
–Cost: Must be cost-effective on a large scale.
Indoor localization to enhance the employee experience in office buildings
Use cases
–Space management: optimizing the use of workspaces and meeting rooms. The first level of use consists of providing presence information or a gauge of affluence.
–Interior navigation: Helping employees locate a meeting room or reserved open space. An application can also be used to guide visitors or occasional users unfamiliar with the premises (e.g. in coworking offices).
–Safety and evacuation: the safety of lone workers, the monitoring of security rounds or the management of emergency evacuations with presence detection are all possible uses for indoor location in commercial buildings.
Constraints
–Shared environments: a building or site can be equipped as soon as it is built, as part of a “smart building” approach. However, different tenants may have different uses, and the system needs to accomodate a multi-tenant configuration.
–Confidentiality: respect for user privacy and transparency regarding data use and storage are essential to the adoption of any system of this type.
–Aesthetics and discretion: devices must be unobtrusive and not detract from the aesthetics of the office.
Indoor location for places open to the public.
Use cases
–Navigation and guidance: Help visitors find their way around complex environments and save time.
–People flow management: Analyze visitor numbers to optimize visitor flows, help manage security by locating the nearest security personnel in the event of an incident, and supervise mobile teams.
–Targeted marketing: sending personalized promotions based on users’ location has historically been one of the first uses of indoor location technology in shopping malls.
Constraints
–High density: the system must be able to handle a large number of users simultaneously. It must be compatible with smartphones, which are the location vector for the public.
–Integration with security/safety supervision systems: information must be transmitted in real time, so that it can be effectively used by supervision teams.
–Ergonomic guidance: navigation guidance for visitors requires ergonomic maps that can be easily consulted on smartphones.
–Data security: Protection of users’ personal information and respect for privacy.
Selection criteria
–Capacity and compatibility: must support a large number of simultaneous users and be compatible with the sensors present on smartphones (Wifi, BLE, GPS).
–Ease of installation and maintenance: the system must be easy to install and maintain.
–Data security: Robust protection and anonymization of user data.
OVERVIEW OF INDOOR LOCATION TECHNOLOGIES
With regard to the different use cases and types of sites mentioned above, there are a number of different technologies available for the indoor localization of people, goods or merchandise. Let’s take a look at their main features.
Wifi
Wifi signals operate in the 2.4Ghz, 5Ghz and latest-generation 6Ghz frequency bands. The detection by a device of nearby Wifi access points, and the relative strength of the corresponding signal for each access point, enable location within a building equipped with such access points to be obtained by trilateration. A prerequisite is that the location of each access point is duly recorded, published and up to date.
Benefits
-Existing infrastructure: Use of existing Wifi networks.
-Extensive coverage: Good coverage in buildings.
Disadvantages
-Limited precision: accuracy is in the order of 5 to 15 meters and depends on the density of Wifi access points. Detection of the exact floor is not guaranteed.
-Interference: Sensitive to interference from other Wifi devices.
BLE (Bluetooth Low Energy)
BLE transmits in the 2.4 GHz frequency band. It works by trilateration, like WiFi. 2 possibilities exist: a mobile BLE tag can emit a signal picked up by fixed BLE anchors connected to a network, and the tag’s position is calculated on the server side according to the strength of the signal received by each anchor. Or, conversely, the position calculation is performed by the sensor according to the signal strength of the anchors it perceives, whose position is known by the sensor.
Advantages
-Wide compatibility: tags as well as smartphones can be easily located.
-Low cost: tags are generally inexpensive and easy to install.
Disadvantages
-Beacon maintenance: regular maintenance of beacons is required, including battery replacement if they are not mains-powered.
-Limited coverage : beacons have a limited range, usually to each room or office, requiring a large number of devices for complete coverage.
-Possible disruptions: BLE systems are easily subject to interference, and any change in interior layout may require recalibration of the system.
RFID (Radio-Frequency Identification)
Gantry-based RFID systems detect the passage of passive tags by supplying them with the energy they need to respond. This is frequently used for tracking in warehouses. Other systems, known as active RFID, allow tags to transmit autonomously, and to be picked up by a mesh of antennas located up to a few dozen meters away.
Advantages
-Low tag unit cost: passive RFID tags require no power supply and have a very low unit cost.
-High capacity: suitable for tracking high-volume or high-frequency objects or goods.
Disadvantages
-Limited range: reading range limited to a few meters for passive tags.
-Interference: highly sensitive to metallic interference.
-High implementation costs for gantry detection systems.
UWB (Ultra-Wide-Band)
UWB operates in a wide range of multiple frequencies from 3.1 GHz to 10.6 GHz. It uses the time-of-flight principle to offer high localization accuracy over relatively long distances. In general, UWB anchors synchronize their clocks via a network connection and transmit the time of their signal detection to a server, which deduces the precise position of the transmitter.
Benefits
-High precision: Accuracy of the order of tens of centimetres or even centimetres.
-Low latency: Immediate reactivity.
-Low sensitivity to interference: thanks to the use of multiple frequency bands.
Disadvantages
-Dedicated infrastructure and complexity: a UWB localization system requires a specific infrastructure, with more complex integration than BLE.
-High cost: equipment is more expensive than other technologies, but since the introduction of UWB chips on smartphones, costs have been on a downward trend.
Inertial tracking
Derived from the inertial navigation systems used in aircraft, submarines and missiles, inertial systems for indoor positioning use miniaturized MEMS sensors such as gyroscopes, accelerometers and magnetometers. They operate by measuring movement in the 9 possible axes from a known starting point. Unlike other systems, they don’t need any type of frequency to calculate their position, but they do need a network to transmit it.
Advantages
-Infrastructure independence: No dedicated infrastructure required.
-Continuous, interference-free tracking: Works autonomously and is therefore not subject to interference or signal interruptions.
Disadvantages
-Sensor drift: accuracy decreases with time and distance travelled, unless recalibrated.
-Sensor cost/precision ratio: high-precision inertial sensors can be extremely costly, and reserved for military and aeronautical applications. Only the rise of MEMS has enabled inertial sensors to enter the indoor positioning market.
5G
5G indoor localization is an emerging technology. It uses triangulation and trilateration techniques based on signals from miniaturized relay antennas (small cells). By measuring the signal travel time (Time of Flight, ToF) between a device and several small cells, it becomes possible to calculate the precise position of this device. The availability of complete private 5G platforms with 5G tags and position calculation servers is still some way off.
Benefits
-High capacity and very low latency: theoretically supports high connection density with very short response times.
-Indoor and outdoor coverage: unlike WiFi, 5G offers complete coverage of a site both inside and outside buildings.
-Security: unlike private 4G or WiFi networks, 5G offers a very high level of security and confidentiality.
Disadvantages
-Limited 5G deployment: few private 5G infrastructures are already operational.
-Cost and complexity: installation and management are more complex and costly.
-Lack of feedback: by 2024, 5G localization capability is still limited to laboratory deployments. IoT versions of 5G (RedCap) are barely out of the lab.
TECHNOLOGY EVALUATION CRITERIA
When evaluating indoor localization technologies, it is crucial to consider the criteria specific to the target environment and the use cases envisaged, which alone enable us to assess the return on investment of a given choice.
General selection criteria include :
–Location accuracy: UWB offers the best current accuracy.
–Deployment and maintenance costs: Wifi and BLE-based systems are considered the least expensive. UWB and 5G require the most investment.
–Ease of installation and infrastructure requirements: autonomous inertial systems requiring no infrastructure are easy to set up, as are systems based on Wifi already deployed. In contrast, UWB, 5G and, to a lesser extent, RFID require specific infrastructures.
CONCLUSION
The choice of an indoor geolocation system in 2024 depends very much on the specific use cases and constraints of the environment concerned.
Industrial sites can benefit from the precision of UWB systems or inertial systems with light infrastructure, while warehouses often prefer RFID. Office buildings are more likely to use BLE, while public areas with a high user density will consider WiFi and, tomorrow, 5G.
More and more hybrid systems are appearing, drawing on the advantages of several complementary technologies. This is the case of SYSNAV, which has chosen to complement its inertial localization with UWB registration to offer an effective solution for industrial sites in particular. More information on this page.