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Unlock the Secret to Business Efficiency: How to Choose the Right Indoor Location System

Satomi Le Guiily Satomi Le Guiily
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7 min read
Indoor location technology

Indoor location systems, sometimes called Real-Time Location Systems (RTLS), are used by an increasing number of businesses. They can offer benefits like improved safety, process optimization, and efficiency increase. What enables those benefits is the ability of indoor location systems to locate personnel, clients, and assets in closed areas, where the Global Navigation Satellite Systems (GNSS, like the American GPS or European Galileo) are unreliable. However, it can be confusing to navigate through all the available technologies.

This article will review the most common technologies with their pros and cons.

How Does it Work?

Indoor positioning technologies can be broadly classified into two types: those that use external devices such as beacons (sometimes called locators), and those that use sensors such as inertial tracking.

When using beacons, triangulation, and trilateration are used to calculate the position.

Trilateration

Trilateration uses the distance of at least three beacons near the target to track. This distance is usually inferred via Time of Flight (ToF), Two Way Ranging (TWR), or Time Difference of Arrival (TDoA).

  • Time of Flight (ToF): method of measuring distance by sending a signal from a sender to a receiver and measuring the time it takes for the signal to travel between the two points. LiDAR and ultrasonic sensors also use ToF.
  • Two Way Ranging (TWR): measures the time the signals travel back and forth between the beacons and the target. TWR is known for its high accuracy but is more complex to set up because it requires synchronized clocks.
  • Time Difference of Arrival (TDoA): measures the difference in arrival times of signals at multiple receivers (like satellites). The GPS and other GNSS use TDoA.

三辺測量

Trilateration: we compute the target’s position using the distance between at least three beacons or more and the object to track.

Triangulation

Some beacons equipped with multiple antennas can estimate the angle at which a received signal is. There are two standard methods: Angle of Arrival (AoA) and Angle of Departure (AoD).

三角測量

Triangulation: using 2 beacons or more, we can locate a target. Bluetooth devices use an array of antennas to estimate the angle at which a signal is received. Beacons come with their pros and cons. The accuracy is usually good or great but at the cost of a complex deployment. Installing 1000+ beacons for tracking assets in multiple buildings is not uncommon. Inertial navigation offers an alternative to using beacons.

Inertial Navigation

Inertial navigation is a self-contained navigation technology that tracks an object’s position and orientation relative to a known starting point, direction, and velocity using measurements from accelerometers and gyroscopes. A key advantage of this method is that it’s self-contained and doesn’t require beacons. However, many inertial navigation systems face challenges with high costs and limited accuracy.

What Technologies Are Available?

Let’s examine the four key aspects of the most well-known indoor positioning systems:

  • Implementation Cost: What are the costs associated with adopting this solution?
  • Accuracy: What level of accuracy can typically be expected?
  • Flexibility: How difficult is it to start a Proof of Concept (PoC)? And what about more complex indoor environments like metallurgy facilities, steel mills, or ships?
  • Suitability for real-time human positioning (or tracking)?

Let’s dive in.

GNSS(Global Navigation Satellite System)

While GNSS systems like American GPS and Chinese BeiDou are widely used for outdoor positioning, their performance changes dramatically when used indoors, making them generally not recommended for indoor positioning systems. While GNSS might be considered depending on the situation, in most cases, RTLS (Real-Time Location System) requires more accurate and reliable technologies. GNSS

BLE (Bluetooth & Bluetooth Low Energy)

Bluetooth uses radio waves for communication between devices. BLE (Bluetooth Low Energy) is a type of Bluetooth that’s widely used in indoor positioning systems due to its low power consumption and long battery life. Furthermore, BLE-enabled indoor positioning systems can perform real-time tracking, geofencing (a system that automatically executes predetermined actions, such as sending messages when specific people or objects enter or exit virtual fences set up on a map), and proximity alerts.

BLE

Since BLE requires beacons, it involves significant installation costs and time, making it less suitable for complex environments like power plants and construction sites. Additionally, when tracking is needed across both indoor and outdoor areas, the setup can become more complicated. Furthermore, Bluetooth signals are affected by metal structures and concrete, and their communication range is limited. High ceilings can also make beacon deployment challenging. Regarding power supply, BLE beacons can operate on batteries for several months. However, in terms of cost-performance balance, BLE offers good coverage with accuracy under 1.5 meters.

Wifi

WiFi is now ubiquitous and can be used anywhere, anytime. As a result, indoor positioning systems that utilize this technology have a lower barrier to entry compared to BLE. However, they face the challenge of lower accuracy. Wifi

If you already have existing WiFi infrastructure and can accept accuracy within approximately 5 meters, WiFi becomes an excellent choice. It offers more flexibility than Bluetooth due to its wider range. However, it can still be affected by metal structures and concrete. Also, it’s important to note that the beacons need to be connected to an external power source. In other cases, you might want to consider other technologies mentioned here.

UWB(Ultra Wide Band)

UWB (Ultra-Wideband) is a relatively new technology. This wireless technology operates in the frequency band of 3.1 to 10.6 GHz. It uses very short radio pulses and ToF (Time of Flight) to determine the position of objects. While it can provide extremely high accuracy, it is more expensive than the technologies previously introduced.

UWB

UWB also requires beacons and has an intermediate range between Bluetooth and WiFi. It is affected by environmental factors such as metal structures. Nevertheless, when proper coverage is ensured, it can achieve indoor positioning accuracy of less than 1 meter. The beacons typically can operate on batteries for over 10 months. If accuracy takes priority over cost and the indoor environment is suitable, UWB is the optimal technology.

NFC (Near Field Communication)

Surprisingly, Near Field Communication (NFC) can be used for non-real-time indoor positioning systems. Simply touching NFC tags allows you to identify the location of objects or people within a building. NFC can be utilized for simple and robust non-real-time positioning systems.

NFC

INS(Inertial Navigation System)

INS

INS (Inertial Navigation Systems) tracks object positions using accelerometers and gyroscopes. This technology is commonly used in boats, submarines, and aircraft.

When high accuracy is required, INS needs expensive wearable devices. If you can afford to use beacons, BLE or UWB would be better options.

Next-Generation RTLS

Zeteoh TRAILS provides a flexible solution that combines INS and AI (Artificial Intelligence). This enables indoor positioning system deployment in just hours instead of weeks. Additionally, TRAILS can track positions across both indoor and outdoor spaces. 次世代RTLS

Summary

Selecting the appropriate technology for indoor positioning is a challenging task. It requires a proper understanding of the advantages and disadvantages of each technology, and choosing the right one based on the site environment, conditions, and required positioning accuracy. Generally, beacon-based solutions offer high accuracy but lack flexibility and involve substantial implementation costs. When properly utilized, indoor positioning technology can bring numerous benefits to your business.

Satomi Le Guiily

Satomi Le Guiily