In our last blog, we explained why GPS is not an ideal indoor location technology, especially in industrial environments. When tracking assets, personnel, and vehicle location, navigating indoors in 1D to 3D modes, and for safety applications like vehicle collision avoidance, sub-meter accuracy matters.
In this article, we will compare four widely used indoor positioning technologies in the market: UWB, BLE, WIFI and RFID, and discuss how to choose the appropriate positioning technology for different application scenarios.
Bluetooth low energy (BLE) indoor location technology uses several access points installed in a space to maintain the network connecting multiple users. The access points are always the gateway of the network, and they triangulate blind nodes in the space by measuring their signal strength to understand their proximity.
Advantages: Small size, short distance, low power consumption, easily integrated into mobile devices.
Disadvantages: Low accuracy, only measures proximity (not distance). Poor stability and scalability in a complex environment. Disturbed easily by noise signals.
Applications: Any small, indoor operations that do not need extreme precision, such as a single-story structured warehouse or store.
There are two types of Wi-Fi location tracking technology. The first uses the wireless signal strength received by mobile devices from three or more access points to triangulate people and vehicles with differential algorithms. The other records (in advance) the signal strength of a large amount of identified location points, and determines their location by comparing the signal strength of the newly added equipment with that of a database with a large amount of location data.
Advantages: High transmission rate, signals can be transmitted through mobile devices.
Disadvantages: Short transmission distance, high power consumption.
Applications: Wi-Fi works well when tracking Wi-Fi enabled devices. It can be a useful tracking solution where analysis of motion profiles is desired, such as navigation of people or cars, event tracking in medical institutions, theme parks, factories, or shopping malls.
Radio Frequency Identification (RFID) is an older indoor positioning technology that uses radio frequency. A fixed antenna adjusts to the radio signals in an electromagnetic field and is attached to a device or label. The magnetic field generated by the induction current sends out the data to track the device’s position.
Advantages: RFID works well over short distances, easy set-up and use, small device size, and low cost.
Disadvantages: No communication ability, the signal is prone to interference, not easy to integrate into other systems, works only over distances of 1m or less, and not secured to protect user security and privacy.
Application: RFID indoor positioning has been widely used in warehouses, factories, shopping malls and more for inventory management.
Ultra-wideband (UWB) technology is a high-precision, wireless, indoor positioning technology gaining popularity in recent years. It uses anchor nodes and bridge nodes with known positions arranged in advance to communicate with newly added blind nodes and uses triangulation or “fingerprint” positioning methods to determine the position. It has a high-resolution time of nanoseconds–higher than any other frequency or technology currently available. Combined with the distance measurement algorithm based on arrival time, it can theoretically achieve the positioning accuracy of within centimeters and meet the positioning requirements of even the most challenging industrial applications.
Advantages: Bandwidth of GHz magnitude, high positioning accuracy, low latency, strong penetrating power and effective for safety applications.
Disadvantages: Higher power consumption and cost relative to other technologies.
Application: UWB technology can be used in any indoor operation that requires extreme precision and low latency, such as vehicle collision avoidance, asset tracking, and indoor navigation. It is suitable for a variety of environments including mining and warehouse management.