The use cases for indoor location services continue to grow—every industry from manufacturing and logistics to law enforcement to healthcare to retail, and dozens of others, can benefit from the ability to determine an object’s precise location indoors. New applications are emerging every day that are expected to drive the global indoor location services market to reach $58 billion by 2023, according to KBV Research.
Bluetooth beacons have been hailed as an excellent solution for indoor location for certain types of applications, and they do indeed have their benefits. Each beacon is a Bluetooth Low Energy (BLE) chip that is fixed in a specific location and transmits a unique signal. Nearby smartphones receive the signals, look up the beacon’s location based on the unique signal it transmits, and use the signals received from multiple beacons to estimate the smartphone’s location. Some signals are received strongly, indicating that the phone is close to the beacon. Others are received weakly, indicating the phone is further away. The simplicity and straightforwardness of how Bluetooth beacons operate is appealing in some use cases.
However, this simplicity also presents several downsides that hinder their effectiveness in many applications:
- Bluetooth beacons are limited to smartphones and do not work with simpler tags and cards.
- Bluetooth beacons can only be used to locate smartphones that have an app installed to calculate location based on beacon signals.
- Bluetooth beacons can only transmit periodically because of the strain they put on battery life. Therefore, real-time location capabilities are not always a reality.
- The accuracy of Bluetooth beacons lacks for applications that need more precise location capabilities. Bluetooth beacons can only measure location to an accuracy of 3 to 4 meters, which is precise enough to know that you’re in a particular store in a shopping mall, but isn’t accurate enough to know in what specific department.
However, new technologies are emerging that already go well beyond the capabilities of Bluetooth beacons. The first big change happening is an industry shift away from mobile-centric beacons, which are specifically made to work with mobile devices such as smartphones, to a network-centric system of receiver antennae. In the network-centric approach, a set of receiver antennae estimates the locations of any Bluetooth-enabled device within their range. These may include smartphones or other mobile devices, but can also be other devices with Bluetooth capabilities such as Bluetooth tags, watches, Bluetooth-enabled ID or visitor badges, Bluetooth bracelets, or anything else with a Bluetooth chip.
Receiver antennae are “smarter” than beacons, in that the brains are in the receiver antennae and centralized software application, not in the smartphone app. Because the network of receiver antennae is smarter, the devices that need to be located can be much simpler, opening the door for a broader range of devices that are Bluetooth-enabled. Technology is also emerging to build tags that have other types of embedded sensors (such as motion sensors) so that they can transmit their signals only when moving and save battery power. They’re even smarter, however, and can also decide how often to transmit a signal based on their location, and can also use these sensor signals to make the location measurements even more accurate.
The biggest difference in emerging technology, however, is changing the way the signals are measured to determine location. Using the strength of signals to determine location is arcane; it does not take into consideration a device’s physical surroundings. Instead, it assumes that a signal is weak because of distance, not because there is a concrete wall between the transmitter and receiver.
A new way of thinking is to determine location using the direction of signals, or their Angle of Arrival (AoA), that pinpoints the exact direction that the device is from the receiver antenna arrays. This method is about 20 times more accurate than Bluetooth beacons, and can locate a Bluetooth-enabled device to within 10 to 20 centimeters. Location results are instantaneous because unlike methods based on signal strength, which requires multiple readings over the course of several seconds to achieve good results, only one reading is required. Angles must be precise and three-dimensional to achieve the most precise location results.
There is also emerging technology that moves the location intelligence back to smartphones and mobile devices if it makes sense for the application. A system like this enables devices to measure “direction of departure,” or DoD, which is the mobile-centric equivalent of network-centric AoA technology described above. A system of this sort can measure locations of significantly more devices, since the work is done on the devices and not in the network, and it also helps maintain location privacy. The Bluetooth Special Interest Group (BT SIG) is working on a new standard for BLE angle estimation.
As technologies mature, and new applications emerge, the market for global indoor location services will continue to grow. There is still uncertainty surrounding how quickly the market will move, but one thing is sure: the future of precision indoor location is moving beyond Bluetooth beacons.
About the author
Fabio Belloni (m), General Manager & Co-founder in Quuppa LLC, PhD, started working for Nokia Research Center (NRC) as Senior Researcher focusing on advanced algorithm development and antenna modeling in 2007. In 2008, he became Principal Researcher working on positioning technologies, hybrid systems architecture, indoor mapping and navigation, while leading the execution of technology pilots and demonstration activities around indoor localization technologies. Fabio received his M.Sc.(Tech.) Ph.D. in Telecommunication Engineering from “Politecnico di Milano”, Italy, in 2003. In 2007, he received his PhD degree with honors from the Helsinki University of Technology (nowadays part of Aalto University), Department of Electrical and Communications Engineering, Finland. He is the author or co-author of numerous academic papers and has several granted patents and pending patent applications
