3 critical questions to choose the right solution
We have recognized that almost everyone is interested in three aspects of IPS: accuracy, update rate, and range. Keeping that in mind, here we offer answers to three questions that will help you choose the right indoor positioning system for your needs.
1. What positioning accuracy do I really need and why?
There are three categories regarding the most accurate positioning technologies: positioning technologies with just a few centimeters of accuracy, with sub-meter accuracy, and with roughly 1 to 5 meters of accuracy. Regarding the level of accuracy your use case demands depends entirely on the value you put on location information. What is the cost of not knowing the exact location of your object?
For instance, hospitals in order to locate patients and assets do not need 10cm accuracy but a few meters. It is important to know the approximate location of a patient, since they can be easily found even if the accuracy is around 2 to 5 meters, and we do not know yet whether precisely zeroing in on their location is going to add much value or not. Hospitals in order to use existing infrastructure and smartphones, prefer to use Bluetooth and Wi-Fi-based solutions.
On the other hand, tracking forklifts in warehouses would demand sub-meter accuracy, especially in case the system is used for collision avoidance. If the forklifts pass each other with 30cm of space between them or crash onto each other is a significant difference. For such cases, the most commonly used technologies are Ultra Wideband (UWB), cameras, or ultrasound-based systems.
2. How often do I need to determine an object’s location?
A critical feature that determines the frequency of tracking the location of an object is the update rate. The number of objects that need to be positioned within a certain amount of space update rate significantly influence the update rate. In case the objects are relatively static or move slowly, a very high update rate is not necessary. Furthermore, if knowing the real-time information of the location is not that important, then positioning doesn’t have to happen as frequently. Bluetooth and Wi-Fi enable an update rate of 1Hz versus the 4-10Hz enabled by Ultra Wideband (see the table below). This means that you can get approximately 4 times the number of data points based on positioning with Ultra Wideband compared to Bluetooth and Wi-Fi.
3. How big is the area I need to cover?
Indoor areas differ greatly in terms of size and shape no matter if you are referring to a supermarket, a hotel unit, or even a manufacturing facility. Successful cover of indoor and outdoor areas is mainly achieved when using indoor positioning technologies. The range and scale requirements differ in each case.
Smartphones are often used to locate customers or visitors, while bluetooth beacons usually are used in retail and hospitals. Phones that are bluetooth ready offer a significantly shorter range of 5-10m, which, by the way, could still be enough for smaller positioning areas. Infrared provides a similar operating range but usually requires a line of sight, for home automation and security applications. Bluetooth can have only a limited number of connections at one time. But, still, for proximity marketing and other similar use cases, Bluetooth can be a suitable option.
Finally, Wi-Fi and Ultra Wideband offer a range of 40-50 meters and, therefore, you can cover larger areas (our field tests have managed to extend the range of our Ultra Wideband solution as far as 160 meters). Every indoor positioning system has its own disadvantages. For instance, the need for dedicated infrastructure in the form of anchors and tags, consist a significant disadvantage for UWB and Bluetooth. With the Wi-Fi RSSI fingerprinting method, all reference points need to be mapped beforehand, increasing the configuration and maintenance costs of the system.