![]() ![]() Although GPS is able to provide highly accurate location data over a wide geographic area, satellite signals are unable to penetrate through solid objects like buildings. Indoor Positioning Systems (IPS), or indoor RTLS, are being built to overcome the physical limitations of GPS. However, these newer applications have been adopted more slowly due to technical hurdles and infrastructure costs.Īs with outdoor RTLS, there are countless use cases for indoor RTLS. Applications range from medical asset tracking in healthcare to supply chain management. For example, locating lost medical devices can help reduce replacement costs and improve hospital logistics. There are also multiple approaches to building indoor tracking solutions that leverage technologies like Bluetooth, WiFi, RFID, Ultra Wide Band (UWB), and Ultrasound. While there are many opportunities for IPS product development in this space, the technologies required to build useful IPS products are not nearly as well understood or as ubiquitous as outdoor technologies like GPS. To better understand and characterize the issues associated with indoor positioning, the Leverege R&D team is building a dynamic, high-resolution indoor tracking system that fuses data from multiple sources. ![]() In this paper, we present one of our Bluetooth RTLS prototypes and walk through some of the core research, design, and engineering considerations that go into building a robust indoor RTLS system. Our R&D team used Bluetooth Low Energy (BLE) tracking tags and programmable location “hub” devices that served as general proximity tag “sniffers.” The devices report tag data as a Received Signal Strength Indicator (RSSI) and an associated Media Access Control (MAC) address, which paired serve as a unique device ID. There is no “right” hardware for all Bluetooth RTLS solutions since the spaces in which the RTLS will operate place unique constraints and requirements on the hardware. Although the maximum range of BLE signal exceeds 20m under ideal conditions, indoor RTLS applications are rarely “ideal” scenarios. They’re dynamic, asymmetrical, and often unique. Signal obstructions like pillars, furniture, and walls can reduce effective signal range significantly. Hub placement and hub density in an indoor space are two important considerations when designing the system. We chose RadBeacon Dots for several reasons: We chose Active RadBeacon Dots as our prototypical asset tracking tags: Our team mapped out the physical space in which the prototype would be tested early on.Compatibility with iBeacon, Eddystone, and Altbeacon Protocols: Depending on which BLE protocol is used (iBeacon, Eddystone, or AltBeacon), additional data such as manufacturing ID is also accessible.Although this data isn’t necessary for this prototype IPS, being protocol agnostic means that the tags can be reused in other indoor tracking applications.Configurable Transmission (Tx) Power: While maximizing Tx power on the tags ensures that the location hubs are able to receive data, this can result in noisy or inaccurate data.Because RSSI is easily attenuated by multiple factors, this can create ambiguity in location determination. By lowering the Tx power, hubs that are farther away are effectively filtered out by being “out of range.” Having a configurable Tx power provides a way to experimentally determine the optimal tag settings for a particular environment.įor the hubs, while there were many programmable microcontrollers with built-in WiFi and Bluetooth chips, the ESP32 development board has extensive documentation and support via its open source community. It is also significantly more cost effective than other WiFi + Bluetooth microcontrollers. Moreover, commercial demos of Bluetooth RTLS solutions can be upwards of $3500 per 100 square meters, so we wanted to assess the true deployment cost of this type of solution through prototyping. (System diagram of Indoor Tracking System Prototype) Image Credit: Leverege Developing the Leverege Location Engine RADBEACON DOT UPDATE FREQUENCY BLUETOOTH Indoor RTLS solutions require not only tuning hardware to the nuances of each physical space but also creating dynamic and reliable positioning algorithms. Our R&D team developed Leverege’s Location Engine through a series of prototypes. RADBEACON DOT UPDATE FREQUENCY BLUETOOTHĮach prototype was more accurate, precise, and robust than the previous version. ![]()
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