Indoor Positioning 101 TECHNICAL)WHITEPAPER) SenionLab)AB) Teknikringen)7) 583)30)Linköping)Sweden)

Indoor Positioning 101 TECHNICAL)WHITEPAPER) SenionLab)AB) Teknikringen)7) 583)30)Linköping)Sweden)

TechnicalWhitepaper)) Satellite-based GPS positioning systems provide users with the position of their smartphones when they are outdoors. Indoors, however, GPS loses its efficacy because the technology relies on very weak signals from satellites that are easily blocked by a roof or walls. The result is a significant drop in accuracy for GPS systems when the user enters a building. Reaching an accuracy of 1-5 meters indoors requires a completely different solution: Indoor Positioning Systems (IPS). POSITIONING(SUCCESS(FACTORS( For an Indoor Positioning System to be useful, five factors must be fulfilled: 1. Accuracy the position given by the system should be within 1-2 meters of the user s actual position in a crowded mall. 2. Responsiveness when the user moves, the position moves with him or her without delay. 3. Robustness the positioning system should work just as well after two years as the day it was installed. 1

TechnicalWhitepaper)) 4. Device agnostic the system should work on any smartphone. 5. No usage limit there should be no limit to how many devices can use the system at the same time. Unless all of these requirements are met, an IPS will not work in a realworld situation. A positioning system that cannot accurately read a user s position, lags ten seconds behind, or works on few models of phones is too limited to deliver true Location-Based Services (LBS). Also crucial for IPS is that the installation procedures are simple; installing the positioning system in a new building should take just a day or two, not a month. Systems that are easy to install are far more cost effective, and easily deployable to multiple buildings around the globe. HOW(IPS(WORKS( Indoor Positioning Systems use two types of sensors built into the smartphone: movement sensors and radio signal sensors. Movement sensors include the accelerometer, which measures acceleration; the gyro, measuring how the device is turning; and, the magnetometer, which functions as a compass. When combined, these sensors provide information about the user s orientation and how the device is moving. Unfortunately, these sensors only provide an understanding of how the position of the phone changes, not about its location. Radio signal sensors are the Wi-Fi and Bluetooth receivers in the phone. They can determine which access points or beacons are within range and can evaluate signal strength. When comparing signals from radio signal sensors to a map of locations in the building where different radio signals should be heard, a rough understanding of the location of the smartphone is given. The combination of the information from the movement sensors, the radio sensors and a map of the building, is known as sensor fusion. Sensor fusion is the technology of combining information from multiple 2

TechnicalWhitepaper)) complementary sources to create one estimate of, for example, a position. This joint position estimate provided through sensor fusion is more precise and reliable than an estimate made from information that is treated separately. LOCAL(COMPUTATIONS(DODGE(LAG(( A potential pitfall of IPS is lag time. With many people in the same general area, in a shopping mall, for instance, data sent to a server to compute the user position must traverse a data connection link, introducing possible time delays in the system. However, when computations are made on the individual user devices, there are no limits to how many people can use the system at the same time, and the issue of potential lag time is eliminated. Performing the computations on the device allows for the positioning to work even if there is no Internet connection available. Using clever algorithms, the computational power of a smartphone is more than enough and the 3

TechnicalWhitepaper)) positioning system does not slow down the device or drain the battery. DIVERSE(RADIO(ENVIRONMENTS( Both Wi-Fi and Bluetooth can be used for radio measurements, but there are important differences. WORLDWIDE(WI6FI(PRESENCE( Today, Wi-Fi is available nearly everywhere. In a mall, for instance, a device might recognize 50 to 100 Wi-Fi access points at the same time. However, ios-based devices are restricted from accessing these measurements, so Wi-Fi-based Indoor Positioning is not possible on an iphone or an ipad. For Android, the Wi-Fi measurements are available and can be readily used by the positioning system. Wi-Fi usage for positioning does have some significant shortcomings. Wi-Fi has been designed with one main purpose: maximizing data throughput. This means various optimizations are being made on the phone and on the access points to maximize data throughput, which affect the radio measurements, thereby affecting the positioning performance. The difference between different phones and different access points is also significant, which is why the quality of a positioning system based on Wi-Fi tends to vary widely depending on phone and Wi-Fi system. 4

TechnicalWhitepaper)) (( PROXIMITY(SOLUTIONS( One way to provide a very simple form of Location Based Services is through the use of proximity beacons, small beacons with a message associated with them. When a phone is nearby, the message pops up on the screen. For the purpose of pushing messages at a certain location, proximity solutions might be just enough. However, in order to provide dynamic and an easy-to-administrate LBS, proximity has several disadvantages. In practice proximity messaging has the risk of becoming a logistical nightmare when launched as an advertising tool on a grand scale. A more customized and seamless user experiences and the ability to collect more sophisticated positioning data require an IPS. Proximity is a good introduction to Location Based Services, but will soon fall short to a wider usage. A basic IPS can easily be upgraded as soon as the requirements change. ( BEACONS(PROVIDE(ROBUSTNESS( A beacon is a small, battery-powered box that broadcast the signals picked up by the Wi-Fi system. The Bluetooth Low Energy (BLE) technology, also known as Bluetooth 4.0, is power conservative, making it perfect for a chip in each beacon, where it can broadcast a signal for years. Most smartphones manufactured in the last two years are equipped with BLE capacities, making a beacon- based positioning system possible. Once the beacons have been mounted in the building, and the system has been calibrated, the system typically can run for years without maintenance. It is simple, effective, low on battery, and robust over time. A good Bluetooth beacon for indoor positioning should be small and discreet, have a powerful broadcasting signal that is sent at least twice per second, yet have a battery strong enough to make it run for many years. 5

TechnicalWhitepaper)) In installations requiring many beacons, for instance a hospital with 500 beacons, changing batteries frequently would be time- and laborintensive. It s also important to know where each beacon is installed and whether it is still running. A Beacon Management System can easily provide an overview of the entire positioning system as well as individual status of each beacon, including location, battery life and more. QUICK(AND(EASY(INSTALLATION( Installing an IPS system in a building should be a quick and straightforward procedure. SenionLab The first requirement is an accurate and up-to-date image of the floor plan. The next step involves mounting the beacons in designated positions and registering each beacon in the Beacon Management System during an installation. When all beacons have been mounted, calibration begins. The calibration is performed by having a designated person walking a number of paths while holding a smartphone. The paths are determined and assigned by an app. The calibration procedure takes as long as it takes to walk throughout all parts of the building. The final step is integrating the positioning software with the app. LOCATION(BASED(SERVICES( A well-functioning Indoor Positioning System is the foundation of any Location Based Service (LBS) system. The purpose of a service may differ but the basic functionality of the LBS can be divided into a couple of categories: Turn-by-turn Wayfinding provides instructions from where you are to where you want to go. GeoMessaging sends a message to a device entering a defined area. This message could be personalized down to individual customers or maintenance personnel. Friend-Finder presents the positions of friends and family in the same building. Advanced analytics can be conducted on the positioning data 6

TechnicalWhitepaper)) from a macro perspective down to individual movement. AudioGuiding gives vision-impaired persons the opportunity to navigate a building without memorizing a tactile map. Asset Tagging keeps track of all critical equipment in a hospital or industrial site. IPS is the enabler of every seamless and dynamic Location Based Service. ( ABOUT SENIONLAB Senionlab brings the GPS-like capabilities to indoor environments. We connect the physical and virtual worlds, bring companies closer to their customers, and help decision makers visualize patterns that never have been observable before. CONTACT Jonas Callmer Product Director jonas.callmer@senionlab.com 7