Pixie Location of Things Platform Introduction Location of Things LoT Location of Things (LoT) is an Internet of Things (IoT) platform that differentiates itself on the inclusion of accurate location awareness, within inches of things location, even through walls. It enables not only communication with things but also taking action related to its exact location and/or distance from other networked things. Since the connected Things in IoT are not stationary but rather are typically out and about in the open world, knowing their exact location is a clear missing function and LoT is a game changer: LoT enables smart Home automation (1,2) with unprecedented automation and control, new social(3) and pet(4) applications, venue tagging (6) with unmatched accuracy and embedding location awareness into brands(5,7,8), consumer products and services. Details and examples: 1. A Smart home LoT solution can turn the light on when you are in a room and turn it off when you step outv, it can be customized to support different users preference right out of the box, create a whole room or whole house continuous ambient effects, and more. 2. A Smart home LoT solution can control window shutters, AC, TV etc. simply by pointing at it, because the LoT lets the phone app know what is pointed at, and communicates to the appliance. 3. Social LoT applications enable people to find each other, locate tagged places (a trade show booth, a meeting room in big complex) and get value added information (museum display, perspectives, retail product display) with unprecedented control and accuracy, indoors or out. 4. Pet LoT tracking will enable visually finding the pet, but also tracking it s vital signs, geo-fencing rooms in the house, alerting when the pet leaves, setting a reliable and efficient alarm in the event of a loss (e.g. only starting the energy costly broadcasting of a signal over cellular network when the pet has in fact broken the set perimeter), turning on the drop-cam when the pet is inside field of vision, etc. 5. Luggage LoT solution enables tracking where it is and where it was, whether its tagged contents are inside or left behind, and communicate sensor data to the phone, or to a cellular network ( just landed at JFK, and am on my way towards you, ETA 22 minutes, or just landed in Jakarta instead of NYC, how did I get here? )
6. Smart store LoT solution will make every beacon aware of where it is, and therefore can enable accurately leading shoppers to a specific product, not just the general area, providing value add information about products (Information about each TV set on the BestBuy display wall), etc. 7. Medication LoT solution makes the pill box track-able and keeps a log of when it was opened, refilled, w the user, etc. 8. Glasses, keys, remotes and other consumer goods will embed LoT hardware inside (along with wirelessly rechargeable battery) to get connectivity and location awareness. Primer - How it all works Location of Things (LoT) is Pixie-Technology extension to the Internet of Things (IoT). With LoT, not only you can collect data from sensors or things and control them, you can also find out where those things are. LoT is a system solution, including remote location sensors called Pixie Points and a powerful management and Location Engine running on any Smart-device (initially ios and Android are supported). Over time Pixie plans to offer an HDK and different form factor LoT sensors that will get embedded into finished goods The Pixie Point The Pixie Point is a technological breakthrough. It is a small form factor element including creative styling and mechanical design, unique antenna design, efficient power management design and innovative overall system and control approach. We were able to squeeze into a small volume, 3 radio technologies managed by a sophisticated control subsystem, and achieve 18 months of battery life, into an unprecedented size and weight. Our mechanical design and manufacturing process lead to a very small and thin design, with an un-compromised RF performance and maintaining dust and water resistance, to an IP67 standard. Each Pixie Point is a remote location sensor that can accurately measure its distance from other Points and share that information with any Bluetooth Low Energy enabled device or with another Points. The Time-of-Flight (ToF) method is used to measure distance is and that makes the solution robust and not sensitive to environment obstacles (as opposed to the Received Signal Strength (RSSI) method commonly used by other products.
Pixie Point basic parameters Size: 45 x 35 x 3.2 mm Weight: < 10 g Indoor communication range: > 30-50 Indoor measurement range: 30-50 Measurement accuracy: < 1 Outdoor communication and measurement range: > 150 Battery lifetime: 18 months (Typ. Use case) Ranging with the Pixie System Pixie system generates an accurate map from distance measurements. To maintain map accuracy a necessary (yet insufficient) condition is to have accurate distance measurements. Rather than use the common and extremely inaccurate method of measuring RF signal strength, (which is trying to estimate distance by correlating it with the attenuation of the RF power) Pixie is measuring Time of Flight (ToF). With ToF, two Pixie Points measure the time it takes to RF signals to travel between them. Measuring ToF leads to accurate and robust distance estimation, relying on the constant RF propagation speed (the speed of light). Unlike signal strength, ToF is only mildly affected by obstacles. Time-of-Flight is also the method used by the GPS system, in a larger scale. The specific method LoT uses is two way ToF measurement. The two way method eliminates the need for fine (<1nsec level) clock synchronization between the Pixie Points. This method is sensitive however, to clock frequency difference (drift) between the Points which results in an error, especially when the processing time is long. A simplified timing flow is shown in the following diagram. One Point (Point_I in the diagram) sends the ranging beacon (message) followed by the ranging signal. After sending the ranging signal Point_I triggers a timer to measure the overall procedure time. This time is marked T_round_trip. The propagation time of the ranging signal between the Points, marked Ƭ is what the procedure aims to estimate. Multiplying Ƭ with the propagation speed (The speed of light c) will result in the distance estimation. After receiving the ranging signal the responding Point (Point_R) starts measuring its processing time. The processing time is the time from the reception of the correlation sequence of the ranging signal till the point completes to send its ranging signal response to Point_I. This time is marked with T_processing. Point_R sends back a ranging signal. Since Processing time is very short, the locations of the Points as well as the environment are not changing significantly within the time of the measurement, so the propagation time of the signal on the way back is also Ƭ. After receiving the
Point_R ranging signal response, Point_I stops its time measurement. It now has an estimation for T_round_trip. Point_R also sends a timing message containing its estimation for T_processing. As T_round_trip= 2* Ƭ +T_processing, Point_I has now all the information to extract Ƭ. The Pixie Network Several Pixie Points form a network, called a Pixie Network. This location sensor-network can measure the distances between all sensor-pairs in the sensor-network. By sorting all the Pixie Points pairs distances, a symmetric distance matrix is creates. The distance matrix is the fundamental data element used later by the Location Engine algorithms. Communication between the Pixie Network and the smart device is done using standard Bluetooth Low Energy (BLE). Communication within the network is done using a special Pixie Protocol leveraging the 2.4GHz ISM frequency band. Pixie Network is very useful in optimizing power consumption of its members as synchronization is maintained at all times so all sensors are always ready to be activated, while keeping minimal power consumption state. From the smartphone perspective, Pixie Network is a single BLE entity. This simplifies things and saves power for the phone as well as the Pixie Points. Pixie application is in charge of managing the network. In addition, the network automatically reacts to changes for example, if you are leaving home, taking several network members with you to go to the office, the network will automatically split to two networks one going with you including the phone, and the other remains autonomous at home. Pixie Network is self-maintained thus enables LoT to run in background, when a smart-device is not in range, while the sensor distance data is stored in the network. Each Pixie Network has a unique ID that is set by the smart device during set up of the specific network. The access to the network can be done only by devices which hold a secret key, so the system is private and can be operated either by the device that set up the network or by an authorized device which got the secret key.
Location Engineering The location Engineering Engine processes the distances measurement data transmitted from the Pixie-network (these arrives in the form of distance matrixes). It builds true maps of the Points in the Pixie network using various triangulation and trilateration techniques, depended on the structure of the network If there are enough Points in range, the location engine will build the map by connecting triangles, where each triangle is determined by the 3 distances between 3 Pixie Points defining the vertices of the triangle. In addition to data processing, the Location Engine contains a module that manages Pixie networks their structure and activity profile, in order to optimize the powe consumption of the Pixie Network while maintaining LoT functionality and performance The Location Engine is also capable of solving the orientation of certain nodes relative to the map of Points, based on movements of these Points. This is required in cases when there is a need to show the map on a smart device screen, and the Location Engine matches the orientation of the map to the orientation of the screen Solving orientation is supported for any number of Point, even if there is only 1 Point in range and a Pixiefied Phone. In that case, described in the diagram, the system performs trilateration over time, while tracking the user movements using the phone s inertial measurement unit (IMU).
Developers and Pixie API We can t even begin to imagine all of the creative uses for the Pixie LoT Platform. That s where you, the developers, come in and use your extraordinary talents to come up with the next greatest use and app. We are already working on making our API available so that you can develop apps whether it s for the company you work for or as independent developer. Get your creative juices flowing, Pixie is your next development opportunity. Pixie API offers abstraction of the operations described earlier. The application does not need to take care for network management, privacy, power optimization or algorithm operation. To access LoT, our APIs offer: Pairing and association with new Pixie Points Inquiry of all Pixie networks in range and their members Probe the distance between any two Pixie Points in range Request a map of a set of Points Define triggers for events, based on map structure and distance between Points Orient the map relative to a certain Pixie Point in the map Documentation development and debugging tools