Generic

The following FAQ (Frequently Asked Questions) cover common questions related to Ultra-Wideband, LEAPS RTLS or PANS PRO RTLS.

I am new to the Real-Time Location System. Do you have a list of basic terminology?

Anchor - AN (Anchor Node) - Infrastructure node with fixed location - reference node capable of measuring location data, data offload and routing.
- An Anchor can have Gateway function enabled - it functions as a gateway between UWB Sub-system and other interfaces, such as Ethernet and WiFi. The UWB Sub-system is connected to the host via SPI or USB interfaces.
Location Engine (LE) - An algorithm for position estimation using measured values. There are two major groups used

Trilateration - Location engine which uses distances between nodes to estimate the position, especially when TWR is used.

Multilateration - Location engine which uses time differences between nodes to estimate the position, especially when TDoA is used.

Navigation - A mode of positioning when the location data are collected and used on the side of the mobile object. In navigation mode of LEAPS RTLS and PANS PRO RTLS, the location is calculated on the module, and the data are available via on-module API. This approach provides very low latency of location data on the mobile device, reduces infrastructure costs, and significantly simplifies deployment. Typical applications are e.g. navigation of drones, robots, tools, vehicles and portable devices.
Node - A network device capable of communicating with other devices (Anchor, Tag, …).
Tag - TN (Tag Node) - Mobile node with moving location - It uses Anchors to measure, locate its position and depending on the mode it can exchange data at a specified update rate.
Time Difference of Arrival (TDoA) - It is a measurement technique where the difference in time is measured between nodes at known fixed locations. The result of the measurement is time difference. The nodes at a known fixed location typically need to be synchronized. TDoA is a hyperbolic location position method that has two major sub-categories

Uplink TDoA (UL-TDoA) - is a tracking mode of the TDoA, where a Tag usually sends at a random time a short message called Blink. The Anchors receive the Blink and use their synchronized time to estimate the Tag’s location using hyperbolic positioning method. This positioning method requires at least 4 measurements and is usually more sensitive to the shape of Anchors deployment. As the Tags need to send only a short blink, this method requires lowest power consumption. A UL-TDoA Tag also has lower requirement for the hardware design and the battery. Network scalability and Tag low power consumption is easier to achieve using this method due to its random access to be media in comparison to a TWR system, where a more complex time scheduling and collision avoidance scheme is required.

Downlink TDoA (DL-TDoA) - is a navigation mode of the TDoA, where a Tag would only listen to the network messages from Anchors containing time and usually Anchor positions. Based on these data, the Tag can calculate its position. It is an analogy to the GNSS (Global Navigation Satellite System) for an indoor use. As the Tags only listen and do not transmit, there is no limit for the number of Tags. This mode allows a complete privacy of the Tags as they do not transmit.

Tracking - A mode of positioning when the location and telemetry data are collected on a centralized server. The data are available via LEAPS Server API. This mode is suitable for monitoring and processing data of a large number of devices in a single place, typically on a server. Typical applications are e.g. asset tracking, zone violation detection, athlete’s performance monitoring and personnel tracking.
Two-way Ranging (TWR) - Is a group of measurement techniques where the range between two nodes is estimated by exchanging messages both way. The result of the measurement is distance. Time synchronization of the nodes is not required for the Tag position calculation.
Ultra-Wideband (UWB) - is a radio technology that can use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum. In comparison to other technology like Bluetooth, WIFI or GPS, UWB is very immune to multipath fading. Hence, this makes it suitable for accurate positioning, especially indoors.