Learn about Real-time Location Systems (RTLS)

How does RTLS work ?

RTLS are used to automatically identify and track the location of objects or people in real time, usually within a building or other contained area. Wireless RTLS tags are attached to objects or worn by people, and in most RTLS, fixed reference points receive wireless signals from tags to determine their location.
Examples of real-time locating systems include tracking automobiles through an assembly line, locating pallets of merchandise in a warehouse, identification of people for security and safety reasons or finding medical equipment in a hospital.
The physical layer of RTLS technology is usually some form of radio frequency (RF) communication, like BLE (Bluetooth 4.0), UWB (Ultra Wide Band ) or propietary systems, etc. Tags and fixed reference points can be transmitters, receivers, or both, resulting in numerous possible technology combinations.
RTLS are a form of local positioning system, and do not usually refer to GPS, mobile phone tracking. Location information usually does not include speed, direction, or spatial orientation. Instead they are very cost effective, need minimal batteries, work indoor and outdoor, do not need a mobile telecom operator and use open protocols.


Different RTLS technologies- Pros & Cons

There is a wide variety of systems concepts and designs to provide real-time locating

– Wi-Fi
– UWB
– Passive RFID RTLS locating via Steerable Phased Array Antennae
– Bluetooth Low Energy or BLE or Bluetooth 4.0
– Low-frequency signpost identification

UWB is the best technology to position, is highly accurate,  predictable and low power.  There are other solutions for indoor positioning – using Bluetooth beacons, or Wi-Fi access points for example – but frankly, these don’t work as well as  UWB for accurate location and reliability. These solutions are based on signal strength, and there are simply too many factors that can vary signal strength by 50% or more (for example the orientation of a smartphone). By contrast, UWB positioning is based on time of flight measurement of an extremely narrow pulse, so it can achieve high accuracy, and is not sensitive to variations in signal strength.

The result is that one can achieve accuracy of 10 centimetres with UWB, over measurement distances of up to 50m, whereas signal strength based methods struggle to achieve accuracy of greater than +/- 1m, over a much shorter range.

BLE is recommended when accuracy is not a major requirement and customers need to track smartphones or to track BLE tags using a smartphone.



UWB RTLS – How does it work

 

  • UWB RTLS is the best in terms of accuracy and way better than WiFI, BLE or RFID because it is reliable, deterministic and inmune to interferences.
  • Such great performance relies on the precise measurement of the arrival time of a signal transmitted from a tag to several receiving Stations (approximately the speed of light or ~300 meters per microsecond)
  • A location algorythm named TDoA, enables efficient position of tags, where a tag transmits with an unknown starting time and the signal is received at various RTLS Stations, with only the receivers requiring time synchronization
  • TDoA enables low power consumption and high density of tags


Applications

RTLS can be used numerous logistical or operational areas such as:

  • locating assets within a facility, such as finding a misplaced tool cart in a warehouse
  • notification of new locations, such as an alert if a tool cart improperly has left the facility
  • to combine identity of multiple items placed in a single location, such as on a pallet
  • to locate customers, for example in a restaurant, for delivery of food or service.
  • to maintain proper staffing levels of operational areas, such as ensuring guards are in the proper locations in a correctional facility
    to quickly and automatically account for all staff after or during an emergency evacuation
  • to automatically track and time stamp the progress of people or assets through a process, such as following a patient’s emergency room wait time, time spent in the operating room, and total time until discharge. Such a system can be used for process improvement.
  • clinical-grade locating to support acute care capacity management.