Ultra-Wide Band RTLS - the Ubisense way

Simon Holloway

Written By:
Published: 29th November, 2007
Content Copyright © 2007 Bloor. All Rights Reserved.

I first came across Ubisense at the RFID ROI Summit at the beginning of the year. I followed this with a meeting at the Cambridge Headquarters, where I got to know the product better. In September, I met up with Richard Green, their CEO, at the IDTechEx RFID Summit and this resulted in a briefing I had with Green and his new VP Marketing, Charles Sturman.

So who are Ubisense and what makes them so interesting? Well firstly they are British—flag waving a necessity after another disastrous week in the national sport of soccer! OK, seriously, what makes them different is that they are one of the first companies to exploit Ultra-Wide Band for RTLS. I have introduced 2 terms that some of my audience maybe unaware of, so I will give a short explanation of these 2 terms, the rest of you may skip the next 2 paragraphs.

So what exactly is UWB? The RFID Journal glossary states that UWB is "any radio technology having a bandwidth exceeding the lesser of 500 MHz or 20 percent of the arithmetic centre frequency, according to the Federal Communications Commission (FCC)." A bit of a mouthful! Sturman described it as "precisely timed short bursts of RF energy to provide accurate triangulation of the position of the transmitting tag. Since the short time UWB signal is very broad in frequency spread (typically 1 to 2 GHz wide) the system can operate on a very low power output and is robust against interference."

So what is RTLS? It is any wireless technology that can be used to continuously determine and track the real-time location of assets and personnel. An RTLS solution typically utilizes battery-operated radio tags and a cellular locating system to detect the presence and location of the tags. The locating system is usually deployed as a matrix of locating devices (or sensors) that are installed at a spacing of anywhere from 50 to 1000 feet depending on the site layout. These sensors determine the locations of the radio tags.

The Ubisense solution consists of three major components; the RTLS sensor network hardware, the Spatial Platform software and a suite of software applications.

  • Slim Tag is designed to be mounted on the side of vehicles and assets or to be worn by a person;
  • Compact Tag is a small rugged device specifically designed for use in harsh industrial environments;
  • Series 7000 sensor contains an array of antennas and ultra-wideband (UWB) radio receivers and calculates the location of the tags based on reception of the detected UWB signals transmitted from the Ubisense tags;
  • Location Engine includes all the software needed to install and tune a Ubisense sensor network and track tags in real time, through a series of configuration wizards;
  • Location Platform provides persistent storage and distribution of real-time location events for multiple clients in conjunction with real-time monitoring and notification of user-specified spatial interactions between objects;
  • Developer is a set of development tools which allow the Location Platform data model to be extended to define new kinds of objects and relationships.

There are some neat features about Ubisense tags. Firstly, they employ a unique dual-radio architecture. Tags transmit UWB radio pulses, which are used to determine location and a conventional bi-directional 2.4GHz radio which is used as a control and telemetry channel. Secondly, they are able to read in real-time to a precision of 15cm in 3D!

The Ubisense Series 7000 Sensor can be incorporated into existing networks, thus keeping down network costs. Each sensor can determine both the azimuth and elevation Angle of Arrival (AOA) of a UWB signal, providing a bearing to each tag. The Time Difference of Arrival (TDOA) information is determined between pairs of sensors connected with a timing cable.

The software elements run on Windows (XP or Vista) or Linux. There is a big tie into Microsoft, where Ubisense were the first RTLS vendor to go into partnership with the new RFID element of Microsoft Biztalk Server 2006 R2. The Location Platform supports 100% managed .NET 2.0 API for viewing of all data and control of every system function, as well as managed DirectX .NET 2.0 2D/3D user-scriptable visualization controls.

Ubisense have seen significant growth during 2007. They have acquired a number of top-notch partners both from an implementation viewpoint as well as from a technology one. They have had some significant customer wins and their vertical strategy is well thought out.

Organisations looking at RTLS should consider the significantly higher accuracy and reliability that UWB can provide for a modest additional investment over other solutions. Bloor strongly suggests that Ubisense's product should be on the evaluation lists of prospective RTLS buyers.

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