Sensor Networks and Real-time Locating Systems


The MIT RFID and Sensor SIG had something for every generation of futurists, from “social tribing” to manufacturing locating systems.


Real-time locating systems (RTLS) applications keep getting more precise, the range keeps broadening and the applications grow richer. Gone are the days of limited locating in a factory or yard. It seems that it takes the younger generation of tech innovators to show us the way out of the factory and into applications with a broad set of benefits in many industries and society and social settings. There is an increasingly strong demand today for continuous visibility of people, items and assets from many sectors.

We had a fascinating session at the Auto-ID & Sensing SIG on May 17th on Real-time Locating Systems. A broad and slightly futuristic perspective beyond the typical RFID conference was given. Our speakers were from the largest firms (GE Pervasive Decisioning Systems) with billions to invest in R&D; to small entrepreneurial and innovative firms (Tagview and SkyHook Wireless); with research fellows (MIT Senseable City Lab) and long term successful traditional industry players (Zebra Enterprise Solutions), a few of which have broadened their solution portfolio to find ways of solving higher level customer problems.

Though the supply chain is still the dominant market for RTLS, the door has been opening for a vast array of applications that can be categorized as follows.

Capacity Management such as:

  • Helping cities manage transit capacity, traffic flow and traveler alerts
  • Helping cell phone coverage with concentrations of calling and texting
  • Commercial services and supplies to concentration sites (crowds after events)
  • Recalls and return flow
  • Inventory ‘build-up’ for shipping or promotions

Tracking and Routing such as:

  • Location, condition and identification related information are the fundamental underpinnings for a broad array of higher level applications. Of course, asset tracking has gotten much better in recent years, but just as soon as new offerings boost performance, expectations quickly morph into an even more aggressive set of demands. Many users today want slot level visibility (bed, parking, etc.), and not simply to know that it is in the building, yard or room.
  • Social networking applications seem to intrigue the new generation with clustering and ‘tribe’ identity that can be applications on top of location based services that leverage cell/smart phones, challenging our traditional concepts of RTLS for asset tracking.

People Management such as:

Enhanced visibility of staff, patients, buyers, suppliers, carriers and others for a multitude of purposes such as access control, egress, coverage, security, enforcement (time, perimeter, etc.), and much more.

Technology and Standards, Still?

It is still important to decipher the variants of the technologies and their methods.

Real-time locating has several approaches – frequencies and locating methods (software for determining the actual location such as trilateralization, triangulation, signal strength, etc. which you can read about in our report on Active RFID) which result in widely varying tag sizes, battery life, read range, localization and more. Standards as well as global reach are critical to assure interoperability for the applications you want to implement, and to boost affordability.

Tom’s Blackboard from MIT session


The industry is now able to deliver not only more precision, range and security features, but intelligence (some call context and others call analytics). Where did this happen? When did it happen? What were the conditions under which it happened? The answers are provided through a combination of sensors and software.

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One presentation by GE also showed an evolution of technology that we considered thought provoking. They spoke about not just data and precision around events, etc., but systems today that can be infused with reasoning.  This is the why it happened.  Two scenarios that were discussed:

  • Service Partners Management—Under what conditions, use cases, did this part fail? Not just that a part failed, but also when it failed, and what were the relevant conditions. This can provide essential feedback in determining how to design better, or can be predictive about other parts within this system of potentially failing. Or maybe training, since the operator may have poorly used the product. And many more.

  • Shopper intelligence—Under what circumstances did this shopper select this item? Simple retail replenishment systems might know something was purchased. But situationally aware systems backed by reasoning may know that she was holding a pair of pants and was trying to match a blouse. Where were these items purchased? How long did it take her to find that match? Should these be marketed together in the future? And many more questions can be determined to improve custom experience, product design and availability.

There are essentially two categories of challenges in each of these scenarios. (1) How to achieve a robust and automatic system of data collection? and (2) once the data has been collected, how best to exploit the data? Raw visibility data is valuable – TIME – DATE – LOCATION – and a UNIQUE IDENTIFIER – but far greater value to the enterprise occurs when visibility data drives corrective action, updated plans, adjusted resource levels, and much more. Effectively absorbing visibility data is not an easy undertaking. Keeping up with the constantly moving target of automatic ID technology developments is equally as challenging.


One big challenge for the foreseeable future is the ‘technical sell’ of these devices and approaches. Users are forced to walk through an in-depth and very specialized set of criteria in order to pick a device and software appropriate for the application. And there are not too many ‘cross over acts.’ Visibility solutions for international shipping using 433 MHz technology are likely to be inappropriate for smaller assets requiring a small tracking device with great precision yielded by an Ultra wide band (UWB) solution. 

User requirements for locating solutions vary widely today, (and some would say even wildly). There is no one size fits all requirements for today, nor for the foreseeable future. There is not even a “no brainer” solution today for locating solutions, and hence there is no consensus on standards. As more proprietary solutions are deployed, clarity will be gained and end users will increase the pressure for interoperability amongst vendors and alternative sources of supply. This is a topic that will only grow in importance, and it’s a lot of fun to determine the best fit for solutions that meet constantly evolving requirements.


Tom Coyle, Wireless Consulting Solutions
Tom can be reached at:; LinkedIn:

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