Tracking your assets wherever they go

GPS‑based asset tracking systems have been a game‑changer for logistics operations, providing real‑time information on the precise position of all kinds of assets, all the time. Well, most of the time. While purely GPS‑based systems perform well under clear sky conditions, anything from a tunnel, a roof, or a GPS jammer can obstruct navigation satellite signals, making your assets disappear temporarily from your radar.

Hybrid positioning: the best of both worlds
In these situations, it’s often better to have a rough idea of where your goods are than none at all. That’s why, back in 2011, u-blox developed a positioning service that relies on cellular network signals called CellLocate.

There are two ways for users to benefit from the service. First, it can be used to add approximate positioning capability to the cellular communication modules. Alternatively, it can be part of a hybrid positioning approach, complementing global navigation satellite system (GNSS)-based positioning in challenging environments.

If your assets go beyond the range of GNSS signals – in indoor carparks, warehouses, offices or factories – they normally still remain well within reach of cellphone signals, which penetrate much deeper into buildings. The hybrid positioning approach, which combines a rough position estimate in absence of GNSS signals with a precise position when they are available, delivers the best of both worlds, ultimately helping you keep tabs on your goods.  

Today, CellLocate is built into many of the 2G, 3G, and 4G cellular communication modules, which are all easily integrated with u‑blox GNSS modules and chips to achieve hybrid positioning. The LARA‑R3121 LTE Cat 1 module module even includes a pre‑integrated GNSS receiver, making hybrid positioning an out‑of‑the‑box option.

To date, u-blox has provided customers over one billion position estimates using the service, in 140 countries worldwide from Afghanistan to Zimbabwe. And in the future, the advent of low Cat LTE cellular technologies such as LTE Cat M1 and NB‑IoT, which are optimised for low data throughput and extra‑long battery life, is likely to lead to an explosion in the number of assets that are tracked globally.

How it works
CellLocate works by harnessing cellular connectivity that is built into the cellular communication modules. First it monitors precisely which cellular network base stations are visible from any specific location and reports them to u‑blox’s online CellLocate server.

The server then matches information from observations of the base stations to its database of cellphone network cells compiled by other users’ devices that use CellLocate. By determining the intersection of the observed network cells, the server determines the approximate position, which it then reports back to the device over the cellular network.

In terms of accuracy, the position provided using cellular network data may not be a match to the accuracy of GNSS, but in many use cases, even a course position can make a big difference. And there are a number of ways to further improve performance. For one, the cellular modules scan the cellular environment for all network operators, particularly in urban areas.

A larger number of observed network cells leads to a smaller intersection between them, and thus a more accurate position estimate. And, as a self‑learning system, CellLocate’s performance continuously improves as more and more observations are added to the u-blox database.

You can learn more about CellLocate on the u-blox technology pages.

Guest piece written by Chris Marshall, Senior Principal Engineeer, Cellular Product Center, u‑blox.

Courtesy of u-blox.