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What’s Up with Outdoor (GPS) Asset Tracking Technology?

Asset locating, tracking, and monitoring are increasingly common activities for businesses and consumers alike. Consumers use products like Tile, a small Bluetooth device, and crowdsourced smartphones as readers to locate everyday objects like keys, remote controls, and smartphones. 

What’s more, transportation, agricultural, and logistics companies have been using GPS asset tracking and other outdoor localization methods for years, to keep up with assets stored beyond the safety of depot, warehouse, and factory walls.

Read more: Here’s a primer on asset tracking.

Some asset tracking technology even monitors the condition of equipment like tractor trailers, combines, and other machinery or supplies (like pharmaceuticals) – all of which are extremely valuable and/or capable of powering asset tracking devices.

And as ever more advanced types of asset tracking hardware enter the market, businesses are able to monitor an increasingly wider range of assets.

These developments have reduced the cost of resource control, while enabling battery-powered devices to generate location data – two improvements that have paved the way for tracking smaller, unpowered, and less expensive (but equally valuable) assets.

Let’s say your company provides project estimates of some kind. You’d likely need a specialized tablet for field use that might cost several hundred dollars. If that asset goes missing, the replacement cost may not be a huge expense, but the impact that loss might have on your bottom line and your reputation could be significant.  

After all, it’s hard to get the job done without the right business tools in hand.  And I’m sure you can see how the strategic benefits of asset management stack up pretty quickly.

So expensive and valuable can mean different things in different contexts.  Likewise, there are plenty more valuable assets to monitor than there are expensive ones – which is why we are devoting an entire post to the ins and outs of GPS asset tracking.

But to kick off the discussion, we want to first establish a common frame of reference for GPS asset tracking – i.e. what it is and what it isn’t.

We’ll then explore how asset tracking works at the highest level, as well as take a look at  both ideal applications for and known limitations of GPS.  Finally, we will address a few of the newer technological approaches that solve for some of these limitations and open new avenues for asset tracking.

What Is GPS Tracking?

GPS stands for Global Positioning System. The original GPS network, developed by the United States, is a collection of satellites circling the Earth that transmit radio signals.

These signals can be collected by GPS receivers (for example, antennas in our smartphone); and if an antenna can clearly detect a large enough array of GPS signals, the device can complete a calculation that accurately pinpoints an outdoor location expressed as latitude and longitude (Read this article for more info on the basics of how GPS and geo-spatial location is calculated.)

Likewise, there are other satellite networks that can provide similar data for enabled devices, including GLONASS, Galileo, and Beidou, which provide geo-spatial location as longitude and latitude. These GPS coordinates can then be combined with mapping applications to power the satellite navigation many of us rely on to get around.

When reading about GPS and other satellite networks, you may run across the initials GNSS, which stands for Global Navigation Satellite System, a broader concept that covers all of the different satellite networks, not just GPS technology.

Over time, the term GPS has become common shorthand for the universe of satellite navigation systems, especially in the United States. Additionally, we increasingly use GPS as a stand-in for a broader range of geo-spatial outdoor localization systems.  Most of us have accessed mapping apps on our smartphones, and almost all of us recognize the GPS icon.

But what many people may not know is that smartphones do not typically use GPS alone to determine device location (although there are other digital tools that do, like the watch I use for running).  In fact, it only happens when the user has turned off all other means of location – which is impossible on some phones – or if the phone is in a location where there are no other available technologies.

For example, I once had to navigate my way through a rural part of Southeastern Arkansas to get to my cousin’s farm. I’d downloaded the local maps to my phone, so that my GPS antenna could continue to work even in the absence of a cell connection – which it thankfully did. 

Of course, it greatly simplifies the discussion when we use GPS as a blanket term for multiple technologies.  However, when a business is looking to introduce an asset system, the distinct differences between GPS (GNSS) and other means of outdoor asset location can actually make or break the business case. 

Let’s talk a little bit about why that is...

Where GPS is Alive and Well in Outdoor Positioning

Once the US military opened its outdoor positioning satellites for public use, technology companies rushed in to incorporate GPS receivers into their tracking products.

On the consumer side, this took the form of the initial Garmin platform and similar navigation products for rental vehicles and personal use. Smartphones and other digital devices eventually followed suit.

Even earlier on the commercial side, receivers were built into GPS tracking devices that could be plugged into the OBD2 port, or similar power options, below the steering wheels of tractor trailers and other large equipment. Under this scenario, the location data could either be stored for local download or transmitted via cellular connection to the Internet.

These original devices had to be constantly charged, given both the high power needs of cellular connections and the fact that GPS is a relatively power-hungry process. Keep in mind that satellite signals are very faint, and receivers must therefore be on for long periods of time to “hear” them clearly enough to generate a location.

Processing received signals also takes time, which means using even more power. Newer GPS-enabled devices for locating and tracking semis, large agricultural equipment and the like incorporate a variety of other sensors and capabilities, often at the expense of increased power consumption.

Still, when all is said and done, these powered GPS tracking devices have served a multitude of uses, over a long period of time. 

Take telematics, for example, a term that refers to any device that combines telecommunications with informatics, particularly with respect to vehicles and other large moving equipment.

As one of the first major use cases for GPS tracking devices, telematics make it possible to map and record, in real-time, the location, speed, orientation and condition of vehicles like combines, tractor trailers, mining trucks, and delivery vans, to name a few.   

And because these vehicles were not only expensive, but typically transported high-value cargo, the business case was a no-brainer.

Equally important, telematics has proven that...

GPS Can’t Do It All

 

As I said earlier in this post, smartphones rarely use GPS alone to activate that familiar icon on your mapping application.  That’s because it can’t provide highly accurate location information in all cases.

Imagine, if you will, an unaided smartphone GPS receiver struggling to hear the right signals as it enters a building.  And the deeper it goes, the harder it becomes, given the interior barriers it encounters – like walls, ceilings, and floors that absorb RF (radio frequency) energy. At the same time, building materials such as concrete, cinder and brick are really tough for RF to permeate.

On top of that, in urban areas with tall buildings and lots of glass windows, signals bounce between structures, often confusing the calculation, which in turn, results in GPS positions that differ from your actual position. 

Equally problematic, GPS asset tracking devices sometimes get packaged inside of RF absorbing or reflecting material - like a metal case - and then shipped inside a metal shipping container attached to a tractor trailer. Likewise, as these vehicles travel through a tunnel or under a highway overpass, the GPS signal can be lost altogether. 

And because, as we said before, GPS signals are comparatively faint - they are coming from satellites, after all – it takes significantly more power to zero in on location coordinates than it does using other methods. 

 Not surprisingly, excessive power requirements can make it difficult to implement asset tracking – especially when it comes to sustaining battery-powered applications for long periods in the field.

For example, constantly transmitting location to provide real-time data can be power-intensive on a cellular device, depending on the technology used.  Conversely, data loggers are often the ticket for non-real-time applications, given that they can record and download information at specified intervals for up to years at a time. 

These are just some of the challenges associated with using GPS as the sole locating technology for a consumer or business asset tracking solution.  And they are especially pronounced for battery-powered devices that cannot be easily and regularly recharged.

Belt and suspenders, anyone?

Chock full of other radios - WiFi, cellular, Bluetooth - smartphone location engines and applications can take advantage of an array of other types of asset tracking technology at their disposal – which they use to improve accuracy, enable better indoor location, and potentially decrease power consumption.

In some devices, the order of technology deployed can be set.  Likewise, in some cases, testing may prove that a non-GPS location technology is a sufficient solution. Which is why companies should look for business asset tracking solutions that actually meet their unique needs, at a price point that fits their budget. 

The universe of non-GPS outdoor location technologies is vast and growing, with most of them using multiple signal inputs to get the job done.  In fact, additional signals typically provide location information that is consistently more accurate. 

Among the technical approaches currently available, several are worth noting here. What’s more, given that some of these technologies also function well indoors, they are effective complements to GPS, particularly relating to IoT asset management and digital transformation.

Bluetooth

Bluetooth beaconing is a straightforward and potentially low-cost way to augment GPS for smartphones, vehicles, telematic devices and related platforms - especially as an indoor positioning system or even an underground one.

Put simply, this technology is a form of wireless communication that uses beacons (small radio transmitters) to send signals to “smart” devices located in close proximity.  So, by transmitting information, these beacons identify approximate asset location.  (Think about connecting your smartphone to your car’s Bluetooth system to enjoy your favorite playlist as you drive.) 

As such, Bluetooth asset tracking[2] [3] , especially Bluetooth Low Energy (BLE), is a proven indoor location technology that consumes very little power, thus making it a good bet for preserving battery life.  It can also track large numbers of assets in real-time. 

WiFi Sniffing

So-called “WiFi sniffing” is yet another established method for calculating outdoor location. Indeed, smartphone users are already familiar with this technology, because, yep, our phones are kind of like a wireless network hound dog.

Think back to the last time you used a smartphone to join a WiFi network.  How many different WiFi networks (BSSIDs) did your phone “see?” 5? 10? 15? Often several at once. And most phones are designed to record the BSSID of every network it “hears,” while measuring the signal strength.

The underlying data displayed on your screen can also be used by other devices for WiFi sniffing location.  These data are sent to a database maintained by Skyhook, Google, and others, where they are then plugged into an algorithm that generates location information. And the more data inputs (i.e. BSSIDs/WiFi networks) heard, the more accurate the location result typically is.

Over time, these results have improved dramatically, and in many locations WiFi sniffing is a viable alternative to GPS in terms of precision.  For one thing, it requires far less power to obtain the necessary data, which extends the device’s battery life; for another it is more effective for indoor use.   

And in urban environments, this technology often performs better than GPS, given that it doesn’t suffer the same reflection challenge from bouncing off of tall buildings.

Cell ID

The simplest outdoor locator you can use is called Cell ID, better known as the cellular tower through which an asset tracking device sends a message. As we’ll see shortly, there are ways to use cell towers for triangulation.

For gross location precision, Cell ID is a reliable technology that requires even less power than WiFi sniffing.  To be sure, it’s a viable option as a backup location finder or if you need to know that a device is still alive and within cell range.  But it may not be the right solution for primary location, simply because it is typically less accurate than other geo-positioning technologies.  

Nevertheless, transmissions from cell towers can be used to triangulate position. As with WiFi sniffing, a device can record cell tower IDs, along with signal strength, and use those data points to approximate a location.

What’s more, cellular signals have additional attributes that when optimized can improve location accuracy, both inside and out.  Companies like Polte are leading the way in implementing this approach for outdoor use.

Which Technology is Best for Outdoor Asset Tracking?

When choosing a technology or hardware platform for generating outdoor location data, users should keep in mind that GPS is not the only technology in town. 

It’s always worth remembering that just like your smartphone, an outdoor asset tracking device need not be constrained to one technology for providing location data. 

Truth is, when it comes to high performance, you will want something agile, which can be effectively deployed inside and outside, in urban environments and rural areas.  That will mean a device that combines the best of multiple technologies, rather than one that depends on a single method, like outdoor GPS asset tracking technology. 

That said, we hope you will feel free to reach out and let us help you find the right system for meeting your unique requirements.

Written by Dominic Marcellino

Dominic is the Product Manager for AirFinder. He manages our core Symphony Link products, and he is also responsible for managing the development of new products. He keeps the Engineering, Operations, Marketing/Sales, and Strategy teams working together to get our products to market looking great and performing even better.

Prior to Link Labs, Dominic worked for ten years at the Environmental Defense Fund and Ecologic Institute US (EIUS) solving key policy problems in renewable energy, energy efficiency, transportation, and climate change. He ran EIUS as Executive Vice President in 2014; while there, he obtained nearly $1m in grant funding for projects, including the Emerging Leaders in Environmental and Energy Policy Network, which he co-founded. Dominic holds a bachelor’s degree in philosophy from the University of Dayton. He was a Fulbright Scholar in Germany from 2002-2004 and a Robert Bosch Fellow from 2008-2009.

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