Microsoft Is Quietly Building A Low-Tech Alternative To GPS

Designed for malls, skyscrapers, and other large buildings, the app relies on users, not satellites, for accurate maps.

GPS has changed the way we navigate the world, but that convenience still doesn’t extend to indoor spaces. Finding a meeting room in an unfamiliar office building or tracking down a specific store in a large shopping complex can be time-consuming and frustrating as a result–especially when all you have to work with is an out-of-date map or terribly designed mall directory.


Microsoft Research recently released a prototype app called Path Guide that addresses this decades-old issue, providing navigation indoors with an alternative to GPS. It functions like a high-tech version of follow-the-leader: The app relies on one person recording directions within a given building that anyone can then follow on their own phones. For instance, if you’re meeting a friend at a cafe inside a mall, your friend can simply use the app to record their path–which Microsoft calls a “trace”–inside the building for you to follow digitally when you arrive. The trace is uploaded to the cloud and other Path Guide users are able to use it to navigate to the same spot in the future.

GPS signals are unreliable inside of buildings because they don’t easily go through walls. Other solutions to indoor navigation rely on systems that must be installed in the building, like Wi-Fi, Bluetooth beacons, and other less ubiquitous types of technology like cameras, RFID, infrared, ultrasound, or even lasers. Besides the technological constraints, there’s also a problem with finding accurate maps of indoor spaces in the first place.

Other tech giants are tackling this problem, too. Google is using Project Tango to create 3D scans of indoor spaces. At Google I/O this year, the company announced what it’s calling its “Visual Positioning Service,” which would use Tango to enable indoor navigation using augmented reality. Other researchers are looking into how to expand the range of GPS into other hard to reach places–like under the ocean. DARPA is currently developing a wayfinding service for drone submarines that uses underwater sound broadcasts to help subs navigate deep waters.

In comparison, Path Guide is relatively simple. But the app remains an intriguing solution to a complex problem in that it uses widely available technology. Path Guide’s strength is that it doesn’t require any infrastructure inside the building or any maps whatsoever. It only uses what’s already inside users’ smartphones–sensors like the accelerometer, gyroscope, and electronic compass. Over time, the number of publicly available indoor paths that users would be able to take would grow, as more and more people record paths for colleagues, friends, and family. Microsoft says that the system would be able to merge overlapping paths, adding even more options for users.

The user interface of Path Guide is relatively straightforward, with a similar appearance to other mapping apps. The only difference is the ability to record traces, to which you can add notes, images, and voice recordings. These traces can be accessed via a URL for those who don’t have the app (which is only available on Android), so they could be included in emails or on websites. If you’re forgetful as to where you park your car, Path Guide is one way to remember–you could record a trace away from your car and then reverse your steps to find it again.


Path Guide isn’t just applicable to finding your way through maze-like malls and offices. It could also help people navigate big-box stores, universities, museums, and even skyscrapers. As tall buildings continue to spring up and urban areas continue their sprawl, having technology to help make sense of the extraordinary size of these indoor spaces will become even more important.

And for the visually impaired, it could be a means for independence. In keeping with Microsoft’s focus on inclusive design, Path Guide also makes indoor spaces more navigable for the visually impaired while providing a useful tool for everyone.

You can download Path Guide via the Google Play Store, but it’s worth remembering that it’s a research project two years in the making. The researchers admit it might be a bit rough around the edges. Even so, the app nods toward the possibility of a more open and accessible world.

About the author

Katharine Schwab is an associate editor at Co.Design based in New York who covers technology, design, and culture.