ION GNSS+ 2014: Indoor Location Technology Takes a Step Forward

A few weeks ago I attended ION GNSS+ 2014 in Tampa. The conference is called ION GNSS (Institute of Navigation / Global Navigation Satellite Systems) because the days of simple U.S.-built GPS are gone. There are now several countries that have put up their own satellite arrays: the original United States GPS, the Russian GLONASS, the European Galileo, the Chinese BeiDou and soon Indian and Japanese systems. So rather than the limited term “GPS,” everyone is using the more general term GNSS. The “plus” symbol additionally denotes that “all” new location technology, not just satellites, will be considered.  Although the GNSS conference was loaded with highly technical presentations and exhibits that were over my head, there were many items of interest to us geospatial people.

The opening plenary session Tuesday night included a series of very short “ignite” presentations that were moderated by Alan Cameron of GPS World. Ignite or “Pecha Kucha” sessions are usually done in the middle or end of a conference to let presenters who weren’t selected for full presentations to at least get on the program and be heard. This was different in that key presenters who were giving full sessions were also given an opportunity to “plug” their session by whetting the appetite of attendees with a four-minute preview. I’m completely sold on the concept of these short ignite presentations since they were quick, kept my interest, and drew my attention to sessions that I might not have attended. All conferences should start with this kind of quick preview of things to come.

As you would expect, many sessions and exhibits covered complex technical issues and equipment. There was so much information presented in the sessions and expo that I can only provide some highlights that caught my attention. I recorded a number of short video clips of exhibitors that will give you a sample of some of the technical subjects.

Many sessions focused on jamming, spoofing and interference. I didn’t realize how much of a problem this had become.  There were many examples of equipment designed to spot, identify and counter the problem. Although considerable attention was given to GNSS as used in UAVs, there was also concern that FAA restrictions on UAV flights was going to severely limit their use despite increased precision and effectiveness.

Most top-end systems demonstrated at the show incorporate RTK (real-time kinematic) to achieve very high accuracies. Gone are the old days when the GPS signals were deliberately modified to degrade the accuracy with a system called Selective Availability (SA). This was done to prevent enemies from using GPS for targeting. However, when needed, the U.S. military could override SA to greatly improve accuracy when they needed it for targeting. To get decent accuracy, civilian users had to set up fixed base stations at known locations to measure the GPS location errors and apply those corrections to field GPS receivers through post processing. RTK uses measurements of the phase of the GPS signal’s carrier wave and a single reference station to provide real-time corrections which provide centimeter accuracies without the need for post processing.

One topic that caused a lot of buzz at the conference was the incorrect orbit insertion of two European Galileo satellites using Russian rockets. Although the satellites are working perfectly, the wrong orbit makes them essentially useless, and the error occurred at about the same time as the Ukrainian/Russian military action and subsequent sanctions. Is this a coincidence or just poor rocket science? No one knew for sure, but the loss of two critical satellites was a major setback for the European system.

An especially interesting live demo session by several exhibitors showed indoor location technology. Some were not at all “ready for prime time,” a few showed promise, and some were quite refined. Most systems used GPS to fix a user’s location while outside a building, then, as the user entered a building and lost the GPS signal, two approaches were dominant. Several systems used IMUs to measure a user’s movement from the GPS starting point. All those systems suffered from IMU drift, which caused increasing errors the longer the user moved without GPS correction. The other systems used devices in the building such as RFID tags or Wi-Fi transmitters to fix subject locations inside the buildings. Some of these worked quite well, but the systems had to be preinstalled in a building to do the tracking.

The ability to accurately and reliably track a firefighter in a building not equipped with tracking systems is still a dream, but one system by Trusted Positioning, Inc., of Calgary, Alberta, Canada, might be on a viable path. The company uses a technique of identifying overlapping radio and Wi-Fi signals in the air to create an electronic “map” of a given area. Using this footprint as a reference, the system then combines a subject’s movement derived from the motion-detection capability of a smartphone to measure the steps taken by the subject thus providing a surprisingly accurate track.

The Trusted Portable Navigator (T-PN) is touted as being the first navigation software to use motion sensor data from multiple mobile/wearable devices to more accurately locate a person indoors. The software collects movement information from the user’s phone, tablet, watch, wearable or glasses to better position how a person is walking when GPS is unavailable in places such as shopping centers, airports or urban centers. Note this example from their demonstration video that shows a subject walking through a parking lot (red track), then two loops indoors. This is pretty amazing, considering the fact that the system uses only software, a smartphone worn by the subject, and ambient radio signals.

This was the most exciting technology I saw, because I see the potential to save a lot of firefighters, first responders and military service members in hostile locations.