Smartphone sensors used for non-GPS navigation

By Amy Rollins Skywrighter Staff
Originally Published in the Skywrighter, Friday, 19 Aug 2016, Page A10

Capt. Piotr Smagowski, a Polish officer who took part in the Engineer and Scientist Exchange Program (ESEP) at the Air Force Institute of Technology's Autonomy and Navigation Technology Center at Wright-Patterson Air Force Base, knows a thing or two about smartphones - such as how to know where you are without using GPS. His work ultimately may help warfighters with their navigation needs.

Smagowski was hosted from October 2015 to June 2016 through ESEP, a Department of Defense program promoting international cooperation in military research and development through the exchange of defense scientists and engineers. His work at the ANT Center, which seeks to identify and solve challenging navigation and autonomous and cooperative control problems, demonstrated a new non-GPS navigation capability using only smartphone sensors. His project fit well with the ANT Center's goal of developing navigation technology that ensures people can navigate anywhere, anytime, using anything.

Smagowski's work led to a paper,  " Smartphone Navigation Using Barometric Altitude and Topographic Maps." The paper is currently in review for the Institute of Navigation's annual GNSS+ (Global Navigation Satellite System) international conference in Portland, Oregon, Sept. 12-16. Additionally, the ANT Center has already received funding from the Army related to the ESEP-developed algorithm, and other funding opportunities exist with AFRL's rapid development center.

" We were able to develop the algorithms and Capt. Smagowski was able to implement them," said Dr. John Raquet, AFIT professor and ANT Center director.

He served as Smagowski's advisor and developed the idea for the project, which the captain executed. The capability is only available for demonstration currently.

Raquet explained that smartphones are readily available and contain software for counting steps and a magnetometer for determining the direction one is heading. With those, one can develop a sense of where he or she is going as one walks along.

" But over time, that has errors and will not give you a very good trajectory. It's very rough," Raquet said. " To correct it, we added a third piece of information - this is the novel part - which uses the smartphone's barometric altimeter. That's a sensor that can tell altitude based on pressure, and it's the same basic thing that planes use."

With that measurement and comparison to an altitude map of the area being traversed, Smagowski developed an algorithm that was able to correct the trajectory and determine exact location.
" We chose multiple testing areas which had different kinds of difficulties and features," Smagowski said. " Those helped the algorithm to work."

Charleston Falls Preserve in Miami County and greenspace near AFIT's location in Area B served as test areas. Smagowski led ANT Center interns on a number of hiking expeditions to test the capability, Raquet said.

" At a technical level, I think it's been very successful," Raquet said. " I think Piotr did a fantastic job in solving a lot of very practical problems to make the system work. He answered the big question of whether the capability could be developed. Because of his work, we were able to add a new approach to the ANT Center's research. We want to continue to develop the concept and build on Piotr's work."

The captain said he was interested in the many layers and aspects of the project, which ranged from mathematics to software to the practical. While he is pursuing a Ph.D. in signal processing in Poland, there is little relation to his ANT Center project.

Smagowski said his participation in the exchange program benefited his language skills and helped him develop an idea of how the center's and AFIT's work is organized. He is filing a report with his superiors soon and looks forward to sharing his experiences with many others in the Polish armed forces, he said.

" I would like to emphasize that the non-GPS navigation is very, very important, so this contribution is something I would like to give to the Polish armed forces, including the technology and important details," Smagowski said. " I'm glad I was able to be a part of the ANT Center and receive technical knowledge from Dr. Raquet and the other colleagues."

Smagowski's presence had a personal as well as a professional side, Raquet said.

" All of us enjoyed getting to know Piotr and learning about Poland. We also enjoyed meeting his wife and new baby son as well," Raquet said.