A research team at UCR within the Bourns College of Engineering (BCOE) has established a computationally efficient way to increase the accuracy of location by the Global Positioning System (GPS) from the meter-level to centimeters.
UCR Professor and Chair of Electrical and Computer Engineering Jay Farrell has led the research project with the results being published in the Institute of Electrical and Electronic Engineers’ (IEEE) academic journal “Control Systems Technology.” Farrell earned his Bachelor’s of Science degrees in physics and electrical engineering in 1986 from Iowa State University. He later went on to receive his Master of Science and Ph.D. in electrical engineering in at the University of Notre Dame in 1988 and 1989, respectively.
Yiming Chen and Sheng Zhao, both of whom have earned their Ph.D’s at UCR, have also worked with Farrell on this project.
Reformulating the equations used to determine a GPS receiver’s position has been the crucial aspect in creating centimeter-level accuracy. In addition, less computational effort will be required to obtain these stronger results.
The GPS works through a network of 31 satellites, which rotate around the Earth at an altitude of 20,000 kilometers. Radio signals that are broadcasted from the satellites help to determine location by measuring the amount of time it takes to send signals and be received. Current actual user accuracy — the accuracy of an individual’s location — that can be obtained by the United States GPS is less than 3.5 meters of horizontal accuracy. The accuracy of the GPS is also influenced by external factors such as atmospheric effects, sky blockage and quality of the receiver being used.
Differential GPS (DGPS) is another method that has been used to enhance GPS technology in realtime through usage of GPS receivers known as base stations, which are set up in a known location. From these base stations, calculations are done by comparing its position based on satellite signals with the location of the known location.
The team’s research will be used in the development of autonomous vehicles to calculate latitude and longitude when navigating. By improving accuracy of location, these vehicles will be able to correctly navigate themselves without human interference.
GPS in autonomous vehicles need to meet certain safety and automation requirements in order to safely maneuver along roads without hitting other vehicles. For both of these requirements to be met, GPS measurements with data from an inertial measurement unit (IMU) need to be combined through an internal navigation system (INS).
In the past, achieving the required level of accuracy using GPS and IMU data has been expensive, but the UCR research team has developed an innovative approach that requires less computations while vastly increasing accuracy.
“Achieving this level of accuracy with computational loads that are suitable for real-time applications on low-power processors will not only advance the capabilities of highly specialized navigation systems, like those used in driverless cars and precision agriculture, but it will also improve location services accessed through mobile phones and other personal devices, without increasing their cost,” Farrell told UCR Today.
Aviation and naval navigation systems will also be impacted by improvements in precision by this technology. Other everyday technology that has GPS capabilities, such as mobile phones and wearable technology, will be able to receive location data with only centimeters of error, and without demanding additional processing power.
The UCR Office of Technology Commercialization has submitted applications to patent their inventions.