The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is to make critical United States infrastructure less dependent on the Global Positioning System (GPS). The transportation industry, power grid, banking operations, and communication systems are all interconnected and heavily rely on GPS for accurate and reliable positioning or time synchronization. This project addresses this single point of failure by providing accurate positioning and timing, completely independent of GPS. Additionally, the emerging autonomous vehicle market requires a more reliable positioning, navigation, and timing (PNT) system than GPS can provide alone for the market to reach full potential. Addressing the known pain points of GPS signal jamming and spoofing will improve vehicle safety and consumer confidence in autonomous applications ranging from self-driving cars, and package delivery drones, to autonomous search and rescue. This impact will increase sales for autonomous vehicle manufactures and supporting technology companies, such as sensor, battery, and computer chip manufacturers. This Small Business Innovation Research (SBIR) Phase I project studies the feasibility of using a network of ground stations to receive low Earth orbit (LEO) satellite signals that were never designed for PNT and convert them into PNT-usable signals. Thousands of LEO satellites are being launched into space for internet and communication. However, unlike the GPS signal structure designed for extraction of PNT measurements, the signal structure transmitted from communication and internet LEO satellites was never intended for PNT. GPS satellites transmit accurate satellite ephemeris, atmospheric, and clock information to the GPS receiver, whereas this information is typically unavailable for LEO satellites. This project proposes to deploy a ground network to determine this information from LEO satellite signals and make this information available for PNT purposes. To this end, this project involves the following research thrusts: 1) find the optimal geometric distribution of the ground stations to minimize LEO satellite ephemeris, clock, and atmospheric errors, 2) develop special signal processing and estimation theory techniques to extract accurate PNT measurements from existing and future LEO satellite signals for free (without a subscription to their network), and 3) derive theoretical limits on PNT estimation errors when using the ground networkÂ’s produced information.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
