Emerging Global Positioning System (GPS) technologies aim to combat well known GPS vulnerabilities: GPS signals struggle to penetrate through natural and man made structures, are easily jammed by malicious actors, are susceptible to spoofing attacks, which can trick GPS receivers into devising a false PNT solution. The US Army conducts tests of emerging GPS technologies on static, dynamic, and autonomous platforms. A system to provide ground truth PNT is needed in order to effectively test these technologies without relying on GPS signals. Current solutions to provide ground truth positioning during GPS denial have become very complicated and involve many time-consuming steps. Our solution is produce an easy to deploy system that converts non-PNT radio frequency signals of opportunity into PNT-usable sources during GPS denial. Signals of opportunity include terrestrial transmitted signals: AM/FM radio, cellular, digital television and satellite transmitted signals: low Earth Orbit (LEO) satellite signals. These signals are abundant, available at diverse geometric configurations, various frequency bands, and with special signal processing are free to use. These attributes make them attractive as a precise PNT source during GPS-denial. Signals of opportunity were never intended for PNT purposes. As such, they are not equipped with GPS-quality stable atomic oscillators and their positions may be known. Furthermore, receivers to extract measurements from their signals and produce a PNT solution are not readily available on the market. The proposed approach conducts novel processing steps to convert signals of opportunity into GPS-quality signals that are usable for precise PNT in complete GPS-denial.
