Cooperative Handheld Location Device Using Signals of Opportunity

This Phase I effort will show that cooperative receiving devices can determine their locations with good accuracy using only signals of opportunity without a global positioning system (GPS). Using emitter of known location, algorithms for calculating receiver location from cooperative signal processing routines will be developed. The focus of the Phase I effort will be on high-power terrestrial broadcast signals from AM, FM and TV stations, but other signals of opportunity such as cellular base stations and wireless access points will be considered. By completion of this project, a cooperative handheld location device using signals of opportunity will be developed and demonstrated through modeling by: (1) developing algorithms sufficient for determining TDOA of transmitted signals to cooperative receiver devices; (2) developing algorithms sufficient for determining location of receivers from TDOA information related to emitters of known location; and (3) preparing a detailed computer simulation to characterize performance of the algorithms using signals of opportunity. The accuracy of a number of scenarios will be characterized – including variations in transmit / receive geometry, signal to noise ratio, and numbers of emitters and receivers – by developing a detailed simulation in order to perform a Monte Carlo analysis across the variations. BENEFIT: The utility of cooperative receiving devices that can provide location information in GPS deprived environments has numerous applications in military and commercial applications. Such a handheld unit would help ensure no loss of capability when GPS is unavailable, including within buildings. Within military applications, the threat of GPS denial is real. This may include jamming, blocking or spoofing. By integrating a secondary capability to ascertain position information that does not rely on GPS, a more robust capability will be provided to the warfighter. Also, in both military and commercial applications, the need to determine precise position within a building is not met by GPS. Warfighters, firefighters and other law enforcement personnel operating within buildings, where it may further be desired to determine elevation information, would benefit greatly from this device.