SBIR-STTR Award

NORS (Networked OFDM Ranging System) is a complete positioning solution, composed of an engineered combination of innovative ranging, networking, waveform, and localization technologies. Technical components were selected to perform in the very environments where GPS is most susceptible to failure (urban and subterranean.) The proposed system also achieves GPS level accuracy over an existing communications infrastructure. The NORS system includes an innovative, narrowband ranging technique that is tightly coupled with the OFDM waveform. Furthermore, the implemented system will be capable of establishing range estimates by sniffing conventional JTRS-WNW OFDM data packets. With no transmitter modifications required, a NORS receiver can even derive range estimates from legacy equipment. A networked localization algorithm is also proposed for combining multiple range measurements into the triangulation of each node's absolute position. Range, position, velocity, and time information will be distributed over the network in a completely ad-hoc fashion. This will allow the flow of positioning information from advantaged nodes to disadvantaged (GPS-denied) nodes. The system has also been designed for low power consumption, achieved via a one-way passive ranging algorithm that sharply reduces the amount of data transmitted and through intelligent networking methods that take each node's power attributes into consideration when establishing routes

Despite recent and ongoing improvements to the GPS infrastructure, GPS-aided positioning is often jeopardized by both intentional and incidental jammers. GPS services are not available in many desired areas of operation, including indoors, under foliage and in urban canyons. A fall-back capability to augment the GPS-aided positioning is highly desirable. The proposed NORS program takes an unconventional approach to solving the GPS augmentation problem. NORS is a software solution that can be easily inserted into software defined radios such as JTRS. The client node can operate in receive-only mode, enabling LPI/LPD functionality.

Keywords:
Gps, Anti-Jamming, Location, Navigation, Gps-Supplement, Gps-Augmentation, Jtrs, Software Defined Radio