Low Probability of Intercept PNT Augmentation Network

ABSTRACT: Echo Ridge proposes to design and performance characterize an LPI/LPD PNT augmentation system (including beacons and user equipment) using a hybrid frequency hopping, spread spectrum signal-based waveform which we believe can achieve compliant performance in ground applications.We have chosen this waveform class for its unique combination of PNT performance and low probability of intercept.We will build upon an existing Echo Ridge signal-based PNT waveform where we have demonstrated compliant location accuracy.This waveform has been analyzed by outside experts for LPD/LPI performance.In addition to PNT and LPI performance, a key criteria in our design is operational utility measured in terms of flexibility/lack of constraints and SWaP-C.For operational flexibility and low cost, it will include battery and prime-powered beacons, and vehicular and dismount user equipment.The LPI PNT augmentation will include the ability to take advantage of partial GPS availability, and transparently and seamlessly maintain PNT performance.Both the beacons and user equipment will be based on SDR technology, allowing PNT and communications functionality to be hosted economically on a common platform.In Phase I and Phase II, existing Echo Ridge SDR platforms will be used for proof of principal demonstrations, and lab and field-based performance characterization.; BENEFIT: This effort will develop Navwar technology for an LPI PNT augmentation system which can provide horizontal location accuracy to less than 10 meters of error to ground users in GPS-denied environments, while simultaneously minimizing detectability by adversaries operating in the environment.The capability will be designed to be SWaP-C compatible with mission and equipment constraints for mounted and dismounted warfighters.The technologies proposed solve routinely identified problems in both the military, other public and commercial marketplaces (unreliable PNT in challenging environment (indoors, urban canyons, jamming)).Rebroadcasting GPS/GPS-like signal from other platforms/localities has been the traditional approach.This has been principally driven by the established confidence in GPS waveforms with respect to PNT performance, and the availability of hardware/software to effectively repeat/generate GPS/GPS-like signals.A GPS re-broadcast is easily detectable by all standard techniques, and therefore easily jammed by adversaries.It is therefore not an optimal solution for operational scenarios where adversaries are present.Technologies and operational considerations are changing that create the opportunity for alternatives to GPS/GPS-like waveforms for pseudolites.These include the proliferation of digital radio networks (including SDR-based) which provide communications facilities between users, and between users and the control segment.They also provide the ability to program new functionality (including sharing the radio resources between multiple functions) into the radio network.These digital radio facilities can therefore be used for traditional communications, passing PNT-related information (such as key distribution, ephemeris/almanac, etc.), and generating/receiving PNT ranging waveforms.