Systems and methods for long range, high-capacity multipoint distance and velocity measurement

Abstract

A round-trip, spread-spectrum navigation and locating system achieves high capacity and large processing gains in one-to-many and many-to-one configurations using round-trip signaling with frequency division based upon precise responding device carrier frequency offsets. Reduced cross-correlation is achieved by assigning these very small disparate frequency offsets to replies from interrogated devices so that the long-term correlation between disparate reply sequences is reduced almost to that of random noise of equivalent energy. The invention supports simultaneous interrogation of multiple responding devices, which responding devices respond essentially simultaneously at a fixed delay after receiving the query. The originating and/or responding devices may be fixed or mobile, permanently or temporarily deployed, terrestrial, airbourne or space-based with any source of power including batteries and solar without limitation. The signaling may be electromagnetic or acoustic with the potential for under-water use.