Covert ground and port surveillance using Hyperbox®: Rayleigh backscattering from fiber optics

Abstract

A fiber optic interrogator has been developed with software (SAV) that will detect people walking, vehicles and digging across a 100 m swath around a buried fiber optic cable. These activities cause minute pressure waves that transmit through the ground to the buried fiber. The pressure waves then hit the fiber causing minute changes in the fiber index. Rayleigh backscattering is extremely sensitive to these index changes. The three activities are distinguished from each other with SAV and the activities can be located within a few meters along the fiber. The temporal frequency of this backscatter allows discrimination of the targets. The resultant system is analogous to an array of geophones where the number and sensitivity of the geophones is programmable. The interrogator was field tested with 40 Km of buried fiber providing definitive discrimination of all three target types. This system was designed for maximum versatility with SAV controlled variable pulse width to improve target location, SAV controlled variable pulse rate and data sampling to optimize storage requirements, and SAV controlled variable output power to allow increased sensitivity at longer ranges. The buried fiber GPS coordinates are correlated with Google maps to allow the events to be overlaid onto a topographical map. The result is a color coded real time pictorial of events over the entire fiber length (>80 Km) fused with a map of the area giving operators total situational awareness. The entire interrogator and processing computer have been packaged into a portable ruggedized 19” rack. Data is transmitted across an Ethernet connection for analysis at a central location. This system is suitable for use on any border. For the US Northern border: There are only 2,200 U.S. agents (4 agents/10 Km average). For the U.S. Southern border: there are 17,659 US agents (56 agents/10 Km average). The Hyperbox® would reduce the number of required agents by providing a force multiplier with a few dozen installations and 24/7 coverage at a price that is the lowest cost/Km of any other available surveillance technology.