Non-GPS Sonobouy Positioning System

Quick and accurate sonobuoy location is becoming more critical in the airborne ASW problem as multi-static active search systems and data fusion techniques play more dominant roles. Sonobuoy locations must be determined automatically and constantly updated in order to estimate target locations as soon as target detection clues are available to the acoustic subsystem. Obsolete methods of buoy location such as “Mark-on-Top”, and systems based on assumptions that the target will be held in contact for significant periods will not work. In Phase I, RDA proposes techniques that can be used to automatically locate sonobuoys by extracting information from the sonobuoy signals. Techniques include Angle-of-Arrival (AOA), and Doppler extraction. The AOA approach is applicable to multi-antenna sonobuoy receiving systems, whereas the Doppler extraction approach requires only a single antenna to produce the sonobuoy location. The techniques can also be combined to provide a comprehensive sonobuoy location system. The techniques address the various sonobuoy types and consider the real-world constraints and parameters, and performance is modeled in MATLAB. Preliminary design for a prototype and definition of a transition path to fleet avionics is also part of the Phase I.