Fault Location in an Intelligent Open Sensor Network

A procedure has been developed to refurbish hemispherical infrared (IR) windows designed for use on the Infrared Search and Track (IRST) System. The two stage program will enable repair of the surface coated germanium (Ge) windows, more commonly known asdomes, which have failed to meet IR transmission and focus specifications. Failure to meet specifications is due to a high density of pits in the aperture area generated from exposure to adverse environmental conditions at high velocities. Stage 1(immediate) involves removal of surface material, which will result in a finished dome that meets transmission requirements with 4.7% maximum deviation from the specified focus. This process may introduce slight image aberration, which may or may not bewithin acceptable tolerance of the optical system. A dome refurbished using stage 1 will be delivered at the end of SBIR Phase I. Stage 2 will implement a process to add Ge to the dome surface in an amount necessary to allow resurfacing to the originaldesign dimensions. This process would return the dome to the like-new operational performance. Feasibility for stage 2 will be demonstrated during SBIR Phase I. Delivery of domes refurbished using stage 2 would occur during SBIR Phase II.The electric power utility industry utilizes IR sensors in the same bandwidth as the IRST sensor to perform evaluation on above ground power transmission lines for insulation leaks. These leaks result in power transmission loss costing the utilitycompanies millions of dollars annually. To identify failures in power line insulation, public utilities use specially configured aircraft that fly over the nation's power lines using IR sensors to detect the leaks. The location of the failed insulationalong the power line is detected and the information sent to the power company for repair. The IR systems used in the utility company's aircraft have the same type of IR window used in an IRST system. While less harsh (lower speed), the utility companyaircraft's IR system is subject to much of the same environment as the F-14D IRST. The utility companies' IR systems experience more usage than the IRST. Further, flights are made at lower altitudes where airborne particulate matter has a greateropaqueing effect on the IR window. Resulting failure of the IR window occurs at least as often in the IRST. Development of a refurbishment process can be directly applied to this particular commercial application.