Electronic Prognostics - A Case Study Using Global Positioning System (GPS)

Prognostic health management (PHM) of electronic systems presents challenges traditionally viewed as either insurmountable or not worth the cost of pursuit, but recent changes in weapons platform acquisition and support requirements has spurred renewed interest in electronics PHM, revealing possible applications, accessible data sources, and previously unexplored predictive techniques.

Naval Air Warfare Center, Patuxent River, Maryland

Many types of circuits compose avionics systems. One of the following categories can be used to classify each circuit topology at the time this research was performed:

High frequency analog

Low frequency analog

Low impedance

High impedance

Common failure mode mechanisms for analog circuits depend largely on the architecture and relative operating frequencies of the circuit. In this research, high frequency analog circuits are categorized as operating above 1GHz, while low frequency analog circuits operate below 1GHz. High frequency analog circuits are sensitive to small changes in device parameters, resulting in non-destructive, or operational, failure modes. Unlike physical device failures, the cause of operational failures cannot be traced back to individual components. Low frequency analog circuits are more likely to undergo physical device failure. The accompanying figure illustrates the relationship between the operating frequency of an analog circuit and the different types of failure modes.