Current and future requirements of the aerospace sensors and transducers field call for the design and development of highly reliable, cost-effective data acquisition devices and instrumentation systems. New designs that incorporate self-health, self-calibrating, and self-repair capabilities allow for greater measurement reliability and extended calibration cycles. With the addition of power management designs and components, state-of-the-art data acquisition systems allow data to be processed and presented with increased efficiency and accuracy.

A smart signal conditioning amplifier was designed incorporating these requirements. This device provides increased reliability by utilizing techniques to automatically reroute signals through different paths when the processor identifies a component malfunction.

The analog signal path design architecture presented addresses the issues of signal redundancy and signal integrity without taking the traditional approach of providing total hardware redundancy for every channel and every function block of a data acquisition system.

In addition to signal redundancy issues, the need for self-calibration verification capability has also played a major role in defining the approach followed by this project when formulating its architecture. Data acquisition systems such as those used in spacecrafts need the ability to calibrate automatically without external intervention. Furthermore, the quality of the measurement provided by the system is directly related to the system’s ability to ensure a proper calibration through the life of the process being monitored.

Finally, the capability of the data acquisition system to perform system health checks, failure detection, and failure prediction, as well as automated self-repair, plays a paramount role in systems for which operator intervention is not an option. Again, deep space spacecrafts require the ability to automatically reconfigure their data acquisition systems as failures are identified.

The traditional approach has basically provided systems with total hardware and software redundancy to overcome failures (two complete, independent redundant channels for every measurement required). This approach usually is very costly and adds significant weight, size, and power requirements to the systems it is supporting. All these characteristics are undesirable when dealing with aerospace systems.

The approach taken by the KSC Sensors Group is based on a concept we call “spare parts – tool box.” As with any process that has identifiable critical components, we identified and assessed areas of the data acquisition system’s analog signal path with specific reliability problems. An initial reliability assessment based on data acquisition system exposure to external conditions was implemented. Data acquisition system areas such as signal inputs and outputs were considered high-risk areas, while internal areas of the system not exposed to external environment were considered lower risk areas. A more detailed assessment that includes component reliability assessment (mean time between failures, etc.) will be implemented when specific components are baselined for the design.