Testability of the PAALS auto-align sensor system

The author addresses the testability design of the precision accelerometer alignment and leveling system (PAALS) auto-align sensor system. The PAALS module is a sensor system for measuring the alignment of avionic packages relative to the system reference axes. PAALS stores the measured alignment parameters in memory as updated by command from the main system computers, and is designed to be co-located on active targeting sub-systems. The PAALS auto-align sensor system is designed to provide accurate alignment data with a high degree of reliability and extremely low maintenance. To achieve these requirements, the PAALS design incorporated testability to verify the accuracy and insure reliability. The testability design consists of four parts: functional partitioning, enhanced reliability design, internal self-test design, and offline testing