Build-in Test Design for Civil Aircraft Radio Altimeter

Abstract:
The radio altimeter for civil aircraft is introduced. Firstly, the hardware hierarchy is analyzed, and the BIT design criteria and fault detection process are given. Then the hardware and software BIT design principles for fault detection and isolation of servo loop/micro-processing components and low-frequency/frequency discrimination components are discussed in detail. By considering the compromise between false alarms and accuracy requirements, the detection tolerance is reasonably determined. Finally, the software detection process design and anti-false alarm measures under PBIT and CBIT are given. The actual test results show that the design method is reasonable and effective, which improves the fault detection rate of the radio altimeter, thereby improving its testability and maintainability.