本文探討設計一個三軸之低成本的電子式飛機失事感測器。此失事感測器的主要功能為持續監視飛機飛行狀態，並在飛機失事之瞬間，自動送出警示信號給緊急定位信號發射器，發送飛機位置訊號，以縮短搜救的時間。失事成測器之桔心為微機電加速儀，利用PIC 單晶丹微控制器負責執行加速度信號擷取、分析及屆主動警示命令等動作。
失事條件判斷乃利用加速儀量測之加速度信號和計算速度變化率來決定警示之時機。為保證系統的穩定工作，本失事感測器也包含了鋰電池之備用電源，以確保在飛機失去電源時，系統仍可持續正常的工作。此外，為了解飛機失事時，加速度信號之特性，特別設計了一個失事感測器之落地實驗，並成功地執行了驗證工作，以協助了解落地瞬間之加速度特性及速度變化情況。 This paper discusses the design and implementation of a low cost three-axes electronic crash sensor for airborne application. The primary function of crash sensor is to continuously monitor the flying situation of air vehicle, and to engage the ELT system in the case of crash incident occurs. The core component of the crash sensor is the MEMS accelerometers. The data acquisition, reduction, and crash determination are accomplished using a low cost PIC microcontroller.
The crash condition is determined based on vehicle acceleration and variation of velocity. A backup Li-Ion battery is incorporated into the system to prevent power shut down. A drop test is also developed and performed to investigate the characteristics of impact accelerations.
