Accurate Reliability Prediction Based on RIDM

Abstract

The reliability of an item is the probability that it will adequately perform its specified purpose for a specified period of time under specified environmental conditions [1]. Uncertainty [2] in reliability prediction for complex electronic systems/equipment is mainly originated from the incomplete considerations on the specified environmental conditions and on the impacts to the equipment. This paper focuses on the incomplete considerations on the space radiation environment (SR see Acronyms in table 1) and their impacts on complex electronic equipment in satellites, airplanes, and ground network computers working daily in SR. Based on Risk Informed Decision Making (RIDM) analysis framework [3], this paper proposes an accurate reliability prediction method to accommodate SR and SR impacts on complex electronic equipment to avoid uncertainties originated from the incomplete considerations on SR theoretically more complete or accurate than the traditional methods, such as FIDES [4], MIL-HDBK-217 [5], etc, which has not considered SR. This paper is creative on the following 3 novel points. (1) SR reliability concept: For accurate reliability prediction, this paper proposes an SR reliability concept based on RIDM framework. The concept accommodates SR and SR impacts critical to mission success by the SR reliability definition and the RIDM 5 steps analysis method to have a close loop systematic thinking on incomplete considerations on SR. (2) SR reliability model: For an accurate reliability prediction based on the SR reliability concept, this paper proposes a new SR reliability model focused on the SR impact rate for complex electronic equipment, connecting the incomplete considerations of SR with mission success in a close loop by 1) The relationship [6] between Reliability and SR impact rate, 2) The relationship [6] between SR impact rate and TID, DD, and SEE impact rate, 3) The relationship between SEE impact rate and SEE effect rate. (3) SR reliability prediction application and verification: This paper provides 3 case studies on satellite, avionics, and ground network computer applications. Additionally, the SR impact rate for avionics of a satellite navigation receiver prototype is predicted and compared with the test results [7] with good agreement. Case studies show that for safety critical applications, the SR impact rate is significant and not negligible. And the SR reliability concept and model is practical and useful for displaying possible key contributions to SR mitigation strategies or Defense-in-depth systematically for mission success.This paper gives an example for the accurate reliability prediction based on RIDM, focusing only on accommodating SR. However, as a general systematic method, it can be applied in broader areas on more SR and non-SR stresses.