An Extensible Architecture for Avionics Sensor Health Assessment Using Data Distribution Service (Draft)

Avionics Sensor Health Assessment is a sub-discipline of Integrated Vehicle Health Management (IVHM), which relates to the collection of sensor data, distributing it to diagnostics/prognostics algorithms, detecting run-time anomalies, and scheduling maintenance procedures. Real-time availability of the sensor health diagnostics for aircraft (manned or unmanned) subsystems allows pilots and operators to improve operational decisions. Therefore, avionics sensor health assessments are used extensively in the mil-aero domain. As avionics platforms consist of a variety of hardware and software components, standards such as Open System Architecture for Condition-Based Maintenance (OSA-CBM) have emerged to facilitate integration and interoperability. However, OSA-CBM is a platform-independent standard that provides little guidance for avionics sensor health monitoring, which requires onboard health assessment of airborne sensors in real-time. In this paper, we present a distributed architecture for avionics sensor health assessment using the Data Distribution Service (DDS), an Object Management Group (OMG) standard for developing loosely coupled high-performance real-time distributed systems. We use the data-centric publish/subscribe model supported by DDS for data acquisition, distribution, health monitoring, and presentation of diagnostics. We developed a normalized data model for exchanging the sensor and diagnostics information in a global data space in the system. Moreover, Extensible and Dynamic Topic Types (XTypes) specification allows incremental evolution of any subset of system components without disrupting the overall health monitoring system. We believe, the DDS standard and in particular RTI Connext DDS, is a viable technology for implementing OSA-CBM for avionics systems due to its real-time characteristics and extremely low resource requirements. RTI Connext DDS is being used in other major avionics programs, such as FACE™ and UCS. We evaluated our approach to sensor health assessment in a hardware-in-the-loop simulation of an Inertial Measurement  Unit (IMU) onboard a simulated General Atomics MQ-9 Reaper UAV. Our proof-of-concept effectively demonstrates real-time health monitoring of avionics sensors using a Bayesian Network –based analysis running on an extremely low-power and lightweight processing unit.