Design and Implementation of a Low Cost, Hierarchical and Modular Avionics Architecture for the DragonFly UAVs

We present the design and implementation of the safety critical avionics for the Stanford DragonFly Unmanned Aerial Vehicles (UAVs). The software architecture of the avionics is based on the Server-Client architecture of QNX Neutrino, the real-time operating system used. Our architecture is hierarchical and modular: it isolates user-defined applications from underlying low-level system services for implementing inter-process communication, data-acquisition, and associated hardware management. Also, we employ a new run-time scheduling algorithm to maximize the execution of tasks within a given deadline. The integrated hardware architecture is based on standard PC/104 and RS232 technology, making it possible to use Commercial O-The-Shelf (COTS) components and provide an ecient means of communication between components. We have developed this architecture in parallel (and in conjunction) with Boeing’s Open Control Platform (OCP) architecture, which is a new software infrastructure based on real-time CORBA technology, and we use the OCP to implement ground station functionalities. We present the design principles and choices, the resulting avionics architecture, and the implementation in a robust and compact avionics package. We then present initial results of the avionics in car tests, and discuss the results.