Which Is the Best Real-Time Operating System for Drones? Evaluation of the Real-Time Characteristics of NuttX and ChibiOS

With the evolvement of various drone platforms, the constraints of such embedded systems are getting more and more strict and specific. As the low-level technology, correct behaviours and decent performance of an RTOS play a vital role in guaranteeing such constraints. This paper studies the real-time performance and behaviour of two popular RTOSs used in drones, presenting both quantitative and qualitative results. We also exploited the source code to locate the origin of possible misbehaviours. By analysing the results, we draw several conclusions on the comparison of NuttX and ChibiOS, which can be useful for drone developers and users. NuttX has a vital defect in the implementation of priority inheritance. And in most tests, ChibiOS beats NuttX, therefore, it is the winner in this comparison.