Wireless Extension of an Avionics Bus for Prototyping and Testing Reconfigurable UAVs

Abstract

** * * , This paper presents current research to extend the electronic systems of a UAV via a wireless link. Augmenting the onboard system with external resources offers a flexible testing environment and allows rapid prototyping of new hardware and software components that may not be adapted to meet the weight, space, and power restrictions of a small UAV. Additionally, keeping expensive prototypes on the ground lowers the risk of damage during experimentation. We are currently evaluating a number of hardware components and software techniques to wirelessly extend an onboard network. I. Introduction IGHT UAVs constitute a large percentage of UAVs being developed for both military and domestic applications. Developing avionics systems for these vehicles requires greater time and expense to miniaturize designs to fit on a compact UAV. There are also higher risks assumed when placing one-of-a-kind systems into a test environment. The approach presented in this paper addresses these issues by proposing that only the minimal hardware for control and communications is placed onboard the aircraft while additional hardware (and software) resources remain on the ground. The challenge lies in making the wireless link layer transparent to all hardware and software modules on the aircraft and on the ground. Benefits gained from the physical separation of system components are threefold. Integration tests of expensive sensor packages can be done with the sensor in a protected environment separate from the aircraft. The computing resources of large and power hungry prototypes can be easily made available to the UAV avionics systems, greatly enhancing the speed of development. Time spent testing in the field can be optimized by removing the need to land the aircraft and replace onboard systems; instead these can be hot-swapped while the aircraft remains in the air. The design and verification of light UAV avionics is more constrained than that of larger vehicles. The economics of a large-scale system require that much of the verification be conducted through simulation before any flight testing is performed. Compact vehicles are often field tested with software and hardware that lack this testing because the systems are typically cheaper to replace in the event of a failure. Although this difference promotes rapid development, the inherent risks can become unacceptable as the systems increase in cost. Small UAVs possess significantly less onboard resources compared to larger aircraft. The fundamental constraints of size, weight, energy storage capacity, and processing power must all be managed. Traditionally, the only option is to build prototypes that conform to these constraints. This step is often expensive and time consuming. A solution to these problems is to link computing resources on the aircraft to resources on the ground. Although remote processing is not a new concept, the specifications of such a system are typically determined at design time and many aspects of the system must take this into account. The novelty of the approach presented here is that processing elements may be arbitrarily located and relocated at any time (bench test, field test, deployment, etc.) without modifying hardware or software modules. The technique is based on the wireless extension of automatically reconfiguring multiprocessor systems which is described in the next section.