Low-power global navigation satellite system-enabled wireless sensor network for acoustic emission localisation in aerospace components

Structural health monitoring systems for the localisation of acoustic emission (AE) events have been developed in the past few years for aircraft components. However, these systems still require complex and heavy electrical wiring for each sensing device and sophisticated algorithms for the localisation of AE signals, which inevitably increases both weight and costs. This paper reports the creation of a low-power (few hundred mW) and low-weight (similar to 30 g) global navigation satellite system-based wireless sensor network for the identification of AE events in aircraft structures. Each wireless node is instrumented with a low-power micro-controller, a radio frequency wireless transceiver, an analogue-to-digital converter, and a global navigation satellite system receiver for accurate time synchronisation. The AE coordinates and the speed of propagating waves are determined by using a localisation algorithm relying on time of arrival measurements. A peak amplitude detection system is implemented to process the AE data recorded by the wireless sensor network. The AE time features are locally extracted by the individual wireless modules and transferred to a remote processing unit for the execution of the localisation algorithm. Experimental results revealed that AE sources generated by low-velocity impacts are identified with a high level of accuracy. The successful implementation of the proposed wireless sensor network demonstrates its suitability for continuous and autonomous structural health monitoring aerospace applications.