Optimising the design of a pressure transducer for aircraft altitude measurement using optical fibre Bragg grating sensors

The air data system of an aircraft is an essential sensor system used for primary flight data, including altitude measurements. These systems make use of electronic encoders and traditional mechanical pressure transducers to convert outside air pressure into altitude measurements. The objective of this research is to optimize the design of a meso scale pressure transducer to facilitate the use of an optical fibre Bragg grating sensor to measure the altitude of an aircraft. Optical fibre systems offer a weight saving advantage and an improvement in fire safety, when compared to traditional electrical system. Optical fibre Bragg grating sensors are typically sensitive to strain; hence a transduction mechanism is required to convert pressure into strain. A diaphragm is an ideal mechanism for this. Here it is shown that the parameters of the diaphragm can easily be optimized to achieve the desired longitudinal strain in an attached fibre Bragg grating.