Picked up your smartphone lately? Of course you have. Looked at an image or a video? Yup. Which way round did you look at it – portrait or landscape? So how does the phone know which way round you wanted to view it – and what the heck has that got to do with aviation? Quite a bit actually.
At the heart of a smartphone is a tiny set of what look like microchips, but are in fact incredibly small machines. These Micro Electro Mechanical Systems have quite literally revolutionised all of our lives in so many ways. Each MEMS ‘chip’ as we shall call them, can be built as an accelerometer, a gyroscope, or a magnetometer. So just like our big, clunky, clumsy stable-platform INS, or our slightly better strap-down IRS, these chips can detect and report on pitch, roll, yaw and ‘heave’ (vertical) attitudes; rates of acceleration in each axis; and even measure the Earth’s magnetic field. And yet all of that is done with internal components ranging from 1 to 100 micrometres in size, in a chip measuring from 20 micrometres to 1 millimetre. You know, quite small.
Naturally, saving weight and size in components for aviation makes for more efficient flight due to better power-to-weight ratios, so these gizmos are great news for aircraft designers. Multi-channel Inertial Management Units (IMU), incorporating Air Data Computer (ADC) functions, are flying right now in aircraft, and occupying less than the size of a coffee cup in the avionics bay. But are they accurate enough for aviation? Heck, yes! These things detect, for example, deviations in attitude in the order of hundreds of degrees per second, down to decimal points of a degree per hour. Okay, that’ll do…
The miniaturisation of these machines will keep your aircraft in the right place in the sky just as easily as they keep that video the right way up in your iPhone or Android. But there’s more. Miniature IMUs have paved the way for the explosion in drone technology. Even the tiniest of flying machines can benefit from MEMS, improving their controllability and stability in the sky. So stable are these little flying machines that anyone could be flying them with no training just a few minutes after unpacking them from the box. Is that a good thing for the rest of aviation? Well, it will be once electronic conspicuity like ADS-B has become compulsory for drones. And progress is being made there, with tiny ADS-B units down to just a few grams in weight. Watch this space…
Links to MEMS videos/articles
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