TECH FOCUS REMOTE SENSING


Preventing air turbulence


with lidar technology Scientists are developing an on-board laser system that could help pilots avoid, or take better precautions for, clear-air turbulence


H


aving to endure unpleasant air turbulence on flights


could be a thing of the past, thanks to long range lidar technology being developed by Boeing and the Japan Aerospace Exploration Agency (JAXA). The new system could potentially reduce turbulence- caused injuries by 60 per cent. Boeing and JAXA will


flight-test the long-range light detection and ranging (lidar) technology, which will be capable of detecting once-undetectable clear-air turbulence from a distance of 17.5km, next year. The on- board system will help provide pilots with sufficient time to take appropriate action to avoid wind-shear and clear-air turbulence, which does not have any visual cues such as clouds.


Boeing and JAXA have been collaborating on the integration of lidar technology into a commercial airplane platform since 2010. According to figures quoted


by JAXA, more than 50 per cent of domestic airline accidents over the past 10 years were caused by turbulence. Whereas turbulence accompanied by rain clouds can be detected to some degree using weather radar and/or by consulting weather forecasts in advance, it is difficult to foresee possible turbulence unaccompanied by rain clouds (clear-air turbulence). By emitting two laser beams


from an aircraft, receiving scattered light from small dust and other particulates suspended in the air, and analysing light wavelength variation caused by the Doppler effect, the lidar system can determine transitions in


34 Electro Optics November 2017


“The lidar system will be tested next year, along with more than 30 technologies as part of Boeing’s ecoDemonstrator flight-test research programme”


airflow – otherwise known as turbulence – based on wavelength variation. This makes it possible to detect clear-air turbulence that weather radar on most aircraft fail to identify. Because of the high altitudes


at which commercial flights fly (more than 10km) the aerosol density drops, and scattered light weakens so that a more powerful laser beam becomes necessary. JAXA’s Doppler lidar weighs


just 83.7kg, but can be made even smaller if used exclusively at low altitudes and low speeds, such as during take-off and landing. This technology


warns a pilot with an alarm to avoid danger when turbulence is detected during landing approach.


The lidar system will be


tested next year along with more than 30 technologies as part of Boeing’s ecoDemonstrator flight-test research programme. This will allow JAXA to evaluate the system from an aircraft manufacturers’ point of view and identify any technical hurdles that will need to be tackled to make the system viable as a practical application. It will also help promote the


effectiveness of the system among airline companies and manufacturers, which in turn will catch the attention of standardisation and regulatory organisations, JAXA has said. ‘Boeing’s ecoDemonstrator


programme provides us with a valuable opportunity to evaluate our system’s capability on large commercial aircraft, which will help accelerate practical


implementation of our system in a real environment,’ said Fumikazu Itoh, director general of the JAXA Aeronautical Technology Directorate. ‘Boeing is very pleased with


the collaborative relationship we have had with JAXA,’ added Naveed Hussain, Boeing research and technology vice president of aeromechanics technology. ‘We look forward to demonstrating the benefits of lidar technology, which offers significant opportunities for aircraft safety and performance.’ In addition to looking into


further miniaturisation and power enhancement of the lidar system at high-altitudes, JAXA is developing gust alleviation technology that reduces aircraft shake by automatically controlling the control surfaces (hinged flight surfaces that affect the attitude of the aircraft) based on estimated airflow vector data detected by two laser beams. EO


@electrooptics | www.electrooptics.com


Jaromir Chalabala/Shutterstock.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36