Uncrewed Systems Technology 049 - April/May 2023

23 system, largely because of its narrow field of view as well as the scattering. “As the drone flies, the laser shoots directly downward and captures only what is immediately under it. You can fly in a pattern, but you have to do it multiple times,” she says. “You get a noisy, averaged look at the scene, although you get some good information.” These limitations led Heiks and her team to put together a new system called RetraSpectra. “We were thinking of inventing a systemwith amobile retroreflector either in the air or on the ground, while the laser couldmove around with respect to that reflector as it flew around a target area to collect clear information,” she recalls. “But we found that The Aerospace Corporation, which is a federally funded lab, had patented the exact thing we wanted, so we licensed their technology to commercialise it.” In support of that, Censys has won a Small Business Innovation Research grant from the US Environmental Protection Agency (EPA). The system Censys is developing consists of a ground-based laser on a gimbal that is free to turn through n x 360o, and a UAV carrying a retroreflector. The UAV flies around the survey area and ‘targets’ the laser beam with the retroreflector to provide a strong return signal. “A retroreflector is very similar to a mirror, but it is tuned to the wavelength and is very tolerant of errors in targeting,” Heiks explains. “It has many features that make it similar to reflective tape, which you can always see when driving at night, even if your lights are not shining directly at it, but it is a little more complex at the wavelengths used.” She notes that the laser does not generate a single narrow beam but uses a lens system to create a much broader beam, characterising it as a big, wide- open eye. Censys expects the system to tolerate errors amounting to several metres of lateral displacement and of the order of 10-20o of angular displacement. “We are conducting tests of this right now for the EPA. Initially we are doing static tests and we’ll go flying in phase two of our programme.” The system has also demonstrated good range and sensitivity, detecting methane at concentrations as low as 10 parts per million. “We are now concentrating on testing and training the targeting system. Laser systems have been developed before to do this kind of work, but targeting of the retroreflector is one of the difficult parts.” Heiks adds that the CensWise system is being applied to detecting and tracking objects. More broadly, she considers that there is a great deal of as yet untapped potential for remote sensing from UAVs using sensors more often associated with military than commercial and environmental applications. Untapped potential “We are developing sensors such as magnetometers for detecting metal,” she says. “There are also millimetre- wave sensors that can look through tree canopies and, potentially, see metal and other objects. “Sensors were my background before I got into UAVs, and I think there is a huge amount of capability in the millimetre- wave spectrum as well as the microwave spectrum, including being able to see underground, for example. These capabilities haven’t really been exploited, because they are usually the purview of military systems and, generally, they are bulky and heavy.” However, what she considers most important is that advanced sensors in UAVs feed the mobile command centres with their AI/ML algorithms so that the system can discern significant patterns, particularly in methane and CO 2 emissions. “I hope we can combine the data we get from the RetraSpectra systemwith data on humidity, wind direction and so on with modelling, and connecting that to a whole-Earth model to really understand the effect we are having on our atmosphere.” Uncrewed Systems Technology | April/May 2023 Noel Heiks grew up around robotics and industry, spending much of her childhood and teens in her father’s automation business. She pursued her further education at Virginia Tech, earning a bachelor’s degree in physics in 1992 and a master’s in electrical engineering in 1997. Co-founding optoelectronics company Haleos, her first start-up, in 1996, she served as vice-president before joining the company to which she sold the business, Rohm and Haas Electronic Materials, in 2002. She founded OptiSales in 2007 and defence electronics company Nuvotronics in 2008, serving in senior roles until April 2019. She joined rail inspection and security systems company Duos Technologies as president and COO in March 2018, leaving to join the board of broadband and military navigation electronics specialist Emcore in September 2019, where she still serves. Heiks became a board member at Censys Technologies in January 2020, and managing partner at venture capital company Kirenaga Partners in February 2021. She is now chairman of the board at Censys, and has recently launched Azultera, a new venture firm. Noel Heiks