Through challenges to success – Kim Kalmankoski developed lidar technology in his doctoral research

Kim Kalmankoski, a graduate of the DSII (Doctoral School of Industry Innovations), developed a laser radar, or lidar, with extremely accurate color separation capabilities in his doctoral dissertation research. The title of his doctoral dissertation in the fields of physics is Spectral Detection of Molecular Scattering with Coherent Heterodyne Lidar. The journey towards his dissertation encountered many challenges that had to be overcome before a concrete, functional product was ready.

Text: Julia Koski

Photo: Julia Koski

After graduating with a master's degree in engineering, Kim Kalmankoski noticed that Vaisala was starting a collaboration with DSII doctoral school in the very same laboratory where he had worked during his studies. Kalmankoski started to work on his doctoral dissertation in collaboration with Vaisala and Tampere University. Vaisala is a measurement technology company that develops and manufactures measuring instruments and systems for environmental and industrial measurement needs. 

“Vaisala was an interesting choice for this dissertation project, and the topic was also quite relevant to my own background”, Kalmankoski explains. 

Collaboration with the company went well right from the beginning. Kalmankoski says that he became an important part of the team and got acquaintaned with different people and experts. 

“I got to do my own research at Vaisala’s office, and above all, I got to know the field I was working for. I got to see what it’s like to do research with commercial equipment and what kind of signal processing algorithms and iron they use.” 

According to Kalmankoski, the best part of his studies were the people he got to work with.

“All my coworkers will remain in my memory for a long time. Even though I never really had my own team, one of the best things was the people who came from different places and helped me with my work.” 

Doctoral research led to a new type of technology 

The subject of Kalmankoski's doctoral dissertation was color separation of light scattering using laser radar, or lidar. Lidar can be used for continuous monitoring of the composition of the atmosphere. When a laser pulse emitted from the ground hits objects in the sky – such as clouds or other types of particles – it is reflected back to the ground. The backscattering of light provides information about – among other things – small particles in the air, pollen, and air pollution. 

In order for the data obtained to be as accurate and realistic as possible, molecular scattering must also be measured at the same time. Fine particle scattering and molecular scattering differ in color, and distinguishing between them requires a lot of luminous power and good color separation capabilities. The precise scientific equipment required for this is extremely expensive, while the data obtained with cheaper commercial equipment is not accurate enough to be used in all situations. 

Kalmankoski came up with the idea of applying cheaper wind lidar technology, which is widely used in air traffic, for example. 

"To achieve this, we had the opportunity to develop a new laser source that was significantly more powerful than any previously used laser in commercial devices”. 

Kalmankoski succeeded in performing color separation electronically, i.e., without optical filters such as colored glasses. In addition, he built a prototype device that was also used to take measurements. 

"We went to Kuopio to take measurements with other similar devices and achieved performance levels similar to those achieved by current scientific equipment”, he says. 

In the future, this type of equipment could potentially be used, for example, in increasingly accurate weather research and forecasting. 

Overcoming challenges inspired to continue working 

Conducting the research was not entirely straightforward, and during his work Kalmankoski had to overcome various unique challenges in order to complete the final result. Creating a totally new laser source was a big part of the work. 

“The results were globally significant. There was more power than anyone had ever achieved before with that kind of technology", he says. 

Another major challenge was the enormous amount of data being stored. Initially, the data flowed at a rate of 20 terabytes per hour, but eventually Kalmankoski managed to condense the data to only four gigabytes. According to Kalmankoski, when he finally had a working device in front of him, the feeling was amazing. 

"When we had assembled the device and fired the lasers into the sky – and finally saw something other than just noise on our devices, it was a really big victory", Kalmankoski describes with a smile. 

He says that this type of research had hardly been actualized at this level before. Conducting this kind of new research was very exciting, but it was also quite nerve-wracking.  

"It was the best and the worst at the same time, because for a long time it was quite uncertain whether I would succeed or not." 

"Of course, small successes always help you keep going", he adds. 

 

Company visits left a lasting impression 

According to Kalmankoski, DSII offered him a lot during his studies. He particularly highlights the joint round-up meetings, which were attended by representatives from various companies, along with fellow doctoral researchers from DSII.  

“Definitely one of the best things about DSII was that we got to hear representatives from different organisations talk about their companies and their stories. In my opinion, that was the core of DSII, which sets it apart from other basic doctoral school environments.” 

Kalmankoski also has fond memories of the DSII summer day events. According to him, the summer days provided an opportunity to get to know other students more well and discuss their own challenges and successes with their dissertations. 

Kalmankoski recommends the DSII doctoral school to others who are planning to do their doctoral studies. 

“Through DSII, you can find a good company partner. It’s a big deal for a doctoral student to be able to join a company and see how it operates. It also boosts your confidence and gives you experience of the industry – even if you don't end up working for the company you did your dissertation with. Corporate collaboration is definitely the golden thread running through DSII."