OES Distinguished Technical Achievement Award: 'Icing on the cake' for Dr. Peter Mikhalevsky

Last September, Leidos Senior Scientist Peter Mikhalevsky received the Institute of Electrical and Electronics Engineers' (IEEE) Oceanic Engineering Society's (OES) award for Distinguished Technical Achievement.

We recently interviewed Dr. Mikhalevsky over email about this achievement and his nearly half-century studying the oceans. Here is our conversation: 

Congratulations on your award! When were you notified and what was going through your mind?

I was notified a few weeks before the IEEE's OES fall meeting, when the DTA award is traditionally presented. Unfortunately I had a previous commitment and could not attend the meeting, so the award ceremony has been postponed to their spring meeting in Kobe, Japan this May. The formal DTA award announcement was published in the December issue of the OES Beacon, the newsletter of the OES.

When I was first notified, I was completely taken aback, at once humbled, honored and excited. I certainly did not expect it! I really enjoy what I do. I was working on my latest project that involves a very interesting idea for long range underwater acoustic navigation that I recently filed for a patent. This award was truly like icing on the cake.

You’re no stranger to awards – where does this one rank for you?

There is no question that this award ranks at the top as it recognizes a large body of work over my entire career. There can be no better accolade of one's work than that of being recognized and honored by your professional colleagues.

You were given this award for technical achievement and contributions to advances in acoustics, oceanography, and tomography. Could you briefly explain what those things are and why they’re important?

The deep ocean cannot be penetrated by electromagnetic energy (e.g. light, radio, radar, etc.). Acoustic pressure waves on the other hand can propagate with low loss across thousands of miles in the ocean. Thus with acoustics, we can listen to close and distant sounds from ships, whales, submarines, wind, underwater earthquakes, etc., to get an acoustic “picture” to “see” the undersea world. We use acoustics to transmit sound through the ocean for communications, sonar, ocean sensing of temperature and currents, bottom bathymetry, and sub-bottom probing.

Ocean acoustic tomography and thermometry (OAT) use acoustic signals to measure ocean temperature and currents. Since the sound speed depends on temperature, a measurement of the travel time between sources and receivers is directly dependent on the temperature. This is fundamentally how OAT works. Currents can be measured by taking the difference in travel time from reciprocal acoustic transmissions between two points to get the average net advection by the current of the sound along the path between those points.

Using many appropriately placed sources and receivers, acoustic tomography can provide four-dimensional maps of the ocean temperature and currents showing the ocean fronts and eddies. Acoustic thermometry is the term for using a single source receiver path to measure the change in average temperature along that path. OAT can be used to monitor long-term changes in ocean temperature for climate change studies. The applications of acoustics in the ocean are vital for national security as well as science.

Your 45-year career has spanned the military, academia and private industry. What has allowed you to succeed at every stop along the way?

The U.S. Navy gave me a lot of opportunity and responsibility at the very beginning of my career, with exciting technical jobs and challenges. One of my first jobs was ASW Officer on a destroyer, responsible for all sonar systems and ASW weapons. At 23 years old, I was in charge of FOX (ASW) Division with  20 sailors. Our ship was selected as the test platform for the first prototype destroyer towed array in the fleet in 1973. There was flag interest and visibility of the program all the way to the Chief of Naval Operations. As ASW Officer, the testing and operation of this prototype was my responsibility and this effort led to the development and fleet deployment of the SQR-18(V) and SQR-19 tactical towed array sonar (TACTAS) systems.

I experienced firsthand working with new technology and having great success in the field that also fueled my love of working at-sea. This is what inspired me to go to graduate school at MIT for my PhD, supported by the Navy, focusing my interest more deeply into the technology of underwater acoustics, signal processing, and oceanography, and taking my ideas to sea to see if they really worked.

That ultimately led to my leaving the Navy to join the faculty of MIT to teach and learn more, and finally to Science Applications International Corporation (SAIC), now Leidos, to apply this knowledge to develop real systems and deploy them at sea. At my job, I’ve had tremendous freedom to pursue my technical interests and work on projects that would have real impact for the Navy and other customers. One of the most satisfying aspects of working here was to be able to start and grow a division and hire the best people and work with them on many exciting projects during my 32 years of service. 

You spent a couple of years on MIT’s faculty. What was your teaching experience like?

A lot of work, but very stimulating. Teaching at MIT was like getting another PhD or two. As they say, you never really learn a subject until you teach it and the MIT students will keep you on your toes. I ended up hiring several MIT grads when I was at SAIC. I was working with my PhD thesis advisor Ira Dyer, one of the greats in our field, who recruited me to MIT from the Navy. He was a mentor and great supporter of me and my career. It was Ira who had started a program funded by the Office of Naval Research for acoustics research in the Arctic Ocean in the late '70s that launched my life-long interest and work in that incredible part of our planet.

How much has the technology in anti-submarine warfare advanced over the course of your career?

It has been huge, especially from the perspective of my career that started in the early 1970s. The major advances have been in our understanding of the physics of acoustic propagation in the ocean, the development of computer codes that can accurately compute the acoustic sound fields, the advances in computer technology that have made calculations that can be done in fractions of a second today that would have taken days early in the 1970s, and the understanding of the propagation medium itself, the ocean, and its scales of variability that directly affect sound propagation.

The advances in oceanography, the discovery of the ubiquitous mesoscale fronts and eddies (ocean weather) comprising 90% of the oceans’ kinetic energy and the development of general ocean circulation models (GCMs) that now ingest satellite data, data from ocean going vessels, manned and autonomous, and acoustic tomography, provide more accurate input to the acoustic models, and consequently more accurate output.

The technology of undersea moorings, arrays, hydrophone and vector sensors, accurate clocks, GPS, and high speed data collection and storage has vastly improved our capability to collect and analyze data from the ocean. The development of spectral analysis, the FFT and advances in signal and array processing techniques with the much more accurate sound fields coupled with data validation at sea enabled discovery of new ocean acoustic phenomena that led to new ASW systems, concepts, and capabilities — most of which are classified, as you might expect.

On my destroyer we would compute what was called “the range of the day;” that was one number that gave us some idea of how our sonar might perform. This is a very far cry from the sophisticated consoles and displays with high resolution real-time ocean information and systems performance data onboard today’s ships. These advances have all improved our ability to develop, build and test new technology, and systems as well as improve training and at-sea execution using accurate virtual/simulated oceans from anywhere in the world.

Robotics and autonomous systems are also having a lot of influence that will only increase in the future. Just one example is the development of the 140 ton MDUSV (Medium Displacement Unmanned Surface Vessel), aka Sea Hunter, under our contract with DARPA. Vessel development started in 2010 with the first feasibility studies, it was officially christened by the Navy in 2016, and it's now undergoing testing for a variety of missions.

You were one of the first people to successfully experiment with matched field processing and acoustic thermometry in the oceans. Can you tell us more about those experiments and how they helped advance your field?

Matched field processing (MFP) involves using ocean models to predict the acoustic field received on your sensors and “matching” that against the actual data received on the sensors. This work and work by others highlighted and quantified the benefits and need for better ocean models. During that time in the mid-80s, there was a lot of debate about the stability/variability of the acoustic sound channel and whether “coherent” processing like MFP was even possible over long ranges in the ocean due to fluctuations of sound speed as result of ocean internal waves. Coherent processing is needed to achieve processing gains for signal detection, communications, and travel time measurements.

My experiment in 1987 showed that it was possible and also informed the design of my acoustic thermometry experiments seven years later in the Arctic Ocean. I was the first to use acoustic thermometry in the Arctic Ocean. (Note: I was among the first to test MFP over long ranges in the ocean, but for acoustic thermometry I was not the first “in the oceans” overall. Ocean acoustic tomography and thermometry was first proposed and published by Walter Munk, SIO, and Carl Wunsch, MIT, in 1979 with many experiments being conducted in the '80s and early '90s, before my work in the Arctic, 1994-1999). The 1994 acoustic thermometry experiment in the Arctic (and the subsequent 1998-99 experiment) proved that coherent processing was possible over the trans-Arctic ranges of  2,700 kilometers.

These acoustic experiments also detected warming in the Arctic Ocean that was later confirmed by submarine and ice breaker measurements. The 1994 experiment was one of the first measurements of warming in the Arctic Ocean and the first done with acoustics. As it turned out, they were prescient observations. The ensuing years and the now well-publicized warming and ice melting in the Arctic have proven the validity and value of such measurements. I proposed unsuccessfully for the installation of permanent acoustic monitoring in the Arctic back then. I have been a strong supporter for an in-situ ocean observing system for the Arctic with an acoustic component and I am one of the leaders of an effort called Arctic Watch that includes many like-minded scientists and engineers around the world.

Finally, where do you see technology going and what advancements lay ahead in oceanography?

Our vast ocean has been woefully under-sampled in space and time even to the present day. In the future for oceanography, as in many fields, I see autonomous systems playing a larger and larger role. Unmanned surface and sub-surface vehicles and floats large and small will be plying the oceans with advanced autonomy and a plethora of sensor suites for physical, chemical, and biological measurements that will be used for scientific, commercial, and national defense missions.

I also see technology advances for permanent ocean bottom deployed moorings, cables, and observatories in addition to the mobile sensor systems. The combination of these in-situ assets throughout the world’s oceans from the surface to the bottom will provide increased resolution in space and time with long term 24/7/365 observations, much like the satellites that today observe the Earth's surface and atmosphere. Below the surface of the ocean, acoustics will play a critical role. It is an exciting prospect and there is a tremendous amount of fascinating work that needs to be done and incredible discoveries that will be made. I wish I had another 45 years!