ActiveTarget: How Navico developed industry-leading live sonar Navico

We sat down with Navico’s Acoustic Transducer Design Engineer, Jayme Caspall, to find out about the game-changing technology behind Lowrance’s ActiveTarget live sonar and how it was developed throughout 2019-20, against all odds.

Could you tell us a little bit about the history of ActiveTarget?

The project behind ActiveTarget was born in 2019. Our objective was simple: to build the most advanced, highest resolution live imaging sonar on the market and help anglers catch more fish.

For those that may not know, could you explain (in Layman’s terms) how our sonar technology works?

The way a sonar formulates a picture of what is below your boat is essentially down to the correlation and timing of acoustic waves coming from the transducer, spreading out into the water and returning back to the transducer after bouncing off of the various objects in the water, including the lake bottom, submerged trees, rocks, and of course, fish.  The transducer is that part of the system that converts electrical signals to mechanical vibrations and, in a reciprocal fashion, converts mechanical vibrations into electrical signals.

For a single beam transducer, such as the sonar bullet in our Hook MFD range for Lowrance, the image is formed by mapping the received echo signal on the display, with the surface of the water at the top of the image and the bottom of the lake at the bottom of the image. A single ping produces a one time record of echoes that is mapped to one vertical slice of the image. The pings become vertical lines on the display, painting a picture of the scene beneath the boat as a continuous series of vertical lines that develops as the boat moves over the water.

​​​​Now, imagine we had a long board (say 100 meters long) with 200 Hook bullets attached to it spaced one half meter apart, we could ping them all at once and obtain an instant image of that 100 meter swath of lake. The point of this thought experiment (very doable in reality) is that we need data simultaneously from multiple beams to produce a “live” image. Simplistically, this is a bit like how the ActiveTarget transducer works. It is comprised of three arrays, each having 140 individual transducer elements, for a total of 420 elements.

Just how big a step forward is ActiveTarget in Lowrance’s sonar offering?

Within an array, you have a bunch of elements which produce unique signals that are sent from the boat that return at different times. The more elements you have in your array, the more detailed picture you will see. For ActiveTarget, we decided to start with superior physics compared to the competition. We have a total of 420 elements per transducer (132 more elements than the competition) so it gives a much more detailed picture.

 For sports fishing, does having the best sonar eclipse anything else?

I only recently got into fishing but for me the answer is “yes” – you absolutely need live imaging sonar! I recently went to a cattle farm and we fished in a large pond (about 3 acres).  I took an ActiveTarget along to test its effectiveness in this fishing scenario. We paddled out to the middle of the pond and hung it over the side of a little John boat. We instantly saw little fish swimming in schools. We cast the lure (crawfish crankbait) into a school. A fish only about twice the size of the lure chased the lure back to the boat and struck right in front of my eyes at the surface. The fish was too small to eat, but it was still fun catching it.

The fact that you can go into a situation, see where the fish are, cast in their direction and watch them chase the lure makes for some fun “video game fishing” as it has become known. The downside is that you can see practically all of the fish in the pond. If you don’t have any big fish in there, you will learn the awful truth. There were no big fish, only one big turtle.

How did COVID-19 impact the team’s work – did it make things harder?

COVID threatened us at nearly every step. We knew that ActiveTarget was a mission-critical project for Navico and that missing deadline was not an option. Personally, I hate to hear “It can’t be done,” – so we committed to completing at whatever cost. We lost personnel in the lab to the shutdown, leaving only one person, me, as “essential personnel” to handle the testing and fabrication requirements. We had planned to send our dicing machine to Ensenada for the design validation run, but the factory shut down at this critical time, so we had the dicing machine delivered to Tulsa and committed to performing it in the lab.

In order to facilitate the dicing procedure we had to develop a special interface plate for the dicing machine. After many delays, including machinists out due to COVID, it was clear that these necessary parts were not going to arrive in time. Rather than accept the patent answer, “Sorry, it can’t be done,” we ordered additional plates out of spec and hand worked them ourselves to achieve working fixtures.

​​​​For ‘the lapping process’ (normally done by machinery to achieve a certain flatness condition) we purchased materials and lapped them by hand. Pete Sandretto provided the physical force necessary to remove the bulk of the steel. We probably put about 20 hours of rubbing time on these stainless steel plates to get them into operating condition!

​​​​​​​The lockdowns all over the world meant that our partners couldn’t produce and deliver components on time, so we produced them in-house instead. The turn-around time was beyond our deadline, so we instantly went back to the drawing board and redesigned for speed of development. We were still in the validation phase, so we used our in-house 3D printers to produce components, which was a massive challenge!  We had people printing parts in Tulsa, Ensenada, and Auckland!

Now you’ve delivered on this major milestone, what’s next?

I was 100% on ActiveTarget for almost two years and it was great to have that focus. Now, things are shifting and there are new projects on the roadmap; new transducers; and applications for transducers. My goal is for us to be leading with the best ideas first.

It’s a constant battle with the competition as all parties are constantly raising the bar. It can be uncanny how ideas follow each other too. I relish the battle and never more so than when someone says “it can’t be done.” We need people in our group that don’t settle for that. Do the best you can with the tools you have – if you don’t try you’ll never know. We have that spirit. Give us a task!

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