Sonar pushes the limits
6/7/2021

Innovation in marine electronics, no matter what the device or software, tends to advance in stages with technological leaps followed by incremental refinements. Over the past several years sonar technology has been a star player, moving ahead with more revolution than evolution and driving healthy sales for many brands. Below is part 1 of a two-parter that checked into the trend for Marine Electronics Journal.

By Zuzana Prochazka

Converting electrical energy to sound energy and interpreting the results isn’t new. In fact, the first sonar was patented in 1913 by Germany’s Alexander Behm. But sonar has made some noteworthy advancements, especially recently. Today, we have CHIRP, multibeam and live sonar with videogame-quality graphics and an outlandish reach.

Some units are really more of a commercial system but demonstrate what sonar can be. Take Furuno’s Omni CSH8LMK2 8L for example. With over 420 transducer elements, this system looks 360 degrees around the boat at individual targets or schools of fish nearly a quarter mile away. Meanwhile, Garmin’s Panoptix LiveScope and the new Lowrance ActiveTarget Live deliver game-changing resolution for shallower waters with "live” sonar with real-time detail.

Multi-beam units are popular, such as Furuno’s DFF-3D deepwater sonar, which fuses its fishfinder and commercial phased-array technologies. Raymarine’s RVX1000 delivers CHIRP, down and side scanning and their RealVision3D which is beam stabilization. Humminbird’s Mega Series leans heavily on multitasking too, including dual-spectrum CHIRP, down and side imaging, and Bluetooth networking with Minn Kota trolling motors.

Let’s pause here to explain the difference between sonar and echo sounding. Echo sounding is a subset of sonar. Sounders generally work on higher frequencies with a narrow vertical beam while true sonar uses much more power and scans horizontally. "Although there are technical differences, it boils down to the term a specific customer set is used to hearing and saying,” says Jeremiah Clark of Navico. "In the recreational world, the difference is terminology.”

For our purposes we’re going to stick with the encompassing term, sonar. We’ll outline its three main components and how developments in each have driven massive improvements in the way that boaters fish, anchor and find their way into new areas that may be fraught with underwater hazards.

1) Transducers
A transducer converts energy from one form into another, and in the process tradeoffs have to be made. More power provides better reach and faster returns, but it can also generate clutter that needs to be filtered out during digital processing. Meanwhile, higher frequencies produce great detail but less range so they’re better for shallow-water applications. Most of the major electronics manufacturers use Airmar transducers, which are available in all flavors including CHIRP and broadband. However, a few companies rely on proprietary transducers for some product lines.
 
The physical design of transducers has changed. They’re smaller and more efficient. The Q-factor (basically the vibration or ringing) has improved, and less vibration equals a clearer image and enhanced target definition. Single-function transducers are nearly a thing of the past as multibeam units deliver across a wider spectrum. Simrad’s Active Imaging 3-in-1 works with DownScan, SideScan and CHIRP and can be paired with a broader range of fishfinder base units.

"We all used to have standalone systems, but the capabilities are integrating and the focus has been on the common transducer that can do it all,” says Jim McGowan of Raymarine. "The new transducers push more power as well as higher frequencies so there’s more reach, detail and resolution.”

Transducers have also become more affordable when you consider functionality per dollar spent. The key is to get the right one for the right application which is why the choice of transducer bears a long discussion before an install and includes an estimate for work on additional necessary peripheral equipment upgrades like cabling and power sources.

2) Processors
Signal processing is the slicing and dicing of the information that bounces back from the transducer. DSP, or digital signal processing, has become the secret sauce for sonar companies. "Great sonar requires great hardware,” says Clark. "But a very big part of the magic of great sonar is in the processing software that’s driving the hardware.”

Today’s fishfinders and sonar units are high-powered computers with lightning-fast processors that churn through the data in record speed. Of course, the amount of data that is provided by the transducer is only useful if it can be processed into accessible and useable information for the boater. DSP isn’t new but it has touched just about every industry where volumes of data are morphed into useful information. As Garmin’s Dave Dunn says, "All the wizardry happens in the processor.”

3) Displays
The interface screens used to be a sonar bottleneck. Some of the more interesting advancements weren’t possible early on because more sophisticated screen technology wasn’t available 10-15 years ago. However, improvements in the color palettes, refresh speeds and resolution have changed that. Higher resolution screens that are daylight viewable at most angles are key to any sonar and the bigger they are, the more boaters like them, even on small boats.

IPS (in-plane switching) was introduced a few years ago. Screens leverage liquid crystals aligned in parallel to produce rich, saturated colors and that changed what MFDs can do with cartography, video and sonar. "A few years ago, when we changed to IPS screens on our high-end [MFD] series, we heard comments about how much better the sonar was in our new units,” says Clark. "This particular MFD generation was using pretty much the same sonar hardware as the previous one, but a better screen made our sonar just seem better.”

Other advances in screen technology have focused on better heat dissipation and waterproofness. A hurdle to still overcome is the energy draw since the large screens can be power hogs.

Of course, today’s MFDs have had to contend with mission creep. They no longer just display cartography or sonar images. Instead, they’ve become engine monitoring systems, remotes for audio/visual equipment, and full communication devices. Screen technology may hit a point of diminishing returns in the future because most sonar units aren’t outputting 4K resolution—yet. For now though, it doesn’t seem to matter. "Most [units] are doing just great at the old 1080p HD or less,” adds Clark.

What’s driving advancements?

There are many types of sonar and each kind represents a different tool for finding fish or for operating a boat in general. Traditional sonar is still important, but with the advent of imaging sonars (side and down) and live sonars (where you can see your lure in the water), anglers have been given more to work with. "Customer demand keeps pushing all of us in the industry to find ways to help anglers find fish and to take the interpretation out of what they’re seeing on screen,” says Clark.  

Furuno uses focus groups to delve into what the market wants. "People are fishing multi-species,” says Furuno’s Wood. "They want clear live images and they also want to target individual animals 1,000 feet away.”

Next week: More on advancements, transducers-and what’s ahead.


About the author

Zuzana Prochazka is a freelance writer and photographer who contributes regularly to over a dozen sail and power boating magazines and web publications. A USCG 100-Ton Master, Zuzana has cruised, chartered and captained flotillas in many parts of the world and serves as an international presenter on charter destinations and technical topics. She is the Chair of the New Product Awards Committee for the National Marine Manufacturers Association, which judges innovative boats and gear, and Executive Director of Boating Writers International.



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