Understanding Modern Marine Electronics

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Lowrance’s “Little Green Box”

The speed of today’s electronics may present boaters with overwhelming amounts of data in the blink of an eye, but it’s more than processing power that lets these devices deliver. Here’s what makes the difference.

Hertz So Good

Nearly 60 years ago, a fishing enthusiast named Carl Lowrance designed a portable sonar unit, using the newly invented transistors instead of bulky, fragile, and expensive glass triode valves, and in 1959 he set up his own company to produce it. Lowrance’s Fish-Lo-K-Tor was rugged, reliable, portable, and cheap. At $150—equivalent to about $1,200 today, but less than a tenth of the price of some of its competitors at the time—it revolutionized small-boat electronics.

The latest generation of multifunction displays (MFDs) includes the equivalent of a billion transistors on each processor—a silicon “chip” the size of a postage stamp.

The mainstream manufacturers are all pretty cagey about exactly which processors they are using. “We’re utilizing a latest-generation multi-core mobile chipset, not unlike what is powering today’s highest-end tablets and smartphones,” is as far as Raymarine’s marketing manager Jim McGowan was prepared to go.

Carly Hysell, senior media relations specialist for Garmin, was a little more forthcoming. “Garmin mostly uses ARM processors in its marine product line-up,” Hysell told me, “ranging from single-core versions on the low end, up to dual core in the higher-end plotters.”

Simrad also uses ARM processors. Echoing McGowan’s words, Steve Thomas, product line director for Simrad, says, “They vary between individual products, but in general they’re similar to the ones used in tablets and smartphones like the iPhone 5.” (which has a dual-core ARMv7 processor running at 1.3 GHz.)

Compared with a typical entry-level desktop PC, which may well have a quad-core processor running at about 2 GHz—that doesn’t sound particularly impressive. “But the performance of tablet-type processors is more than adequate,” Thomas says. “And they are designed for rugged mobile applications at relatively low cost, which allows us to hit key price points. They are a good fit to our requirements.”

Raymarine’s McGowan used almost exactly the same words, explaining the manufacturers’ unanimous choice of ARM processors by saying, “They’re a fantastic fit in a marine multifunction display because they are extremely fast, rugged, and they feature low power consumption too. For most of the ‘traditional’ navigational functions they offer far and away more speed and power than is truly needed. This allows us to deliver products that are fast and responsive to users’ inputs, with lots of overhead room to allow us to grow the features and capabilities.”

“When you start with a powerful platform and ample memory, you have room to expand the product’s software capabilities far beyond what might be originally scoped,” McGowan says. “That’s certainly the case with our MFD line. We’ve added new features and capabilities that did not even exist when the product was first conceived. I’m very proud of the fact that someone who bought one of our original e7s back in 2011 can download the latest software (version 13) and it will run on their hardware with the same speed and responsiveness as a new unit purchased today in 2015.”

Garmin’s 7600 series multifunction displays

Clock Speeds, Cores, and RISC

A few years ago, savvy computer shoppers looked to the clock speed of their prospective purchases as a guide to their performance. The principle was that each instruction within a program requires a certain number of “ticks of the clock” to execute. So the faster the clock ticks, the faster the program will run. You could expect a PC with a clock speed of 3.2 GHz to perform a particular task twice as quickly as one with a clock speed of 1.6 GHz.

Almost all desktop and laptop PCs these days, and a growing number of smartphones and tablets, use multi-core processors. As the name suggests, a “dual-core” machine has two processors working together. So you might expect a 1 GHz dual-core machine to match the performance of a 2 GHz single core, while a quad-core 1 GHz processor would have double the performance of a 2 GHz single core.

In fact, it’s not as simple as that: a lot depends on the program or programs being run. But multi-core machines are particularly good at multitasking, and are generally faster than machines with the same clock speed but fewer cores.

Comparisons between desktop PCs and mobile devices (including most MFDs) are particularly unreliable, because most mobiles use processors that were designed and licensed by ARM (Advanced Risc Machines) to use Reduced Instruction Set Computing (RISC).

PCs usually use Complex Instruction Set Computing (CISC), in which each of the program’s instructions to the processor may take more than one “tick” of the clock to execute. RISC processing uses much simpler instructions, each of which can be executed in a single tick. Unfortunately, using simpler instructions means that a RISC processor needs more instructions to carry out a task than a CISC processor. Whether it is quicker to do “more, faster” (the RISC strategy) or do “fewer, slower” (the CISC strategy) is far from being a simple decision.

Just remember: Don’t use clock speed as a guide to processor performance.

Built-in Is Better

Simrad’s Steve Thomas highlights the fact that these modern processors have a built-in graphic unit, giving faster processing of graphics, along with bigger caches, faster memory access, and more peripheral functions. Tasks that would once have required additional circuitry are now built in, giving better performance while at the same time reducing production costs. “Seven years ago,” he reminded me, “a typical 7-inch MFD would have sold for about $1,500 to $1,800. Now, it’s more like $700 to $1,000.”

A good example of those peripheral functions is GPS. GPS has been a pretty obvious must-have in a navigation system for a long time now, but even ten years ago, GPS positioning was almost always achieved by connecting a separate external sensor. Today’s chipsets are designed with GPS positioning as an integral part of their architecture.

Along with the established navigation functions, such as charting, radar, and sonar—all of which would have required separate processors in stand-alone units at the turn of the century—boaters are now looking for functions that they would never have even considered as little as five years ago.

Bluetooth and Wi-Fi have become “must-haves,” along with support for AIS, thermal cameras, side-imaging sonar, integrated fuel- and electrical-management systems, engine monitoring, and autopilot controls. “Fifteen-plus years ago, it took individual processors in stand-alone units to process radar, fishfinder, and GPS data,” says Jeff Kauzlaric, advertising and communications manager for Furuno USA. “Today, those features and functions are all combined in an MFD with a common processor. In fact, we are able to include many advanced commercial workboat applications, that could only be handled with much larger systems, now in our recreational MFDs. This allows us to bring our commercial technology into our recreational products.”

Current technology is allowing us to process more data and to handle things like overlaying radar images on charts, while simultaneously processing data from multiple sonar transducers to produce side-view imaging.

Raymarine’s SL72RC—from 2002—put charting and radar on one grayscale display.

Fast and Happy

Undoubtedly though, the greatest improvement is in the user interface. Faster processors make for a product that is snappy and responsive. When you press a key or touch the screen, it responds immediately, and when you change chart scales, you don’t have to wait for your chart to appear. Five years ago, it could take up to 45 seconds to redraw a chart. Now, it’s a matter of seconds—not quite instantaneous, but fast enough that it looks that way for most procedures. Hand-in-hand with this goes the ability to drive larger, higher-resolution displays.

Gazing into a crystal ball to predict the future gives a far hazier picture of what lies ahead in the fast-moving world of electronics. For years, now, industry experts have been predicting that “Moore’s Law”—which suggests that processor power and screen resolutions will double every two years—must one day run out of steam. Certainly there must come a point at which it is physically impossible to make transistors any smaller. But the pace of change shows no sign of slowing yet. It may not be accelerating as fast as it was when the cofounder of Intel first proposed the “Law” which bears his name, but it is far from flatlining.

So what’s next? We’ll likely see display resolution continue to improve, and systems become more centralized as navigation, communications, entertainment, security, monitoring, and control technologies converge.

This article originally appeared in the May 2015 issue of Power & Motoryacht magazine.

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