Product Focus: Mil-Std-1553

It’s been about 18 months since the introduction of a new standard for high-bandwidth data bus networking based on Mil-Std-1553 technology. How it’s gone since then for what’s become known as "Extended" 1553 depends on whether you played a role in defining the standard.

At the moment, the development of E1553 is primarily a club of two: the U.S. Air Force and Edgewater Computer Systems of Ottawa, Ontario, which worked together to develop the standard.

"The military has found that the existing wire is not adequate," said Louis Berube, executive vice president of Edgewater. "For example, to get good resolution from a video sensor in a weapon and display it to a pilot in the cockpit you need to transmit at well over 1 Mbps. And there are more and more applications that need to communicate at the same time over the wire, which puts pressure on network capacity."

The military addressed the shortfall in April 2006 when it released Mil-Std-1553B Notice 5, calling for communications at 200 Mbps over a 300-foot bus. A clarification, Notice 6, was released this year, but did not affect the speed requirement.

Edgewater’s E1553 databus technology allows wideband data to be carried over existing aircraft 1553 wiring and bus components without interruption or interference of other systems by maintaining the deterministic command-response nature of the legacy system. Since E1553 meets the USAF’s basic data-rate acceptability criteria, while maintaining reliable operation and interoperability with 1553B terminals and cable assemblies, it enables the creation of a separate network on the existing 1553 wiring infrastructure.

"It will give the military a way to provide their legacy equipment with modern capabilities," said Berube. "It is a huge opportunity for cost avoidance and in getting legacy platforms integrated into some of the more forward-looking strategic pictures involving multiple platforms, particularly in the C4ISR arena."

In July, the technology was flight tested in a 20-year-old Block 30 F-16 at the Air National Guard Air Force Reserve Command Test Center, in Tucson, Ariz. The F-16 performed typical mission flight and aircraft maneuvers, including multiple target tracking with radar and sensor systems and high-G turns. Two flight-certified line replaceable units were equipped with E1553 network interface cards — a programmable display generator and a commercial central interface unit, both provided by Edgewater.

During the test, E1553 operated concurrently with the legacy 1553 bus. According to Berube, there was no interference or impact to the legacy 1553 operations before, during or after the flight test, while high-speed video traffic was communicated bi-directionally across the E1553 network.

Another goal of the test was to build momentum for high-bandwidth data bus networking within the community of manufacturers that build 1553 hardware. That’s because much of the industry is still taking a wait-and-see approach.

Industry wide acceptance of E1553 hasn’t been helped by the fact that all of the world’s most advanced fourth- and fifth-generation fighters — F-35, F-22, Gripen and Eurofighter — were designed and are being fielded with alternate technologies like Ethernet and fiber channel, not because E1553 wasn’t worthy but because those aircraft were developed long before E1553 became a reality.

"High-speed 1553 is not necessarily a disruptive technology, but is an inflection point," said Michael Hegarty, Data Device Corp. (DDC) marketing manager. He defined "disruptive" as something that changes everything that came before, using digital camera film as an example.

"Extended 1553 started three to four years ago and we wanted to be a part of where that was going. It was not developed in the public domain, though. The Air Force hired Edgewater to develop the technology for them. Last year, they released to the world what they were thinking about. But rather than wait for the standard to be released we went down our own path.

"What we came up with was not necessarily compatible with Extended 1553; we went in a parallel path," Hegarty said. "We will have to modify our implementation to be compliant with it. We’re in a position to do that, but whether we will is another matter."

DDC, based in Bohemia, N.Y., calls its high-bandwidth data bus networking solution "HyPer" 1553, which it believes to be a less risky approach that builds transmission speed incrementally 50 Mbps at a time rather than an E1553 that starts at 200 Mbps and is envisioned to reach 500 Mbps.

"The reality is that you’re dealing with a very noisy environment and real world constraints," said Hegarty. "What can you do realistically? We started with 50 Mbps, got that to work reliably and then bumped it up to the next level. We wanted to deliver reliable 50 Mbps rather than promise 500."

Hegarty says that DDC has one big problem with Edgewater’s E1553 — it’s a proprietary standard. "The world is moving to COTS (commercial off-the-shelf) open standards, industry consensus standards," he said. "With this we’re moving back to the old model of developing a proprietary solution, putting it out and expecting people to use it."

And it’s not just individual companies that are bothered by the lack of transparency in the development of E1553. Traditional standards making bodies feel left out, too. "We haven’t accepted it very well because the government went about developing the standard without SAE," said George Sponsler, chairman of SAE’s AS-1A Avionics Network Subcommittee. "We’ve always been the caretakers of 1553."

Regardless of whether SAE was involved in E1553 or not, Sponsler believes it is only a "band aid" solution for aging aircraft. "I think fiber channel will eventually be the winner because it is cost effective and will only go faster," he said.

Dissatisfaction over the way E1553 was developed coupled with strong competition from alternatives like fiber channel and Ethernet has, however, left manufacturers in a quandary about which direction they should go.

"All you can do is latch onto the coattails of a big program and hope that’s the trend that others will follow," said Sponsler, vice president of Excalibur Systems, Elmont, N.Y. "COTS initiatives allow companies to do anything that makes sense. But a winner always comes out at some point in time and if you go the wrong way you can be out of business."

Traditional 1553

Hegarty described the market for traditional 1553 as a "healthy, flat business" that’s already seen its best days. "We don’t see it declining any time soon because the 1553 wiring infrastructure is the core network in all major fighters, transports and helicopters," he said. "The military is not changing the core avionics architecture, so the market for 1553 products won’t change."

As such, improvements will continue to be made to traditional 1 Mbps 1553 products. DDC, for example, is developing plastic encapsulated chips that provide almost as much protection against moisture as do hermetically sealed ceramic encased chips. New manufacturing techniques and materials also let them operate through an extended temperature range.

National Hybrid Inc. (NHi), based in Ronkonkoma, N.Y., in April introduced a new, low-cost integrated terminal as part of its PBGA (Plastic Ball Grid Array) family of Mil-Std-1553 products. Measuring 0.75 by 0.75 inches, the multi-protocol 1553/1760 data bus interface is the smallest terminal available and addresses the problem of solder shorts between balls by providing oversized solder balls with "a generous pitch" to maximize mechanical/electrical integrity, NHi says.

"I see miniaturization taking place, and I see coming out with smaller products offering more reliability," said Roy Nardin, NHi director of engineering. "… Other (products) we’ll be coming out with are miniature transceivers in 7mm packages."

The standalone, miniature transceivers are an option for avionics developers who want to use either a third-party or their own 1553 intellectual property (IP) core in a Field Programmable Gate Array (FPGA) with an external transceiver and random access memory. NHi can supply the full 1553 terminal, with protocol chip, transceivers and memory, or components as required.

"What we’re doing is we’re supporting the total 1553 market that way," Nardin said. "If somebody wants an integrated device, fine, the smallest thing available — we’ve got it. If they have an application where they want to use their IP, fine, we’ll give them the best transceiver that works for their application."

Ballard Technology, Everett, Wash., is taking orders for its "AB2000" series box, a ruggedized superset of its Avionics BusBox multi-protocol data converter, with production deliveries starting next spring. The compact, 7.5 X 5.25 X 2.5-inch AB2000 series has built-in interfaces for 1553 and ARINC data buses as well as Ethernet, USB, serial, discrete I/O (input/output) connections and an expansion PMC interface.

As a protocol converter or a standalone controller, the AB2000 series facilitates integration of commercial and military avionics, acting, for example, as a 1553 monitor and an ARINC 429 transmitter. The Ethernet port can be used as an Ethernet-to-avionics bridge, an avionics data server or a remote monitoring interface. Aircraft data can be recorded on a CompactFlash disk for maintenance uses and downloaded over USB.

"Our goal is to bring COTS back to where you once envisioned — to have these conduction cooled DO-160 tested AB2000 boxes deliverable in a 4-to-6-week period, configured with these I/O options," said Bill Schuh, Ballard Technology vice president of sales and marketing. "And of course, there’s a PowerPC system onboard to support the user’s applications."

Among other product developments:

GE Fanuc, Charlottesville, Va., says its EPMC-1553 is the first PCI Mezzanine Card module to offer up to 8 dual redundant Mil-Std-1553B Notice II channels. The EPMC-1553 is available in commercial, ruggedized and conductively cooled versions with one, two, four or eight dual-redundant channels, and includes advanced API (Application Programming Interface) software that reduces application development time.
Excalibur Systems introduced the 1553 ccPMC card, a multifunction, conduction-cooled PMC card supporting up to four redundant 1553 channels; and the EXC-1553PCMCIA/Px, a credit-card sized interface supporting up to two dual redundant 1553 channels, applicable for system simulation.
Holt Integrated Circuits, Mission Viejo, Calif., in October introduced the HI-611ORTC dual redundant Mil-Std-1553 Remote Terminal (RT) demonstrator board. "The HI-6110RTC Remote Terminal Demonstrator Board illustrates how Holt’s monolithic CMOS message processor — HI-6110 — can be used to design a complete remote terminal application, requiring minimal external host overhead," said Anthony Murray, director of business development.

NHi’s Nardin believes the rumored decline of 1553 is greatly exaggerated.

"I think 1553 is going to be around for many, many years," he said. "They’ve been reporting the demise of 1553 probably for the last 20 years. It’s been dead, and then it comes back. The reason is because 1553 was designed for command and control, for high reliability working in noisy environments. It has to work that way because you’re controlling flight surfaces, you’re controlling weapons, you’re controlling navigation, all the radars and things like that…. For what 1553 is meant for, it’s the absolute best."

The traditional role 1553 technology plays in weapons delivery will remain strong, even with the latest fighters. For example, the F-35’s fiber channel network will be complemented by the usual 1553 technology for weapons delivery. The Mil-Std-1760 communications bus being developed for smart bombs includes 1553 in its signal set.

"There’s a lot of legacy 1553 business going on, especially as the (Iraq) war drags on and planes and helicopters see more time on wing," said Anthony Jordan, Aeroflex Colorado Springs director of standard products. "We are seeing steady 1553 business to the point where we’re investing in a new, 3-volt transceiver.

"We’ve also completed development of a 1553 IP that can be implemented in Field Programmable Gate Arrays and applications specific integrated circuits. And we continue to see high-volume 1553 applications in munitions systems."

Excalibur is doing likewise in the area of IP and embedding processors in gate arrays. Said Sponsler: "We’ve just finished our own IP and it lets you get a much higher density. This helps to stave off obsolescence and keeps the price low."

Future Challenges

It does seem likely, however, that Extended 1553 or HyPer 1553 or some other form of high-bandwidth data bus will be part of the future. But there are challenges in developing such products.

"In terms of making it better, we need to reduce the form factor and get more capability in the same box," Berube said. "We need to increase performance because that need will always go up. There will always be the desire to do more over the same wire. We also want support for multiple channels and support for continuous wire diagnostics."

A possibly even greater challenge has nothing to do with the high-speed 1553 technology in itself, but in the way other avionics manufacturers will react to the technology.

"When you implement high-data bandwidth communications on air platforms you also impact how other systems are designed," Berube said. "Nowadays, if you need to get data from one area of the aircraft to another, the data goes through the mission computer. That takes processing power. If you start to ramp up the amount of data that needs to be transferred you’re loading down the mission computer and creating a bottleneck.

"So you don’t want to use the mission computer. You want to use switches and routers instead. That will create a paradigm shift in that the systems integrators need to be persuaded that it is acceptable to have data communications and processes that don’t involve the mission computer.

"Any change will produce some reluctance. Taking some control out of the systems integrator’s hands can be perceived as a threat, but it can also be viewed as a significant business opportunity by developing a new community of people that operates off your platform."

Market Moves

Following are some recent developments announced by companies in the Mil-Std-1553 field.

A new company, Alta Data Technologies, of Rio Rancho, N.M., was started by former senior managers and engineers of Condor Engineering, SBS Technologies (now GE Fanuc) and DDC.
The principals are CEO Rick Schuh, former Aerospace Group president of SBS and Condor/GE; COO Rich Wade, former general manager of SBS; Chief Technology Officer Jake Haddock, former senior design engineer for SBS/Condor; and Vice President of Sales Harry Wild, former regional manager for Condor/DDC.
Alta Data’s first product line supports multi-channel 1553 with a new 32-bit based protocol engine called "AltaCore." The company also claims new functionality with an advanced 20 nsec signal generator, which enables full SAE AS4111 RT Protocol testing — the first COTS product to fully implement this level of protocol validation with standard tools, Alta Data says.
Future product plans include high-speed 1553 and a full ARINC 429 product line. IP cores are sold on a limited, program basis.
"Our company goal is to provide a technology refresh with excellent technical support for the avionics market," said Schuh. "Most current designs are old, 16-bit based designs with 10-year-old architectures. By starting fresh with the latest development tools, we’ve been able to provide some exciting new features and a whole new level of quality and testing capability."
A new corporate entity, GE Fanuc Intelligent Platforms, was established, combining GE Fanuc Embedded Systems, GE Fanuc Automation and CNC. "We are giving formal recognition to our new technology environment," Maryrose T. Sylvester, Intelligent Platforms president and CEO, wrote to customers. "We are also encouraging employees to foster cross-pollination of technology between different parts of the company to give you more options for the future."
Ballard Technology in late October moved its headquarters to a new location at 11400 Airport Road, Everett, Wash. The new location is a three-story glassed building with 11,000 square feet of space, nearly twice the size of Ballard’s former facility.
"We had just simply outgrown our facilities in downtown Everett," said Bill Schuh, vice president of sales and marketing. "The company is staging for more growth. This year has been a banner year. It’s been just phenomenal." — Bill Carey