ATM Modernization, Business & GA, Embedded Avionics, Military

Automatic Dependent Surveillance-Broadcast Decoded: A look at product solutions

By by Woodrow Bellamy and Chelsea Bryan | April 22, 2014
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One core airspace modernization technology, Automatic Dependent Surveillance-Broadcast (ADS-B), is a top priority in worldwide mandates with upgrade deadlines fast approaching for Europe and the United States. As a technology that will revolutionize routing, safety and position awareness, ADS-B will bring pilots pinpointed aircraft position in non-radar airspace, new flight plan options and re-routes that can save hundreds of miles and fuel costs, lower aircraft separation distances, free traffic and weather info on cockpit displays and, for the first time, direct awareness of the location of other aircraft in the vicinity.

Australia was first to leverage the powers of ADS-B at large as the Civil Aviation Safety Authority (CASA) launched a full nationwide ADS-B network in December 2013, concurrent with a mandate that all Instrument Flight Rule (IFR) aircraft flying at or above 29,000 feet fly ADS-B equipped. Lower altitude mandates are planned for dates in Australia through 2017. Meanwhile in Europe, the mandate is divided into two parts: first for new forward-fit aircraft, beginning in January 2015, and then for existing aircraft that need a retrofit ADS-B upgrade, required by Dec. 7, 2017, though according to Jens Hennig, vice president of operations at the General Aviation Manufacturers Association (GAMA), 18-month delays put forth by the European Commission may go into effect.

In all other global mandates, besides the FAA’s ADS-B mandate effective Jan. 1, 2020 for all aircraft flying in Class A, B, C and E airspace, aircraft position must be broadcast on 1090 MHz frequency using a Mode S Transponder with Extended Squitter (1090 ES). That means any U.S.-based operator planning to leave domestic airspace will need the 1090 ES — but for GA, the alternative frequency Universal Access Transponder (UAT) remains popular, as it comes with free weather and traffic updates.

NavWorx & the ‘Texas Two-Step’

In view of keeping the cost of compliance down for older aircraft, NavWorx provides several upgrade paths that include getting a certified GPS — also part of the U.S. mandate — in any given aircraft. They call their solution the Texas Two Step. The main footwork involved is that NavWorx’s ADS600-B GPS (the cheaper of two solutions) comes with the option to upgrade to a certified GPS anytime before 2020. This is because, while the GPS in the ADS600-B is not certified for the GPS part of the mandate, NavWorx’s President Bob Moffitt points out that “You can install whatever [GPS] … into the airplane now” and he will upgrade your box to the certified standard by 2020. The advantage of delaying that second step is that it will be half the cost after 2016. To help the budget-conscious further along, aircraft owners can also get a fully compliant GPS and transponder up front from NavWorx with the ADS600-BG; it just costs more.

Aspen Avionics’ ‘Four Scenarios’

Aspen Avionics has four products for what it sees as the four scenarios in which aircraft owners might find themselves. Like NavWorx, all four are UAT only. In the first scenario are aircraft that already have a certified transponder and mandate-compliant GPS; the second is for those who don’t have a Mode S 1090ES transponder, but do have a certified GPS; the third involves those who don’t have either requirement; and the fourth includes those flying with experimental and uncertified equipment.

If you fit into the first scenario, your certified transponder and GPS mean you’re already NextGen ADS-B Out compliant, yet you still don’t have the much talked-about ADS-B In benefits: traffic and weather. This is where the ARX100 can help; it’s a UAT that receives traffic and weather on 1090 and 980 MHz — but it doesn’t do Out and it has no GPS built-in. It’s strictly for those who are already compliant but now want to know where other aircraft are in their vicinity and what the weather is going to be.

“You’d be surprised, a lot of the higher-end aircraft, the old Beechcraft crowd, they fit very strongly into category one [ADS-B Out compliant],” says George Pariza, director of product marketing at Aspen Avionics.

In Aspen’s second scenario, those who have already met half of the mandate with a certified GPS get the ATX200, which just includes a compliant transponder. The ATX200 also acts as a receiver to provide the traffic and weather of ADS-B In, in addition to broadcasting ADS-B Out.

The ATX200G — “G” is for GPS — takes care of aircraft that have neither the GPS that meets the 2020 mandate or the ability to broadcast out. This solution is likely to be a good fit for an older Moonie, Beechcraft or experimental aircraft that needs to be fully up-to-date and where pilots also want traffic and weather info via bonus In. The price tag is higher, but Pariza says it costs half of the price of a NavCom WAAS GPS.

Trig Avionics

Trig Avionics CEO Andy Davis has likewise tapped into the non-certified In market, with bases in Edinburgh and Wichita to ensure fast and available maintenance for the international GA community, whether in the U.S or the U.K.

Unlike NavWorx or Aspen, however, Trig sells the Mode S 1090 ES transponder, yet Davis is not shying away from the U.S. at all. Instead, says Davis, Trig outfits American operators with ADS-B Out, primarily on piston twins and singles, and then leaves the In to what Davis calls “cheap and happy” uncertified solutions. But the chief draw of Trig transponders, says Davis, is that getting ADS-B Out is actually sort of free: operators who already have a Trig transponder, Davis explains, can get it updated to broadcast certified ADS-B Out for no cost. This does require operators already have a certified GPS, however.

He hopes Trig’s lower prices will draw customers who like their transponders. Davis is also very honest and up front about costs. “It’s not necessarily free to the customer because, to get the full features, they’ll then have to add, potentially, some wiring to the airframe … but the total cost [of installation] to the customer is small.”

As for the weather and traffic draw, Davis feels that the non-certified In route is obvious. Since ADS-B In doesn’t have to be certified, he figures Trig can just focus on providing one of the best ADS-B Out situations and leave traffic and weather to an affordable order put in elsewhere.

Davis argues that UAT “is a market that we’re less convinced about because, even within the U.S., there are restrictions,” he says, referring to travel to the Bahamas from Florida, to the Caribbean, or offshore from continental U.S. spots. Davis just doesn’t think GA should have to keep out of the rest of the Americas, in addition.

“We actually think that a significant proportion of our light GA aircraft will, even the below 18,000 feet crowd, still use 1090 [MHz] Out as their ADS-B solution, because we believe that it is more cost-effective for them to do it that way and allows them more flexibility of where they can operate,” says Davis.

FreeFlight Systems

FreeFlight Systems is perhaps the most experienced ADS-B provider, having already supplied 600 aircraft owners and avionics shops with ADS-B in Alaska under the Capstone upgrade program. As a result, FreeFlight has produced a set of real-world reference data on ADS-B installations and pilot experiences. The Capstone program was set up by the FAA in Alaska to fulfill the agency’s commitment to aircraft owners and pilots who installed the Version 1 ADS-B avionics during the initial launch of the program in 2001.

The FAA funded the installations in exchange for feedback from the pilots, as the program originally was designed to improve the harsh flying environment in Alaska where many areas are beyond radar coverage. After working with avionics shops, pilots and owners to install the Version 2 ADS-B avionics, FreeFlight concluded that there are two types of aircraft and associated owners. First, there are those with newer avionics existing on an integrated flight deck that prefer to keep their setup integrated. Then there are the owners of legacy aircraft who primarily just want to comply with the mandate based on the airspace that they fly in, with a minimally invasive solution.

FreeFlight also gathered data on avionics shops, which it found are focused on providing inexpensive and low-risk ADS-B installations. Man-hours needed per aircraft, the necessary cabling, connectors and antennae, the panel or airframe space needed, the overall fit and finish, and the sign-off on the installations are all factors that shops also consider when deciding which products to offer.

After all that research, FreeFlight offers the Rangr family of products that operate at 978 MHz, including the TSO’d RANGR 978 available with Out only transmitters as well as the XVR Transceiver configuration with In and Out capabilities. The Rangr RX-P25 GPS is designed for Part 25 operators, integrating a certified 15-channel WAAS/GPS ADS-B Out position source and a FIS-B ADS-B weather data receiver.

“Our GPSs don’t require that complete Flight Management Sytem (FMS), and those are very, very expensive,” says Jessica Power, director of sales and marketing at FreeFlight. “Our Rangr 978 product line offers customers a low cost ADS-B solution that is fully integrated into one box. Not only does that help reduce cost and installation time, but also reduces the amount of weight that you need to add to the aircraft.”


Bill Stone, aviation product manager at Garmin, compares the cost barrier situation in upgrading to ADS-B for some owners to the situation in the 1970s, when the FAA required aircraft to equip with a Mode T transponder, an expensive product at the time. “The pushback on price is nothing new,” said Stone. “In 1975 dollars, that was a highly expensive piece of equipment. But we lived through that, right? And the system got better because of it, and I think we’re looking at a similar situation.”

The easiest path to compliance for the U.S. mandate with Garmin, according to Stone, is the GDL 88, which can be configured with a WAAS GPS and operates with a Dual-link UAT. It can also provide ADS-B In information when paired with a compatible display or with Garmin’s GDL 39 ADS-B receiver which, while not certified, can receive ADS-B In weather and traffic information for display on portable smartphones or tablets.

The only downside? Garmin’s products are on the expensive side. Even though Garmin is not the affordable option, that “pushback on price” is tempered by the brand’s popularity. Bill Moffitt of NavWorx, a competitor of Garmin, admits his GPS is a Garmin — and that he wouldn’t have it any other way. Moffitt just wishes Garmin would make the whole ADS-B process more affordable for GA pilots by publishing the interface allowing providers like NavWorx to connect Garmin’s GPS signal feed into other UAT products.

“If a customer comes in with a Cessna 177 with a Garmin 430 or 430W today I’m going to say, ‘Well, unfortunately I can’t use your GPS Out signal,’ … I would sell him an ADS600-B certified transceiver and, [if Garmin publishes the GPS interface], we would merely write free software updates to connect over to that 430W and that would meet the second mandate of being GPS certified for 2020.”

Garmin’s release of that secret interface is not likely, however. But that won’t stop Moffitt and others from hoping.

Equip Now or Later?

In addition to costing far less for the FAA to operate from ground stations in comparison to radar coverage, ADS-B info about aircraft position is also broadcast a lot faster, updated once per second, compared to the 12-second sweep of a radar antenna. According to Hennig of GAMA, aircraft owners need to plan their upgrade now or else risk being denied access to airspace come 2020.

“We’re getting close to that time horizon where an operator knows their plan [for their aircraft over the next few years]. Four or five years ago we were in a [economic] position where, if you own an aircraft, you may not have known if you were going to own it by the end of the decade,” Hennig says. But now, he adds, fleet operators, air carriers and also the GA pilot are in a position to start looking at their aircraft and, as ADS-B’s 2020 mandate approaches, plan for their aircraft to continue flying.

Chelsea Bryan is the junior editor for Avionics Magazine.

Woodrow Bellamy is the community editor for Avionics Magazine.

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