We have received a fair amount of mail, with many in the general aviation community seeking information on ADS-B hardware. The question that comes up most often is the current state of ADS-B installations throughout the U.S.

With just seven years to go before the 2020 requirement for mandatory ADS-B equipment for aircraft flying in the busiest airspace, almost all of the more than 800 ADS-B antennas have been installed.

Figure 1 demonstrates how well, despite financial cutbacks, the folks at the FAA have done with keeping things as close to schedule as possible. The turquoise areas are ADS-B installations that are already installed. The yellow areas are the remaining locations that will be completed by the end of 2013.

You may find it interesting to know why the area that has the yellow circle was picked on Dec. 17, 2009, to be one of the first areas for ADS-B deployment.

Historically, the Gulf of Mexico has been a problem area when it comes to navigating aircraft. Because there was limited offshore radar coverage throughout the region, ATC could never actually see air traffic in this area. Add to that limited radio frequency transmission, which meant pilots flying in this area routinely had to relay their positions and messages to dispatchers on the mainland, who in turn relayed the messages to ATC. This increased the level of errors made in communicating and the time it took to get a message where it needed to be. These delays caused all kinds of problems when approaching weather conditions came in, allowing for little to no time for evacuating people from these petroleum platforms.

From a meteorology standpoint, this region is very active.

It is also home to more than 3,800 oil and natural gas platforms. Over the years, helicopter air traffic has increased to between 5,000 and 9,000 flights per day. Yes, I said per day.

A system was developed to navigate within this region by using a grid of squares. A series of 20 mile by 20 mile virtual squares was set up throughout the Gulf. Only one helicopter can be inside one of these squares at a time.

With ADS-B, all of this goes away. In the Gulf it was a walk in the park to install ADS-B antennas and transceivers on top of strategically located oil platforms. This provided a complete ADS-B system to pilots and ATC throughout the region.

Taking full advantage of these oil platforms, weather-sensing equipment also was installed on strategically located platforms, offering far superior weather reporting to aircraft flying in those areas.

ADS-B has eliminated the grid routing system. Now helicopter pilots in this region can fly direct to their destination with just in-time communications. To add even more benefits to this system, spacing between aircraft is reduced to five miles. The same thing holds true for the commercial guys. While in this area, spacing between aircraft will decrease from 120 miles down to the same five miles used by the choppers.

These services soon will be part of NextGen for pilots across the country. By 2020, any aircraft flying within controlled airspace will be required to have both ADS-B in and ADS-B out.

Worried about what that will cost you? In the past year manufacturers of GPS products, flight planning systems, audio systems, interface electronics, and communications are either delivering ADS-B products or are in the development stages. These products are being introduced with all kinds of options that can be fine-tuned for each and every airplane in GA, from a non-electric Aeronca Champ to Piper Navajos. The best part? The prices of these systems are already dropping like a rock.

In addition, we went even further, delivering an historical perspective of the entire National Airspace System. We believed it was necessary to remind each aviator that our way of life will always be in a state of change.

Even more important is that these changes are not linear by any means. In fact, they follow more of an exponential curve than anything else. The more we learn and the more we develop, the larger the level of technological growth over every year.

Will it end here? Not a chance in hell. So why do GA pilots need to wrap their arms around all of this? Answer: To adapt to these new systems and to practice our legal right to fly.

While researching these articles over the past 16 months, we have had the opportunity to meet other GA pilots, industry leaders, sales organizations and, yes, even some of the regulatory people who keep things legal. In doing so we discovered that the majority of general aviation pilots we sat with and interviewed had negative responses to NextGen for two primary reasons: Costs and the unwillingness to learn a new system.

We spearheaded the cost early on in the series, advising the entire GA community that the market would, in fact, drive new products supporting NextGen and that prices would decline over time. Plus, given the importance of NextGen, there would be plenty of educational material available to get everyone up to speed with the operation of ADS-B.

That was over a year ago and what do you know? In just one year makers of GPS products, flight planning systems, audio systems, interface electronics, and communications are now either delivering ADS-B products or are in the development stages. These products are being introduced with all kinds of options that can be fine-tuned for each and every airplane in GA. Price, form, power requirements and even antennas have all been engineered to be retrofit and operate in GA aircraft ranging from a non-electric Aeronca Champ to Piper Navajos. In fact, it seems that the entire GPS sector is now moving into ADS-B and NextGen almost as if we asked them to go there. Not sure we can take that kind of credit, but the fact remains, they’re here.

The job now is to research these products as they hit the marketplace to see exactly what each system can offer each GA pilot. A discovery process will take place reviewing these systems in an effort to detail each product’s capability including:

• Features and Benefits
• Ergonomics
• Form Factor and Size
• Readability
• Operation
• User Interface
• Installation (if any)
• Power Requirements
• Remote vs Wired
• Companion Products if required
• Graphics with Display Devices
• Brightness
• Portability
• ADS-B In or ADS-B In and Out
• True Battery Life compared to claims
• RF Sensitivity
• Certified or Non Certified
• And, the big one: Price.

We will also take suggestions from you, the reader, on any functions that you may want to be informed about. As an example, we have many people out there who have no electrical power in their aircraft. These people alone have a relatively large dynamic of requirements for what they would like in their particular aircraft. Being able to speak to so many people that live within GA will allow for a true understanding of what people were looking for.

Each product will first be bench tested in our labs for their operational characteristics. This is were all the measurements will take place, such as DC current demands, battery life, heat, harnesses, and RF measurements depending on each system.

From there we go to the air with two types of aircraft, our very own Aeronca Champ and our Rockwell AC 11. In-flight testing will bring up even more information on each product from both the practical and technical side of operations.

All the companies out there that are dibbling and dabbling with ADS-B for GA, please contact us and send your products in so we can “show your stuff.”

Does it stop there? No, we have just begun.

At this year’s SUN ’n FUN, slated for April 9-14, General Aviation News and Matchbox Aeronautical Systems will provide live courses on NextGen. I promise this will not be the typical boring presentation you would get from a PowerPoint, talking points event. This will be a presentation with fully animated slides teaching and explaining the entire system. We will follow the history as we did here in print and demonstrate how the system works globally. It will be very interactive and, for sure, lots of laughs. Of course, there will be time for open discussions and a Q&A at the end. We can also provide you first hand information on some of the systems we were able to sample.

So if you are going to SUN ’n FUN, make sure to check out SUN ’n FUN Today for the schedule.

This is the latest in a series of articles looking at the impact of the Next Generation Air Transportation System (NextGen) on GA pilots. All articles are archived on GeneralAviationNews.com. Go to Blogs, then NextGen to catch up on the series.

Compound that with the FAA’s Next Generation Air Transportation System (NextGen), which will also provide aircraft with a newer and even more improved Service Oriented Architecture (SOA). This will improve the interoperability of a host of services inside and outside the NAS, including more flexibility, an ability to respond quickly, and being more efficient to any changes within the system. All this will be provided to aviators by way of a program called System Wide Information Management (SWIM). SWIM has the power to reduce the information congestion inside each pilot’s head by allowing him to fine-tune what and when he needs information.

So what is SOA and why have we not talked about or used these services before?

In reality we have. The only difference is that it has been an antiquated system that is not very efficient. You have to compare all of the aviation services available as you would any ordinary service provider from the Internet.

Figure 1 shows a typical type of architecture that we are currently using. No rocket science here — you ask and you will receive. We use these Requests (Reks) and Acknowledgements (Acks) all day long in data communication and system management, which is where everything is going these days. The only catch here is that in our current system it isn’t that simple to implement.

There is a huge information resource that many GA pilots don’t even know exists. The services that we are aware of already improve safety, increase situational awareness, keep us ahead of the airplane and, at the end of the day, provide pilots with a far more enjoyable experience. This relates to both recreational flying or flying for work. With SWIM, everyone will have the opportunity to know all the information that is available, where it is located and how to access it. This will improve situation awareness far beyond our current level.

Take, for instance, a few common services that pilots use in any typical flight experience, such as ATIS, AWOS, FSS, TFRs, NOTAMs, weather, including Sigmets and Convection Sigmets, flight following, ATC instructions, traffic, IFR filing, and more. All of these services are requested and acted upon, but all in their own unique way.

The reason for this is that all of it has been added or modified over time. That’s not a bad thing — it is just the natural progression that takes place when services are added or subtracted over time. As things are created and come alive they are added, and as they lose effectiveness they are used less and die.

Due to the continuing growth of the aviation community, the time has come to start cleaning this up and implement a new system than can be modified on the fly while still maintaining its structure and efficiency throughout the NAS. A standardized interface is needed allowing all services to “speak a common language.”

Figure 2 drives this home with more detail. On the left side is our current system, which is more a point-to-point type of information system. Each service has it own point or “connection interface” and it gets routed throughout the system that way.

I love it when people in the know say things to me like “don’t worry, you’re in the system.” What system? This mess? You really have to give all those ATC and support people credit for successfully using these legacy systems.

However, where we are going is what you see on the right side of Figure 2. It’s basically a cloud-based system with just one connection to the Cloud. Almost all of it can come to you as text messages and not necessarily voice. This one feature alone will allow pilots to be able to check each instruction without having to make that ugly call back to ATC, “Say again?”

Since there is so much information available like flight management, air space status and weather, the need to know every single part of it can overwhelm a pilot. There is quite a bit of information a pilot may never really need for the particular type of flying being executed. With SWIM all of these services can be customized to what information you want and when you want it. You don’t have to accept everything, you only set it up to what you want.

Why is this such a big deal? Why, all of a sudden is this worth talking about? The answer is really simple. It is our friend, technology, and how it has such a huge influence on every part of our lives, including NextGen. With these new system designs we can adapt to all aviation changes as they occur, now and in the future.

This is the latest in a series of articles looking at the impact of the Next Generation Air Transportation System (NextGen) on GA pilots.

The last discussion on Traffic Information Service–Broadcast (TIS-B) was a clear example of how the FAA is trying to put together a Next Generation Air Transportation System (NextGen) program that all of us in general aviation can sink our teeth into. Flight Information Services-Broadcast (FIS-B) is no different. Again, it is offered to primarily general aviation airplanes that incorporate a Universal Access Transceiver (UAT) to operate under ADS-B.

So what is FIS-B? Flight Information Services-Broadcast will provide free weather to pilots, along with all the goodies that all of us use when planning most flights. I say “most” because I still see so many of my fly buddies go for weekend putts and never even consider any of these services.

This feature holds more power than many want to talk about. When we say free weather we mean the entire gamut of features and products that every pilot should be looking into. Many generalize these features down to meteorological and aeronautical information.

However there are some key attributes that are imported directly into the cockpit without even requesting them. It can be displayed either by a full color graphics overlay on your GPS display and/or written to the cockpit and displayed again on your cockpit display by way of text messaging. These text messages, in my opinion, are very powerful, if not only for the fact that at any time you can go back and review each report without having to contact ATC or FSS. This will just make cockpit management that much more efficient, not to mention increase safety. If you look at it from strictly a statistical viewpoint, more than 20% of the reported NTSB accidents are weather related.

Wow, sounds cool but wait, there is more:

• We will get routine weather blasts by way of text messages and/or displayed text for weather reporting at fixed intervals (METARs).
• Special Aviation Reports (SPECIs)
• Terminal Area Forecasts (TAFs), including amendments
• NEXRAD regional and CONUS participation maps (Doppler)
• Airmens Meteorological Conditions (AIRMET).
• Significant Meteorological Conditions (SIGMET), including Convective SIGMET
• Pilot Reports (PIREPS)
• Temporary Flight Restrictions (TFRs)
• Winds and Temperatures Aloft
• Status of Special Use Airspace (SUA)

Just imagine having all these tools at your fingertips any time you fly — how awesome is that! So the next question is “All these features are fine and good but what about their performance characteristics?” Let’s dive into this and see just what kind of job was done with this.

• All AIRMETs are updated when they are available and are transmitted every five minutes.
• Convective SIGMET are reported when they are available…then every 15 minutes for a full hour.
• METARs and SPECIs come in every minute and as available
• NEXRADs Reflectivity (CONUS and Regional) reports every five minutes or 10 minutes in Clear Mode
• All AIRMETs are updated when they are available and are transmitted every five minutes.
• METARs come in every minute and as available
• PIREPs and SUV comes in as they are available
• Winds Aloft every 12 hours
• SIGMETs as Available and then every 15 minutes
• TAFs comes in every eight hours

It is almost like calling FSS without the need to contact them.

FIS-B and TIS-B are considered by the FAA as “essential” services enhancing the situational awareness for each pilot. These are solely advisory services. Neither need to be certified and do not have published operating procedures.

Over the course of the last year or two these two features have been available on several ADS-B In products that output all this data on top of some moving map program “apps” for iPads. Although not certified and not UATs, this, again, shows how the market is adopting to these new technologies while at the same time keeping the pricing relatively low in comparison to what a full fledged ADS-B system can actually cost.

This means for all you guys with no electricity in your aircraft, you can run these things on batteries and fly safe. So all you pilots flying Aeronca, Cubs and the like out there, it pays to check this out.

Jeffrey Boccaccio is a private pilot and chief engineer at MatchBox Aeronautical Systems (Matchbox-Systems.com). You can reach him at NextGen@GeneralAviationNews.com or Jeff@Matchbox-Systems.com.

In my last post, ADS-B: Twice as nice, I spent a fair amount of time detailing the fact that there are two separate ADS-B systems in the U.S. — one for the big boys at 30,000-plus feet and another for the rest of us at 20,000 feet and lower having all the fun.

However, the FAA knew straight away that there was going to be an issue with GA in implementing ADS-B, due to costs, so agency officials started thinking of ways to bribe us into coming “on board” with ADS-B.

The FAA will offer two services that should be beneficial for all of us. One is TIS-B (Traffic Information Service–Broadcast) and the other is FIS-B (Flight Information Service–Broadcast). I doubt that any GA pilot would refuse either of these services, so it does seem that the FAA came up with a cool little offer to get all of us on board. That being said, there is still a ways to go before everyone out there goes for it, but it is at least a start.

All of the services having to do with ADS-B were split into two separated services or levels. Level one is “Critical” and it has to do with aircraft surveillance and separation, while level two is called “Essential,” which includes TIS-B and FIS-B.

So let’s take a closer look at TIS-B and see just what the FAA has in store for us.

TIS-B allows pilots using ADS-B to visually see any traffic, both in the air and on the ground, including support vehicles at airports. Using this service gives all ADS-B users a much better picture of the traffic in the area where they are flying.

But one very special point you need to know: TIS-B was never intended to be used as a collision avoidance system nor does it relieve pilots from being responsible toward other aircraft and vehicles. Each pilot must still practice the “see and avoid” method for safety. The bottom line here is that you cannot use TIS-B when there is no visual contact with other traffic.

TIS-B operates by way of the ADS-B ground-based communication system. This service is provided by our old standby, SSR (Secondary Surveillance Radar). Data coming from a non-ADS-B aircraft can enter the system by way of SSR, then be routed directly to the ADS-B ground-based data-linked system. From there it is sent out to all ADS-B aircraft and ground vehicles. This is all really cool, but will only work if the non-ADS-B aircraft is within the coverage of any SSR and Ground Base Transmitters (GBT).

In order for this to work, only conventional Mode C and Mode S transponders will respond. As always, barometric altitude is included in the transmitted data providing altitude, speed and heading for Non-ADS-B aircraft. Any aircraft that is still using Mode A or no transponders would be invisible to all ADS-B users.

Another very important point: Coverage for this service is limited to below 18,000 feet. The decision to restrict the altitude to 18,000 feet was primarily to reduce display clutter. Limiting the altitude reduced the amount of players within these Radar and GPT areas.

So this is good, right? Well, kind of since there are still so many GA airplanes out there that do not have any traffic warning systems. The only gotcha here is that we have to stay within the parameters of accuracy that only SSR currently provides. This means that the system refreshes only about every five to 12 seconds. That’s kind of slow compared to twice every second, which is what a full-blown ADS-B TIS (Traffic Information Service) currently provides.

There are still other factors that can cause errors and distort the results. There have been issues with a type of ghosting of aircraft while under this type of traffic avoidance process. In the early days it was found that ground vehicles on the airport surface would get false readings due to a multipath issue. This is caused when radio frequency (RF) signals reflect off buildings and planes and produce multiple RF signals that get received at different time intervals. This is currently under review to rectify this problem, however to make matters a little worse, this type of ghosting can also appear in your plane. Errors can occur when linking ADS-B devices to SSR devices. These problems may be minimized by some filtering techniques either by software, hardware, or both.

Next post we’ll focus on FIS-B, which offers more goodies for GA.

Jeffrey Boccaccio is a private pilot and chief engineer at MatchBox Aeronautical Systems. You can reach him at NextGen@GeneralAviationNews.com or Jeff@Matchbox-Systems.com.

Are two systems better than one? For Automatic Dependent Surveillance-Broadcast, the cornerstone of the Next Generation Air Transportation System (NextGen), the answer is yes and no.

Any time there are “fixes” put into a program, things very seldomly go smooth. But again that’s me using the experience I have had in newer technologies not only with aviation but with consumer electronics. When fixes are put in place, an avalanche of rules, procedures, and committees are added to the mix, taking up more space, more time and, of course, more money.

The dual system ADS-B we discussed last time is a perfect example of this. To recap: We have the big boys generally using 1090ES (Extended Squitter) ADS-B systems, while the general aviation guys use the more robust UAT (Universal Access Transceiver ) ADS-B system. On top of that is another system, called ADS-R for repeater, which sends out information every second so that those with UAT can see those with 1090 and vice versa. You also need to remember that UATs in the US max out at 18,000 feet. Got it?

You also need to know what is mandated by the FAA. By the year 2020, all aircraft flying in certain areas are required to have ADS-B Out. If you are going to be flying in Class A, B, or C airspace, you’ve got to have ADS-B Out. Additionally, any aircraft in E airspace above 10,000 feet and within a Mode C veil also must have ADS-B Out.

While it’s not mandated, ADS-B In is really a no brainer at this point. In fact most decent GPS receivers today, whether they be portables or panel-mounted devices, have the capability for ADS-B In, which means you can receive and take information in, such as weather, traffic avoidance, and all the rest of the goodies that come with TIS-B (Traffic Information Service-Broadcast) and FIS-B (Flight Information Service-Broadcast).

Between the two, the mandated ADS-B Out is the big monster because it has to send out information that is dead nuts (which means manufactured to very tight tolerances). You know, like CERTIFIED! Any time you add that swear word to the mix the price only goes up.

Let’s take a look at a typical GA installation for both systems that we may see in your airplane. We will use the illustration presented here.

Obviously there is a little bit more going on here than your normal everyday GA airplane. First notice that we still have the basics, which are transponders and altimeters. However we also will need a 980UAT ADS-B Out system, a GPS with WAAS, two additional antennas and, to make it all nice and pretty, some kind of display device.

We use two antennas to guarantee reception from both top (up) and bottom (down) of the aircraft. This allows for a much broader coverage in the traffic avoidance department. With TIS-B, all other traffic is linked directly to the cockpit by way of the ADS-B ground infrastructure. That information is combined with additional data from the Secondary Surveillance Radar system so that when using TIS-B, you will see all airplanes in the area, whether they are ADS-B equipped or not.

However, there is on gotcha here. To increase the efficiency of the system to prepare for the number of aircraft expected to be flying in the next 50 years, TIS-B is not on all the time. Yep, I said that right. The system is smart enough to only come on when needed. For a ground station to even start to transmit TIS-B data to an aircraft, two factors must come into play: The aircraft that has ADS-B Out must be transmitting both In and Out; plus there has to be other traffic somewhere in the vicinity of that aircraft. This means that if a non-ADS-B-equipped airplane is in an area and there is no ADS-B aircraft present, the system does not transmit that data. Hmmm, interesting.

If you look at the illustration a little closer and you will notice that the display is showing weather for this particular set up. This weather is by way of ADS-B In and it is free, no subscriptions needed.

It’s also important to know that FIS-B weather and other data is only broadcast where ground stations are located. It is transmitted all the time with no need to be “triggered” by another ADS-B aircraft and it only is received by UATs.

Next month we will dig deeper into these features and dig out of it more details that generally do not surface in most reports on NextGen.

See you then.

Jeffrey Boccaccio is a private pilot and chief engineer at MatchBox Aeronautical Systems. You can reach him at NextGen@GeneralAviationNews.com or Jeff@Matchbox-Systems.com.

Sounds like a sale doesn’t it? Well, not really. Instead, it’s a reference to the FAA’s decision as part of the Next Generation Air Transportation System (NextGen) to use two different “systems” within the ADS-B environment, so everyone on both sides of the aisle would be happy.

This is how it came down: The big boys on top, the transport carriers, have been using the newer Mode S 1090ES (Extended Squitter) transponder system that we discussed last month for some time know. Perfectly understandable since they have all the necessary attributes to work in the proposed ADS-B system environment.

But — don’t you just hate those buts? — the Mode S transponders have some limitations.

Mode A, C and S transponders all have the ability to be assigned airframe identities, while C and S systems also have altitude reporting as a feature. However, over time the number of aircraft, both commercial and GA, grew so fast there were tons of airplanes all over the place. Besides radar screens getting loaded up with N numbers, there were many “False Reply Uncorrelated in Time” (FRUIT) issues that popped up. Here, one plane’s transponder would interfere with another plane’s transponder, inducing “garbling.” This occurs when multiple interrogations being requested are all keyed at once. It is similar to what pilots dislike so much when they talk on their radios and someone steps on them with another transmission. Take that to the next level of 10 or 20 aircraft stepping on your interrogation response.

Mode S transponders offer the additional benefit of providing permanently programmed identifiers. Now ATC does not have to assign your airframe a unique squawk number, it already has one fixed inside the unit. To complement that, Mode S transponders have the ability to transport additional cockpit data information over the same system.

As we all know, ATC interrogates your transponder and reads the 4096 code that was assigned to your airplane. These interrogations are done with short 8 to 20 microsecond transmission pulses. This is transmitted to the transponder’s 1030 MHz frequency.

In Mode S transponders, the interrogations are transmitted by using a modulation scheme called Differential Phase Shift Keying (DPSK), designed to improve the efficiency of the interrogation frequency and reduce the FRUIT interference with Mode A and C systems. In addition Mode S offers the ability for up to 4 MB/s of data to be transferred back and forth which supports its data link.

In response to those interrogations, Mode S transponders send out a response verifying the requested information and signal integrity of the system using a Pulse Positioning Modulation (PPM) transmission system by way of the 1090 MHz frequency. The idea with Mode S is to reduce as much FRUIT garbage out there as possible, especially in high traffic areas. Mode S transponders are interrogated 50 times per second (50Hz) and Mode A and C are interrogated 230 times per second (230Hz). You can see how much more efficient it is just by minimizing the interrogated refresh rate.

Mode S transponders also include an “Extended Squitter” function not available on our typical GA Mode A and C transponders.

So what is all this squitter about? It is a form of “Unsolicited Replies” that the airplane’s transponder uses to help acquire and track other Mode S airframes. Now you have TCAS out there listening to all the squittering going on, which contains your airplane’s discrete address. This limits all the unnecessary transmission we had when the airwaves were loaded with interrogation requests, which reduces much of the FRUIT floating around. Remember, one of ADS-B’s big goals is to make things more efficient and this is just one tool that helps with this.

Well kind of, because this is when things went south.

That’s because while Mode S transponders have the ability to use DPSK data transmissions, the overall bandwidth of 1090ES is limited and does not provide all the goodies the FAA intended for GA.

Yeah, that’s right, here they are offering all these goodies, but didn’t have the 1090ES frequency band real estate to support it! Oh, that is just wonderful, isn’t it?

So here comes the band aid: The FAA added a dual link strategy by incorporating the system they used during the original ADS-B testing in Alaska called Universal Access Transceiver (UAT) in addition to the main 1090ES system. Now this puppy has BANDWIDTH, which allows the FAA to offer all kinds of goodies for the GA guys, including Traffic Information Services (TIS-B) and Flight Information Services (FIS-B).

The 1090ES system is not be able to incorporate FIS-B but, then again, it doesn’t really have to. Typically the big guys have all the top-end avionics in their cockpits already. I’m surprised they can’t make burgers while they fly too.

So at the end of the day, both 1090ES and UAT systems can utilize TIS-B for traffic avoidance.

But wait, doesn’t that create another problem? How does UAT tell 1090ES and how does 1090ES tell UAT where they are if they are on two different systems? If we have GA on UATs and the big guys on 1090ES, how the hell are the big guys going to know where the little guys are?

A new band-aid appears with the introduction of ADS-R, with the R standing for REPEATER. Yep, you got that right. All the traffic information from both the big guys and the small guys gets routed through ATC’s master networks so everyone knows where everyone is — and all this occurs in about 1 second.

But things aren’t as rosy as many would think. We will dig a little deeper next month.

Jeffrey Boccaccio is a private pilot and chief engineer at MatchBox Aeronautical Systems (Matchbox-Systems.com). You can reach him at NextGen@GeneralAviationNews.com or Jeff@Matchbox-Systems.com.

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ADS-B is the system that literally allows NextGen to become “The Next NextGen.” It stands for Automatic Dependent Surveillance–Broadcast. But what does that all mean?

Automatic: This basically means when this puppy goes live it stays live, operating on its own with no need for external interrogation or pilot involvement.

Dependent: Tracking and positioning is totally dependent on the ship’s own GPS and Nav system. No longer does radar have to track you.

Surveillance: Emulating “Big Brother,” this feature is like a big megaphone telling the world your airplane’s tail number, type, position (you can’t hide), emergency status, altitude, heading, velocity, and whether you brushed your teeth that morning. If you’re in the air, everyone knows!

Broadcast: All this data is transmitted all over the place. It gets transmitted to more than 700 ground stations, all airborne receivers, not to mention the uplink systems to the “birds in the sky.”

There is one important point I want to slam home on this: This puppy is accurate — I mean real accurate. We will discuss that later on, but my point here is that the quality of service ADS-B provides will give us far more and improved surveillance and situational awareness for pilots and ATC.

Although this sounds pretty straightforward, it has a whole lot more depth to it than just the name. ADS-B is a system. It is not something you just purchase over the counter, slap your credit card down, then sign and drive. It gets a little more involved than that when you consider the hardware, software, procedures, and operation that make it up.

It will be a transition by using current technologies, such as WAAS and transponders, along with our current radar system currently in use. So let’s start from there and gradually build into it, rather than everyone just jumping in and getting totally lost.

Primary Surveillance Radar (PSR)

Historically the surveillance system in the U.S. has been implemented by ground-based radar. Originally, after World War II, Primary Surveillance Radar (PSR) was implemented with radar transceivers that transmit an output pulse of RF energy. We technically refer to this as the “Goes Outa.” It goes out, gets reflected off any metallic objects like aircraft, and comes back into the transceiver as a “Goes Inta.” No, you won’t find those terms in Funk and Wagnalls dictionary, for sure!

The system knows what time the energy left the antenna and measures how long it takes to return. The further the object is, the more power and time it takes to “ping” the target. By using this method, radar can determine your airplane’s bearing and distance.

Nice idea, but this baby is a power-hungry tool proportional to its distance of reach. That means that PSR systems must put out an enormous amount of energy when reaching out for long-distance reflections up to 150 nm. Its reflected yield is relatively small and can ride pretty close to the noise floor of the radar system itself. Throw some interference in there and the system’s integrity goes right into the toilet.

You can see from the chart that the propagated radar waves diminish to the square of its distance. The return trip is no better and eventually goes into the dirt if the object is too far away. Later this was changed to 75 nm distances using less power.

One also has to consider its refresh time for each reflection. Radar surveillance systems can take as long as 12 seconds for a sweep or refresh to take place, unlike ADS-B’s refresh rate of twice per second.

In order to get aircraft positioning, ATC would have to ask planes to make turns to identify who was who. DME was eventually implemented, providing a distance position report along a known track, which made things a whole lot better.

 Secondary Surveillance Radar (SSR)

Then came Secondary Surveillance Radar (SSR), introducing a new device known as the “transponder.” First used in World War II as an Identification Friend or Foe (IFF), the transponder brought a whole new meaning to surveillance.

It was a Mode A transponder that was nothing more than a radio transmitter operating on the same frequency radar uses. Each aircraft is assigned a four-digit transponder code or “Squawk” number that the pilot sets upon ATC’s request. From there on, that Squawk number identifies the aircraft until radar is terminated.

Incidentally, the term Squawk originated back when using IFF. At the time they developed a code name for the transponder system called “Parrot.” When ATC wanted pilots to turn off their transponders, they would say “Strangle Your Parrot.” However, when instructed to Ident the transponder, it was “Squawk” your transponder. And, as I am sure everyone knows, Squawk is still used today.

Mode C introduced altitude reporting derived from on-board barometric pressure values typically taken right off the altimeter or an external sensor. This information then gets reported, as does the plane’s Squawk number.

The most recent transponder revision Mode S (Select) permanently assigns your transponder with an aircraft ID. Now ATC’s radar can spot these Mode S airplanes very easily, reducing garbling on SSR return reflections responses. In addition, the system was designed to upload specific data from ground-base stations to aircraft.

One of ADS-B’s key features is the ability to have a data link to and from ATC and other aircraft. Mode S transponders support this for ADS-B. In fact, as we go deeper into ADS-B, you will see how Mode S plays its role.

Next month we explain why there are two types of ADS-B — UAT (Universal Access Transceiver) and 1,090 MHz Mode S Extended Squitter or1090ES. What’s the deal here? You will see next month.

Jeffrey Boccaccio is a private pilot and chief engineer at MatchBox Aeronautical Systems. You can reach him at NextGen@GeneralAviationNews.com or Jeff@Matchbox-Systems.com.

What the heck is this all about? NextGen really not NextGen?

Over the course of the last 10 months we have reviewed quite a few navigation techniques that always brought something new to the table. It could be in hardware, procedures, rules, or even just seat of the pants know how. Each and every addition added improvements in safety, efficiency, or speed.

So were these previous developments considered NextGen? You bet they were. The point we have been trying to drive home is that the latest NextGen will not be nor will ever be the last NextGen. There will be others — and the younger people just getting their wings will no doubt see more changes to the National Airspace System (NAS).

So how did we adapt? How did we make these shifts and changes along the way?

It began with bonfires, evolving to lights and towers and more. We went from an archaic visual system to radio Nav with Four Course, ADFs, NDBs, VORs, and GPS with WAAS. Have we not adapted to these new systems? Were there not new rules as these systems came to life and expanded? Without a doubt, the answer to all these questions is yes and we did it because it made things better. Was there moaning and groaning? Yep, we call those growing pains.

So let’s look at some details and drill into the bowels of all this to see just what it means for general aviation.

Let’s start with the components of NextGen:

• ADS-B (Automatic Dependent Surveillance-Broadcast). This is the big enchilada. This one thing will bring all the goodies in.
• SWIM (System Wide Information Management). This just makes sure everyone knows what everyone else is doing.
• NNEW (NewGen Network Enabled Weather). Live Weather, a bone thrown into the mix of goodies. This is free!
• Next Gen Data Communications. Text messaging and data providing a historical prospective of communication data.
• NVS (NAS Voice Switch). New and improved voice switches.
• Approach and Procedures, including more smaller airports that could never have these benefits.

In addition to all this we will get:

• True traffic avoidance
• Terrain overviews
• Flight information by way of TIS-B and FIS-B
• NOTAMs and TFRs
• Improved ATC traffic flow management
• Better VFR Flight Following
• IFR separation even in non-radar airspace
• Flight tracking, including a faster and more accurate search and rescue response.

So what red flags come up with all this in GA? The big one is money. It will cost for these upgrades. Have we done it before? Sure we have, and there are ways to do it all over again.

When we talk money, we talk hardware and, whether you like it or not, the market has much to do in driving that, much as it did in another industry: Television.

Do you have a flat panel TV set yet? Are you watching high definition television yet? Don’t fool yourselves — all of you are. I know it because I was part of that expansion and I can tell you the FCC did a great job in getting this deployed with little to no pain. There was a bit of an inconvenience due to delays, but other than that it was smooth sailing.

If there were any remnants to this big change, it was with the participants, not the system. Those who didn’t care would be happy watching some game show in black and white on a round picture tube, but anyone who gave a hoot respected this NextGen in home entertainment and its technology. What do you think the big fear was at the very beginning? Here we go again: Money.

Again, when we talk money, we talk the market place. It was the market place that really drove HDTV and the same will happen to NextGen. More marketing leads to more interest, more interest leads to more sales, and more sales means more R&D. All of this brings prices down.

With that in mind, I decided to ask Rick Garcia, president of Gulf Coast Avionics (GCA), about this very issue.

Jeff: Rick, how does GCA judge new technologies like NextGen?

Rick: We put a tremendous effort in keeping up with new technologies. NextGen is the future for the NAS. We need these skills and resources in order for companies like GCA to be proactive with these new advancements.

Jeff: Will GCA sell both certified and non-certified ADS-B products?

Rick: Yes, we already are There is a need for both types of products due to the wide demographic within the general aviation sector, both from performance and cost.

Jeff: What comes first when deciding on products like ADS-B?

Rick: Performance and specification traditionally sets the bar first for its acceptance as a product in GCA, and then, of course, costs. We continually work at getting a wide assortment of products to fit every budget.

Come to think of it, how many of you GA pilots out there don’t have some kind of GPS? This includes all handheld units. Not many. Why? Because the market saw this coming and, in order to compete, these products hit us like bullets.

So as we dive into the latest NextGen system, let’s not think about the dollars and cents just yet. The verdict is still out on that, so we need to keep moving forward. Next month we will provide the backbone of ADS-B and take it from there. Stay tuned.

Jeffrey Boccaccio is a private pilot and chief engineer at MatchBox Aeronautical Systems. You can reach him at NextGen@GeneralAviationNews.com or Jeff@Matchbox-Systems.com.

People who read this article also read articles on airparks, airshow, airshows, avgas, aviation fuel, aviation news, aircraft owner, avionics, buy a plane, FAA, fly-in, flying, general aviation, learn to fly, pilots, Light-Sport Aircraft, LSA, and Sport Pilot.

First I would like to thank all the readers who have responded to the NextGen series. Feedback is always beneficial in providing a clearer understanding of each article’s content. It also allows us to modify and improve the content by way of specific requests and additional information from you, the reader. We thank you for that.

With that, we have received a fair amount of mail asking to provide more information on WAAS before we dive into ADS-B. WAAS is a more involved GPS system and does deserve more attention than just a mention since it will play a part with ADS-B and NextGen.

First let’s review a little bit on WAAS, which stands for Wide Area Augmentation System.

The WAAS GPS system is unlikely to easily integrate with legacy aircraft. Systems like this also cannot be installed with typical field approval procedures. They have to be installed by a certified facility and get an STC approval. These systems also require annunciators, whether internal to the WAAS system or as an external device. This all may sound way out of our typical GA pilot’s working environment, but by the time NextGen becomes real for the GA pilot, new and less expensive systems should be available. But for right now, these are the necessary building blocks towards the newer NextGen navigation system.

The third word in WAAS — augmentation — simply means that we are expanding or improving the accuracy of the system by determining ionosphere delays, clock drifts or ephemera (a satellite’s integrity and exact location data). This highly accurate GPS system was designed to function on its own, allowing aircraft the ability to perform all phases of flight, including precision approaches, by only using GPS. Accuracy with these new systems has improved from 20 meters down less than 2 meters.

There are three types of Augmented GPS Systems:

1. ABAS: Aircraft Based Augmentation System;
2. SBAS: Space Based Augmentation System;
3. GBAS: Ground Based Augmentation System.

The current GPS space-based systems do not provide the reliability and accuracy required for the next phase of navigation. With traffic expected to double by 2025, a far better system will be mandatory.

NextGen will incorporate the SBAS. The system is made up of:

• 31 GPS satellites with two additional stationary satellites for data correction retrieval;
• two geosynchronous stationary satellites;
• 38 perfectly located ground-based WAAS Reference Stations, which are used to provide perfect satellite correctional data. They will also be used to gather and processes pertinent GPS information that then gets routed directly to two master WAAS stations;
• Two WAAS Master Control Stations (WMS), which take in all the GPS information and sends it to WAAS GPS receivers in aircraft by way of two geosynchronous satellites (Satellites 135 and 138);
• Four discrete uplink stations, which transmit signal data up to Satellites 135 and 138;
• Two centers for operation and control, which process all the data received back from the reference stations.

GPS satellites that orbit around the North American continent send their own signal data down to 38 Wide Area Reference Stations on Earth. These stations are place in strategic locations so that errors within the GPS signal can be detected. This information is then transmitted by terrestrial transmission methods to two master stations in Washington, D.C., and Los Angeles.

These two stations are the main stations where all the WAAS augmentation messages are processed. At these stations all errors that were detected are removed, which substantially increases GPS location accuracy and reliability.

These new augmented messages are sent over the four uplink stations, where they are transmitted up to the two geosynchronous stations satellites. These satellites broadcast the augmented signal to your aircraft. The GPS WAAS receiver processes this data as part of the new estimated position.

Incorporating two WAAS GPS systems allows aircraft to fly LPV approaches. In the past, LNav and VNav were the only GPS type of approach procedures typically used. They do use GPS for lateral navigation, but there is no vertical guidance and will typically take the aircraft down to 400 feet. LNAV/VNAV offers lateral guidance from the GPS or WAAS but relies solely on vertical guidance from a barometric altimeter.

However, with Dual WAAS GPS systems, LPV can be used in a precision approach with just a GPS. LPV approaches can take an aircraft down to a 200- to 250-foot decision height. There are currently about 1,900 runways that support LPV approaches.

While many of us in GA do not have WAAS or Dual WAAS systems, this gives you a pretty good idea as to the expected performance of NextGen and ADS-B (Automatic Dependent Surveillance-Broadcast, which is the cornerstone of NextGen).

A special effort was put forth to keep the details of WAAS somewhat light and straightforward in this article, however it really needed to be brought to the table before we dive into ADS-B.

In some ways ADS-B will be easier to understand and use. Consider for a moment the fact that we are currently using 38 ground reference stations in WAAS, while in ADS-B there will be almost 800 sites scheduled to be deployed upon completion. They will be able to handle far more tasks in supporting ADS-B.

Jeffrey Boccaccio is a private pilot and chief engineer at MatchBox Aeronautical Systems. You can reach him at NextGen@GeneralAviationNews.com or Jeff@Matchbox-Systems.com.

People who read this article also read articles on airparks, airshow, airshows, avgas, aviation fuel, aviation news, aircraft owner, avionics, buy a plane, FAA, fly-in, flying, general aviation, learn to fly, pilots, Light-Sport Aircraft, LSA, and Sport Pilot.