Portable ADS-B out for renters for under $3300

J

Jim Logajan

En-Route
Joined
Jun 6, 2008
Messages
4,024
Display Name
Display name:
.
Looks like Skyvision Xtreme has packaged up a NavWorx ADS600-B ADS-B transceiver to produce a portable box (briefcase really) with not only ADS-B In, but Out as well for $3295 (price is mentioned by company principal Harry Sanders in an AVweb podcast.) The Out (transmitter) is needed to increase the utility of the traffic alerting aspect. Acts as a Wifi access point, allowing it to be used with tablets like the iPad. Pricey, but less than the $10k I once read was the likely price for such a thing. Would be nice to see the transceiver prices fall under $1500 someday....
 
Interesting. Why is there so damn much competition in ADS-B but virtually none in approach-certified GPS? Grrr.
 
As a fellow renter, I have thought about ADS-B as well.

For ADS-B out, I assumed that most FBOs would be upgrading their aircraft to be compliant, thus only giving at most a 7-year span of time when you would need to have your own tranceiver.

IMHO, it still seems like a good bit of cash for something that may very well be a duplicate of required equipment in 7 years (or sooner)...



- Jon
 
I think I will wait for the back pack version with the antennas on it. I would have never though about this. Great for renters. Forget about saving for that dream plane and get one of this together with a pair $1k Bose headsets and that $4K Rolex pilot watch.

José
 
I'm also waiting to hear if NON-TSO'ed ADS-B out will come under regulatory scrutiny. Nobody really cares if you make a receiver. Transmitter? May be different.
 
TMetzinger said:
I'm also waiting to hear if NON-TSO'ed ADS-B out will come under regulatory scrutiny. Nobody really cares if you make a receiver. Transmitter? May be different.
Click to expand...

Not to mention that you would need a hefty portable battery for that ADS-B out transmitter, connections to your altitude encoder and aircraft ICAO address programming. After all flight following is not a bad option and is free.

José
 
Piloto said:
I think I will wait for the back pack version with the antennas on it. I would have never though about this. Great for renters. Forget about saving for that dream plane and get one of this together with a pair $1k Bose headsets and that $4K Rolex pilot watch.

José
Click to expand...

lol, great response.

I plan to be a renter for a year or so. The only toys I am buying, are those that will go right into the plane I buy.

This would not be one of them.
 
Hard to imagine a portable that meets the TSO for ADS-B position out. Understand certified accuracy for ATC surveillance is different than certified accuracy for navigating an approach. ATC has set hard fast position accuracy and signal availability performance requirements before they will want to use Your ADS-B out data to ensure your separation in IFR. ADS-B out almost certainly will have to be a certified installation.
 
kontiki said:
Hard to imagine a portable that meets the TSO for ADS-B position out. Understand certified accuracy for ATC surveillance is different than certified accuracy for navigating an approach. ATC has set hard fast position accuracy and signal availability performance requirements before they will want to use Your ADS-B out data to ensure your separation in IFR. ADS-B out almost certainly will have to be a certified installation.
Click to expand...

Interesting comment. I would expect that virtually any GPS derived position would be far more accurate than the position determined by the combination of ATC radar and a transponder/encoder.
 
kyleb said:
Interesting comment. I would expect that virtually any GPS derived position would be far more accurate than the position determined by the combination of ATC radar and a transponder/encoder.
Click to expand...

You will be surprised how accurate and jam free radar can be. Radar range is determined by signal delay to an interrogation without being affected by GPS ephemeris errors of two separate position sources. In the case of ADS-B the position reports are once a second while radar interrogation rates are over 200/second. This ADS-B delay introduces a position error that is unaceptable for TCAS II purposes. GPS signals can be easily jammed by one watt hand carry transmitter like a cell phone size thus inhibiting ADS-B position reports. While multiple over 1KW transmitters would be required to jam an ATC radar. Not to mention the ATC radar heavy weather penetration vs ADS-B.

José
 
TMetzinger said:
I'm also waiting to hear if NON-TSO'ed ADS-B out will come under regulatory scrutiny. Nobody really cares if you make a receiver. Transmitter? May be different.
Click to expand...

I question this too, because I read that there is a requirement that the altitude reporting source needs to be the same as the transponder. There are some other requirements for the altitude reporting source that seems to ensure it is from a GPS source, as well. It seems that this would negate most mode c installs out there and pretty much any portable application.
 
TMetzinger said:
I'm also waiting to hear if NON-TSO'ed ADS-B out will come under regulatory scrutiny. Nobody really cares if you make a receiver. Transmitter? May be different.
Click to expand...

It depends if it starts to cause problems, same as everything.
 
John221us said:
I question this too, because I read that there is a requirement that the altitude reporting source needs to be the same as the transponder. There are some other requirements for the altitude reporting source that seems to ensure it is from a GPS source, as well. It seems that this would negate most mode c installs out there and pretty much any portable application.
Click to expand...

Right, you can tap that mode C signal with an attached box to blue tooth or wifi or LAN cable... It all works. They hear the the complaints about cost, they are many themselves aircraft owners. There are rumblings about owner maint experimental which would be most excellent although I'm willing to go R&D rules to hang a pair of Diesels.
 
TMetzinger said:
I'm also waiting to hear if NON-TSO'ed ADS-B out will come under regulatory scrutiny. Nobody really cares if you make a receiver. Transmitter? May be different.
Click to expand...

Even though NavWorx ADS-B transmitter is not yet TSO'ed by the FAA, it is FCC approved: http://www.navworx.com/articles04.php

According to a response by NavWorx president to this blog (scroll down to comments) the FAA created a specification to allow non-certified devices. Since it looks like it costs $600 to get a copy of that spec, DO-282B, I haven't reviewed it myself.
 
I was a transponder system engineer for 2 major airlines (for about 9-10 years). I sat in on endless planning and NPRM meetings, and reviewed the final rule pretty carefully when it came out.

Granted, airlines are affected by required equippage for OPS in class A airspace. Aircraft that operate under FL24 use a different format. I believe both FAR paragraphs point to TSOs. Each TSO points to minimum operational operation performance specifications in an RTCA document.

The RTCA specs define the data ADS-B broadcasts have to contain, and how it is formatted and arranged. The FARs also contain additional performance requirements, for certification.


On a higher level, ADS-B is being adopted globally. There are really two versions in use. ADS-B for non radar airspace (Canada and Australia) and what the FAA is doing. Eurocontrol recognizes the non- radar airspace spec too. That will change pretty soon too. That version of the spec was released early and is considered accurate enough to provide 3 & 5 mile separation, like radar. It was adopted early on because it is much cheaper than building a network of radar installations. It is also a good choice where it's not practical to build radar installations.

The US already had near 100% radar coverage to provide 3 & 5, at least at altitude. The version the FAA is implementing is accurate enough for 1 & 3 mile separation, to support higher traffic density for Next Gen.

I dug all through the specs for the 1090 version to put training materials and briefings together. I haven't taken the time to dig through it all for UAT. I since changed jobs. Some things will be different, some things won't be different because everybody has to play together nicely at lower altitudes to land in IFR.

One thing that struck me when i was Going through the material was that this is all about automated communications between airplanes and ATC ground stations. Flight crews don't really play a role beyond maybe turning the gear on. The 1090 version has provisions for data exchange in both directions. It will be interesting to see how it all shakes out. There is a lot going on.
 
kontiki said:
One thing that struck me when i was Going through the material was that this is all about automated communications between airplanes and ATC ground stations. Flight crews don't really play a role beyond maybe turning the gear on. The 1090 version has provisions for data exchange in both directions. It will be interesting to see how it all shakes out. There is a lot going on.
Click to expand...


You noticed that, yeah they have been bringing transPacs in direct best glide to the runway on a data pack into SFO for a while now on computer generated routes.

The system is preparing for autonomy and we will have to play. That is what gives me hope owner Maint exp will happen, to get te equipment in planes at an acceptable cost and get some other savings benefits too.
 
Last edited:
Henning said:
You noticed that, yeah they have been bringing transPacs in direct best glide to the runway on a data pack into SFO for a while now on computer generated routes.

The system is preparing for autonomy and we will have to play. That is what gives me hope owner Maint exp will happen, to get te equipment in planes at an acceptable cost and get some other savings benefits too.
Click to expand...

If I got it correctly, I think what you're describing is the use of Required Nav Performance routes, there's RNP, and ANP, you can fly the RNP if your Actual Nav Performance equal or better than RNP for a route. And ATC clears you for it.

That's all about GPS based navigation though, something different than ATC surveillance tracking.

Position data for the nav system does not necessarily have to come from the same GPS receiver sending position data to the transponder or UAT.

In as much as the specs are all written to define performance standards, the FAA intentionally wrote the specs so no specific technology is called out. If you come up with a position sensing method that certifiably meets performance standards, it should be approvable for use.
 
All blocks of the same autonomy structure, it's coming, it was decided long ago, it's what NextGen is about.
 
Interesting comment. From what I heard that was a big complaint of the airlines, that is that the FAA couldn't explain how all the benefits of ADS-B adoption were going to work. It was like, well if we toss all the technology elements into a bag and shake it all up, it will all come together to allow better handling, higher density etc.

There are some real cost drivers. The US ATC surveillance radar system has been evolving since the 50s. Some of those assets are very expensive to maintain and operate. ADS-B receivers are relatively cheap.

The cost burden also shifts too.

Once some of the burden is shifted to aircraft owners, for accurate position source and compatible transceiver, ATC has a data source for tracking aircraft position. Then they can stop funding radar Maint and turn them over to the military to keep funding them, if they see the value.

Of course it's a silly game, the data comes from the military satellite constellation.

Here in again was another color of money issue. With better than X satellites up there, WAAS (generically SBAS) may not be required. This was a problem the airlines the airlines pointed out too, the cost of equipping for WAAS to get the required accuracy and availability.

Why set it up around two types of satellite? But that's what it's become.
 
It's all about saving fuel and getting humans out of operations. Autonomous planes can be built with no public interface.
 
kontiki said:
The US already had near 100% radar coverage to provide 3 & 5, at least at altitude. The version the FAA is implementing is accurate enough for 1 & 3 mile separation, to support higher traffic density for Next Gen.

It will be interesting to see how it all shakes out. There is a lot going on.
Click to expand...

I don't think the 1 mile separation is a safe or practical distance for the following:

At 1nm from runway threshold you will be at DH (300ft) for most approaches. That would mean that when you come out of the clouds would see the plane ahead just touching down. What would you do, continue your approach or go around. If you continue there would be two planes on the runway at the same time. But wait, the third plane on the approach now see two airplanes on the runway. What he will do?

On take off and climb the wake turbulence of the B747 ahead is bad enough at 2nm. At 1nm you are fighting it to keep the wings level.

Even enroute at 1nm separation you would have the TCAS alarm sounding off all the time and probably issuing RA, thus in conflict with ATC assigned altitude.

1nm separation implies 3 airplanes per minute at 180kts each on approach. That would mean 180 airplanes/hour added to that airport every hour. Assuming a 1hr turn around it would require 180 gates airport capacity.

With more people opting for FEDEX/UPS ground service a decreasing GA population and the rising cost of air travelling I don't see will ever have a need for such traffic density. It is plainly unaffordable.

José
 
NextGen is about high traffic density. Inside three and particularly one mile is handled through omnidirectional onboard radar coverage.
 
Going back to the original thread, wouldn't this prevent the portable application from being legal?

http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC 20-165.pdf

b. Installation Guidance.
(1) The barometric altitude used for the ADS-B broadcast must be from the same source as the barometric altitude used for the ATC transponder Mode C reply, if an altitude-encoding transponder is installed in the aircraft.
(2) 14 CFR §§ 91.225 and 91.227 do not alter any existing regulatory guidance regarding the barometric altitude accuracy or resolution. For example, if an operation requires a 25 foot altitude resolution or a 14 CFR part 91 appendix G, Operations in Reduced Vertical Separation Minimum (RVSM), accuracy, that resolution and accuracy should be reflected in the ADS-B message.
(3) If a secondary altitude source is utilized when a secondary transponder is selected or a secondary altitude source is selected for a single transponder, the altitude source for ADS-B must also be changed so that the altitude source remains the same for both the transponder and ADS-B.
 
Piloto said:
You will be surprised how accurate and jam free radar can be. Radar range is determined by signal delay to an interrogation without being affected by GPS ephemeris errors of two separate position sources. In the case of ADS-B the position reports are once a second while radar interrogation rates are over 200/second. This ADS-B delay introduces a position error that is unaceptable for TCAS II purposes. GPS signals can be easily jammed by one watt hand carry transmitter like a cell phone size thus inhibiting ADS-B position reports. While multiple over 1KW transmitters would be required to jam an ATC radar. Not to mention the ATC radar heavy weather penetration vs ADS-B.

José
Click to expand...

Where are you getting this? Last time I looked, the circular scan rate of typical surveillance radars was on the order of several seconds between updates, not 200/second. Longer range center radars would be even longer. Radar accuracy/resolution are affected by distance to the antenna, weather and atmospheric conditions. Turn off your transponder and see how often you'll get "negative contact." GPS derived positions are generally consistently accurate.
 
Witmo said:
Where are you getting this? Last time I looked, the circular scan rate of typical surveillance radars was on the order of several seconds between updates, not 200/second. Longer range center radars would be even longer. Radar accuracy/resolution are affected by distance to the antenna, weather and atmospheric conditions. Turn off your transponder and see how often you'll get "negative contact." GPS derived positions are generally consistently accurate.
Click to expand...

You are right Tim but I was referring to the one second delay of ADS-B vs TCAS that can go up to 1000Hz. Approach radars can rotate to about 60rpm. BTW when a GPS satellite is put into orbit is guided by ground radar sites into proper orbit, no ADS-B there. Radar technology is used exclusively to guide spacecraft into Mars and other celestial bodies, no ADS-B there. Radar is also used to guide precisely missiles to an oncoming threat, no ADS-B there. And finally is used for that pink slip that you get for exceeding the speed limit, no ADS-B there.:)

José
 
It's about capacity and the limitations of centrally located radar installations. Radar needs to transfer to short range aircraft based. ADS-B is good enough accuracy outside that range and can do the job well. We have had AIS traffic for quiets sometime in the maritime sector, it works pretty good for the most part.
 
Piloto said:
. This ADS-B delay introduces a position error that is unaceptable for TCAS II purposes.
José
Click to expand...

TCAS II listens for and can interrogate for the encoded mode s address and baro altitude. Its encoded in a mode s transponders squitter broadcast.

Azimuth and distances are calculated by TCAS ll from RF characteristics of the signal (time delay and timing/ phase delay perceived at the 4 element directional antenna).

A DF 11 (downlink format 11) is the legacy 56 bit Mode S Transponder broadcast, a DF 17 is a 112 bit format for ADS-B. The added 56 bits contain the lat long and etc register contents used for ADS-B.

Are you saying that the added message length is creating some type of problem for TCAS II?

Thats the first time Ive heard of that. It's really late in the game for someone to have to address that for the first time. Are you sure you're talking about TCAS ll? TCAS ll refers specifically to units that meet RTCA DO-185. Thats not the usual flavor seen on GA aircraft.

There is a relatively new RTCA spec for hybrid TCAS which is gps based, but I didn't know of anyone working on it when I was watching.
 
kontiki said:
TCAS II listens for and can interrogate for the encoded mode s address and baro altitude. Its encoded in a mode s transponders squitter broadcast.

Azimuth and distances are calculated by TCAS ll from RF characteristics of the signal (time delay and timing/ phase delay perceived at the 4 element directional antenna).

A DF 11 (downlink format 11) is the legacy 56 bit Mode S Transponder broadcast, a DF 17 is a 112 bit format for ADS-B. The added 56 bits contain the lat long and etc register contents used for ADS-B.

Are you saying that the added message length is creating some type of problem for TCAS II?

Thats the first time Ive heard of that. It's really late in the game for someone to have to address that for the first time. Are you sure you're talking about TCAS ll? TCAS ll refers specifically to units that meet RTCA DO-185. Thats not the usual flavor seen on GA aircraft.

There is a relatively new RTCA spec for hybrid TCAS which is gps based, but I didn't know of anyone working on it when I was watching.
Click to expand...

DF 17 is a squitter broadcast that happens once a second unlike the other DF messages that respond to a UF message request at what ever rate TCAS II is requesting (up to 1000/second). Because of this TCAS II can determine minute changes in range and angular position of the traffic that would not be possible with once a second DF-17 broadcast. This may not be that critical except in a close encounter when RA are issued to both aircraft and a fast precise tracking loop need to be maintained. Keep in mind that unlike the request/reply scheme at 1000Hz the DF-17 broadcast could be missed all together by garbling from other traffic in the area, or the onboard DME/transponder/TCAS II. When this happens you would need to wait another second for another DF-17 broadcast. Lateral position accuracy improvement would not change the TCAS II scenario since all the RAs issued are based on barometric altitude separation. And you will still need the two way UF/DF Mode S link to insure the proper RA is issued to each aircraft.

There has been some discussion on TCAS IV (lateral evasive maneuvers) but none of the maneuvers prove to be safer than a change in altitude. This is partly due to trying to maintain specific turning radius and potential conflict with other traffic in the vicinity.

José
 
The interval for a squitter broadcast is pseudo randomized to prevent pattern nulls.

DF17 is an extended squitter. Before 1090ES squitters were activated, Mode s transponders squitted DF11s.

Some transponders have been pumping out DF17s since the EHS mandate on 2005. My packages turned the ES off , but not everyone did that.

Unfortunately, most extended squitters were activated before there was a GPS position source on any of the airplanes. So the airplanes were squitting whatever happened to be in the register.

It just happened to be part of the software updates deployed to accommodate Eurocontrol EHS&ELS. typically the software update that enabled the extended squitter was pushed out as part of the requirement to put flight ID in the squitter (DF 11 & 17). Pretty much everyone's software upgrade activated the ES and activated the pin to disable it.

That mod was sold to the airline customers as a software only mod almost universally, so the wiring was not done to use the pin and shut the ES off until the transponders were connected to a position source. It didn't matter so much, no one was really listening to them anyway.

I think you are saying the extra length of the message plays a role in TCAS, but you're not being specific.



.These sorts of protocol changes are modeled six ways to Sunday by the 30 pound brains at the MITRE labs. If they did botch it up, the AD will be in the works soon.

Also, making these posts on an iPad is awful.
 
Current TCAS II algorithm for issuing RAs is based on slant range and baro altitude. Traffic azimuth was never involved. DF-17 has no effect on TCAS II performance because the message is ignored. But maybe later on it will be considered. As you mention on some of these broadcast the position field is empty but not the baro altitude field.

José
 
Piloto said:
I don't think the 1 mile separation is a safe or practical distance for the following:

At 1nm from runway threshold you will be at DH (300ft) for most approaches. That would mean that when you come out of the clouds would see the plane ahead just touching down. What would you do, continue your approach or go around. If you continue there would be two planes on the runway at the same time. But wait, the third plane on the approach now see two airplanes on the runway. What he will do?

On take off and climb the wake turbulence of the B747 ahead is bad enough at 2nm. At 1nm you are fighting it to keep the wings level.

Even enroute at 1nm separation you would have the TCAS alarm sounding off all the time and probably issuing RA, thus in conflict with ATC assigned altitude.

1nm separation implies 3 airplanes per minute at 180kts each on approach. That would mean 180 airplanes/hour added to that airport every hour. Assuming a 1hr turn around it would require 180 gates airport capacity.

With more people opting for FEDEX/UPS ground service a decreasing GA population and the rising cost of air travelling I don't see will ever have a need for such traffic density. It is plainly unaffordable.

José
Click to expand...

Jose,

I can only guess the hope is in some magical ADS-B in application, that is to enable crew awareness at greater distances while still in the clouds.

I think the traffic bottleneck is really in the US northeast corridor during peak daytime hours.

I have no idea what UPS is looking at, they have been on the leading edge for ADS-B (IN) applications for improving efficiency and closing up separations.

FedEx didn't seem to jump into all of that so much. I understood that traffic density hasn't really been an issue for them. Getting into most fields late at night is when traffic is low is pretty easy.
 
denverpilot said:
Interesting. Why is there so damn much competition in ADS-B but virtually none in approach-certified GPS? Grrr.
Click to expand...

Two words: FAA Certification. The process has become so daunting that it actually now makes us LESS safe IMO. :frown2:
 
flyingcheesehead said:
Two words: FAA Certification. The process has become so daunting that it actually now makes us LESS safe IMO. :frown2:
Click to expand...

Yeah, I know. It was a somewhat rhetorical question used to point it out again.

Gee, you'd think AOPA (you know, because of that O in their name) would be trying to change that. ;)
 
You must log in or register to reply here.
Back
Top