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  #1  
Old 05-27-2014, 11:36 AM
jjhoneck jjhoneck is offline
 
Join Date: Aug 2011
Location: PORT ARANSAS
Posts: 419
Default How Does One Test ADS-B?

We have the SkyRadar ADS-B system, coupled to our GRT Horizon HXr EFIS. This gives us ADS-B in, while our Trig Mode S transponder gives us ADS-B out.

We have gone for several flights lately where we visually saw traffic that never showed up on the EFIS, and it quickly became apparent that I had no idea if it was because the guy was flying without a transponder, or if the ADS-B ground transmitter was "down", or if my system was malfunctioning.

I'm wondering if there's a standard way to check the functioning of an ADS-B system in an airplane?

Thanks!
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  #2  
Old 05-27-2014, 11:45 AM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 7,282
Default

Jay,
I have an HX so your HXr is a bit different, but I see, in the lower right side of my map page, a box that says "ADSB -3" or something like that. The 3 in this case is the number of ground stations being received. I'm sure the HXr must have a similar feature.
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  #3  
Old 05-27-2014, 11:49 AM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
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Also, in the HXr set up menu, you can filter out traffic a certain altitude above or below you. Maybe you want to loosen up the limits until you are sure it works.

Also, you should be getting weather.
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  #4  
Old 05-27-2014, 11:55 AM
chipf chipf is offline
 
Join Date: Feb 2008
Location: Austin, TX
Posts: 179
Default

Not sure about the traffic, my system is using TIS from the Trig transponder for traffic. I do know that I can pick up TIS traffic in your area.

But you should be able to pick up weather info. Radar, METARS, TAFs should all be available.

If weather info is not showing up, go through the configuration options again.

Also, you should be able to connect to the Skyradar unit with an iphone or ipad. You can use that to verify that that part of the system is working.
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  #5  
Old 05-27-2014, 12:05 PM
jjhoneck jjhoneck is offline
 
Join Date: Aug 2011
Location: PORT ARANSAS
Posts: 419
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Sorry, I should have been more clear -- we are receiving weather. And we have received traffic info on many flights, so I know the system is/was working.

My question pertains to an "on-the-fly" check. If I see traffic visually, and it's not displayed on the Horizon, how do I check to see that the system is working at that moment?
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  #6  
Old 05-27-2014, 12:11 PM
jjhoneck jjhoneck is offline
 
Join Date: Aug 2011
Location: PORT ARANSAS
Posts: 419
Default

An adjunct question to this: On several flights I have received "Traffic Warnings" -- the pop-up window that gives a potential collision warning -- on what was probably US.

Here's the sequence of events:

1. The warning window pops up.
2. I look at the screen, and it paints a target at about the 11 o'clock position, which quickly slides behind us.
3. It then reappears, several times.

On one flight, it did this over and over for ten minutes.

Why? Why would it do that on some flights, but not all?
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  #7  
Old 05-27-2014, 12:13 PM
jclark jclark is offline
 
Join Date: Jan 2005
Location: Columbia, SC
Posts: 804
Default It may be just fine ....

Quote:
Originally Posted by jjhoneck View Post
Sorry, I should have been more clear -- we are receiving weather. And we have received traffic info on many flights, so I know the system is/was working.

My question pertains to an "on-the-fly" check. If I see traffic visually, and it's not displayed on the Horizon, how do I check to see that the system is working at that moment?
Jon,

I did a lot of the testing of the ADS-B stuff on the GRT system.
(See an article in the JULY issue of Kitplanes)

As others have mentioned, the lower right corner will tell you the number of ground stations that are being received. If you have a non-zero number, you should be getting stuff. If you have received any weather or METARS or WPT DETAILS, you are receiving.

Now, you need to make sure that the Trig is set up correctly for ADS-B out. Actually I think you said that you have SkyRadar which is dual band so the setting I was thinking about may not be an issue.

There are scenarios that I have encountered (with a WORKING system) where the traffic did NOT show up. ADS-B is still in the early stages and there are a few unique cases that I have seen where stuff is missed.

Contact me offline for more details.

James
jclarkmail blah blah gmail
803-238-2113
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  #8  
Old 05-27-2014, 02:08 PM
esco esco is offline
 
Join Date: Jan 2011
Location: SoCal
Posts: 402
Default Adjunct question - response

Jay:

ADS-B "ghosting" is a common occurrence. VAF posters have reported it on occasion:


"...if you're within range of an aircraft with ADS-B out, you can see your own radar return on the traffic display, complete with latency and mode-C altitude reporting error..."

and

"...The ghosting would happen when crossing the same exact point because I was in range of two radar stations. Each station was reporting me as traffic..."

My theory is it arises when there's a conflict between positions reported by ADS-B (GPS-based) and radar (ground-based sensors), combined with latency of processing and transmission.

Dynon has filters which, if selected, will eliminate ghost images.
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  #9  
Old 05-27-2014, 02:29 PM
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rzbill rzbill is offline
 
Join Date: Nov 2005
Location: Asheville, NC
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Default

Quote:
Originally Posted by jjhoneck View Post
I'm wondering if there's a standard way to check the functioning of an ADS-B system in an airplane?
I have asked a number of controllers with the intent to learn if anything on THEIR scopes is different between ADS-B and non-ADS-B indications.

Usually the answer is "Negative" and said somewhat tersely.

However, I was up in the KAVL tower last week on a social visit and one of the controllers there said that the newer installations would have different indication iconography and the ability to retrieve more data if they went to the trouble to dive in a bit further.

So, to your point, I have no way to really know that the outbound signal is actually working or whether ATC is simply seeing my 327.

As a recent convert, I have to say ADS-B inbound is nice. Helped with wide spaced Tstorms yesterday and also with traffic that Center never mentioned.
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  #10  
Old 05-27-2014, 02:59 PM
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MarkW MarkW is offline
 
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Location: Edgewater, FL. KSFB
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I have a different brand of equipment but I can say that on occasion I do not receive some traffic but do receive weather all the time.
I have never had the ghosting.
I am hoping it is a FAA thing that will improve.
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