The ADS-B System is flawed

[ajay]

Originally Posted by flyvans.com

ads-b is great for remote areas like alaska and may allow to save a radar or two somewhere in the outback. but as soon as you are getting into reasonably dense areas and especially into the vicinity of large airports, the 3nm radar separation (or possibly mulitlateration) standard is going to be here for a long time yet.

Bernie,

3nm radar separation is nothing to brag about, that is pretty poor in a dense congestive environment. The problem is Radar is measuring in 1D range (distance). Radar has azimuthal errors which become significant at distances greater than 30 NM. At that range, 1 degree of azimuth error becomes half a nautical mile wide. What ADS-B offers is better accuracy ~+/- 5m constant at all ranges since it is based on your gps (multilateration geolocation from 3-5 satellites). Hence better separation, situational awareness, etc.

also, ads-b has many serious security flaws (specs stem from pre-9/11).
spooffing (creating false targets), gps jamming or tweaking (invalidating positions of true targets) etc... way way worse than with radar, especially when multi-radar tracking is done. or anyone truly believe AF1 will ever be cooperative?! it shouldn't be, feel free to add all other "sensitive flights" and therewith fails the concept.

Way worse than radar? Radar is not inherently resistant to any of this. Radar jamming and spoofing has been an active development and well documented for over 50 years. Ads-b is certainly vulnerable to jamming, but the methods are a lot less mature to date. Sure AF1 can turn off their transmitters as any of us can. However, I wouldn't expect this to happen, AF1 always fly's under ATC control, hence, transponder on. Except in time of war which means they'll be closing down the airspace anyway.

ajay

[RV9A Bill]

Brantel and Walt, thanks. Better than last time I had checked.
RV9A Bill

[RV3bpilot]

I have ADS-B out only so others can see me but because I do not have the right GPS for the transponder all that is going out is the S-mode. So the only thing that air traffic control is lacking from me is my exact speed, exact GPS location, and GPS altitude.
As far as who I am and general tracking they have all of that now through the S-Mode of the transponder. There is no reason they can not tax me for my miles flown NOW even though gps part is not working.
There is no reason to get all shook up about a new tax or if they are going to tax GA. I feel they are already taxing us. In Minnesota to register my aircraft they made me pay taxes for what I felt my aircraft was worth so I had to guess with a reasonable dollar value.
My home airport KULM has just extended the runways and re-built the taxi-ways to include very nice class 5 packable soil to hold heavy aircraft. That is not cheap to do something like this. I can not imagine how much AV-gas it would take to pay for something like this. I don't like the $6.18 per gallon they charge here but I sure like the new runway.
I drive truck for a living and the government tracks us via GPS for all our highway use tax! In the past we had to write down all the miles we drove in each state so each state could get their share of tax but now with GPS tracking it is much easier for everyone. We even have electronic logbooks to track our driving time so there is no cheating. If anything hope the government does not require a log book to verify that we are not tired before we fly! Working a full day at work would be considered on duty not flying and would therefore count against your flying time!

[BCP Boys]

There are thousands of pilots in this country that don't have and don't want to even use a transponder with mode C. They continue to fly around or under airspaces that require you to have a mode C today. That's not going to change, so how do you suspect the government will tax those folks?

[N941WR]

There are also hundreds, if not thousands, of airplanes flying without any type of transponder due to their lack of electrical system.

I suspect that at some point the FAA will mandate battery powered portable transponder. The question there is, how to do you verify their installation & accuracy. With GPS, you remove the variances in static systems, so that might be the answer.

[jjhoneck]

BTW: Mac has a good article in EAA Sport Aviation this month about "What happens if you don't add ADS-B by 2020?".

The bottom line answer, for many of us, is "nothing". Basically, you won't be able to fly anywhere that you can't fly today if you don't have a Mode C transponder.

Thus, for many pilots, the ADS-B mandate is no big deal, and doing nothing is a good option.

[jjhoneck]

Originally Posted by Walt

Jay,
Where are your skyradar and GDL39 antennas mounted?

The two SkyRadar antennas are permanent, mounted on the bottom of the plane.

The GDL-39 antenna is the little one that comes with the unit, and is mounted inside the front cockpit, on the right side.

Surprisingly, there is no qualitative difference between reception of the two systems. That GDL-39 antenna picks up 99.9% of what the permanent antennas see, despite its less optimal location. It's a good piece of kit.

[FasGlas]

Originally Posted by BCP Boys

There are thousands of pilots in this country that don't have and don't want to even use a transponder with mode C. They continue to fly around or under airspaces that require you to have a mode C today. That's not going to change, so how do you suspect the government will tax those folks?

I think if you start by finding as many aircraft as you can (the new 5 year registration requirement) and then mandate a tracking system in each aircraft (ADS-B). After it's all in place, you pass a few tax laws (user fees) and there ya go. All the pieces in place. And just because ADS-B will only be required in more dense airspace that doesn't mean that it won't change to ALL (or most) airspace in the future.

[BobTurner]

Originally Posted by jjhoneck

The two SkyRadar antennas are permanent, mounted on the bottom of the plane.

The GDL-39 antenna is the little one that comes with the unit, and is mounted inside the front cockpit, on the right side.

Surprisingly, there is no qualitative difference between reception of the two systems. That GDL-39 antenna picks up 99.9% of what the permanent antennas see, despite its less optimal location. It's a good piece of kit.

My Skyradar antennas are glued to the fiberglass door posts (RV10) and work just fine. I typically see multiple ground stations.