FlightAware Discussions

ADS-R & TIS-B Data

So, I’m trying to address a few knowledge gaps I regarding the ADS-B system operational theory and component architecture, and while I have studied the two components at hand extensively, I’ve never come across anything detailed enough.

Really quick explanation for those unfamiliar with the ADS-R and/ or TIS-B components.

Automated Dependent Surveillance - ReBroadcast: This was the FAA’s answer to reconciling the issues surrounding the decision to deploy two incompatible systems. The obvious issue is that if two aircraft are operating IVO each other, both have ADS-B in, but one is using 978MHz and the other using 1090MHz. Neither is aware of the other and thus creates a safety issue.

Now this is a watered down, oversimplified description, I’m leaving some details out:

The ADS-R does what it’s name implies, it rebroadcasts signals. They will always consist of 2 receivers and 2 transmitters, one that receives ADS-B track data signals on 978MHz and rebroadcasts them on 1090MHz, and vice versa.

Traffic Information System - Broadcast
TIS-B, is a far more powerful and capable component and does what ADS-Rs do, and a whole lot more. The TIS-B is basically the bridge connecting the legacy with the latest and greatest surveillance systems, and does so on account of the configuration of each station. If able, TIS-B is networked with one or many flight track data flows of any non-position reporting aircraft which is being tracked by a legacy FAA terminal and/or enroute Secondary Surveillance Radar (SSR) systems. If they can get it, sometimes they can use DoD SSR feeds as well. I’m still not totally clear on how the TIS-B is able to do the rebroadcasting process, so please drop a reply for us.

Ok, my questions regarding these systems.

  1. Do the signals being transmitted by either option have some sort of imbedded metadata disclosing the type of component sent these signals?

  2. If so, is the FlightAware system able to somehow distinguish between the various ADS-B signal sources?

  3. Does the FlightAware system receive, process, and plot air traffic track data which is originating from a TIS-B or ADS-R transmitter?

Thanks!!!

I think you are asking if you can identify messages that are ADS-R or TIS-B from the message content. Yes you can.

Yes

No, we discard it as we prefer the primary sources (ADS-B directly from the aircraft, or mlat via FlightAware’s systems, or FAA data via asdex/sfdps/etc)

Question Next: Regarding the TIS-B transmitter hardware and equipment, are there distinct components used only for TIS-B services, or does TIS-B do it’s thing using the same equipment which the standard FAA ADS-B receivers deployed CONUS?

Glancing back at that last question, are TIS-B and ADS-B always deployed in pairs? Can TIS-B be deployed on it’s own and without a nearby standard FAA ADS-B receivers deployed CONUS?

Basically everything you know about TIS-B kit!

Thanks!!

Don’t know the details but I’d expect the FAA’s receiver and transmitter network to be somewhat independent (they may share some physical sites, but the hardware you need for a transmitter looks quite different to the hardware for a receiver)

AIUI the TIS-B transmitters are fed from the combined FAA network, not only local data.

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