Electric
Pre-Flight
Are there portable GPS that will display TIS traffic if hooked up to a mode S transponder?
Are there portable GPS that will display TIS traffic if hooked up to a mode S transponder?
I believe that the Garmin x96 handhelds will display TIS-B targets. My XRX provides a
faux TIS-B stream that my 396 displays and (aural) alerts.
I read recently the FAA is going to start shutting down TIS to force us to start upgrading to ADS-B out.
The x96 handhelds display Mode S TIS, not TISB which is a ground station ADSB generated product. The Zaon XRX uses the serial TIS interface on the x96 to display traffic. With Garmins most recent announcement of the GDL39 ADSB portable receiver, it will display ADSB traffic on the 696, 796, and an iPad. Most traffic will not be displayed unless the aircraft is equipped with an ADSB Out capability.
No, not quite. TIS-B is the uplink of what the ground picture of the traffic is and includes the current Mode C targets that the ground sees as well as any ADSB they detect. It's entirely analogous to the existing mode S TIS service where it exists.
What ADSB OUT gets you is the independent traffic information that your ADSB IN unit will see from nearby aircraft that are using a compatible transmission device (i.e., your UHF UAT box is not going to see Mode S ES position reports).
I read recently the FAA is going to start shutting down TIS to force us to start upgrading to ADS-B out.
John I appreciate your clear explanations of this mumbo jumbo of ADS-B.
I have no ADS-B out.
I have two questions:
If I have the GDL 39 connected to my Aera 560 and I am near an ADS-B out traffic wouldn't I suppose to see my own plane on the traffic display. This way I would know if it will show traffic next to me.
To what aircraft is the displayed relative altitude? Mine or the ADS-B out traffic next to me? How would it know my baro altitude if I have no ADS-B out.
Thanks for educating us on this subject.
José
No surprise, they did the same with Loran. Wonder when is the 500 ADS-B UAT ground stations turn. After all there were only two dozen Loran stations serving the marine and aviation population. While the UAT stations are only useful to the GA population that do not want to pay the XM\WX fee.
José
That is old news (2006) and not totally accurate. The TIS product was provided by the ASR approach mode S radars (ASR-7, 8, or 9). An upgraded digital mode S radar system was developed for the FAA, ASR-11. The FAA didn't purchase the TIS capability for these new radars. They deployed 22 of these systems to replace existing ASR 7 and 8 radars and as a result TIS was lost at those locations. Going to ADSB Out by itself does not provide any capability to receive ADSB targets, that requires an additional ADSB-In receiver. I haven't heard any plans to upgrade the remaining mode S radar sites, so TIS should still be around for a while. See http://www8.garmin.com/aviation/tis.jsp for a map of TIS sites including the ones that were discontinued.
Jose,
The UAT technology/frequency was chosen because it has the capability of transmitting the weather data. It has one other big function, to the extent that it reduces the consumption of precious bandwidth on 1090 MHz, particularly in the high density traffic areas. This is a fundamental decision made by the FAA and is written into the FAA regulations (91.225 and 91.227).
The system wasn't installed for our benefit. It is for the government benefit. Radars are expensive to upgrade and maintain and have limitations on accuracy. In 2020 the FAA is switching from a radar based system to an ADSB based system for surveillance. It will be cheaper for them to operate and they will be able to handle more traffic. About 1/3 to 1/2 of the radars will be retired and the remaining ones will be a backup to ADSB. We get UAT not out of their benevolence, but to reduce the congestion on 1090MHz. The airlines don't see ADSB-In as justified financially as they have their own enroute weather with on-board radar and in flight data from their company. They have TCAS and don't need the traffic function. The traffic feature and the weather is a carrot to GA to offset the big expense they have in installing ADSB-Out. These features are not required for the surveillance system to work and as I previously stated, they were done for the FAA, not us or the airlines.
If the whole objective of the program was to save money it would have been much cheaper just to leave it alone. After all when have you heard traffic delays due to radar performance. The overwhelming delays are due to weather and airport capacity. And if weather dissemination was the objective a lower cost solution than 500 UAT stations would have been leasing a satellite channel just like they do for WAAS and XM do. Can you imagine XM/Sirius switching to 500 ground stations, it will bankrupt them. I think there were a few lobbyist looking for your tax dollar on this.
José
> they were done for the FAA, not us or the airlines.
It was done for the benefit of the contractor(s) - in the case of ADS-B, primarily ITT.
If the whole objective of the program was to save money it would have been much cheaper just to leave it alone. After all when have you heard traffic delays due to radar performance. The overwhelming delays are due to weather and airport capacity. And if weather dissemination was the objective a lower cost solution than 500 UAT stations would have been leasing a satellite channel just like they do for WAAS and XM do. Can you imagine XM/Sirius switching to 500 ground stations, it will bankrupt them. I think there were a few lobbyist looking for your tax dollar on this.
José
What am I missing? John just said that expense of maintaining the antiquated radar systems was the primary driver for ADS-B.
XM/Sirius has been a dead man walking from the financial perspective since their inception. Not a good example of an alternate solution.
JKG
It is about 800 ground stations in the initial implementation, not 500. If you have questions on how the system works, I am happy to try to answer them. I am not that interested in arguing over the justification or if it was a smart idea or not. It is what the FAA has in their plan and what we will have to work with.
If the concept of radar is so antiquated how come the DOD spend billions on them on navy ships and airborne platforms to precisely guide missiles to their target. Not to mention that NASA use them to precisely guide spacecrafts en route to Mars, no ADS-B out there. Not to forget the extensive NEXRAD network of weather radars. And these are over 10 times more expensive than an ATC secondary surveillance radar. If radar is such an antiquated invention can you imagine that of the toilet. Maybe we should look into other ways of doing it. Any suggestions?
José
The concept of radar isn't antiquated, but the existing FAA radar infrastructure is, and that's the point. Since the FAA's use case for radar is much different from other applications of the technology, and the FAA can mandate a participatory system for a captive audience, the theory is that there is a better way. If you have to rebuild it anyway, might as well try the better way. Whether the current ADS-B system is as good as it should be is up for debate, but it does provide benefits that the older system does not.
JKG
Just mention one that will benefit the general public. Do not include those that do not want to pay the $30/month XM subscription fee. For those the US tax payers are already paying the bill on 800 UAT stations that will not be used by the airlines.
José
Still no mention of the added benefits of UAT to the general flying public. In an open public debate the issue of public benefits and how its cost will be subsidized will come up. I just hope there is no an AVGAS surge tax to pay for it. BTW like history has shown before it can take just one member of Congress to change mandates.
José