ADS-B: Aviation’s APRS

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Within the radio hobby, we have not only hams but shortwave listeners, scanner aficionados and many other specialties. And as in ham radio, each category has subcategories – a scanner listener may be interested only in trains. A shortwave listener may only want to listen for commercial RTTY stations.

Those interested in aviation now have another venue available to them that has never before been possible. Until fairly recently, aviation buffs listened to comms on a scanner & enjoyed the routine (and every-so-often, the non-routine) pattern of communications between pilots and air traffic controllers.

That has been the extent of their participation. Until now.

A new technology called ADS-B is on the scene and those interested can see in real-time the locations, ID, speed, heading, altitude and a ton of other data on aircraft within a 100-250 mile radius of the listener’s location.

All commercial aircraft are now fitted with avionic equipment that takes the onboard info (speed, altitude, etc), couples it with the aircraft’s GPS-derived location and then transmits it once per second to ground stations and other aircraft.

As a hobbyist, you can buy everything you need to see the same information aviate- again, in real time – from the comfort of your own home. What you’re buying is a receiver, small antenna and the appropriate software. That’s it.

If you wonder how many aircraft might be within range of you, here is a snapshot of a typical Monday afternoon in the US. Each red dot is an aircraft.

Couple this visual presentation with an airband scanner and now you can hear the pilot whose aircraft you’re seeing on your computer. I’m surrounded by this all day at work and should be jaded by it, yet I can see how this could be a fun past-time for the aviation enthusiast.

The aviation world’s justification for ADS-B has to do with several factors, all compared to radar: economy, precision and coverage. In the US it is mainly used in Alaska and Colorado due to the difficulties of establishing reliable radar coverage in such terrain and in the Gulf of Mexico (serviced out of Houston) to provide air traffic control for helicopters providing service to offshore oil platforms.

But regardless of whether or not ADS-B is used in a particular region, the aircraft overflying that region are equipped and would be observable on the RadarBox. No, I’m not trying to sell these things – just passing along another radio-related aspect of the hobby that others may find interesting. Current price of admission is around $500.

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  2 comments for “ADS-B: Aviation’s APRS

  1. Elwood Downey
    January 18, 2010 at 5:10 pm

    This sounds like fun but I wonder how long it will last. After the Christmas bomber, I notice they no longer display the aircraft location to the passengers during inbound international flights — presumably so a would-be bomber can’t tell where he is. I think it’s all pretty silly, these guys won’t say “gee, I can’t tell exactly where I am so I guess I won’t blow this up after all”. But anyway, this ADS thing seems like another way to track aircraft and I wonder if the Feds will lock it down somehow.

  2. John Harper AE5X
    January 18, 2010 at 8:35 pm

    Elwood, it’s in widespread use in Europe yet you raise a good point. As we know, GPS accuracy can be controlled (selective availability) so why not this…

    Here’s an interesting read along the same lines as your posting:
    http://www.airsport-corp.com/adsb2.htm

    And the FAA’s blurb:
    http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/surveillance_broadcast/

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