Here are the handout and slides from Carl’s great 1/14/2015 presentation on ADS-B, and Still’s demo on how to build a “Stratux” ADS-B In receiver. To download the complete 31MB 10 page PDF of the handout & slides, click this thumbnail image link:
For just the printed handout (first page of the slides, 0.05MB) click this thumbnail image link:
Following are selected pages in web format with links and some notes I took from the presentation. Slides from the presentation containing links to original online sources [Stratux hardware, etc] in the first page below are omitted – click the links here or in the complete PDF to see those clearer and fully functional originals online. Only the slides from ADS-B introduction by Carl are included below. I didn’t take notes on the Stratux building demo, but maybe someone else will post some if you request it. I’ve inserted a few comments from my notes, in green italic font, for the benefit of anyone who wasn’t at the meeting. –JW
Handout (page 1 of Slides)
ADS-B Automatic Dependent Surveillance Broadcast
Once per second. Radar rotates once every 6-12 seconds. Beam width. Multiple hits. Accuracy. Position, Speed, Altitude (plus N number and maybe some more)
978-UAT Mostly GA Below 18,000
1090-ES Extended Squitter. Modified transponder. Required at/above 18,000 and outside US
FIS-B Weather. UAT only Every 2.5, 5, 10, or 15 minutes depending on product
TIS-B Traffic. UAT and 1090 3-13 seconds; radar coverage needed. Only transponder traffic. “Hockey puck” 15nm radius; +/- 3500 feet
ADS-R (Rebroadcast) (AKA ADS-B Traffic) Every second “Hockey puck” 15nm radius; +/- 5000 feet
Own ship shadow
ADS-B OUT Class A, B, C. Class E above 10,000 (but not below 2500 AGL)
Information on how to build your own ADS-B IN receiver:
JW Notes: Total parts $113.90 plus iPad and ForeFlight with subscriptions, for a single-band (dual band in development) “Stratux” similar to the Stratus demonstrated by Carl. John Rodkey uses a Stratux with the less capable but free Avare app on an inexpensive Android Nexus 7, thus saving on the iPad and subscription expenses. I also briefly mentioned the simpler $13 solution I’ve found for my own Nexus 7 using the same type of “SDR” receiver as Stratux but eliminating the $70 “rPi” computer and $14 battery by using the $2.50 Android ADSB Pro app to display 1090-ES & 978-UAT with free Avare (this works somewhat better than a Stratux for Avare, but has 2-6 hours of battery life unless ADS-B power is swapped to my Nexus 7 in flight).
Software that runs the Stratux:
Pick the first Green, “Latest Release” Image writer software
Mac OS X http://ivanx.com/raspberrypi/
Some ADS-B links
- FAA: http://www.faa.gov/nextgen/equipadsb/ins_and_outs/
- AIM 4-5-7 (page 4-5-14): http://www.faa.gov/air_traffic/publications/media/aim.pdf
- FreeFlight ADS-B University: http://freeflightsystems.com/ads-b-university (Or get it on YouTube)
- Sporty’s 1:06 Webinar on ADS-B: https://www.youtube.com/watch?v=1LvZy59FhQw
(page 2 of slides)
JW Notes: The top image shows dots approximating the locations of ADS-B transmitters and an impression of their coverage areas in the blue circles as of 2014. Carl pointed out the differences between UAT weather update interval & transmission interval (e.g. transmissions are not always the most recently updated weather image). Also note that CONUS (national) images are transmitted less often than regional, so BOS weather can take longer to get flying near SBA than SoCA weather will.
(page 3 of slides)
JW Notes: By using a Stratus or home-built “Stratux” receiver with ForeFlight you can get free UAT weather aloft that is equal in most respects to subscription satellite service. Carl pointed out that both services provide delayed radar images (due to the required processing time) so they should never be used for finding a route through weather.
(page 4 of slides)
JW Notes: At the top-left of the ForeFlight map screen is info about how many ADS-B transmitting towers are being received, and currency of the info.
(page 5 of slides is a blank transition to this page 6)
JW Notes: The top image demonstrates how ADS-B traffic is incomplete, especially when no aircraft are equipped with ADS-B Out. At the bottom-right corner of each image is an inset showing how ForeFlight would depict the situation in your non-ADS-B Out aircraft. The bottom image shows how an ADS-B Out aircraft is provided a “hockey puck” shaped area near that aircraft that only shows those aircraft, and not the one close behind you.
(page 7 of slides)
JW Notes: When you’re flying an ADS-B Out equipped aircraft, all the aircraft nearby (inside your “hockey puck” area) are transmitted to you and anyone nearby with only ADS-B In (Stratux, etc).