For less than $100, you can build a tiny receiver called PiAware that gives you a front-row seat to the automatic dependent surveillance-broadcast (ADS-B) landscape. The PiAware ground station setup employs a Raspberry Pi computer running the Linux operating system. On its website FlightAware has published complete build instructions with the parts needed, and once hooked into the FlightAware network, participating users have free access to the company’s Enterprise account, which normally costs $89.95 per month.
I ordered all the parts from Amazon and spent about a day assembling my PiAware receiver and downloading and installing the software. Now my ground station is busy scanning the slim volume of sky viewable from my Los Angeles home office and helping FlightAware keep its data current and accurate.
The receiver was easy to put together. The parts include the Raspberry Pi B+ ($39), ADS-B USB dongle and antenna ($22), Raspberry Pi power supply ($9), SD card (8 GB minimum), Ethernet cable or Wi-Fi adapter ($9) and enclosure ($13). Because I don’t have an Ethernet connection in my office, I used the Wi-Fi adapter to connect to the Internet. And I had to hook the ground station to a TV with an HDMI cable to set up the programming. The small antenna that I purchased works fairly well, but those with access to a roof with a clear view of the sky can get better reception with an outdoor antenna ($150). The enclosure isn’t required, but the ground station looks much nicer inside the transparent case.
Once the receiver is set up, there isn’t much to do except make sure the ground station is online and that the software is current. There are occasional disruptions when my receiver drops offline, but switching it off then back on restores the connection.
Flight-tracking Data
The data provided by my PiAware receiver is viewable via two web pages. One is a user statistics page that shows a summary of information for my receiver and those operated by other FlightAware ADS-B participants in my region. Bret Aguilar near El Monte, Calif., is the local champion, with a daily average of more than 1,600 flights and 174,000 positions received. This compares to my 344 flights and nearly 5,000 positions, likely because my receiver’s antenna can’t see much of the sky. My FlightAware page also lists aircraft currently and recently viewed by my receiver. I can click on any of these and find out as much information as is available. Another page shows live data in the form of a map with little moving aircraft symbols. I can see the ICAO ID, flight number, squawk code, altitude, speed and track of these targets. One surprising revelation is how many aircraft seem to be violating the 250-knot speed limit below 10,000 feet.
According to FlightAware founder and CEO Daniel Baker, by the end of last year about 2,000 ground stations were delivering data to the company every day, and that number grows by about 100 per week. About a third are PiAware receivers. Third-party ADS-B receivers and FlightAware’s own FlightFeeder account for the remainder. The FlightFeeder is free for locations where there is no existing ground station delivering data to FlightAware, or users can buy a FlightFeeder, beginning in February.
Worldwide Coverage
Looking at the FlightAware ADS-B map shows the extraordinary scope of worldwide coverage. There are plenty of open areas in Africa, Latin America, China and Russia. And there are areas where one might not expect coverage to be available; Cuba, for example, has good coverage in the Havana area from two ground stations in Key West, and I could easily view a Cubana de Aviacion flight there. There is even some partial coverage of North Korea, not that there appears to be much aerial traffic in that country.
The data that FlightAware is processing are ADS-B signals being transmitted on the worldwide 1090 MHz frequency (not the below-18,000-foot U.S. 978 MHz for light aircraft), mode-S transponders and mode-C transponders (this data isn’t used, however).
“We receive tens of gigabytes of data per day and we automatically de-dupe and rate-limit the data,” Baker explained. “We have intelligent rate limiting that lets us use more positions at low altitude or when the airplane is moving than when at cruise. We use the mode-S data to determine takeoff/landing times, tail numbers and approximate airplane positions. We use the ADS-B data to determine takeoff/landing times, tail numbers, exact aircraft locations. The data is seamlessly fused into existing FlightAware interfaces.”
Many aircraft are blocked by their owners/operators, but I can see these when my receiver detects them flying overhead. FlightAware doesn’t show the origin or destination, unless it is my own blocked aircraft that I am tracking.
For receiver owners who worry about showing the world the address where their ADS-B ground station is located, FlightAware allows users to offset the actual location by either one or 10 kilometers. And users can show their FlightAware user name instead of a real name as the owner of the ground station, if they prefer.