FlightAware is the premier site for live, real-time tracking of aircraft around the world, and for the last year or so, Raspberry Pi owners have been contributing to the FlightAware network by detecting aircraft flying overhead and sending that data to the FlightAware servers.
Until now, these volunteers have used Raspis and software defined radio modules to listen in on ADS-B messages transmitted from aircraft. With FlightAware’s new update to PiAware, their Raspberry Pi flight tracking software, Mode S transponders can also be detected and added to the FlightAware network.
Last year, FlightAware announced anyone with a Raspberry Pi, a software defined radio module, and an Internet connection would earn a free FlightAware enterprise account for listening to ADS-B transmitters flying overhead and sending that information to the FlightAware servers. ADS-B is a relatively new requirement for aviators that transmits the plane’s identification, GPS coordinates, altitude, and speed to controllers and anyone else who would like to know who’s flying overhead.
Mode S transponders, on the other hand, are older technology that simply transmits the call sign of an aircraft. There’s no GPS information or altitude information transmitted, but through some clever multilateration in the new PiAware release these transponders and planes can now be tracked.
To get the location of these transponders, at least three other PiAware boxes must receive a signal from a Mode S transponder. These signals, along with a timestamp of when they were received are then sent to the FlightAware servers where the location of a transponder can be determined.
The end result of this update is that FlightAware can now track twice as many aircraft around the world, all with a simple software update. It’s one of the most successful applications of crowdsourced software defined radio modules, and if you’d like to get in on the action, the FlightAware team put together a bulk order of ADS-B antennas.
Is that antenna only good for tracking airplanes, I’m more interested in listening to police scanners in my area (don’t ask :P) would this (antenna) be OK?
if they are talking on 1090MHz then yes :)
read up about radio transmission/frequenices before listening to your friendly cops :)
There are police scanner radios online. Don’t think it’s such a big deal as everyone is making it.
You are confusing public safety scanners with actual police scanners. Police bands are encrypted and not public – it would make zero sense to broadcast your information in an open forum that criminals can listen in on.
Welcome to Australia, we most definitely broadcast our police conversations over the Radios.
First of all, in many countries listening in on emergency services is illegal. Second, the systems used differs widely, and are thus on many different bands all over the world. TETRA here in Western Europe mainly uses 300-400 MHz
This antenna is specifically made for 1090 MHz (ADSB) with a 5dB gain. It will be horrible for anything else.
It is not illegal to listen to police etc, its illegal to act on information received
You are probably going to want either something in the 150-176 range, 450 range, or ~800 range for various police systems, provided you are in the US. Not sure about our OZ or EU friends.
You might have trouble listening in unless you are in a rural area due to Digital or Scramble Analog transmissions. Digital like P25 is getting common and our local Sheriff in podunka Nebraska where I live uses it. WIthout the key you are not going to be able to listen in. Scramble Analog is no big deal. Many scanner now support it so unless you have an older radio (or don’t have the plugin for an SDR receiver) you can listen in.
Otherwise check state and federal rules for legality of the behavior and good luck if the are digital.
In the EU the cops all went digital, and encrypted AFAIK. So no luck there, although they have a publicly accessible message system sometimes.
Nearly all modern LEO radio systems are P25 and encrypted these days. It will take you more than just an antenna and a RasPi to get the lowdown on the fuzz, man.
So it looks like they have you set the location of the antenna / receiver via a manual process. Wonder why they dont have you use a GPS receiver so that you can also ensure that the times of all of the RPis are all synced for better triangulation abilities. A cheap receiver, mag patch antenna, and GPSD+Chrony would ensure some very precise timings.
I bet GPS isn’t used because it’s probably cheaper/simpler/more-more accurate to pick up the radar/radio pulse that’s used to interrogate the transponders and time-correlate off of that.
I’d think they could get a pretty accurate receiver location by just looking at the centroid of the received plane co-ordinates. May need to correct for local terrain, but you could maybe even do some of that from altitude
They don’t use triangulation, ADS-B transmits the location AFAIK, the whole idea is to be safe and not have collisions.
And a stationary receiver doesn’t need a GPS receiver. And since the Raspi is connected to the internet it can sync its clocks with any old NTP server, of which most are based on atomic clocks, like the one at NIST (National Institute of Standards and Technology).
It might be more interesting to couple it with some other sensors like outside temperature or air pressure, or to combine it with the lightning strike detector receiver system, or if you want to go even more expensive, a network of radiation detectors is also handy, since it’s well established the governments WILL lie if there is a radiation leak anywhere. And it would be both informative and scientifically interesting.
Actually, they are using a form of triangulation for the non-ADSB “Mode-S” transceiver signals via time difference of arrival (TDOA). http://flightaware.com/adsb/mlat/
More accurate clocks would certainly give better precision, but they seem to have enough good coverage that they can do pretty well with just NTP.
Will it track military aircrafts too?
On regular flights many military aircraft do indeed send out ADS-B/ACARS for safety reasons, although they do also have their own systems I understand.
Unless the aircraft is running mode 4 or mode 5 for the purposes of excercise/war then no reason you shouldn’t be able to pick them up.
More about the Virtual Radar Receivers on this page.
http://www.radarspotters.eu/forum/index.php?board=40.0