Running view1090 on Rasberian I see the altitude for all flights, the Squawk code for most flights, but the Speed/Heading/Lat/Long for hardly any flights.
This is even when the flights are directly above me and the signal strength is pushing 200 (I’m under a new GPS enforced NextGen arrival route on a rural Island in the Seattle area so now have a jet every minute or so passing 3000 to 6000 directly overhead – from none and peaceful earlier this year).
I’m using a NooElec R820T2 dongle.
I first tried this on Windows and got similar results except the “Mode” was ‘S’ followed by ‘a’, ‘ac’, or sometimes just ‘S’ alone. On Raspberian it’s always just ‘S’ by itself. What is “Mode”?
Is there some setting I can change to get the Lat/Long of at least the flights overhead with strong signals?
The US doesn’t have very widespread ADS-B use (yet) and you will only see positions from aircraft that are ADS-B equipped.
The view1090 mode column tells you which transponder modes dump1090 is receiving for the aircraft. The Mode S vs. A/C thing is, uh, a long explanation, but the short version is that:
Mode A/C gives you aircraft squawk and altitude (but not position or identity). It is exclusively triggered by secondary radar.
Mode S gives you aircraft identity, altitude, and a few other things e.g. ATC ident (but not position). It’s also used for ACAS. It is mostly triggered by secondary radar.
ADS-B is built on top of Mode S; it involves aircraft sending their position/velocity in Mode S messages. This happens even without secondary radar queries.
dump1090 can decode Mode A/C and sometimes pair it up with a corresponding Mode S aircraft if it’s lucky by matching on altitude/squawk. That can give you a slightly clearer view of possible Mode A/C-only aircraft. But it’s not directly useful for flight tracking so the piaware config doesn’t enable it.
You can find positions for (some) Mode S only aircraft via multilateration, which is a cooperative setup involving nearby receivers. To enable that you need to start by setting an accurate location for your receiver in the “My ADS-B” control panel.
Would you happen to know if a plane’s RNP (Required Navigational Procedure) ability is independent of whether it supports ADS-B?
With multilateration is it possible to keep a set of all the position data you helped create by being one of the sites sending the S data? Since the actual calculation is done by FA’s servers it’s not automatic the way I can just keep my own copy of the ADS-B position information.
I’m trying to build a database of the altitudes flights pass a waypoint just normal or me. According to the arrival plate (HAWKZ4) they’re supposed to be >= 6000 feet but in reality they’re between 3000 and 6000 feet.
There is a piaware config option that lets you control how mlat results are returned to you.
By default they will be fed back via port 30104 to your local dump1090 for display, but you can configure extra ways of returning the data too.
For your purposes, probably a Basestation-format listener is what you need:
Then you can connect to port 12345 (e.g. with socat or nc) and you’ll get mlat results in the CSV-like Basestation format (the same format as dump1090 produces on port 30003)
In another thread I saw there was an option for dump1090-mutability called LOG_DECODED_MESSAGES that you could set to “yes”. A couple questions. Does the stock PiAware install have a similar option? If so do I enable it with a ‘piaware-config’ command and where does the file end up?
I’ve been racking my brain trying to figure out how you can possibly get the synchronization precise enough for MLAT to work seeing as the signal travels 186 miles in a msec. In another thread I saw that you wrote this code and it suggested that you use an unrelated ADS-B flight to synchronize between listening PiAware stations. I assume then that a GPS derived timestamp comes along with the location data in ADS-B? Good idea.
In my short experience going through these discussion groups I see you’ve made a lot of contributions and provided lots of help. Thank you very much on behalf of all the newbies. I haven’t used UNIX since the 80s so the help is definitely appreciated.
LOG_DECODED_MESSAGES just omits --quiet when starting dump1090 so you could do the same with the FA version. It is really, really noisy and is probably not what you want! However piaware’s setup doesn’t capture the output of dump1090 anywhere so you’d need to set that up too.
Multilateration with unsynchronized dongles works by using ADS-B position messages as reference beacons, yeah. Those messages do not carry a GPS timestamp, but it doesn’t really matter that the receivers aren’t synchronized to real time, they just have to be synchronized with each other.
Technically Mode A just provides a Squawk. Mode C(or A/C if you like) provides Squawk and altitude.
The are also called mode 3A and 3C.
Both appear to run on 1090Mhz but required a radar trigger on 1030Mhz(as mentioned above).
I have a lot of Mode A/C in the NYC area and have spare SDR dongles to assign to decode it.
