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Modesdeco2 and modesmixer2 Callsign detection

Started by nottledim, August 27, 2020, 05:54:49 PM

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nottledim

Hi,

   I'm using the modes*2 programs to receive signals locally, near Edinburgh airport.  There are a few flights around using older aircraft which do not transmit ADS-B signals so I have to use MLAT to track them.  Somehow md2 and mm2 can find the callsign for these aircraft but can't see any messages from them other than basic DF11 mode-s messages which don't contain the callsign.    Where do these programs get the callsign from?  What am I missing? 


Anmer

Welcome.  What are you using to track them using MLAT?
Here to Help.

nottledim

I'm using PiAware.  rtl->md2 -> piaware -> mm2->vrs

Anmer

Thanks.

Do you need MD2 and MM2?  PiAware is decoding the data.  You can also run VRS directly off PiAware,  Or maybe you're injecting other data?

Do you see the callsign on your PiAware SkyAware map and list?
Here to Help.

nottledim

I've got two sites which I merge.  Piaware and vrs see the callsign.  I've got my own program which creates a log of flights in/out of edi airport and it's only my programs which don't see the callsign.  The big difference between my program and vrs is that vrs receives BEAST protocol whereas I'm using msg (and recently avr).  Md2, at the beginning of the chain,  only has radio input (or possibly network) and it knows the callsign; and that's my question.  Where does md2 get callsign from?


Anmer

Quote from: nottledim on August 27, 2020, 07:30:57 PM
Where does md2 get callsign from?

Do you mean "how to setup MD2 to see the callsign?"

The callsign is part of the Mode-S message.  If PiAware is showing it, the callsign is being transmitted.

From where does your "own program" expect to source the callsign?

I don't run MD2 nor MM2 so I can't replicate your setup.  But your receiver is picking up Mode-S messages that includes the callsign.  Have you tried eliminating MD2 and setting your porgram to get the data from PiAware or VRS?
Here to Help.

nottledim

Quote from: Anmer on August 27, 2020, 07:48:05 PM
Quote from: nottledim on August 27, 2020, 07:30:57 PM
Where does md2 get callsign from?

Do you mean "how to setup MD2 to see the callsign?"
No, I mean which mode-s message is carrying the data?  I can't see any such message.  It is possible that it is looked up somewhere but I'm not aware that md2 has that capability.  It's a mystery to me.  It's coming from somewhere I just don't know where.
Quote
The callsign is part of the Mode-S message.  If PiAware is showing it, the callsign is being transmitted. 
Your reasoning is sound but I don't see any message that contains the data. I don't know why and I don't know which message I'm supposed to be looking for. I'm looking for specifics.  Which message?
Quote
From where does your "own program" expect to source the callsign?
The same place as everybody else :-)  That is my question; where?

Frustrating isn't it!


Anmer

If you can see the callsign (Flight ID) in your PiAware map, it must be present in the Mode-S message.  The transmitted message contains lots of data, including the Flight ID, where it's been entered into the relevant Flight Management System or transponder user interface.  Sometimes there's no Flight ID but this is the exception.

Without a spec. for MD2 message decoding, I can't help identify where the Flight ID can be found in MD2 output. Sergsero is the best person to answer that question.  Or anyone who is knowledgeable on the Mode-S message format.
Here to Help.

abcd567

#8
1. Piaware is not a decoder. It is data-feeder. It gets its data from a receiver-decoder.

There are many receiver-decoder softwares using DVB-T rtl820t tuner. Few are:
ModeSDecoder2
RTL1090
dump1090-fa
fump1090-mutability.

Normally all these output data in two formats
Avr format on port 30003
Beast format at port 30005

The avr format is human readable. You can see it on following address in browser of your Desktop/Laptop

IP-of-Pi:30003

The Flightaware MLAT feedback can be seen here:

IP-of-Pi:30106


If you are using ModeSDecoder2, then configure it for AVR output  at port 30003, and then you can see the data at above address in your browser.


Please also this thread:

Exploring Port 30003 and 30106


.


Anmer

Quote from: abcd567 on August 27, 2020, 11:45:40 PM
1. Piaware is not a decoder. It is data-feeder. It gets its data from a receiver-decoder.

Thanks.  Maybe I could have worded it differently.

If I have a suitable DVB-T receiver, connected to an RPi, I can view my decoded message data on a browser accessing the PiAware app on the RPi.

I'm not using any other app to "decode" the data.  The DVB-T isn't decoding the data, so what is?

I assume it's dump1090-fa, integrated with the PiAware install?  To me PiAware is a "package" of components that includes an OS, decoder, feeding app and GUI.

Do you conur decoded data is available "via" PiAware and MD2 isn't necessary?
Here to Help.

abcd567

#10
Quote
I assume it's dump1090-fa, integrated with the PiAware install?  To me PiAware is a "package" of components that includes an OS, decoder, feeding app and GUI.

The "piaware" and "dump1090-fa" are two stand-alone apps, and  any one of the two can be installed independent of the other. These are installed on Raspbian OS by commands "sudo apt install piaware" and "sudo apt install dump1090-fa".

However if instead of Raspbian image, if piaware SD card image is used, then both of these come pre-installed on it. Although both are pre-installed, but still independent apps.

The decoder + GUI (SkyAware map) is provided by dump1090-fa. It is the dump1090-fa which uses the dvb-t. The piaware has nothing to do with dvb-t or GUI. It is only a data feeder which grabs data from a decoder and sends it to Flightaware.

The piaware is by default configured to grab data in beast format from port 30005. The dump1090-fa is by default configured to output decoded data in beast format at port 30005. This way the dump1090-fa and piaware work as a team.

If on Raspbian image someone does NOT install dump1090-fa, and instead installs another decoder (like ModeSDeco2) and configures it to output decoded data in beast format at port 30005, then piaware starts using its data, and now ModeSDeco2 and piaware work as a team. In this case GUI (map) is provided by ModeSDeco2.

Anmer

The vast majority of PiAware installs, over 90%, use the FlightAware SD image, referred to as PiAware:

https://flightaware.com/adsb/piaware/build

Semantics on my part.  For most, PiAware refers to the "total package".  Not for everyone, but for most.

As I said, I should have worded my response differently but the result is the same.  Assuming nottledim has installed the PiAware "package".
Here to Help.

abcd567

You are right Anmer. Majority of user take "piaware" as piaware sd card image which has both the decoder (dump1090-fa) and data feefer (piaware) pre-installed.

The use of same name for single app (data feeder only) and the package (piaware image) is confusing. This point has been raised often in Flightaware forums since last many years,  but they have not yet taken any action.

The Flightradar24 are better in this respect. They use name fr24feed for their data feeder only, and use a completely different name Pi24 for the image which has the feeder & decoder both.