FlightAware Discussions

Airspy ADS-B decoder

Seems this version (1.39) increases CPU load on my system compared to the previous version (1.38).

I’d go back to 1.38 to double check, but i deleted it already.

Same here

image

I am actually getting lost samples now at 20MSPS where I had none before on my XU4.

droidxu4:~/ppup# sudo journalctl -f -u airspy_adsb

– Logs begin at Sun 2019-10-06 15:57:56 UTC. –

Oct 06 17:01:52 odroidxu4 airspy_adsb[2349]: Listening for beast clients on port 47787

Oct 06 17:01:52 odroidxu4 airspy_adsb[2349]: Acquired Airspy device with serial 91D064DC272C32CF

Oct 06 17:01:52 odroidxu4 airspy_adsb[2349]: Decoding started at 20 MSPS

Oct 06 17:02:04 odroidxu4 airspy_adsb[2349]: Push client connected to localhost:30004 (beast)

Oct 06 17:02:08 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:02:08 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:03:04 odroidxu4 airspy_adsb[2349]: /!\ Lost 262144 samples /!\

Oct 06 17:03:13 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:03:13 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:03:27 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:03:42 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:05:02 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:05:09 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:06:26 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:06:26 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:07:16 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:07:16 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:07:24 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:08:17 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:08:17 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:08:21 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:08:21 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:08:49 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:09:29 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:10:15 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

Oct 06 17:10:15 odroidxu4 airspy_adsb[2349]: /!\ Lost 131072 samples /!\

I also see increase in message rate :slight_smile:

Maybe, but that is so hard to tell…

image

None on my Pi4, but maybe depends how much traffic you see. :thinking:

There will be definitely more decodes. I suspect that’s why the CPU usage also increased in your case.
OK. @wiedehopf proposed a few other optimizations. Let’s try them.

2 Likes

Pi 4 , Mini @20 Mhz , Gain 16

Similar message count, but significantly less a/c, compared to @bramjacobse :confused:

That’s just time of the day:

That was meant in comparison to @bramjacobse‘s feeder :wink:

More Airspy CPU usage, more overall CPU. Otherwise, similar as before.
Still no luck to get the MLAT to sync at 24 MSPS (with or without bit-packing). No lost samples

What’s the message rate with 20MHz and 24MHz?
Btw, 24MHz forces the packing, otherwise you won’t get anything.

Can the AirSpy-Mini be pushed > 12 MSPS? Also is decimation now locked? Not seeing that or -w in more recent builds. Sorry, slight thread hijack, but still pertains to the Airspy decoder :slight_smile:

Can someone dump some raw ADSB data into a file and upload for testing?
You can use airspy_rx -r dump.bin -t 4 -a 20000000 -f 1090 -g 18
The utility can be downloaded from this link: https://airspy.com/downloads/airspy_tools.zip

You linked the windows version, you have a binary for ARM?

I’d say comparable
20: 22%20AM

24:

The difference in airplane count is just timing and some loss of MLAT

For linux, you can build from source. Or just apt-get install airspy.

Thanks. I think the loss of data at 24MHz is quite significant despite the packing.