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jvde-github / AIS-catcher

AIS receiver for RTL SDR dongles, Airspy R2, Airspy Mini, Airspy HF+, HackRF, SDRplay and SoapySDR
https://aiscatcher.org
GNU General Public License v3.0
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🙏 Help4newbie: Connecting to a SDR public feed #22

Closed alsak0de closed 2 years ago

alsak0de commented 2 years ago

hiya, would you please help me with the syntax to fetch from an actual SDR remote signal like the ones listed on https://airspy.com/directory/ ??

I've tried AIS-catcher -t 31.31.235.80 5555 -s 240000 -v as an example but seems the received feed is different and AIS-catcher -t requires a RTLTCP feed that I suppose it is different.

Is there a way to inject a sdr:// feed instead of RTLTCP? If not, are there RTLTCP public servers to get the signal from?

thanks in advance,

jvde-github commented 2 years ago

Hi, it is an interesting idea, you need to find a feed that is close enough to the water and allows to receive on 162 MHz. This reduces the options quite a bit, but there seem to be a few of these in your list. An easy way to check this is to use SDR# and look at AIS signals around 162 MHz (use the Airspy Server Network as source). I managed to found at least one feed which looks to have AIS signals (around Gothenborg).

Then the second step is to decode these messages. Unfortunately, AIS-catcher has the required protocol not implemented. You could record the signal perhaps in SDR# and the decode it in AIS-catcher but I cannot try that at the moment. The other option is to attach AISmon to SDR# output, but this requires some fiddling.

Let me have a look how difficult it is to add airspy server support by adding an extra protocol (currently there is RTLTCP and NONE).

Jasper

jvde-github commented 2 years ago

Turns out that there is a SoapySDR driver for spyserver which has been recently published. So, installing this driver and using the experimental support for SoapySDR and SOXR downsampling, we could theoretically decode these signals, with commands like:

AIS-catcher -d SOAPYSDR -gu device "driver=spyserver,host=143.178.161.73,port=5556" PROBE on AGC off  -s 625000 -go SOXR on -v

Notice that the sample rate you need to provide and needs to be supported by the feed, which can be found by:

SoapySDRUtil --probe="driver=spyserver,host=143.178.161.73,port=5556"

Unfortunately, this does not work yet :-(, the device opens but the streaming stopped immediately in my test. This is likely an issue with AIS-catcher that I need to fix before release.

alsak0de commented 2 years ago

Thanks!! Recording and then passing catcher works but the objective would be to get a RTMP type of audio stream that the catcher can be connected to.

jvde-github commented 2 years ago

Hi, made a small fix and commands like this should work now:

AIS-catcher -d SOAPYSDR -gu device "driver=spyserver,host=143.178.161.73,port=5555"  -s 192K  -go SOXR on -v
jvde-github commented 2 years ago

There is also another route that you could explore. I managed to get some AIS messages with this approach, see below (unfortunately not with the soapysdr driver) . The idea is to use a spyserver client and pipe the input into AIS-catcher:

./ss_client iq - -r 143.178.161.73 -q 5555 -f 162000000 -s 192000 -g 12 |AIS-catcher -s 192K -r CS16 .

ss_client is available here and I installed libsamplerate_dev as dependency:

sudo apt install libsamplerate-dev

I will integrate spyserver support in due time.

Output:

./ss_client iq - -r 143.178.161.73 -q 5555 -f 162000000 -s 192000 -g 12 |AIS-catcher -s 192K -r CS16 . 
iq filename: -
bins for res: 1920   fft bins: 2048   resolution: 93.75Hz
SS_client_if(143.178.161.73, 5555)
SS_client_if: Trying to connect
AIS-catcher (build Jun 16 2022) v0.35
(C) Copyright 2021-2022 jvde-github and other contributors
This is free software; see the source for copying conditions.There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
SS_client_if: Connected

**********
Device Info:
   Type:                 2
   Serial:               825307186
   MaximumSampleRate:    768000
   MaximumBandwidth:     660000
   DecimationStageCount: 8
   GainStageCount:       0
   MaximumGainIndex:     0
   MinimumFrequency:     0
   MaximumFrequency:     1700000000
   Resolution:           16
   MinimumIQDecimation:  2
   ForcedIQFormat:       0

**********
Client sync:
   Control:     Yes
   gain:        12
   dev_ctr:     330000
   ch_ctr:      330000
   iq_ctr:      330000
   fft_ctr:     330000
   min_iq_ctr:  82500
   max_iq_ctr:  1699917500
   min_fft_ctr: 330000
   max_fft_ctr: 1699670000

**********
Client sync:
   Control:     Yes
   gain:        12
   dev_ctr:     330000
   ch_ctr:      330000
   iq_ctr:      330000
   fft_ctr:     330000
   min_iq_ctr:  82500
   max_iq_ctr:  1699917500
   min_fft_ctr: 330000
   max_fft_ctr: 1699670000
SS_client_if: Ready
Exact decimation match
Desired decimation stage: 2 (768000 / 4 = 192000) resample ratio: 1
ss_client: setting center_freq to 1.62e+08
SS_client_if: Starting Streaming
SS_client_if: Lost 1 frames from SpyServer!
!AIVDM,1,1,,A,13aPNrPP00PJp1lMbihh0?vb2@<E,0*48 ( MSG: 1, REPEAT: 0, MMSI: 244850410)
!AIVDM,1,1,,A,13`p=J@P00PJon:MbiP>4?vb20Rc,0*76 ( MSG: 1, REPEAT: 0, MMSI: 244190569)
!AIVDM,1,1,,A,33aDoQ000jPJqk@Mbs3AoAJT05US,0*3A ( MSG: 3, REPEAT: 0, MMSI: 244660100)
!AIVDM,1,1,,B,13aEQ7wP00PJou6MbiS@0?vd20S5,0*58 ( MSG: 1, REPEAT: 0, MMSI: 244670751)
jvde-github commented 2 years ago

Ok, I added some initial SpyServer support which can be activated with a comment like:

AIS-catcher  -y 89.245.170.117 5555 -gy GAIN 14 -v

There are still a few things to clean up (error recovery, more stream formats, etc), but it seems to work:

AIS-catcher (build Jun 26 2022) v0.35
(C) Copyright 2021-2022 jvde-github and other contributors
This is free software; see the source for copying conditions.There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Connecting to SpyServer...
Device info:
  Serial: 942682164 MaximumSampleRate : 768000 MaximumBandwidth : 660000
  DecimationStageCount: 8 GainStageCount: 0 MaximumGainIndex: 0
  Minimum/Maximum Frequency: 0/275000000 resolution: 16
  MinimumIQDecimation: 2 ForcedIQFormat: 0
Client:
  CanControl: 1 Gain : 0 DeviceCenterFrequency : 89600000
  IQCenterFrequency: 89600000  Minimum/Maximum Frequency: 82500/274917500 resolution: 16
SPYSERVER settings: -gy host 89.245.170.117 port 5555 gain 14
Generic settings: sample rate -s 192K  
Client:
  CanControl: 1 Gain : 0 DeviceCenterFrequency : 89600000
  IQCenterFrequency: 89600000  Minimum/Maximum Frequency: 82500/274917500 resolution: 16
[AIS engine v0.35]:                      0 msgs at 0 msg/s
!AIVDM,1,1,,B,4025btl47wk?0<tSF0l4Q@000l5I,0*48 ( MSG: 4, REPEAT: 0, MMSI: 2190067)
[AIS engine v0.35]:                      1 msgs at 0.2 msg/s
!AIVDM,1,1,,A,4025btl47wk?1<tSF0l4Q@000PS:,0*63 ( MSG: 4, REPEAT: 0, MMSI: 2190067)
[AIS engine v0.35]:                      2 msgs at 0.2 msg/s
!AIVDM,1,1,,B,4025btl47wk?0<tSF0l4Q@000d5Q,0*58 ( MSG: 4, REPEAT: 0, MMSI: 2190067)
[AIS engine v0.35]:                      3 msgs at 0.3 msg/s
^C----------------------
[AIS engine v0.35]:                      3 msgs at 0.1 msg/s
jvde-github commented 2 years ago

As Spyserver support is now included I propose to close this issue.