Re: [Discuss-gnuradio] About the decoding result of gr-air-modes

[YAXIONG XIE]

Do you get the GPS  location of the air plane? Or do you get it before?

If it is not the radio or antenna, maybe the environment matters? I didn't do any experiments in a totally open area, so I don't know whether it works under that scenario. If we can decoding the signal in environment, I think it should be very useful.

Yaxiong

2014-05-03 21:54 GMT+08:00 Silverfox <address@hidden>:

I have had the type 24 message for a long time.  However, the new reports seem bogus to me as well.  It is not the result of the radio or antenna as far as I can determine.

73,

Alan - W6ARH

 

 

From: discuss-gnuradio-bounces+alan.r.hill=address@hidden [mailto:discuss-gnuradio-bounces+alan.r.hill=address@hidden] On Behalf Of YAXIONG XIE
Sent: Saturday, May 3, 2014 6:44 AM
To: address@hidden
Subject: [Discuss-gnuradio] About the decoding result of gr-air-modes

 

Hi all,

 

I install the gr-air modes. And the hardware I am using is USRP N210 without GPSDO. The command I am using is the default command of the modes_rx module. And after I run this module, I got the following Results:

 

(-47 32.32056722) No handler for message type 24 from 739803

(-48 34.25826672) No handler for message type 24 from 207ee9

(-48 35.86728697) Type 5 (short surveillance ident reply) from a49b0c with ident 1264 (SPI ALERT)

(-48 35.87198622) No handler for message type 24 from a35558

(-50 35.95602397) No handler for message type 24 from 8b672a

(-49 35.97354972) Type 4 (short surveillance altitude reply) from 6e0c4c at 65200ft (AIRBORNE ALERT)

(-48 36.32546122) Type 5 (short surveillance ident reply) from 69f33f with ident 5514 (SPI)

(-49 37.18337247) Type 0 (short A-A surveillance) from 608e19 at 120900ft (No TCAS) (aircraft is on the ground)

(-48 37.21837897) No handler for message type 24 from e80163

(-50 38.68267197) No handler for message type 24 from b3e6f2

(-48 39.26921197) Type 0 (short A-A surveillance) from 12ff05 at 2250ft (speed 600-1200kt) (aircraft is on the ground)

(-49 40.52049497) Type 5 (short surveillance ident reply) from 38e9a8 with ident 3576 (SPI)

(-48 40.56394397) Type 0 (short A-A surveillance) from cf63e4 at 8700ft (Full TCAS resolution) (aircraft is on the ground)

(-47 40.56904497) No handler for message type 24 from 5353ab

(-48 41.08549722) No handler for message type 24 from b60846

DD(-48 52.18300072) Type 5 (short surveillance ident reply) from da22a7 with ident 3450 (SPI)

(-47 53.62936347) Type 5 (short surveillance ident reply) from 8c773 with ident 3374 (GROUND ALERT)

D(-49 56.62670697) Type 0 (short A-A surveillance) from fa024d at 125800ft (speed 1200-2400kt)

(-47 56.95657397) Type 5 (short surveillance ident reply) from 3b6a76 with ident 5634 (aircraft is on the ground)

(-47 57.34665522) No handler for message type 24 from f9ac8a

D(-50 59.47285847) Type 5 (short surveillance ident reply) from 7d6227 with ident 3510 (SPI ALERT)

(-51 59.49907272) Type 0 (short A-A surveillance) from 581dfb at 76200ft (No TCAS) (aircraft is on the ground)

D(-48 61.03326422) No handler for message type 24 from a90fee

(-48 61.18943772) Type 21 link capability report from 18049d: ACS: 0xd0ccc, BCS: 0xfeae, ECS: 0xa7, continues 4 ident 1810

(-49 62.11700572) Type 4 (short surveillance altitude reply) from 62253 at 17325ft (SPI ALERT)

(-47 62.44659672) No handler for message type 24 from 27adc7

D(-49 64.96764872) No handler for message type 24 from e30901

(-50 64.98554547) Type 5 (short surveillance ident reply) from a39eee with ident 7306 (SPI ALERT)

(-47 65.04707547) No handler for message type 24 from 0ec82e

(-49 65.10223472) Type 5 (short surveillance ident reply) from ca6477 with ident 3034 (AIRBORNE ALERT)

(-48 66.02713647) No handler for message type 24 from b4567c

(-48 66.37042047) No handler for message type 24 from 21544d

(-49 66.49397872) No handler for message type 24 from 759628

(-49 66.62760947) No handler for message type 24 from d79b77

(-48 67.58220572) Type 5 (short surveillance ident reply) from 98fb94 with ident 3334 (AIRBORNE ALERT)

(-49 68.06558797) No handler for message type 24 from 6d93b5

(-48 68.86033522) No handler for message type 24 from 4cc3fd

 

This is not what I want and I don't think it is the correct decoding result, is it right?

 

I did this experiments in indoor environment, then I think maybe the signal is too weak, then I move to the corridor and redo this and get similar results. I can not get the position of the air plane. 

 

So my question is that, is it all about the environment? Is there any other possible bugs or something I missed that cause the output I've received? I am very curious because the corridor is quite close to the out door environment.

 

Thanks a lot.

Yaxiong

 

--

Yaxiong Xie / 谢亚雄

 

School of Computer Engineering

Nanyang Technological University, Singapore

--

Yaxiong Xie / 谢亚雄

School of Computer Engineering

Nanyang Technological University, Singapore