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

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 [email protected]:

Hi all,

at 65200ft (AIRBORNE ALERT)

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

signal is too weak, then I move to the corridor and redo this and get

School of Computer Engineering

Nanyang Technological University, Singapore

*Yaxiong Xie / *谢亚雄

School of Computer Engineering

Nanyang Technological University, Singapore