Hi Nick,
Thanks.
Is it possible to treat the start of the save samples as time 0, then
timestamp following packets accordingly? Well, if not, I think it would be
a good feature to be added in the future.
Best regards,
Cheng Chi
On Thu, Jan 30, 2014 at 12:58 AM, Nick Foster <bistrom...@gmail.com> wrote:
> Oh! Of course. Yes, that's why I wanted to see the complete output --
> timestamps are not kept in the saved samples. You'll only get timestamps if
> you are viewing live data.
>
> --n
>
>
> On Wed, Jan 29, 2014 at 2:24 AM, Cheng Chi <ch000...@e.ntu.edu.sg> wrote:
>
>> Hi Nick,
>>
>> Thanks for your explanation :)
>>
>> Today I have collected some data using the same setup, USRP N210 with
>> GPSDO + WBX. The collection is done at the rooftop with open sky.
>> Gain: 20
>> Sampling Rate: 10M
>> Center Frequency: 1090M
>> Data format: complex float (Use GNUradio Companion for collecting data. I
>> think this should be the same as using uhd_rx_cfile?)
>>
>> As shown below, the decoded data seems correct, but the timestamp
>> information is still quite strange. Is it because the modes_rx program
>> can't timestamp packets for saved data? Do you have any suggestion about
>> how to identify the Mode S packet from the raw data? (I've tried using the
>> preamble to cross correlate with the received data, but no success so far.)
>>
>>
>> command line:
>> {{{
>> modes_rx -s ADSB_10M_JAN29_float_4.dat -r 10000000
>> }}}
>>
>> output:
>> {{{
>> (-55 0.00000000) Type 0 (short A-A surveillance) from 8a0301 at 2450ft
>> (Vertical TCAS resolution only)
>> (-52 0.00000000) Type 20 TCAS report from 76ce4e: (no handler for TTI=0)
>> at 14200ft
>> (-55 0.00000000) Type 0 (short A-A surveillance) from 8a0301 at 2450ft
>> (Vertical TCAS resolution only)
>> (-56 0.00000000) Type 0 (short A-A surveillance) from 76cf27 at 8600ft
>> (Vertical TCAS resolution only)
>> (-50 0.00000000) Type 17 BDS0,9-1 (track report) from 461eac with
>> velocity 191kt heading 23 VS 64
>> (-57 0.00000000) Type 17 BDS0,5 (position report) from 8a01ba at
>> (0.985511, 103.824021) at 5375ft
>> (-56 0.00000000) Type 20 TCAS report from 75029c: (no handler for TTI=0)
>> at 38025ft
>> (-54 0.00000000) Type 0 (short A-A surveillance) from 75029c at 38025ft
>> (speed 300-600kt)
>> (-60 0.00000000) Type 0 (short A-A surveillance) from abee7c at 7100ft
>> (Vertical TCAS resolution only)
>> (-46 0.00000000) Type 0 (short A-A surveillance) from 750279 at 9100ft
>> (Vertical TCAS resolution only)
>> (-58 0.00000000) Type 0 (short A-A surveillance) from 8a1f1a at 2400ft
>> (Vertical TCAS resolution only)
>> (-55 0.00000000) Type 0 (short A-A surveillance) from 8a03c2 at 8075ft
>> (Vertical TCAS resolution only)
>> (-45 0.00000000) Type 0 (short A-A surveillance) from ae075d at 1100ft
>> (Vertical TCAS resolution only)
>> (-50 0.00000000) Type 0 (short A-A surveillance) from 4b1906 at 10100ft
>> (Vertical TCAS resolution only)
>> (-54 0.00000000) Type 20 TCAS report from 76cd88: (no handler for TTI=0)
>> at 4100ft
>> (-51 0.00000000) Type 0 (short A-A surveillance) from 4b1906 at 10100ft
>> (Vertical TCAS resolution only)
>> (-44 0.00000000) Type 11 (all call reply) from 8a01ba in reply to
>> interrogator 0 with capability level 6
>> (-52 0.00000000) Type 17 BDS0,5 (position report) from 76ce4e at
>> (1.148118, 104.249078) at 14225ft
>> (-55 0.00000000) Type 20 TCAS report from 76cd88: (no handler for TTI=0)
>> at 4100ft
>> (-58 0.00000000) Type 0 (short A-A surveillance) from 8a0301 at 2450ft
>> (Vertical TCAS resolution only)
>> (-56 0.00000000) Type 0 (short A-A surveillance) from 732f06 at 3700ft
>> (Vertical TCAS resolution only)
>> (-51 0.00000000) Type 0 (short A-A surveillance) from 7501fd at 33000ft
>> (Vertical TCAS resolution only)
>> (-53 0.00000000) Type 0 (short A-A surveillance) from 76cd88 at 4100ft
>> (Vertical TCAS resolution only)
>> (-55 0.00000000) Type 21 link capability report from 76cd88: ACS:
>> 0x10080, BCS: 0xf600, ECS: 0x0, continues 0 ident 9c
>> (-51 0.00000000) Type 0 (short A-A surveillance) from 76ce4e at 14225ft
>> (speed 300-600kt)
>> (-45 0.00000000) Type 0 (short A-A surveillance) from ae075d at 1100ft
>> (Vertical TCAS resolution only)
>> (-56 0.00000000) Type 0 (short A-A surveillance) from 8a0301 at 2450ft
>> (Vertical TCAS resolution only)
>> (-57 0.00000000) Type 0 (short A-A surveillance) from 76cf27 at 8600ft
>> (Vertical TCAS resolution only)
>> (-54 0.00000000) Type 17 BDS0,5 (position report) from 76cd88 at
>> (0.876299, 103.944397) at 4100ft
>> (-52 0.00000000) Type 0 (short A-A surveillance) from 76ce4e at 14225ft
>> (Vertical TCAS resolution only)
>> (-50 0.00000000) Type 11 (all call reply) from 461eac in reply to
>> interrogator 0 with capability level 6
>> }}}
>>
>> Best regards,
>> Cheng Chi
>>
>>
>>
>> On Tue, Jan 28, 2014 at 1:58 AM, Nick Foster <bistrom...@gmail.com>wrote:
>>
>>> Haven't used bladeRF, but I have used other LMS6002D-based radios with
>>> gr-air-modes, with some success. The problem is Mode S has a weak CRC and
>>> is thus vulnerable to spurious packets. That said, in practice spurious
>>> replies should be under 1% of your total. Experiment with gain and
>>> threshold settings -- your feedback should be nonunique ICAO numbers; in
>>> other words you're looking for multiple replies from the same aircraft. The
>>> "get_dupes.py" script in apps/ will take the output generated by
>>> gr-air-modes and parse it to tell you how many actual aircraft you've heard.
>>>
>>> --n
>>>
>>>
>>> On Mon, Jan 27, 2014 at 2:35 AM, Ralph A. Schmid, dk5ras <
>>> ra...@schmid.xxx> wrote:
>>>
>>>> When having no clue about the data I should expect – how can I find out
>>>> about the real data, and how can I see what is decoded noise? I am using
>>>> the bladeRF, and to me most data looks wrong, too :)
>>>>
>>>>
>>>>
>>>> Ralph-
>>>>
>>>>
>>>>
>>>> *From:* discuss-gnuradio-bounces+ralph=schmid....@gnu.org [mailto:
>>>> discuss-gnuradio-bounces+ralph=schmid....@gnu.org] *On Behalf Of *Nick
>>>> Foster
>>>> *Sent:* Monday, January 27, 2014 9:43 AM
>>>> *To:* Cheng Chi
>>>> *Cc:* GNURadio Discussion List
>>>> *Subject:* Re: [Discuss-gnuradio] Help about using gr-air-modes
>>>>
>>>>
>>>>
>>>> The reason you're seeing lots of false packets is the use of a zero
>>>> threshold. Leave the -T 0 part out of the command line. Your other settings
>>>> are fine, although if you're indoors you probably aren't going to see much
>>>> data at all.
>>>>
>>>>
>>>>
>>>> I'll look into the timestamp issue and see if I can replicate it here.
>>>>
>>>>
>>>>
>>>> --n
>>>>
>>>>
>>>>
>>>> On Mon, Jan 27, 2014 at 12:40 AM, Cheng Chi <ch000...@e.ntu.edu.sg>
>>>> wrote:
>>>>
>>>> Hi Nick,
>>>>
>>>>
>>>>
>>>> The command line:
>>>>
>>>> {{{
>>>>
>>>> modes_rx -T 0 -r 10000000 -s packet_float.dat
>>>>
>>>> }}}
>>>>
>>>>
>>>>
>>>> The setup:
>>>>
>>>> USRP + WBX + VERT900 Antenna, gain is set at 19 when recording the data.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> The output:
>>>>
>>>> {{{
>>>>
>>>> usrp@ubuntu:~/gr-air-modes/apps$ modes_rx -T 0 -r 10000000 -s
>>>> packet_float.dat
>>>>
>>>> Using file source packet_float.dat
>>>>
>>>> Rate is 10000000
>>>>
>>>> Using Volk machine: avx_32_mmx_orc
>>>>
>>>> (41 0.00000000) Type 0 (short A-A surveillance) from 8b11e3 at 43825ft
>>>> (speed <75kt)
>>>>
>>>> (31 0.00000000) Type 0 (short A-A surveillance) from 76ce83 at 19000ft
>>>> (Vertical TCAS resolution only)
>>>>
>>>> (38 0.00000000) Type 0 (short A-A surveillance) from 7805dd at 3025ft
>>>> (Vertical TCAS resolution only)
>>>>
>>>> (26 0.00000000) Type 4 (short surveillance altitude reply) from 53dd8d
>>>> at -1000ft (SPI)
>>>>
>>>> (25 0.00000000) No handler for message type 24 from d9a7dd
>>>>
>>>> (27 0.00000000) Type 0 (short A-A surveillance) from ee5e77 at 44475ft
>>>> (Vertical TCAS resolution only)
>>>>
>>>> (26 0.00000000) Type 0 (short A-A surveillance) from e2683e at 33850ft
>>>> (speed 1200-2400kt)
>>>>
>>>> (38 0.00000000) Type 0 (short A-A surveillance) from 7805dd at 3025ft
>>>> (Vertical TCAS resolution only)
>>>>
>>>> (26 0.00000000) No handler for message type 24 from df163e
>>>>
>>>> (26 0.00000000) No handler for message type 24 from 4dd8f4
>>>>
>>>> (22 0.00000000) Type 0 (short A-A surveillance) from 3b8ec9 at 59100ft
>>>> (speed 75-150kt)
>>>>
>>>> (26 0.00000000) Type 0 (short A-A surveillance) from 9f6f91 at 18450ft
>>>> (speed 1200-2400kt)
>>>>
>>>> (28 0.00000000) No handler for message type 24 from c4b50b
>>>>
>>>> (31 0.00000000) Type 11 (all call reply) from 76ce83 in reply to
>>>> interrogator 0 with capability level 6
>>>>
>>>> (31 0.00000000) Type 21 link capability report from 75008f: ACS:
>>>> 0x10680, BCS: 0xf600, ECS: 0x0, continues 0 ident 564
>>>>
>>>> (23 0.00000000) No handler for message type 24 from 38f620
>>>>
>>>> (26 0.00000000) No handler for message type 24 from d7a547
>>>>
>>>> (29 0.00000000) Type 11 (all call reply) from 76aa6b in reply to
>>>> interrogator 0 with capability level 6
>>>>
>>>> (26 0.00000000) Type 5 (short surveillance ident reply) from b49331
>>>> with ident 7150 (aircraft is on the ground)
>>>>
>>>> (29 0.00000000) Type 5 (short surveillance ident reply) from 8f6b6a
>>>> with ident 7610 (SPI ALERT)
>>>>
>>>> (39 0.00000000) Type 4 (short surveillance altitude reply) from a69223
>>>> at 32975ft (AIRBORNE ALERT)
>>>>
>>>> (25 0.00000000) Type 4 (short surveillance altitude reply) from acc9e9
>>>> at 53700ft (aircraft is on the ground)
>>>>
>>>> (33 0.00000000) Type 0 (short A-A surveillance) from 8a01d4 at 18750ft
>>>> (speed 300-600kt)
>>>>
>>>> (32 0.00000000) Type 0 (short A-A surveillance) from 8a01d4 at 18750ft
>>>> (speed 300-600kt)
>>>>
>>>> (28 0.00000000) Type 0 (short A-A surveillance) from 601589 at 46725ft
>>>> (TCAS resolution inhibited)
>>>>
>>>> (27 0.00000000) Type 5 (short surveillance ident reply) from 4ba262
>>>> with ident 2520 (SPI)
>>>>
>>>> (24 0.00000000) Type 21 link capability report from fba5fc: ACS:
>>>> 0x250aa, BCS: 0xe638, ECS: 0xa2, continues 6 ident 68
>>>>
>>>> (25 0.00000000) Type 5 (short surveillance ident reply) from fbc939
>>>> with ident 3620 (SPI ALERT)
>>>>
>>>> (24 0.00000000) Type 0 (short A-A surveillance) from 7e5086 at 111200ft
>>>> (speed 150-300kt)
>>>>
>>>> (24 0.00000000) No handler for message type 24 from 10b1ec
>>>>
>>>> (25 0.00000000) No handler for message type 24 from 1aba1c
>>>>
>>>> (24 0.00000000) Type 0 (short A-A surveillance) from 9d7554 at 10800ft
>>>> (speed 2400-4800kt)
>>>>
>>>> (23 0.00000000) Type 5 (short surveillance ident reply) from 9da024
>>>> with ident 3540 (GROUND ALERT)
>>>>
>>>> (27 0.00000000) No handler for message type 24 from 9f8569
>>>>
>>>> (24 0.00000000) No handler for message type 24 from 5da41f
>>>>
>>>> (25 0.00000000) Type 0 (short A-A surveillance) from ae194c at 48875ft
>>>> (speed 600-1200kt)
>>>>
>>>> (23 0.00000000) No handler for message type 24 from 11099d
>>>>
>>>> (30 0.00000000) Type 20 TCAS report from 76aa6b: (no handler for
>>>> TTI=0) at 11450ft
>>>>
>>>> (23 0.00000000) No handler for message type 24 from b7a19e
>>>>
>>>> (28 0.00000000) Type 20 link capability report from ef7118: ACS:
>>>> 0x55278, BCS: 0x954d, ECS: 0xb1, continues 14 at 51300ft
>>>>
>>>> (24 0.00000000) Type 0 (short A-A surveillance) from 7f4d04 at 13475ft
>>>> (speed 75-150kt)
>>>>
>>>> (32 0.00000000) Type 17 BDS0,9-1 (track report) from 8a01d4 with
>>>> velocity 406kt heading 150 VS 1984
>>>>
>>>> (28 0.00000000) Type 21 link capability report from 8992dc: ACS:
>>>> 0x100c0, BCS: 0xe600, ECS: 0x0, continues 0 ident 9a0
>>>>
>>>> (37 0.00000000) Type 20 TCAS report from 7805dd: (no handler for
>>>> TTI=0) at 3000ft
>>>>
>>>> (27 0.00000000) Type 0 (short A-A surveillance) from dc2ed9 at 45900ft
>>>> (speed 600-1200kt)
>>>>
>>>> (23 0.00000000) Type 4 (short surveillance altitude reply) from 2443b0
>>>> at 59800ft (GROUND ALERT)
>>>>
>>>> (24 0.00000000) Type 4 (short surveillance altitude reply) from 3b1fc3
>>>> at 3200ft (SPI)
>>>>
>>>> (21 0.00000000) Type 21 link capability report from d5ca0e: ACS:
>>>> 0xda21, BCS: 0xc923, ECS: 0xee, continues 8 ident 123e
>>>>
>>>> (22 0.00000000) Type 5 (short surveillance ident reply) from 5ad8b4
>>>> with ident 728 (GROUND ALERT)
>>>>
>>>> (37 0.00000000) Type 17 BDS0,9-1 (track report) from 7805dd with
>>>> velocity 218kt heading 238 VS -1664
>>>>
>>>> }}}
>>>>
>>>>
>>>>
>>>> Best regards,
>>>>
>>>> Cheng Chi
>>>>
>>>>
>>>>
>>>> On Mon, Jan 27, 2014 at 4:28 PM, Nick Foster <bistrom...@gmail.com>
>>>> wrote:
>>>>
>>>> On Mon, Jan 27, 2014 at 12:23 AM, Cheng Chi <ch000...@e.ntu.edu.sg>
>>>> wrote:
>>>>
>>>> Hi Nick,
>>>>
>>>>
>>>>
>>>> Thanks for your quick reply!
>>>>
>>>>
>>>>
>>>> I have to use a 10M sampling rate in my case, but due to computer
>>>> constrain, modes_rx will cause overflow when used directly with -r
>>>> 10000000. I gauss it's because it's sampling data in float? I am using a
>>>> GPSDO with USRP.
>>>>
>>>>
>>>>
>>>> So I record data in short at 10M sampling rate, convert from short to
>>>> float and then input to modes_rx. The output looks like this:
>>>>
>>>> {{{
>>>>
>>>> (27 0.00000000) Type 0 (short A-A surveillance) from dc2ed9 at 45900ft
>>>> (speed 600-1200kt)
>>>>
>>>> (23 0.00000000) Type 4 (short surveillance altitude reply) from 2443b0
>>>> at 59800ft (GROUND ALERT)
>>>>
>>>> (24 0.00000000) Type 4 (short surveillance altitude reply) from 3b1fc3
>>>> at 3200ft (SPI)
>>>>
>>>> (21 0.00000000) Type 21 link capability report from d5ca0e: ACS:
>>>> 0xda21, BCS: 0xc923, ECS: 0xee, continues 8 ident 123e
>>>>
>>>> (22 0.00000000) Type 5 (short surveillance ident reply) from 5ad8b4
>>>> with ident 728 (GROUND ALERT)
>>>>
>>>> (37 0.00000000) Type 17 BDS0,9-1 (track report) from 7805dd with
>>>> velocity 218kt heading 238 VS -1664
>>>>
>>>> }}}
>>>>
>>>>
>>>>
>>>> The timestamp are all zeros.
>>>>
>>>>
>>>>
>>>> This appears to be a bug. Can you paste the entire output of
>>>> gr-air-modes?
>>>>
>>>>
>>>>
>>>> I'm also concerned by the data you've shown. There is only one real
>>>> reply in the above data -- the last one. The others are all spurious
>>>> replies. Can you tell me the command line you're using as well as the
>>>> equipment setup -- daughterboard, antenna, etc.?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Another question is that if I use modes_rx, how to save the sampled
>>>> complex baseband signal? Is the data saved somewhere that I've missed?
>>>>
>>>>
>>>>
>>>> This is not something modes_rx is designed to do. I suggest instead
>>>> that you record samples to disk using uhd_rx_cfile, and then run modes_rx
>>>> on the saved file using --source=<filename>.
>>>>
>>>>
>>>>
>>>> --n
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Best regards,
>>>>
>>>> Cheng Chi
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Mon, Jan 27, 2014 at 3:57 PM, Nick Foster <bistrom...@gmail.com>
>>>> wrote:
>>>>
>>>> On Sun, Jan 26, 2014 at 11:48 PM, Cheng Chi <ch000...@e.ntu.edu.sg>
>>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I am using gr-air-modes for decoding the air plane signal with USRP.
>>>> I've successfully used the "modes_rx" and "modes_gui" for decoding the
>>>> mode-S packets.
>>>>
>>>> However, it seems that the modes_rx or modes_gui can't provide the
>>>> timestamp of the mode-S packets being decoded. Is there any option that I
>>>> can set to timestamp the mode-S packet? The reason I want this timestamp
>>>> function is that I want to know the decoded packet data correspond to which
>>>> part of the raw data (complex baseband data samples).
>>>>
>>>>
>>>>
>>>> If you're using a USRP, you should be getting a timestamp. It's the
>>>> second number printed, as in the following:
>>>>
>>>> (-14 *1.29258827811*) Type 0 (short A-A surveillance) from ab2984 at
>>>> 3000ft
>>>>
>>>>
>>>>
>>>> If you are using a GPSDO with your USRP, the printed time will be in
>>>> UTC seconds. Otherwise, it will be in seconds since the application started
>>>> running.
>>>>
>>>>
>>>>
>>>> --n
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Thank you for any help you can provide in this situation.
>>>>
>>>> I found that there's a file called "air_modes_preamble.cc" seems to
>>>> provide the timestamp function. Does anyone know how to use this file
>>>> separately?
>>>>
>>>>
>>>>
>>>> Best regards,
>>>>
>>>> Cheng Chi
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>>
>>>>
>>>>
>>>>
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>>>>
>>>>
>>>>
>>>>
>>>
>>>
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