Hi,
I used usrp_fft, and I can see a CW at 1575.42MHz, so it means that it is in the working condition, although I still get the same error msg once everytime i run anything. It says
$python usrp_fft.py -f 1.57542G
usb_contro_msg failed: usb_control_msg: sending control message failed, win error: A device attached to the system is not functioning.
But as I said, that I can see the generated CW on the usrp_fft graph, and the CW displayed on this graph follows the changes in frequency and amplitude made from signal generator, then I think we can ignore this error msg. We should be ready to move forward.
I am trying to use usrp_rx_cfile.py which I have altered as:
u = usrp.source_c (0, options.decim, 1, gru.hexint(options.mux), 0)
u.set_rx_freq (0, options.ddc_freq)
u.set_pga (0, options.gain)
u.set_pga (1, options.gain)
c2r=gr.complex_to_real()
dst = gr.file_sink (gr.sizeof_float, options.output_file)
#fg.connect (u, dst)
fg.connect(u,c2r,dst)
also, I am saving data to file as:
self.dst = gr.file_sink(gr.sizeof_float, filename)
as the data is no more complex.
Now if I connect GPS antenna to my usrp board and run
python usrp_rx_cfile.py -c 1574.015M -o gps_IF_real_samples.dat
where IF = 1575.42M - 1574.015M =1.405M
this should give me a file consisting of real IF samples of GPS data, ok to use with Kai Borre software receiver. but this isn't happening! :S
Am I usring usrp_rx_cfile.py incorrectly or do I need to implement any filtering around this frequency?.... or I am missing a very basic thing here!?
Faisal A. Khan
Doctral Candidate
University of New South Wales
NSW 2052, Sydney, Australia
P) +61-2-93854208 M)+61-401-260728
Date: Tue, 4 Mar 2008 15:16:17 -0500
From: address@hidden
To: address@hidden
CC: address@hidden
Subject: Re: [Discuss-gnuradio] GPS on USRP
I really don't think you should be getting any error messages. Could you copy the entire error message into an email? I might not be able to identify the problem, but maybe someone else on the list can. In the mean time, let's verify receipt of a test signal through the USRP.
I recommend running the example "usrp_wfm_rcv.py", located in /usr/local/share/gnuradio/examples/usrp/ on my Linux installation. It's essentially a limited spectrum analyzer. Hopefully you've got access to a signal generator. Start with a test signal at -40 dBm or so, at L1 (1575.42 MHz) for good measure. The program will likely automatically select your DBSRX card, but if you need to set specific options, use the '-help' flag on the command line to see the options. Do you get errors running this? If so, tell me exactly what they are.
--Paul
Phaysal Khan wrote:
Hi,
yes, I can run the test and it says at the end
Max USB/USRP throughput = 32MB/sec
although it gives that error msg 3 times for each usb throughput check (3 times for each 2M, 4M, 8M, 16M and 32M).
I am using DBSRX daughter card, which covers the GPS band, and this is physically installed. I think we are ready to move forward.
Faisal A. Khan
Doctral Candidate
University of New South Wales
NSW 2052, Sydney, Australia
P) +61-2-93854208 M)+61-401-260728
Date: Mon, 3 Mar 2008 17:02:18 -0500
From: address@hidden
To: address@hidden
CC: address@hidden
Subject: Re: [Discuss-gnuradio] GPS on USRP
I'd start by running usrp_benchmark_usb.py It's a USB speed test script, and it will verify proper communication with the USRP. The script is located in /usr/local/share/gnuradio/examples/usrp/ on my Linux installation.
Do you have a DBSRX daughter card to receive GPS frequencies? If that's physically installed and the test script mentioned above runs, we can move on.
--Paul
Phaysal Khan wrote:
Hi Paul,
Finally I got a working system of USRP radio. The FM radio example runs smoothly (atleast opens up and captures nothing:giving errors like "usb_control_msg failed: usb_control_msg failed: sending control message failed, win error, A device attached to the system is not functioning <--- Is this ok? I am using cygwin, gnu-3.1.1 and python 2.5)!?
Now, I would like to record IF samples and use Kai Borre Matlab based GPS receiver to solve for position. Should we proceed with sample recording. Can you guide me for this?
Faisal A. Khan
Doctral Candidate
University of New South Wales
NSW 2052, Sydney, Australia
P) +61-2-93854208 M)+61-401-260728
Date: Fri, 29 Feb 2008 12:45:29 -0500
From: address@hidden
To: address@hidden
CC: address@hidden
Subject: Re: [Discuss-gnuradio] GPS on USRP
Faisal,
I'm at Purdue University working toward using the USRP for GNSS applications. Check my understanding: are you wanting to use the USRP to record, say, L1 band samples directly to a data file? Would you be performing all of the signal acquisition and tracking in post-processing with a separate software tool?
I'm working on Linux (Debian), but we aught to be able to trade notes. If you've got a working installation of GNU Radio, I can show you how to record samples.
--Paul
Phaysal Khan wrote:
Hi,
I am a newbie to USRP, and still struggling to get it working on my windows machine. I am trying to use cygwin. I reckon that many ppl have already acquired and tracked GPS on USRP. Waht I want to do is to capture GPS IF samples (e.g. at IF=5 MHz) and use a software receiver to process those IF samples on PC. Any suggestions to start?!...
Faisal A. Khan
Doctral Candidate
University of New South Wales
NSW 2052, Sydney, Australia
P) +61-2-93854208 M)+61-401-260728
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