[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] usrp dbsrx to use in seti and radioastronomy

From: Krzysztof Kamieniecki
Subject: Re: [Discuss-gnuradio] usrp dbsrx to use in seti and radioastronomy
Date: Fri, 05 Aug 2005 01:33:13 -0400
User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.8) Gecko/20050511


Loftin, Ben B. wrote:

Excellent, I like the approach of wrapping the code so it can be used by
more than just gnuRadio.  If you're too busy I can attempt to build the

Now that the DBSRX is on the way, I would like to give the GNURadio integration one more try, just so I can get something accomplished with this monster. So give me a bit more time and we will see how things are going. When the wrappers are finished the question becomes how do we integrate GNURadio, my standalone GPS code & wrappers, and possibly GPStk (http://gpstk.sourceforge.net/) into a package that can be used by GNURadio users.

However even with the wrappers written there will still be a lot to do.

1. parsing and use of subframes 4,5 (GPStk?)
2. Atmosphere compensation (GPStk?)
3. velocity?
4. using the almanac to select satellite to track
5. Search and Tracking using FFT
6. Kalmen filters

On your webpage, you mention having some GPS data, do you mind sending
it thru email to me.  If you want I can let you upload to my ftp, just
let me know so I can send account info to only you.


Dave Bengtson is finishing up a schematic for a frontend using MAX 2745.
I'm helping with the layout and hopefully we can have something this

Without all the specs, it is hard to estimate how well or if the dbsrx
can acquire GPS.  It would be nice to be able to slap on a GPS antenna
that includes a LNA (20-26 dB gain?).  But with an 'active' antenna we
need to hook up a dc bias.  Can this be done easily, ideas? Not sure if
the PCB antenna will cut it.  I'm sure in the coming days we will get
the details we need for dbsrx, which will be needed before releasing the
coin :)

Eric mentioned in a later email that the DBSRX does have a bias input, if that was not available the standard method seems to be to use a Bias Tee. (I mention this because if one is not "in the know" it's hard to figure out what such a component is called)

Maybe I can help develop some WAAS code or has someone already done this
too? Thanks for all the info. I'll have fun looking thru kkGPS.
From what I have seen WAAS has not been touched by any Free Software or Open Source projects, I think this is because the final standard is not freely (cash and Freedom) available to the public, and I don't know if the license of the standard would allow a Free Software implementation.


(resent since I forgot so subscribe this email)


-----Original Message-----
From: Krzysztof Kamieniecki [mailto:address@hidden Sent: Thursday, August 04, 2005 6:52 AM
To: address@hidden
Cc: Ben Loftin
Subject: Re: [Discuss-gnuradio] usrp dbsrx to use in seti and

Hi Ben,

Have you taken a look at GNURadio wiki? Specifically the GPS page.

I have some code for software GPS at

My project has been sidetrack by a contract project I am working on
GNURadio. At this point I have decided on a way to integrate my existing
code with GNURadio so that the few people who are using my code to
process raw
data do not have to use GNURadio. I have created a GNURadio block that
wraps my
GPS signal generator. The next step is to create a block that wraps my
Correlator, and then a block that wraps my low level GPS Receiver (a set
synchronized Correlators with a state machine controllers to track the
from the various GPS satellites) I ordered the dbsrx with the hope that
least to possibility of getting realtime GPS signal data may spur me on.


Quoting Marcus Leech <address@hidden>:

Ben Loftin wrote:

Could you elaborate on what you mean by seeing GPS L1.  Does this me

acquisition, tracking, seeing bumps on an FFT, etc.  I ask because I

am starting to build up algorithms for a GPS receiver to use with USRP. I just finished the first simple one of generating the C/A

for each satellite. You can check it out on on my blog at http://www.phys-x.org/grblog/grblog.html (try the link since the higher domain registers need some time to refresh).

Anybody else developing code for GPS so we can pool our efforts?


I just saw the appropriate spectral bumps--I don't have a GPS


Discuss-gnuradio mailing list

Discuss-gnuradio mailing list

Krzysztof Kamieniecki

reply via email to

[Prev in Thread] Current Thread [Next in Thread]