Re: [Discuss-gnuradio] Time of Arrival Hooks

[Tim Pearce]

Devin,

The metadata is already passed to GNURadio by the USRP2 firmware. Its the gnuradio usrp2 source block that doesn't do anything with this information (metadata has the timestamp  for the first sample of each frame)

You can modify the code to provide a second stream, or interleave the data with them somehow by modifying the rx**_fc_handler.h
files (primarily) to get access to this timestamp data in C++ blocks or
post processing in python (all I've done so far).

Look for the "Fixme: Do something with metadata" line!

I've posted a couple of questions about getting timestamps to this mailing list (I don't
need absolute times in my case though so haven't thought about how to
sync these timestamps to real times) which some people (Doug, Juha I think) have helped me out on and I'm just summarising their replies here!

I think I've read something about the 3.3 release implementing this but that might have been about the ability to do TDMA

Cheers,

Tim

On Wed, Nov 11, 2009 at 7:21 PM, devin kelly <address@hidden> wrote:

Hello everyone,

I'm doing a project with the USRP2 that where I need to know the Time of Arrival(TOA) of the waveforms.  This is for a geolocation application.

My understanding as of now is that the hooks to get TOA are there in the USRP2, but the firmware does not provide access to them at this point.  Is this correct?

If the firmware can provide TOA, how can I get that information??

Thanks,
Devin

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