Hi Richard, To clarify, are you using a common Octoclock, with the 3 X300's in the same location, or separate locations with 3x Octoclocks? Do you have equal length cables to the antennas and does the rest of the system match ?
What is your RX frequency ? What daughterboard are you using? You may want to try using a decimation factor that will produce an non-fractional host sample rate, instead of 200e6/22 = 9090909.09090909_ MHz. Does running at 10 MS/s sample rate produce any difference in the result? Regards, Nate Temple On Thu, Jan 9, 2020 at 4:08 PM Brian Padalino via USRP-users < usrp-users@lists.ettus.com> wrote: > On Thu, Jan 9, 2020 at 6:45 PM Richard Bell <richard.be...@gmail.com> > wrote: > >> No I don't need to know phase information. I'm cross correlating the >> pairs of receivers and the location of the peak gives me the TDOA. If the >> hardware chains across different radios introduce different delays, that >> would invalidate the TDOA measurement. So long as the delay is the same >> through all the hardware chains, the TDOA estimate will be accurate. Can I >> assume the hardware delay through X300 USRPs with the same FPGA image and >> set to the same sampling frequency will be the same? >> > > I'd think the group delay should be pretty consistent - at least within > 10's of nanoseconds of each other if the setup is identical. > > What type of variation are you seeing when you perform your cross > correlations? How much variation are you able to handle? > > Brian > >> _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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