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?
On Thu, Jan 9, 2020 at 12:51 PM Brian Padalino <bpadal...@gmail.com> wrote: > On Thu, Jan 9, 2020 at 12:14 PM Richard Bell via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> Hello, >> >> I'm working on a TDOA based localization platform using 3 USRP X300's as >> receivers. I have them synchronized with a 10 MHz ref and PPS signal >> generated by an OctoClock. However, I'm having trouble getting reliable >> localization performance through this system. My TDOA measurements are not >> what I would expect for the geometry I'm using. >> >> If I have the USRPs flashed with the same FPGA image and I use the same >> sample rate (i.e. 200e6/22 = 9.0909 MHz) across them all, is it possible >> the hardware could still be introducing different delays through each >> receiver? >> > > Did you calibrate their phases using some type of calibration signal such > that you know the relative phase offsets of each radio to each other? > > Do you need to not know this information? > > Brian >
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