Hi Daniel, thank you for your reply. This is test code: I'm using tow E312 to estimate the arrive time difference between received signals.The program is explained as follows: uhd::usrp::multi_usrp::sptr UsrpDev = uhd::usrp::multi_usrp::make(“”); UsrpDev->set_time_source("gpsdo"); UsrpDev->set_clock_source("internal", uhd::usrp::multi_usrp::ALL_MBOARDS); ... uhd::stream_args_t StreamArgs; StreamArgs.cpu_format ="fc32"; StreamArgs.channels.clear(); StreamArgs.channels.push_back(0); uhd::rx_streamer::sptr RxStreamDev = UsrpDev->get_rx_stream(StreamArgs); ... UsrpDev->set_rx_gain(curGain); UsrpDev->set_rx_rate(curRxRates); UsrpDev->set_rx_freq(tune_request, 0); ... UsrpDev->set_time_next_pps(uhd::time_spec_t(GpsTime + 1.0)); ... uhd::stream_cmd_t CapCmdContStart( uhd::stream_cmd_t::STREAM_MODE_START_CONTINUOUS ); CapCmdContStart.stream_now = false; CapCmdContStart.num_samps = IQ_NUMS; CapCmdContStart.time_spec = uhd::time_spec_t((double)nextBoardTime); RxStreamDev->issue_stream_cmd(CapCmdContStart); ... size_t RxNums = RxStreamDev->recv( RecvBuffVec, RecvNums, RxMetaData, timeoutD, false ); ...
Right now, the data blocks received from the two receivers have strictly aligned time stamps: MatchTimeD=(E312-A)1508010715.000047200 (E312-B)1508010715.000047200 MatchTimeD=(E312-A)1508010715.010287300 (E312-B)1508010715.010287300 MatchTimeD=(E312-A)1508010715.020527100 (E312-B)1508010715.020527100 MatchTimeD=(E312-A)1508010715.030767400 (E312-B)1508010715.030767400 So,i think GPS locked for two E312. best regards Jon 2017-10-23 23:52 GMT+08:00 Daniel May <danielma...@gmail.com>: > Jon, > > Like I mentioned earlier, I've used E310's for TDOA measurements with > success. I do have the same initial offset issue, but I can either a) > compute the offset and manually correct for it, or b) stop and restart the > stream, and the offset disappears. > > If the offset is drifting, you are not using a GPS disciplined clock. Are > you sure you have GPS lock? > > -Daniel > > On Sun, Oct 22, 2017 at 7:44 PM, liu Jong via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> Hi Marcus, >> I am sorry,the first link as below: >> http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/ >> 2017-October/026761.html >> >> 2017-10-21 21:17 GMT+08:00 Marcus Müller via USRP-users < >> usrp-users@lists.ettus.com>: >> >>> Dear Jon, >>> >>> that first link points to your own GMail account. We can't do anything >>> with that, I'm afraid. >>> >>> Please find the email you're referring to, cite it directly, or link to >>> it on http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/ >>> >>> Thank you! >>> Marcus M >>> >>> On 20.10.2017 03:20, liu Jong via USRP-users wrote: >>> >>> HI all, >>> For multiple E312 synchronizing,we did synchronous reception tests, and >>> specific things as email descriptions: >>> https://mail.google.com/mail/u/0/?pc=topnav-about-en#all/15f >>> 24798ac0bac0b >>> I also noted that said it was a bug: >>> http://permalink.gmane.org/gmane.comp.hardware.usrp.e100/16889 >>> >>> Has this bug been repaired? can E312 be used for TDOA measurement and, >>> if possible, how to implement it in the program? >>> >>> best regards >>> Jon >>> >>> >>> _______________________________________________ >>> USRP-users mailing >>> listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> >
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