[USRP-users] Bug about for E312

liu Jong jongliu1987 at gmail.com
Mon Oct 23 21:31:03 EDT 2017


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 <danielmay83 at 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 at 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 at 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 at lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>>
>>>
>>>
>>> _______________________________________________
>>> USRP-users mailing list
>>> USRP-users at lists.ettus.com
>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>>
>>>
>>
>> _______________________________________________
>> USRP-users mailing list
>> USRP-users at lists.ettus.com
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20171024/69d221a6/attachment-0002.html>


More information about the USRP-users mailing list