Re: [Discuss-gnuradio] about gps lock

[Zan Li]

I have done more tests about the gps message.
        while(1){
        sleep(1);
        std::cout << usrp->get_mboard_sensor("gps_gprmc",0).to_pp_string() << std::endl;
        }

For the output, at the beginning, there are gps_gprmc message outputs but after it runs for a while, there would be no gps_gprmc message output. If I restart, it also works at the beginning. (I update the uhd to 003.005.003 and it works like that. For the old version (003.005.001) I did not meet this problem.) Does somebody know why it is? thanks!

Best regards

Zan

2013/6/10 Zan Li <address@hidden>

Hi Marcus,

We have extend the antenna out to the windows and there is an adequate view of sky. When I use the uhd UHD_003.005.001, there is no such problem but now I upadate the version to UHD_003.005.003.

Best regards

Zan

2013/6/8 Marcus D. Leech <address@hidden>

Dear all,

I meet a problem about the gpsdo for lock. First I check the usrp->get_mboard_sensor("gps_locked",0); it indicates the gps is locked. Then the program is sleep for 5 mins. Then I check the gps again but in this time it does not lock. I do not think that in this 5 mins the gps lost lock because every time I try like this, the first time it is locked but after 5 mins it is unlocked, as follows:


The reference clock is:GPS lock status: locked
Setting device clock source to:external
Setting device clock rate to:1e+08
Setting time source to:external
The reference clock is:GPS lock status: unlocked

UHD Warning:
    get_time: ValueError: get_nmea(): no GPRMC message found

UHD Warning:
    get_time: ValueError: get_nmea(): no GPRMC message found

(Here I can not read the gps time from the gpsdo, I think it is because the gpsdo does not lock).

Does anybody meet the similar problem? Any suggestion would be appreciated.

Best regards

Zan

_______________________________________________
Discuss-gnuradio mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

So, I will ask an obvious question:

Does your GPS receiver have an adequate view of the sky?  That is, does it have an external, amplified antenna outdoors, or near a window that doesn't
  have low-E film on it.

-- 
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

_______________________________________________
Discuss-gnuradio mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio