Every GPS implementation is different. It may be the case that higher SNR is required for timing receivers compared to position receivers.
Sent from my iPhone > On Feb 21, 2021, at 10:13 AM, Johannes Demel <de...@ant.uni-bremen.de> wrote: > > Sure. Generally I wouldn't expect GPS to work in a building. Though, since > we have at least 3 different systems (phone, RPi /w GPS-shield, LTE eNodeB) > that work there, I assumed that the GPSDO would do so as well. > >> On 21.02.21 14:23, Marcus D. Leech wrote: >>> On 02/21/2021 07:15 AM, Johannes Demel wrote: >>> Thanks for your hints. The antennae and devices are indoors. Is there a >>> difference if the device receives a signal and locking onto that signal? >>> e.g. the devices determines the signal too distorted to lock? >> https://itstillworks.com/doesnt-gps-work-inside-building-18659.html >>> >>> On 19.02.21 16:32, Marcus D. Leech wrote: >>>> On 02/19/2021 09:48 AM, Rob Kossler wrote: >>>>> When I first started using UHD 4.0 with the N310 (this past summer), I >>>>> noticed what I thought was a degradation in the device's ability to >>>>> lock. I was comparing one N310 running UHD 3.15 to another running UHD >>>>> 4.0. Both systems were located a few feet apart from each other with >>>>> the same model antenna so they should have produced similar results, >>>>> but it seemed that the 3.15 system achieved lock more easily. In any >>>>> case, I never spent the time to "prove the case" and then got >>>>> distracted on another issue and never returned to it. Not sure if this >>>>> is relevant in this discussion, but I thought I would mention it. >>>>> Rob >>>> The N310 uses one of these modules: >>>> >>>> http://www.jackson-labs.com/index.php/products/lte_lite >>>> >>>> Pretty sure that UHD4.0/UHD3.15 wouldn't affect the operation of that >>>> module, but, you never know. >>>> >>>> >>>>> >>>>> On Fri, Feb 19, 2021 at 9:12 AM Marcus D Leech via USRP-users >>>>> <usrp-users@lists.ettus.com> wrote: >>>>>> Are the antennae situated outdoors? >>>>>> >>>>>> It can take almost an hour to achieve lock from a cold start. >>>>>> >>>>>> Sent from my iPhone >>>>>> >>>>>>> On Feb 19, 2021, at 4:14 AM, Johannes Demel <de...@ant.uni-bremen.de> >>>>>>> wrote: >>>>>>> >>>>>>> Each USRP has its own GPS antenna. One of those you buy at ettus.com >>>>>>> as a recommended accessory. >>>>>>> >>>>>>>> On 18.02.21 15:05, Marcus D Leech wrote: >>>>>>>> How are you delivering the GPS antenna signal to the USRPs? Via a >>>>>>>> splitter? Does that splitter provide DC pass-through? >>>>>>>> Sent from my iPhone >>>>>>>>>> On Feb 18, 2021, at 7:07 AM, Johannes Demel via USRP-users >>>>>>>>>> <usrp-users@lists.ettus.com> wrote: >>>>>>>>> Just a quick follow-up. The B210 finally got a GPS lock. (I had to >>>>>>>>> wait for ~2h). Though, all N310s still don't. >>>>>>>>> >>>>>>>>>> On 18.02.21 10:12, Johannes Demel via USRP-users wrote: >>>>>>>>>> Hi all, >>>>>>>>>> I have some N310s and a B210 that I try to sync with a GPSDO. All of >>>>>>>>>> them recognize their GPSDOs but fail to lock. >>>>>>>>>> My phone can see ~7 Satellites. We have a RPi with a GPS module that >>>>>>>>>> locks to GPS in the same hall. We switched antennas but still, we >>>>>>>>>> can't sync any of the USRPs to GPS. >>>>>>>>>> I tried: >>>>>>>>>> ``` >>>>>>>>>> lib/uhd/utils/query_gpsdo_sensors >>>>>>>>>> ``` >>>>>>>>>> and >>>>>>>>>> ``` >>>>>>>>>> lib/uhd/examples/sync_to_gps >>>>>>>>>> ``` >>>>>>>>>> but even after a day, they always return "GPS does not have lock" >>>>>>>>>> and "WARNING: GPS not locked - time will not be accurate until >>>>>>>>>> locked". >>>>>>>>>> `gpsmon` on the N310s reports 0 Satellites. But it has a list of >>>>>>>>>> satellites. >>>>>>>>>> Since we have several devices in that room that are able to acquire >>>>>>>>>> a lock but none of our USRPs with their GPSDOs, I wonder what is >>>>>>>>>> going on. Do they need a very strong signal? >>>>>>>>>> Cheers >>>>>>>>>> Johannes >>>>>>>>> _______________________________________________ >>>>>>>>> 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 >>>> _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
