Nexus 5 - In both Pure Maps and Unav, maps will "hang" during navigation

  • @normandc said in Nexus 5 - In both Pure Maps and Unav, maps will "hang" during navigation:

    Not sure if it's the same issue or not, the end result is the same: unreliable GPS location, losing it and not getting it back most of the time. I've been wondering if it was a system or hardware issue.

    Or my poor coding 🙂 you can forget about the initial script Utrack should be more stable. (however i still need to nail one issue...)

  • As I said I have the same problem with apps, so I doubt your coding is at fault.

  • @normandc Hello, I'm using Pure Maps on Nexus 5 and I'm experiencing the same problem regarding the "unreliable GPS location".
    Having a look at the SensorsStatus app, it seems normal not to have a pinpoint accuracy because the indicated "accuracy" (which indeed might be the standard deviation computed by the GPS receiver itself) is never under around 10 m.
    So I have another question pending: is it possible to find a datasheet of the GPS receiver? That would be helpful to know what's behind the receiver's outputs (GPS alone? GPS + GLONASS? GPS + SBAS?) and to know if the observed positioning accuracy is consistent or not with them.
    Thanks for your help, and as I'm pretty new here, if there's on this forum a dedicated section for GPS receivers on UT phones feel free to tell me but I haven't found it yet 🙂

  • I'm afraid I can't answer here - it much exceeds my knowledge.
    I would just like to clarify my statement about GPS positioning: my problem is not one of accuracy, it's that it loses its position altogether. When I use an app that requires GPS tracking, either it never starts tracking, or it loses tracking along the way; sometimes I get tracking back, sometimes I don't.

  • Ok thanks I better understand your problem.
    Just a quick question: are you satisfied with the positioning accuracy when you're using apps such as Pure Maps, Unav or Utrack?
    I'll continue to try to find out why there's such a poor positioning accuracy (in my point of view) on the Nexus 5 and what could be done to improve it.

  • @waynejohnson Hi,
    There is no A-GPS available I think.
    So it's hard to have a better precision than 5 to 10 meters AFAIK.

  • @AppLee that is not what AGPS does.
    AGPS is referencing the coordinates from the nearby cell tower to speed up initial location finding, accuracy is not improved at all.

    Maybe UT doesn't reference additional GLONASS, Galileo etc. sattelites to increase accuracy of the intentionally low accuracy GPS?

  • @poVoq I thought AGPS could also use local adjustment to improve accuracy. And not just speed up the GPS fix...

  • @poVoq I agree with you AGPS is here to improve the Time To First Fix (TTFF) but it has no influence on the positioning accuracy.
    We would just need to find out what output of the Nexus 5 GNSS receiver is used in UT; most of the time a receiver offers different types of outputs, more or less accurate: GPS alone, GPS coupled with GLONASS (seems like the Nexus 5 GNSS receiver uses both constellations), GPS coupled with SBAS (WAAS over the US, EGNOS over Europe, etc.).
    Maybe we should get in touch with the developers of UT regarding this specific issue in order to find a way to improve the positioning accuracy. How can we reach them on that subject?

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