libera/#maemo/ Thursday, 2019-05-30

sicelore - supl-proxy : i'm having difficulty to get consistent results with it - maemo seems to make only one a-gps request in a looong time. Hence even daemonizing the proxy might have limited benefits :-(17:31
siceloin all my tried today, i haven't been able to get an a-gps lock17:32
siceloor is there a known good way to nudge Maemo into making more supl requests?17:48
KotCzarnymaybe it uses supl when you lose signal?17:49
siceloi never got a lock though, so i would expect/hope it would make more supl requests, but thatwas not to be.17:53
bencohsicelo: :(18:14
bencohdid you run supl-proxy before running gps customer app?18:15
bencohand no, I wasn't really able to understand when/why it makes supl requests18:16
bencohalthough I far as I can tell, requests come from the modem itself18:16
bencohthe host cpu only wraps/forwards it, and returns back rrlp response18:16
bencoh(or supl, dunno, in which form it returns it)18:16
siceloyes i ran it before, and when it exited after providing data, i restarted it (supl-proxy) - no further requests were made even though i never got a lock. closing an re-opening gps consumer didn't make any difference either (i used Location Test application, and I was outside)18:27
bencohthen my first impression was a good one, and we still don't have a proper fix I guess18:57
bencohack then I suspected the connexion between proxy and google broke in the middle (with part of the needed bits of information missing / waiting to be tranfered)18:58
bencohthen once outside I got a quick fix and thought it still worked anyway18:59
DocScrutinizer05bencoh: you're most likely right about how host CPU gets (not) involved into SUPL and RRLP21:05
DocScrutinizer05RRLP is basically "supl on control tier" AIUI21:06
DocScrutinizer05~gsm-agps21:06
infobotRRLP is the Radio Resource LCS (Location Service) Protocol as specified first in GSM TS 04.31, or http://osmocom.org/projects/security/wiki/RRLP21:06
DocScrutinizer05sorry, "signaling plane" not "control tier"21:07
DocScrutinizer05for RRLP to work, modem needs to identify/log-in to a cellular carrier network21:08
DocScrutinizer05giben that, and carrier supporting RRLP, I get fix within an instant - like less than 5s. Particularly thanks to U-TDOA21:09
DocScrutinizer05even indoors21:10
DocScrutinizer05~u-tdoa21:10
infobotwell, u-tdoa is http://en.wikipedia.org/wiki/U-TDOA21:10
DocScrutinizer05technically U-TDOA can provide a XY location fix, and - exploiting doppler effect - even a XY velocity vector dix, within <<1s. Where U-TDOA epically fails is any Z / altitude measurement, due to all BTS being basically located in one plane and probably also same like the ME21:43
DocScrutinizer05so the altitude of ME has no impact on timing observed by the Location Measurement Units in BTS21:46
DocScrutinizer05you'd need LMUs on different altitudes to measure altitude of ME21:47
DocScrutinizer05for GPS the SVs have different apparent altitude thanks to the sphere they move in21:48

Generated by irclog2html.py 2.17.0 by Marius Gedminas - find it at https://mg.pov.lt/irclog2html/!