On Tue, 2009-04-07 at 23:49 +0100, Joerg Reisenweber wrote: > Am Sa 4. April 2009 schrieb Stefan Schmidt: > > OpenBmap likes to have more fields > > for quality informations about GPS and GSM. > > I strongly suggest to include fields for TimeAdvance values for each BTS. > TA is a much better and more reliable value for distance to Base Transmitter > Sation than dB signal strength. > See: > http://lists.openmoko.org/pipermail/openmoko-kernel/2008-April/002434.html > and > http://lists.openmoko.org/pipermail/openmoko-kernel/2008-June/002987.html
As Jörg said, the timing advance is only valid while a channel to the BTS is open. An active GPRS connection is enough, but the TA for that is sent in the EM command for GPRS. When it is invalid 255 is sent, otherwise the actual value. You may need to create traffic to see a vaild TA here. The TA field for voice calls uses '0' for invaild, so it's not as nice for getting proper readings. -- Jan Lübbe <jlue...@lasnet.de> http://sicherheitsschwankung.de gpg-key 1024D/D8480F2E 2002-03-20 fingerprint 1B25 F91F 9E7B 5D4F 1282 02D6 8A83 8BE4 D848 0F2E _______________________________________________ devel mailing list devel@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/devel
