-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Somebody in the thread at some point said:
Thanks for your work Stacy. |> About the 600sec thing, you can get the GPS chip to report 4 times a |> second instead of once a second, maybe that can be to do with it. But |> it is strange, noticing the heavy filtering on our results I wonder if a |> lot of those samples coming so quickly were actually synthetic. | | It would seem that they are synthetic and have to do with how GPSD | parses and interprets NMEA sentences. The other two reference receivers | are put in SiRF mode and don't seem to suffer this effect. Has anyone | figured out how to kick the GPS receiver into UBX mode? I would be | curious to see if that changes anything. It's actually documented by Ublox in here (Okular eats it) http://www.u-blox.com/customersupport/gps.g3/ANTARIS_Protocol_Specification(GPS.G3-X-03002).chm Here's a UBX packet generator in Bash http://lists.openmoko.org/pipermail/openmoko-kernel/2008-July/003782.html and here is how to inject the packets from Ash echo 0 > /sys/class/i2c-adapter/i2c-0/0-0073/neo1973-pm-gps.0/pwron && sleep 1s && echo 1 > /sys/class/i2c-adapter/i2c-0/0-0073/neo1973-pm-gps.0/pwron && stty -F /dev/ttySAC1 -echo && cat MY-UBX-PACKET >/dev/ttySAC1 && cat -u /dev/ttySAC1 | grep -v ^$ |> For the last result, it seems to show only 2 / 2500 results from GPS are |> within 20 Million meters of the location. It's hard to square that with |> the other decent results that have been reported for tracking, including |> ones pulling maps from SD Card, although I guess you are spamming the |> card as hard as you can for this test. | | It seems that gpsprof gets a value of 10,000,000,000 for NaN and doesn't | check if lat/long values are in range before calculating the average. It | doesn't take very many 10 Billion values to really screw up the average | :-) I modified gpsprof to toss out invalid lat/long values. OK makes a lot of sense :-) | Additional test results (from 20080802) are up at | http://www.millions.ca/~stacy/neoFreeRunner/gpstale.html | | I did some more testing yesterday after compiling the latest version of | GPSD for the FreeRunner (it no longer dies when I spam the SDCard... | that's progress :-) but have not yet got the results pulled together. Doesn't look a million miles away from being right... there are two outliers shown and I guess the filtered NaN(s), but basically all the other samples are in a decent place. - -Andy -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iEYEARECAAYFAkiYdOsACgkQOjLpvpq7dMrLkACgjAm1Img8f2Loku2+o84kHx/y jjYAnjAtxtRk5l3iu2H2F7HyBvT8NW1F =Z++i -----END PGP SIGNATURE----- _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community