Andy Green wrote: > These are really interesting, thanks. > > | d i min / avg / max > | 0 0 35.20/ 55.33/144.30 <=== > | 0 1 37.39/ 77.76/315.76 > > | 3 0 36.07/ 42.07/ 47.82 <=== > | 3 1 97.46/173.09/359.69 > > These relative numbers are a bit counterintuitive... it might be worth > trying it again from a "very cold boot" but with the script > > for DRIVESTRENGTH in 3 2 1 0 > > and seeing if the bias to a worse max moves accordingly.
So I broke the first rule of testing, and changed a bunch of things and then reran the test. First, instead of doing a power off/power on of the GPS, I used Andy's handy dandy UBX construction kit to issue a cold restart to the chip. If I understand the documentation correctly, this will wipe everything from the GPS's memory and do a hardware reset; that should take care of any concerns about residual fix information surviving a power cycle. Second, as Andy suggested, I reversed the order of DRIVESRENGTH values. And finally, I left WLAN enabled (mainly because I did a reboot of the FreeRunner and then ran the test). Here are the results: d i min / avg / max 0 0 36.41/ 51.53/ 84.83 0 1 40.41/ 59.13/128.33 1 0 36.98/ 45.45/ 51.03 1 1 40.94/ 63.74/111.77 2 0 31.43/ 45.08/ 52.31 2 1 32.57/ 57.50/ 76.06 3 0 32.10/ 43.75/ 57.98 3 1 40.34/ 61.71/ 96.67 BTW, the magic incantation to generate the cold restart is ubxcs b5 62 06 04 04 00 ff ff 00 00 > coldstart.ubx Then to issue the command, cat coldstart.ubx > /dev/ttySAC1 grep '$GPTXT,01,01,02,u-blox' -q -m 1 /dev/ttySAC1 The grep command looks for the powerup message from the GPS to make sure that there is no RMC sentence sitting in a buffer somewhere. -stacy _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community