Hello Tomoji, as promised, here's a report of my attempts to use rtklib for post-processing.
Hardware setup ============== 1) neo1 is an openmoko gta02V5. 2) neo2 is an openmoko gta02V7. 3) Both devices are outside on a wooden table. 4) The LCD of each device faces downwards. 5) The "up" direction of each device points to South-East. 6) Distance between the devices is one meter (give or take a few centimeters). 7) neo2 is North-East of neo1. Captured data ============= http://iki.fi/lindi/gps/experiment/1/neo1.ubx http://iki.fi/lindi/gps/experiment/1/neo2.ubx Post-processing steps ===================== $ rtklib-convbin neo1.ubx $ rtklib-convbin neo2.ubx $ rtklib-rnx2rtkp -p 1 -l 60.217480929 24.393206102 71.2617 neo1.obs neo2.obs neo1.nav > neo1-neo2.pos $ head -n20 neo1-neo2.pos % program : rnx2rtkp ver.2.3.0 % inp file : neo1.obs % inp file : neo2.obs % inp file : neo2.nav % obs start : 2010/07/22 06:25:13.0 GPST (week1593 368713.0s) % obs end : 2010/07/22 08:29:45.0 GPST (week1593 376185.0s) % ref pos : 60.217480929 24.393206102 71.2617 % % (lat/lon/height=WGS84/ellipsoidal,Q=1:fix,2:float,4:dgps,5:single,ns=# of satellites) % GPST latitude(deg) longitude(deg) height(m) Q ns sdn(m) sde(m) sdu(m) sdne(m) sdeu(m) sdun(m) age(s) ratio 2010/07/22 06:29:01.998 60.217692722 24.393138007 61.6161 4 4 2.3673 0.9796 2.9740 -1.1745 -1.0261 -0.5434 0.00 0.0 2010/07/22 06:29:02.998 60.217716772 24.393110643 65.7936 4 4 2.3680 0.9798 2.9741 -1.1751 -1.0262 -0.5407 0.00 0.0 2010/07/22 06:29:03.998 60.217727627 24.393090583 69.9502 4 4 2.3688 0.9801 2.9742 -1.1758 -1.0263 -0.5379 0.00 0.0 2010/07/22 06:29:04.998 60.217727239 24.393083772 73.7900 4 4 2.3695 0.9803 2.9744 -1.1764 -1.0265 -0.5352 0.00 0.0 2010/07/22 06:29:05.998 60.217700360 24.393116329 72.5172 4 4 2.3702 0.9805 2.9745 -1.1770 -1.0266 -0.5324 0.00 0.0 2010/07/22 06:29:06.998 60.217646591 24.393137804 75.9859 4 4 2.3709 0.9807 2.9747 -1.1776 -1.0267 -0.5296 0.00 0.0 2010/07/22 06:29:07.998 60.217605988 24.393149454 77.8729 4 4 2.3717 0.9809 2.9748 -1.1783 -1.0269 -0.5268 0.00 0.0 2010/07/22 06:29:08.998 60.217573994 24.393164286 76.2576 4 4 2.3724 0.9812 2.9750 -1.1789 -1.0270 -0.5240 0.00 0.0 2010/07/22 06:29:09.998 60.217562704 24.393172695 76.4654 4 4 2.3731 0.9814 2.9751 -1.1795 -1.0271 -0.5212 0.00 0.0 2010/07/22 06:29:10.998 60.217558401 24.393176600 73.0197 4 4 2.3738 0.9816 2.9752 -1.1802 -1.0272 -0.5183 0.00 0.0 Evaluation ========== Scatter plots of neo1.pos, neo2.pos and neo1-neo2.pos are at http://lindi.iki.fi/lindi/gps/experiment/1/scatter.html Histograms of distance to average (simple sqrt((lat-lat_avg)**2 + (lon-lon_avg)**2)) are at http://lindi.iki.fi/lindi/gps/experiment/1/histo.html Open questions ============== 1) Is it normal that neo1-neo2.pos has 1380 points while both neo1.pos and neo2.pos have over 7200 points? 2) Did this really improve anything? ;-) Since the number of points is different I am not quite sure how to interpret the scatter plots. -Timo _______________________________________________ This message is sent to you from [email protected] mailing list. Visit http://lists.osgeo.org/mailman/listinfo/foss-gps to manage your subscription For more information, check http://wiki.osgeo.org/wiki/FOSS-GPS
