Hi Skip, Your message 30,30 is nearly identical to mine on 3-2-14 2:00mst
I just realized I been putting my time stamps as pdt should be pst (pacific standard time). Anyway the supperb time rate from svn64 prn30 changed from execellant to average. Compareable to the other sats on 2/26/2014 01:34:33 pst here is my data. 3.8706945954e-010,-2.7224445300e-014 02/25/2014 14:25:20 3.8088047897e-010,-2.8666966126e-014 02/25/2014 14:28:50 3.8088047897e-010,-2.8666966126e-014 02/25/2014 14:28:50 3.7882484806e-010,-3.0106044610e-014 02/25/2014 14:30:20 3.7575403151e-010,-3.0106044610e-014 02/25/2014 14:31:50 -7.6402494734e-007,3.6402148657e-012 02/26/2014 01:34:33 -7.6389389961e-007,3.6402148657e-012 02/26/2014 01:35:33 -7.6336994898e-007,3.6386020065e-012 02/26/2014 01:37:33 I'm at somewhat of a loss to explain this change in clock rate (stability). Perhaps the military signal is derived from the better clock ? and the civilians get a less stable clock rate/signal ? I haven't rulled out dopplar shift or my mis-understanding of how gps works and what msg 30 really means. Perhaps the sat is broadcasting the bias and drift every minute and the gps receiver is dummer than I thought ? Here is my data from the approximate time as your data. GeoNav PC Time=1393793993 03/02/2014 12:59:53 30,30,7.55669999999e+004,-1.0512244642e+007,-2.0403662041e+007,1.3915637457e+007,1.4887479321e+003,8.9976062727e+002,2.4431245733e+003,1.3331348485e-006,3.6930953087e-012,4,4.0960000000e+005,1.0816000000e+004,1.5091755390e+000 I would have thought our messages would be more exact to each other as I've run two receivers from my location running sirf twice on the same pc with both sirf III and sirf IV receivers simotainiously logging and the comparied messages are within 2 or 3 least significant digits of each other.. PRobably are location differences are the reason for a less equal comparison. sunday 3-2-14 the sat passed nearly overhead at my location which would have presented the maximum dopplar shift. but that wouldn't explain the dramitic shift in the clock stability seen on 2-26-14. I will be logging the data daily hoping to see the prn30 clock go back to the better stability. I put and sd card in my laptop pc and now run sirfdemo from the sd card and log to that sd card. I feel it puts less where on my harddrive.. I can easily see prn30 orbit moving westwardly each day across the sat mapping screen. very cool !! I also have written a program to parse out the clock bias and drift. here is its output. prn clk bias clk drift 30sec drift 30sec clk bias next orbit clk bias update & utc 01 5.419324e-07 1.939370e-1213 1.350894e-14 2.4980e-10 0714 3.056667e-08 0316 02 4.801467e-04 -6.812491e-13 -2.547918e-14 -7.5000e-12 1332 1.832122e-07 0619 03 3.292035e-04 -7.611533e-14 1.553618e-14 -2.2900e-12 1529 -1.075634e-07 150 14 5.685252e-06 -6.154375e-13 2.511121e-14 -8.2501e-12 1112 5.062425e-08 0459 05 -3.874342e-04 2.121078e-123 8.206977e-15 9.7660e-11 1433 3.457315e-08 0838 06 2.857013e-04 1.634064e-11 5.935703e-14 4.9022e-10 1529 6.195851e-07 1344 07 3.165876e-04 1.958476e-12 5.030264e-15 7.9590e-11 0610 -5.385762e-07 222 08 1.200872e-05 -4.117289e-12 1.142446e-14 -3.7056e-11 0723 -3.790054e-07 234 09 3.072839e-04 5.659474e-125 3.575135e-14 8.4890e-11 0728 3.072825e-04 0025 10 -1.154085e-04 -3.748887e-12 2.945560e-14 -4.8740e-11 1212 -1.017679e-08 075 11 -4.664052e-04 -7.469855e-12 1.838373e-14 -1.1952e-10 0611 -1.192491e-08 021 12 1.880373e-04 3.790502e-12 -6.092783e-15 9.0580e-11 1316 1.010878e-07 0640 13 2.713727e-05 -3.561521e-12 1.282676e-14 -6.0546e-11 0424 2.726619e-05 2116 14 1.961350e-04 -3.153479e-12 1.802226e-14 -9.4600e-11 1529 -2.227599e-07 144 15 -1.645517e-04 -3.145682e-12 1.313034e-14 -7.8620e-11 1529 -1.402962e-08 113 16 -2.304940e-04 3.668937e-125 9.299852e-15 1.0947e-10 1529 5.328928e-08 1304 17 -7.047949e-05 -4.629986e-12 -2.057078e-14 -3.1959e-10 1008 -7.042604e-05 030 18 3.034303e-04 7.149177e-123 -5.420144e-15 2.1093e-10 1529 7.296043e-08 1140 19 -4.404313e-04 -2.519745e-12 1.712601e-13 -9.5182e-10 0445 -1.502963e-08 235 20 1.639282e-04 3.410605e-12 -1.746089e-12 2.3873e-09 0822 8.219745e-08 0635 21 -3.453992e-04 4.039002e-134 -4.799720e-14 1.0840e-11 1529 -1.898633e-07 102 22 2.150482e-04 4.723546e-12 6.304853e-15 1.4105e-10 1529 1.237934e-07 1302 23 1.918922e-06 -6.003539e-12 4.613150e-14 -6.0035e-12 0306 2.001197e-06 1931 24 -2.378059e-05 -1.316009e-12 -5.128276e-16 -3.9554e-11 1529 1.192998e-08 1507 25 1.573178e-05 2.737902e-122 -1.925977e-15 5.2020e-11 1416 6.875391e-08 0820 26 1.577180e-04 -1.734294e-11 2.159037e-14 -4.5705e-10 1521 -7.768384e-08 112 27 -1.932695e-05 -8.357383e-13 1.904347e-15 -2.5027e-11 1529 -3.765017e-08 140 28 3.344866e-04 -3.703717e-13 -8.318476e-14 -3.8030e-11 0842 3.343273e-04 0104 29 5.130142e-04 3.020466e-12 -4.085924e-15 9.0540e-11 1529 1.704589e-07 0854 30 -1.273339e-10 -6.295711e-14 8.385220e-16 -1.7857e-11 1044 -6.734891e-04 073 31 3.334261e-04 2.777229e-125 -2.872355e-14 5.2549e-10 1226 -3.812314e-07 180 32 -4.815533e-04 8.795522e-12 -2.272228e-14 2.6264e-10 0021 -1.415768e-06 174 msg36 1780 574194000 02 22 2014 15:29:38000 76137 78585 000 06304 cli00 hed00 hpe529 vpe081 ck 1451592983 dft 1832528 cder0 dist0 derr0 hder0 sats9 hdop4 dop0 how long have you been using sirfdemo program? _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
