GPS start time is Sun Jan 6 00:00:00 1980 Receiver Position is -1283633.472000 -4726429.196000 4074798.092000 No of types 8 L1 L2 C1 C2 P1 P2 S1 S2 GPS time is Sat Sep 1 16:00:00 2018 Navigation file is gps_data/p0412440.18n 6.519300e-09 1.490100e-08 -5.960500e-08 -1.192100e-07 77824.000000 32768.000000 -65536.000000 -196610.000000 1.862645149231e-09 2.664535259100e-15 61440 2017 UTC GPS week is 2017 End of Navigation file reached Receiver Position is -1283633.472000 -4726429.196000 4074798.092000 No of types 8 L1 L2 C1 C2 P1 P2 S1 S2 GPS week is 0 Epoch is 0 No sats is 9
Here we see information from the Observation file and Navigation file header records
No of Sats observed is 9 Observation time Sat Sep 1 16:00:00 2018 TOW 576000 Sat 3 Ephemeris toe is 518400 Next toe is 523800 too is 576000 Sat 3 Ephemeris toe is 523800 Next toe is 525600 too is 576000 Sat 3 Ephemeris toe is 525600 Next toe is 531000 too is 576000 Sat 3 Ephemeris toe is 531000 Next toe is 532800 too is 576000 Sat 3 Ephemeris toe is 532800 Next toe is 537900 too is 576000 Sat 3 Ephemeris toe is 567000 Next toe is 568800 too is 576000 Sat 3 Ephemeris toe is 568800 Next toe is 574200 too is 576000 Sat 3 Ephemeris toe is 574200 Next toe is 576000 too is 576000 Sat 3 Ephemeris toe is 576000 Next toe is 581400 too is 576000
Then we loop over the Ephemeris parameters to get the ones closest to the time of the measurements we will use to calculate the users position.
No of Sats observed is 9 Observation time Sat Sep 1 16:00:01 2018 TOW 576001 Sat 3 pseudorange is 25546071.328000 Sat 5 pseudorange is 24777825.094000 Sat 24 pseudorange is 22995038.695000 Sat 25 pseudorange is 24043487.625000 Sat 19 pseudorange is 21405104.891000 Sat 6 pseudorange is 20586686.297000 Sat 12 pseudorange is 20647710.398000 Sat 2 pseudorange is 21014246.734000 Sat 17 pseudorange is 23383519.695000 User position is 0.000000,-1283633.472000,-4726429.196000,4074798.092000 Calc position is 2.056906,-1283631.739198,-4726428.064192,4074798.084050 Position error is 2.069699 no Sats used is 9 Epoch is 0 No sats is 9
Here we see the pseudoranges read from the observation file and the users position compared with the surveyed location of the CORS GPS receiver antenna. As you can see the difference is fairly small.
No of Sats observed is 9 Observation time Sat Sep 1 16:00:02 2018 TOW 576002 Sat 3 pseudorange is 25546584.969000 Sat 5 pseudorange is 24777123.969000 Sat 24 pseudorange is 22995479.813000 Sat 25 pseudorange is 24042840.250000 Sat 19 pseudorange is 21405460.063000 Sat 6 pseudorange is 20586976.039000 Sat 12 pseudorange is 20647391.438000 Sat 2 pseudorange is 21014018.664000 Sat 17 pseudorange is 23383938.719000 User position is 0.000000,-1283633.472000,-4726429.196000,4074798.092000 Calc position is 1.633958,-1283631.728408,-4726428.708999,4074798.152765 Position error is 1.811346 no Sats used is 9 Epoch is 0 No sats is 9 No of Sats observed is 9 Observation time Sat Sep 1 16:00:03 2018 TOW 576003 Sat 3 pseudorange is 25547097.500000 Sat 5 pseudorange is 24776422.547000 Sat 24 pseudorange is 22995920.680000 Sat 25 pseudorange is 24042194.234000 Sat 19 pseudorange is 21405815.250000 Sat 6 pseudorange is 20587265.883000 Sat 12 pseudorange is 20647072.367000 Sat 2 pseudorange is 21013790.383000 Sat 17 pseudorange is 23384357.461000 User position is 0.000000,-1283633.472000,-4726429.196000,4074798.092000 Calc position is 1.471582,-1283631.201925,-4726429.521647,4074797.891976 Position error is 2.302020 no Sats used is 9 Epoch is 0 No sats is 9Back to Top of Page