Two weekends ago I replaced the internal memory batteries in one L1/L2 unit and set it up as a test. Once it was warmed up it tracked 8 satellites. I stay with a 10° horizon and during that observation the following satellites were above the horizon: 3, 7, 8, 13, 16, 19, 23, 27. That means I had 100% of the available satellites. Here is the result of my progressive OPUS-RS submission:
This is the original RINEX file. The first minute included only 3 satellites. My legacy Ashtech Z-12s are slow getting started, but after that work like champs.
SOFTWARE: rsgps 1.37 RS83.prl 1.99.2 START: 2014/04/27 21:02:30
EPHEMERIS: igr17900.eph [rapid] STOP: 2014/04/27 21:25:10
NAV FILE: brdc1170.14n OBS USED: 1809 / 2187 : 83%
ANT NAME: LEIAT502 NONE QUALITY IND. 32.49/ 5.73
ARP HEIGHT: 0.000 NORMALIZED RMS: 0.387
REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08 (EPOCH:2014.32023)
X: 1234138.308(m) 0.011(m) 1234137.477(m) 0.011(m)
Y: -4683916.255(m) 0.038(m) -4683914.820(m) 0.038(m)
Z: 4135721.333(m) 0.033(m) 4135721.283(m) 0.033(m)
LAT: 40 40 53.62281 0.007(m) 40 40 53.65538 0.007(m)
E LON: 284 45 39.78297 0.004(m) 284 45 39.76432 0.004(m)
W LON: 75 14 20.21703 0.004(m) 75 14 20.23568 0.004(m)
EL HGT: 78.425(m) 0.051(m) 77.179(m) 0.051(m)
ORTHO HGT: 112.569(m) 0.052(m) [NAVD88 (Computed using GEOID12A)]
I trimmed the first minute and submitted the file from the 4 satellite mark. as you can see from the observations used, OPUS-RS did not use the only 3 satellite data in the prior solution.
SOFTWARE: rsgps 1.37 RS52.prl 1.99.2 START: 2014/04/27 21:03:30
EPHEMERIS: igr17900.eph [rapid] STOP: 2014/04/27 21:25:10
NAV FILE: brdc1170.14n OBS USED: 1809 / 2160 : 84%
ANT NAME: LEIAT502 NONE QUALITY IND. 32.37/ 5.74
ARP HEIGHT: 0.000 NORMALIZED RMS: 0.387
REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08 (EPOCH:2014.32023)
X: 1234138.308(m) 0.011(m) 1234137.477(m) 0.011(m)
Y: -4683916.255(m) 0.038(m) -4683914.820(m) 0.038(m)
Z: 4135721.333(m) 0.033(m) 4135721.283(m) 0.033(m)
LAT: 40 40 53.62281 0.007(m) 40 40 53.65538 0.007(m)
E LON: 284 45 39.78297 0.004(m) 284 45 39.76432 0.004(m)
W LON: 75 14 20.21703 0.004(m) 75 14 20.23568 0.004(m)
EL HGT: 78.425(m) 0.051(m) 77.179(m) 0.051(m)
ORTHO HGT: 112.569(m) 0.052(m) [NAVD88 (Computed using GEOID12A)]
I then trimmed to the 6 satellite mark and resubmitted. Note that fewer observations were provide but more observations were used than previously. OPUS-RS is happier when it has the better data to start with.
SOFTWARE: rsgps 1.37 RS93.prl 1.99.2 START: 2014/04/27 21:05:30
EPHEMERIS: igr17900.eph [rapid] STOP: 2014/04/27 21:25:10
NAV FILE: brdc1170.14n OBS USED: 1935 / 2043 : 95%
ANT NAME: LEIAT502 NONE QUALITY IND. 32.18/ 7.36
ARP HEIGHT: 0.000 NORMALIZED RMS: 0.385
REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08 (EPOCH:2014.32023)
X: 1234138.307(m) 0.011(m) 1234137.476(m) 0.011(m)
Y: -4683916.253(m) 0.039(m) -4683914.818(m) 0.039(m)
Z: 4135721.332(m) 0.034(m) 4135721.282(m) 0.034(m)
LAT: 40 40 53.62283 0.007(m) 40 40 53.65540 0.007(m)
E LON: 284 45 39.78295 0.004(m) 284 45 39.76430 0.004(m)
W LON: 75 14 20.21705 0.004(m) 75 14 20.23570 0.004(m)
EL HGT: 78.422(m) 0.052(m) 77.177(m) 0.052(m)
ORTHO HGT: 112.566(m) 0.053(m) [NAVD88 (Computed using GEOID12A)]
Finally I trimmed to the 8 satellite mark. OPUS-RS used fewer observations because there were fewer there but it used 99% of those submitted. I do not recall ever seeing that high a percentage used in any other submission ever. OPUS-RS clearly loves good clean data.
SOFTWARE: rsgps 1.37 RS83.prl 1.99.2 START: 2014/04/27 21:08:00
EPHEMERIS: igr17900.eph [rapid] STOP: 2014/04/27 21:25:10
NAV FILE: brdc1170.14n OBS USED: 1836 / 1854 : 99%
ANT NAME: LEIAT502 NONE QUALITY IND. 32.28/ 6.09
ARP HEIGHT: 0.000 NORMALIZED RMS: 0.387
REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08 (EPOCH:2014.32024)
X: 1234138.307(m) 0.011(m) 1234137.476(m) 0.011(m)
Y: -4683916.254(m) 0.037(m) -4683914.819(m) 0.037(m)
Z: 4135721.332(m) 0.032(m) 4135721.282(m) 0.032(m)
LAT: 40 40 53.62281 0.007(m) 40 40 53.65538 0.007(m)
E LON: 284 45 39.78294 0.004(m) 284 45 39.76429 0.004(m)
W LON: 75 14 20.21706 0.004(m) 75 14 20.23571 0.004(m)
EL HGT: 78.423(m) 0.049(m) 77.178(m) 0.049(m)
ORTHO HGT: 112.567(m) 0.051(m) [NAVD88 (Computed using GEOID12A)]
There was no substantive change in the observed position, so all in all the extra effort was totally unnecessary in this case. I doubt I will ever progressively trim a RINEX file again, but I will continue to trim to the clean data at the 5-6 satellite mark.
I had one abort after I started trimming because the data began with too many cycle slips, but since I did not save every progressive trim I do not have the number of satellites details.
Paul in PA