IRU GYRO BIAS MONITORING AND TRENDING

Gyro bias drift rate is monitored and trended below for the period from January 2000 through November 2001 below. The bias drift (arcsec/s) is averaged on various timescales (15 minutes, 1 hour, and 8 hours). The bias links below show monthly and weekly plots of the 1 hour averages. The drift over 1 hour is computed and plotted in histogram form (see hist links). Two-tailed confidence intervals are then computed to determine the 1%, 0.5%, and 0.1% outliers, when the data is considered on 15m, 1h, and 8h intervals. We find that for 99.5% of the time in this period (01/2000 - 11/2001), the change in roll bias drift (AOGBIAS1) is less than 0.0048 arcsec/sec in one hour, the change in pitch bias drift (AOGBIAS2) is less than 0.0056 arcsec/sec in one hour, and the change in yaw bias drift (AOGBIAS3) is less than 0.0048 arcsec/sec in one hour.



Mission since JAN00
bias hist


Weeklies
May08 - May14 bias hist
May15 - May21 bias hist
May22 - May28 bias hist
May29 - Jun04 bias hist
Jun05 - Jun11 bias hist
Jun12 - Jun18 bias hist
Jun19 - Jun25 bias hist
Jun26 - Jul02 bias hist
   
2008     bias     hist
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
   
2007     bias     hist
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
   
2006     bias     hist
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
2005     bias     hist
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
   
2004     bias     hist
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
   
2003
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
2002
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
   
2001
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
   
2000
JAN FEB MAR
bias hist bias hist bias hist
APR MAY JUN
bias hist bias hist bias hist
JUL AUG SEP
bias hist bias hist bias hist
OCT NOV DEC
bias hist bias hist bias hist
   

Histogram statistics

Below are statistics for the combined Jan 2000 - Nov 2001 dataset, suggesting gyro drift alert limits on various time scales.


15 minute averages
Axis % lower limit upper limit N violations
Roll 1.0 -0.00248455 0.00249476 543
Roll 0.5 -0.00351867 0.00350602 271
Roll 0.1 -0.0177470 0.0171639 54
Roll 0.04 -0.0266322 0.0265264 23
Pitch 1.0 -0.00141267 0.00141263 543
Pitch 0.5 -0.00264712 0.00264508 271
Pitch 0.1 -0.0107628 0.0108922 54
Pitch 0.04 -0.0167505 0.0173604 23
Yaw 1.0 -0.00127865 0.00127778 543
Yaw 0.5 -0.00220820 0.00223517 271
Yaw 0.1 -0.0144483 0.0144352 54
Yaw 0.04 -0.0222723 0.0210106 23
1 Hour averages
Axis % lower limit upper limit N violations
Roll 1.0 -0.00304388 0.00308949 155
Roll 0.5 -0.00485336 0.00479615 77
Roll 0.1 -0.0340143 0.0287690 15
Roll 0.15 -0.0116037 0.0135655 23
Pitch 1.0 -0.00336428 0.00338862 155
Pitch 0.5 -0.00564847 0.00565001 77
Pitch 0.1 -0.0187967 0.0190333 15
Pitch 0.15 -0.0161198 0.0145732 23
Yaw 1.0 -0.00352202 0.00344177 155
Yaw 0.5 -0.00480193 0.00466856 77
Yaw 0.1 -0.0196659 0.0235405 15
Yaw 0.15 -0.0123201 0.0108282 23
8 Hour averages
Axis % lower limit upper limit N violations
Roll 1.0 -0.00233298 0.00329379 20
Roll 0.5 -0.00510184 0.00644035 10
Roll 0.1 -0.168789 0.151870 2
Roll 1.1 -0.00233298 0.00197181 23
Pitch 1.0 -0.00728608 0.00902818 20
Pitch 0.5 -0.0146907 0.0138476 10
Pitch 0.1 -99 0.0664886 2
Pitch 1.1 -0.00617128 0.00646225 23
Yaw 1.0 -0.00535165 0.00546757 20
Yaw 0.5 -0.00792442 0.00885538 10
Yaw 0.1 -0.126831 0.104861 2
Yaw 1.1 -0.00535165 0.00438930 23


Top 10 Violations

Below are the largest drifts seen in the combined Jan 2000 - Nov 2001 dataset. The top ten violations for each axis are shown based on various criteria (15m, 1h, 8h averages).


15 minute averages
Axis Date Shift
Roll2000-Feb17-08:02-0.127808
Roll2000-Feb18-00:530.156652
Roll2000-Feb18-01:100.369540
Roll2000-Feb18-02:25-0.377209
Roll2000-Feb18-04:53-0.0840628
Roll2000-Feb18-12:560.188448
Roll2000-Sep20-00:51-0.0594412
Roll2000-Oct26-08:250.0644341
Roll2001-Apr21-21:410.164739
Roll2001-Apr21-23:51-0.136660
 
Pitch2000-Feb17-08:02-0.0384665
Pitch2000-Feb18-00:53-0.0569180
Pitch2000-Feb18-01:10-0.134269
Pitch2000-Feb18-02:250.221531
Pitch2000-Feb18-03:20-0.0560750
Pitch2000-Feb18-04:530.0475832
Pitch2000-Feb18-12:560.0423664
Pitch2000-Sep20-00:510.0357104
Pitch2000-Oct26-08:25-0.0387349
Pitch2001-Apr21-21:410.0370355
 
Yaw2000-Feb17-08:020.0799821
Yaw2000-Feb18-00:53-0.125617
Yaw2000-Feb18-01:10-0.296329
Yaw2000-Feb18-02:250.325168
Yaw2000-Feb18-04:530.101689
Yaw2000-Feb18-12:56-0.0973905
Yaw2000-Sep20-00:510.0489646
Yaw2000-Oct26-08:25-0.0549260
Yaw2001-Apr21-21:41-0.0851350
Yaw2001-Apr21-23:510.0692016
1 Hour averages
Axis Date Shift
Roll2000-Feb17-07:09-0.0879474
Roll2000-Feb17-08:14-0.0691662
Roll2000-Feb18-00:230.459214
Roll2000-Feb18-02:28-0.329176
Roll2000-Feb18-04:38-0.0794284
Roll2000-Feb18-12:130.147393
Roll2000-Apr05-23:290.0763844
Roll2001-Apr21-20:590.139647
Roll2001-Apr21-23:09-0.126500
Roll2001-Apr22-00:14-0.0729445
 
Pitch2000-Feb17-07:09-0.0287817
Pitch2000-Feb18-00:23-0.166851
Pitch2000-Feb18-01:250.0424438
Pitch2000-Feb18-02:280.102498
Pitch2000-Feb18-04:380.0449598
Pitch2000-Feb18-12:130.0331365
Pitch2000-Feb18-15:290.0316042
Pitch2000-Apr05-23:29-0.0464522
Pitch2000-Jul23-19:54-0.0318690
Pitch2001-Apr21-20:590.0313945
 
Yaw2000-Feb17-07:090.0542815
Yaw2000-Feb17-08:140.0438306
Yaw2000-Feb18-00:23-0.368238
Yaw2000-Feb18-02:280.238190
Yaw2000-Feb18-04:380.0960828
Yaw2000-Feb18-12:13-0.0761730
Yaw2000-Apr05-23:29-0.0650450
Yaw2001-Apr21-20:59-0.0722585
Yaw2001-Apr21-23:090.0649079
Yaw2001-Apr22-00:140.0401292
8 Hour averages
Axis Date Shift
Roll2000-Feb17-04:01-0.168789
Roll2000-Feb17-20:030.151870
Roll2000-Feb18-04:05-0.0695214
Roll2000-Feb18-12:060.0804628
Roll2000-Apr03-13:22-0.00510184
Roll2000-Apr05-13:250.00644035
Roll2000-Apr06-09:16-0.0103164
Roll2000-Sep20-00:09-0.00511757
Roll2001-Apr21-14:060.0626383
Roll2001-Apr21-22:07-0.0606482
 
Pitch2000-Jan16-19:08-0.0309904
Pitch2000-Jan24-19:250.0270081
Pitch2000-Feb17-04:01-0.0511001
Pitch2000-Feb17-20:03-0.0476665
Pitch2000-Feb18-04:050.0664886
Pitch2000-Feb18-12:060.0689607
Pitch2000-Jul23-14:33-0.0152994
Pitch2000-Jul28-22:420.0147122
Pitch2001-Apr21-14:060.0138476
Pitch2001-Apr21-22:07-0.0146907
 
Yaw2000-Feb17-04:010.104861
Yaw2000-Feb17-20:03-0.126831
Yaw2000-Feb18-04:050.0844720
Yaw2000-Feb18-12:06-0.0430379
Yaw2000-Apr06-09:160.00885538
Yaw2000-May22-12:50-0.00795762
Yaw2000-Jul21-06:290.0142166
Yaw2000-Jul23-14:33-0.00792442
Yaw2001-Apr21-14:06-0.0321291
Yaw2001-Apr21-22:070.0319858
   
1 Hour averages of interest
Axis Date Shift
Pitch 2001-Sep22-10:55 0.0214237
Yaw 2001-Sep22-10:55 0.00611266


Maintained by bspitzbart at cfa dot harvard dot edu