From gonzalez@lsu.edu Wed Aug 13 17:22:20 2003 Date: Sun, 10 Aug 2003 09:58:27 -0500 From: Gabriela Gonzalez To: John Zweizig , Daniel Sigg , Gabriela Gonzalez , Keith Riles , Ed Daw , Peter Fritschel , Brian O'Reilly , Rauha Rahkola , Robert Schofield , Stan Whitcomb , Rana Adhikari , Peter Shawhan , Mike Landry , Brian O'Reilly , Akiteru Takamori , Luca Matone , Peter Fritschel , Rana Adhikari , Gabriela Gonzalez , Patrick Sutton Subject: L1 calibration problems Hello, don't get scared by the subject, this is just a list of times for when we don't have good calibration. I got version 2 of the calibration coefficients calculated by SenseMon (aka Patrick Sutton), and made a list of the times with abnormally low alpha*beta. In principle, the possible range for the alpha*beta as normalized in v2 (different than v1), is 0.6-2.1. On the low end, we expect abnormal behavior near 35 Hz, where the open loop gain has a dip and may touch unity with something close to the wrong sign. At the high end, we expect oscillations and instability at 400 Hz. In practice, the value of alpha*beta during science segments for L1 is between 0 and 1.35, so there are no worries at the high end. I looked in Patrick's list of alpha*betas the times when alpha*beta was smaller than 0.6: this is about 2.4% of the data. I attach these times in a file, divided in three categories: 1.- Times when alpha*beta=0 because the calibration line was not turned on. I propose in each case discarding the time when this happens. Next to each of these 41 segments, I write either the time to be discarded or whether the whole segment should be discarded (which is the case for many short segments). 2.- Times when the value of alpha*beta=0, only in the last minute of the segment. I think this happens because of the sync problem between the time stamp for trend minutes and the actual time when the calibration was measured. I think somebody (Patrick?) should study whether we should change the time stamp for the trends in these minutes, or make a recommendation to use a time shift for the calibration in these segments when doing analysis. As is, only the last minute would be useless (b/c alpha*beta=0), but the rest of the segment probably has the wrong calibration by something between 30 and 60 sec. 3.- Segments where alpha*beta was close to, but below 0.6. These segments probably have some bizarre behavior near 35 Hz, and should be investigated further. I'll try to do this, but will not get offended if somebody beats me to it. We should decided whether to veto these segments, and/or find out a reasonable lower limit of alpha*beta to be used a threshold to veto segments (if at all). I am not recommending any vetoes associated with these times yet. I will assemble more information (histograms, unity gains, etc) in a document soon, but thought I should send this out hoping it makes it for v3 of the data quality segments. Gaby. PS: for those who heard me complain about an apparent hard cutoff at the higher end of alpha*beta as calculated with SenseMon, this was true in v1 but not in v2 of SenseMon, at least for L1. The histogram of alpha*beta (also attached) looks very reasonable, with a median of 0.85 (~150 Hz ugf). I don't know what the problem was before, but I'm glad it got fixed!! -- ################################################### Gabriela Gonzalez Assistant Professor Department of Physics and Astronomy Louisiana State University 202 Nicholson Hall Tower Drive Baton Rouge,LA 70803 Phone: (225) 578 0468 Email: gonzalez@lsu.edu http://www.phys.lsu.edu/faculty/gonzalez/ ################################################## [ Part 2: "Attached Text" ] Times with no calibration lines: ================================ Seg 1, 1729304210-729305791: No calibration lines, discard segment (1581 sec) Seg 2, 729308373-729313554: No calibration lines, discard segment (5181 sec, ouch!). Seg 3, 729331024-729335369: has calibration line and thus reliable calibration only after 729332040. Use only times 729332040-729335369. Seg 10, 729372304-729374047 : calibration line was on only in the last 5' of the segment, but even then it shows large fluctuations and implausible values for calibration. Discard segment(1743 sec). Seg 15, 729396789-729400124 : calibration line is on only after 729398220. Use only 729398220-729400124. Seg 30, 729499829-729500062 : only calibration point trended is close to impossible. Discard segment (233 sec). Seg 38, 729536475-729537337: has calibration line turned off after four minutes; discard segment (862 sec). Seg 39, 729537800-729540143: no calibration line; discard segment (2343 sec, ouch!). Seg 40, 729540297-729540487 : calibration line turned on after first minute; discard segment (190 sec long). Seg 41, 729540710-729543545 : Calibration pine changes strength during segment; alpha*beta is only reasonable after change in strength. Use only 729541320-729543545. Seg 55, 729587723-729588376 : calibration line turned on only at the end; discard segment (653 sec long). Seg 71, 729700710-729704095: calibration line turned OFF at the end, use only 729700710-729702900. Seg 72, 729704716-729706321 : calibration line turned ON a few minutes after started, use only 729705000-729706321. Seg 199, 730922406-730922997 : no calibration line, discard segment (591 sec long). Seg 223, 731195735-731196532 : calibration line turned late, use only 731195880-731196532. Seg 245, 731299369-731299635 : no calibration line, discard. Seg 253, 731336217-731336280 : probably not enough time to estimate line amplitude reliably, discard (only 63 sec long). Seg 254, 731340040-731343750 : line was off, then on, then off, then on again (?). When line is on, gain is suspiciously low, it should be investigated. Seg 271, 731446085-731446359: line is off, discard segment (274 sec long). Seg 290, 731573682-731573832: line amplitude is very small, discard segment (150 sec). Seg 315, 731738589-731742446: line was off in the beginning, use only 731738760-731742446. Seg 320, 731755077-731755362: lline was off, discard segment (285 sec). Seg 324, 731766924-731767279: line was off, discard segment (355 sec). Seg 328, 731794054-731794405: line was off, discard segment (351 sec). Seg 342, 731908883-731909088: line was off, discard segment (205 sec). Seg 359, 731984816-731988260: line was off in the beginning, use only 731985300-731988260. Seg 394, 732206663-732206953: line was off in the beginning, discard segment (290 sec). Seg 418, 732411348-732413086: line was off, discard segment (1738 sec, ouch!). Seg 433,732513175-732528903: line amp is low in the first two minutes, use only 732513300-732528903. Seg 438, 732551389-732552682: no calibration line, discard segment (1293 sec). Seg 439, 732556361-732558989: no calibration line, discard segment (2628 sec). Seg 458, 732694004-732694184: calibration line only in the last minute, discard segment (180 sec). Seg 467, 732768186-732780219: line turned off at the end, use only 732768186-732779880. Seg 483, 732905513-732905940: line turned off at the end, discard segment (427 sec). Seg 520, 733302422-733303668: lien was not on, discard segment (1246 sec). Seg 531, 733412034-733412218: line was not on, discard segment (184 sec). Seg 535, 733457330-733457459: line was not on, discard segment (129 sec). Seg 545: 733531647-733532582: line was not on, discard segment (935 sec). Seg 563: 733725825-733727970: line was not on, discard segment (2145 sec, ouch!). Seg 577: 733931740-733935034: line turned on after begining, use only 733932780-733935034. Seg 592: 734253696-734253814: : line was not on, discard segment (118 sec). Times with low calibration lines b/c of sync problems: ====================================================== Seg# GPS min alpha*beta 67 729680220 0.0000 103 730125900 0.0000 149 730513680 0.0000 235 731253720 0.0000 269 731433840 0.0000 434 732532020 0.0000 Times that should be investigated (suspiciously low alpha*beta) =============================================================== Seg# GPS min alpha*beta 31 729507360 0.5714 95 730023600 0.5983 95 730023660 0.5923 95 730023900 0.5933 95 730023960 0.5947 95 730024020 0.5912 95 730024080 0.5877 95 730024200 0.5789 95 730024320 0.5910 95 730024380 0.5933 95 730024440 0.5854 95 730024500 0.5766 95 730024560 0.5849 95 730024620 0.5998 95 730024800 0.5929 95 730024920 0.5768 95 730025040 0.5881 95 730025100 0.5872 95 730025160 0.5879 244 731286180 0.5657 244 731286240 0.5659 244 731286300 0.5547 244 731286360 0.5638 244 731286420 0.5606 244 731286480 0.5839 244 731286540 0.5610 244 731286600 0.5999 244 731286660 0.5888 244 731286720 0.5760 244 731286780 0.5862 244 731286840 0.5885 244 731286900 0.5772 244 731286960 0.5676 244 731287020 0.5671 244 731287080 0.5901 244 731287140 0.5945 244 731287200 0.5778 244 731287260 0.5514 244 731287320 0.5888 244 731287380 0.5568 244 731287440 0.5573 244 731287500 0.5897 244 731287560 0.5560 244 731287620 0.5708 244 731287680 0.5815 244 731287740 0.5633 244 731287800 0.5816 244 731287860 0.5650 244 731287980 0.5754 244 731288040 0.5635 244 731288100 0.5937 244 731288160 0.5815 244 731288220 0.5971 244 731288280 0.5810 244 731288340 0.5702 244 731288400 0.5718 244 731288460 0.5592 244 731288520 0.5709 244 731288580 0.5675 244 731288640 0.5614 244 731288700 0.5782 244 731288760 0.5635 244 731288820 0.5696 244 731288880 0.5961 244 731288940 0.5466 244 731289000 0.5449 244 731289060 0.5870 244 731289120 0.5635 244 731289180 0.5829 244 731289240 0.5517 244 731289300 0.5848 244 731289360 0.5356 244 731289420 0.5602 244 731289480 0.5526 244 731289540 0.5519 244 731289600 0.5641 244 731289660 0.5646 244 731289720 0.5781 244 731289780 0.5786 244 731289840 0.5537 244 731289900 0.5590 244 731289960 0.5793 244 731290020 0.5671 244 731290080 0.5623 244 731290140 0.5601 244 731290200 0.5561 244 731290260 0.5578 244 731290320 0.5632 244 731290380 0.5923 250 731320260 0.5830 250 731320320 0.5995 250 731320440 0.5955 250 731320500 0.5833 250 731320560 0.5837 250 731320620 0.5817 258 731387640 0.5863 258 731388600 0.5968 258 731388660 0.5978 259 731403960 0.5878 259 731404020 0.5760 259 731404080 0.5899 263 731411160 0.5258 263 731411220 0.5539 264 731411820 0.5474 264 731411880 0.5556 264 731411940 0.5557 264 731412000 0.5709 264 731412060 0.5641 264 731412120 0.5444 264 731412180 0.5668 264 731412240 0.5367 264 731412300 0.5492 264 731412360 0.5764 265 731412600 0.5751 265 731412660 0.5773 265 731412720 0.5768 265 731412780 0.5767 265 731412840 0.5836 265 731412900 0.5725 265 731412960 0.5798 265 731413020 0.5644 265 731413080 0.5850 265 731413140 0.5483 265 731413200 0.5697 265 731413260 0.5852 265 731413320 0.5644 265 731413380 0.5956 265 731413440 0.5850 265 731413500 0.5666 265 731413560 0.5897 265 731413620 0.5732 265 731413680 0.5510 265 731413740 0.5859 265 731413800 0.5940 265 731413920 0.5897 265 731413980 0.5669 265 731414040 0.5660 265 731414100 0.5746 265 731414160 0.5792 265 731414220 0.5866 265 731414340 0.5909 265 731414400 0.5566 265 731414460 0.5772 265 731414520 0.5696 265 731414580 0.5967 265 731414640 0.5759 265 731414760 0.5784 265 731414820 0.5803 265 731414880 0.5846 265 731414940 0.5731 265 731415000 0.5998 265 731415060 0.5854 265 731415120 0.5861 265 731415240 0.5895 265 731415300 0.5880 265 731415360 0.5875 265 731415420 0.5900 265 731415480 0.5794 265 731415600 0.5844 265 731415720 0.5677 265 731415780 0.5820 265 731415840 0.5760 265 731415900 0.5869 265 731415960 0.5795 265 731416020 0.5884 265 731416140 0.5853 265 731416200 0.5903 265 731416260 0.5837 265 731416320 0.5915 265 731416380 0.5947 265 731416560 0.5986 265 731416680 0.5946 265 731416740 0.5939 265 731416800 0.5815 265 731416860 0.5992 265 731416920 0.5875 265 731417100 0.5924 265 731417220 0.5813 265 731417340 0.5687 265 731417460 0.5932 265 731417520 0.5735 265 731417640 0.5825 265 731417700 0.5968 265 731417820 0.5753 265 731417880 0.5815 265 731417940 0.5958 265 731418000 0.5803 265 731418060 0.5848 265 731418120 0.5901 265 731418180 0.5777 265 731418240 0.5852 265 731418360 0.5890 265 731418420 0.5948 266 731421840 0.5958 273 731494080 0.5158 273 731494140 0.5153 273 731494200 0.5155 273 731494260 0.5161 273 731494320 0.5162 273 731494380 0.5181 273 731494440 0.5173 273 731494500 0.5162 273 731494560 0.5145 273 731494620 0.5179 273 731494680 0.5143 273 731494740 0.5135 273 731494800 0.5201 273 731494860 0.5177 273 731494920 0.5169 273 731494980 0.5158 273 731495040 0.5140 273 731495100 0.5172 273 731495160 0.5173 273 731495220 0.5146 273 731495280 0.5222 273 731495340 0.5178 274 731495520 0.5172 274 731495580 0.5186 274 731495640 0.5194 274 731495700 0.5236 274 731495760 0.5231 274 731495820 0.5208 274 731495880 0.5205 274 731495940 0.5213 274 731496000 0.5172 274 731496060 0.5202 274 731496120 0.5212 274 731496180 0.5196 274 731496240 0.5227 274 731496300 0.5197 274 731496360 0.5215 405 732339840 0.4775 [ Part 3, Image/JPEG 72KB. ] [ Unable to print this part. ]