Known time desc » History » Version 31
Nicolas Aunai, 16/06/2017 03:18 PM
| 1 | 31 | Nicolas Aunai | Known time description |
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| 2 | |||
| 3 | |||
| 4 | ======================== |
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| 5 | 1 | Anonymous | |
| 6 | 31 | Nicolas Aunai | Double Time ranges : date from 01/01/1970 to 01/01/2100 |
| 7 | |||
| 8 | --------------------------------------------------------- |
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| 9 | 1 | Anonymous | |
| 10 | 31 | Nicolas Aunai | - seconds from 01/01/1970 00:00:00 : 0 to 4 102 488 000 |
| 11 | - milliseconds from 01/01/1970 00:00:00 : 0 to 4 102 488 000 000 |
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| 12 | (ambiguity for the first 48days of 1970 with previous time format) |
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| 13 | - seconds from 01/01/0000 00:00:00 : 62 168 472 000 to 66 270 960 000 |
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| 14 | (no ambiguity) |
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| 15 | - milliseconds from 01/01/0000 00:00:00 : 62 168 472 000 000 to 66 270 |
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| 16 | 960 000 000 (no ambiguity) |
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| 17 | - seconds from 01/01/2000 00:00:00 : - 946 728 000 to 3 155 760 000 |
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| 18 | (TT2000) |
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| 19 | - milliseconds from 01/01/2000 00:00:00 : - 946 728 000 000 to 3 155 |
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| 20 | 760 000 000 (ambiguity with TT2000 in seconds?) |
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| 21 | 23 | Anonymous | |
| 22 | 24 | Anonymous | µs, ns, ps might also be needed for tt2000 |
| 23 | 18 | Anonymous | |
| 24 | 31 | Nicolas Aunai | Double (IEEE754) |
| 25 | 64bits |
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| 26 | min value: –1.7977E+308 |
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| 27 | 18 | Anonymous | max value :1.7977E+308 |
| 28 | |||
| 29 | 31 | Nicolas Aunai | Number of seconds per year = 60\*60\*24\*365.25 = 31 557 600 |
| 30 | Numbers for 100 years : |
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| 31 | 3 155 760 000 s = 3.15576 e+9 s |
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| 32 | 3 155 760 000 000 ms = 3.15576 e+12 ms |
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| 33 | 3 155 760 000 000 000 µs = 3.15576 e+15 µs |
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| 34 | 3 155 760 000 000 000 000 ns = 3.15576 e+18 ns |
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| 35 | 18 | Anonymous | 3 155 760 000 000 000 000 000 ps = 3.15576 e+21 ps |
| 36 | |||
| 37 | 31 | Nicolas Aunai | Typical dynamics for a double seems to be 15 digits, after that we might |
| 38 | experiment precision loss. |
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| 39 | Recommendation is to store time in QLop as microseconds since Epoch |
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| 40 | (01-01-1970 00:00:00) |
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| 41 | |||
| 42 | |||
| 43 | 27 | Anonymous | |
| 44 | |||
| 45 | 31 | Nicolas Aunai | Known time description |
| 46 | |||
| 47 | ------------------------ |
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| 48 | 27 | Anonymous | |
| 49 | 31 | Nicolas Aunai | |*.Mission Name |*.time var name |*. units |*.DEPEND |
| 50 | |*.LABLAXIS|*.FIELDNAM |*.CATDESC |*.Type |*.VIRTUAL|*.nb of |
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| 51 | records|\_.VAR\_NOTES| |
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| 52 | |Cluster FGM |time\_tags\_\_CDFNAME |ms |0 |UT |Universal Time |Interval |
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| 53 | centred time tag |CDF\_EPOCH | |normal |field missing| |
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| 54 | |Cluster HIA |time\_tags\_\_CDFNAME |ms |0 |UT |Center Time |Interval |
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| 55 | centred time tag |CDF\_EPOCH | |normal |field missing| |
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| 56 | |||||||||||| |
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| 57 | |Themis Efi,SCM |VARNAME\_time |sec |TIME |UT |Same as time var |
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| 58 | name|UTC, in seconds sinc 01-Jan-1970 00:00:00|CDF\_DOUBLE | |normal |
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| 59 | |Unleaped seconds| |
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| 60 | |Themis Efi,SCM |VARNAME\_epoch |field missing|0 |UT |Same as time var |
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| 61 | name|Unrelated |CDF\_EPOCH |true |0 |field missing| |
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| 62 | |Themis Efi,SCM |VARNAME\_dot0\_epoch0|msec |