/**********************************************************************/
/* RPWS_SCLK_SCET.FMT */
/* describes the structure of the spacecraft clock and spacecraft */
/* event time objects common to many Cassini RPWS archive files. */
/**********************************************************************/
OBJECT = COLUMN
NAME = SCLK_SECOND
DATA_TYPE = MSB_UNSIGNED_INTEGER
START_BYTE = 1
BYTES = 4
DESCRIPTION = "Spacecraft clock counter increments each
second, beginning at approximately 1958-01-01T00:00:00Z."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = SCLK_PARTITION
DATA_TYPE = MSB_UNSIGNED_INTEGER
START_BYTE = 5
BYTES = 1
VALID_MINIMUM = 0
VALID_MAXIMUM = 255
DESCRIPTION = "Spacecraft clock partition.
A value of ZERO or ONE indicates the first partition
(i.e. the spacecraft clock has not been reset)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = SCLK_FINE
DATA_TYPE = MSB_UNSIGNED_INTEGER
START_BYTE = 6
BYTES = 1
VALID_MINIMUM = 0
VALID_MAXIMUM = 255
DESCRIPTION = "Spacecraft clock modulo 256 counter
increments 256 times per second. Since the RTI increments from
0 through 7 in this same interval, SCLK_FINE / 32 yields the
RTI count.
For RPWS, SCLK_FINE is maintained within the instrument to an
accuracy of one RTI period. Time tags should occur only with
the following values for SCLK_FINE : 0, 32, 64, 96, 128, 160,
192, and 224"
END_OBJECT = COLUMN
/**********************************************************************/
/* Note about archive product time-tags: */
/* We should be masking (removing) the lower 5 bits */
/* of SCLK_FINE prior to using SPICE to calculate SCET. */
/* */
/* RPWS time keeping occurs only with a resolution of the */
/* RTI period (ignore the sub-RTI counter we use with the */
/* WBR, the sub-RTI timing is included in the WBR minipacket). */
/* Both HRP and LRP use bit 0 to indicate a CDS clock */
/* update has not occurred in the last second (should always */
/* be clear on LRP and always set on HRP). */
/* Both LRP and HRP use bits 1-4 to hold a CDS packet count. */
/* LRP sets this counter to 0 while HRP start this count */
/* at 1, incrementing with each packet that is processed */
/* within any RTI period (in other words, HRP resets this */
/* counter to 1 when the RTI interrupt occurs). */
/* */
/* This has the side-effect that all SCLK values delivered by */
/* RPWS are unique. This also makes query by SCLK or SCET */
/* return data in an unambiguous order. */
/* */
/* BUT!!! It is necessary to clear bits 0-4 of the SCLK_FINE */
/* in order to get back to the intended (correct) time. */
/**********************************************************************/
OBJECT = COLUMN
NAME = SCET_DAY
DATA_TYPE = MSB_UNSIGNED_INTEGER
START_BYTE = 7
BYTES = 2
DESCRIPTION = "Spacecraft event time days since
1958-01-01T00:00:00Z"
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = SCET_MILLISECOND
DATA_TYPE = MSB_UNSIGNED_INTEGER
START_BYTE = 9
BYTES = 4
VALID_MINIMUM = 0
VALID_MAXIMUM = 86401999
DESCRIPTION = "Spacecraft event time millisecond
of day allowing for up to two leap seconds."
END_OBJECT = COLUMN
/* END OF RPWS_SCLK_SCET.FMT */
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