Some NCDC systems will be down for hardware maintenance
on Saturday November 22, 2008.
Some NCDC systems will be down for hardware maintenance
on Saturday November 22, 2008.
NOAA KLM User's GuideSection 8.3.1.8.3 |
Introduction Page,
NOAA KLM TOC,
AcronymsA sequence of SEM data records follow the header record in an incremental file. Usually an incremental file contains about one orbit's data or about 6000 seconds. A single physical 512 byte data record in the file contains two seconds of data so that each incremental file contains about 3000 physical data records. Each two second data record contains 20 TIP minor frames of data, parsed so that the first minor frame is always mod 020. That is, the first TIP minor frame in each data record is either 000, 020, 040, 060, 080, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280 or 300. Table 8.3.1.8.3-1 contains a byte-by-byte description of the contents of an incremental file data record.
The SEM-2 Data Record format is documented in Table 8.3.1.8.3-1. See the legend in Section 8.3.1.1 for further explanation of the headings on this table.
| Field Name | Start Octet | End Octet | Data Type | Word Size | Number of Words | Scale Factor | Units | Notes |
|---|---|---|---|---|---|---|---|---|
| TIP Major Frame number (0 to 7) | 1 | 2 | u | 2 | 1 | 0 | ||
| TIP Minor Frame Number (cyclic: 0, 20,...,280,300; at start of this 2-second data record) | 3 | 4 | u | 2 | 1 | 0 | ||
| Minor Frame Year (at start of this 2-second data record) | 5 | 6 | u | 2 | 1 | 0 | year | |
| Minor Frame Day of Year (at start of this 2-second data record) | 7 | 8 | u | 2 | 1 | 0 | day | |
| <Zero Fill> | 9 | 10 | i | 2 | 1 | 0 | ||
| Satellite Clock Drift Delta (relative to UTC; nominally near zero) | 11 | 12 | i | 2 | 1 | 0 | milliseconds | |
| Minor Frame UTC Time of Day | 13 | 16 | u | 4 | 1 | 0 | milliseconds | |
| Satellite Travel Direction indicator (required for calculation of sensor look angles with respect to the geomagnetic field) 0 = northbound data; 1 = southbound data |
17 | 18 | u | 2 | 1 | 0 | 1 | |
| <Zero Fill> | 19 | 28 | i | 2 | 5 | 0 | ||
| QUALITY INDICATORS | ||||||||
| Quality Indicator Flags (These bytes indicate various timing and earth location problems
according to the following bit assignments. If a bit is on (=1) then the statement is true.) bit 8 (MSB of byte 29): this 2-second frame is not valid bit 7: time sequence error in this 2-second frame bit 6: data gap precedes this 2-second frame bit 5: <Zero Fill> bit 4: earth location data not available (bytes 65-72 set to zero) bit 3: first good time following a spacecraft clock update bit 2: SEM instrument status changed beginning with this frame bit 1 (LSB of byte 29): <Zero Fill> bytes 30-32: <Zero Fill> |
29 | 32 | u | 4 | 1 | 0 | ||
| Time Quality and Satellite Location Quality Flags (If a bit is on (=1) then the statement is true. These
bytes provide details of the problems flagged in bytes 29-32.) Time Problem Code byte 33: <Zero Fill> bit 8, MSB of byte 34: time is bad but can probably be inferred from the previous good time. bit 7: time is bad and cannot be inferred from the previous good time. bit 6: there is a time discontinuity, including a clock update. bit 5: this time starts a sequence that duplicates previous times. bits 4-1: <Zero Fill> byte 35: <Zero Fill> bit 8, MSB of byte 36: No earth location because of bad time; bytes 65-72 zero filled. bit 7: Earth location questionable because of questionable time code. bit 6: Earth location questionable -- marginal agreement with reasonableness check. bit 5: Earth location questionable -- fails reasonableness check. bits 4-1: <Zero Fill>. |
33 | 36 | u | 4 | 1 | 0 | ||
| <Zero Fill> | 37 | 48 | i | 2 | 6 | 0 | ||
| NAVIGATION | ||||||||
| Navigation Status Bit Field bits 31-17: <zero fill> bit 16: 1 = earth location corrected for TIP Euler angles (not applicable for SEM) bits 15 - 12: earth location indicator (0 = earth location available; 1 = user ephemeris files greater than 24 hours old; 2 = no earth location available) bits 11 - 8: spacecraft attitude control (0 = operating in YGC or NOMINAL mode; 1 = operating in another mode; 2 = attitude exceeds nominal tolerance; 3 = both 1 and 2) bits 7 - 4: attitude SMODE (0 = NOMINAL mode; 1 = rate nulling mode; 2 = YGC mode; 3 = search mode; 4 = coast mode) bits 3 - 0: attitude PWTIP$AC (0 = NOMINAL mode/no test; 1 = yaw axis test in progress; 2 = roll axis test in progress; 3 = pitch axis test in progress) |
49 | 52 | u | 4 | 1 | 0 | 2 | |
| Time Associated with TIP Euler Angles | 53 | 56 | u | 4 | 1 | 0 | seconds | 3 |
| TIP Euler Angles Bytes 57-58: Roll Euler Angle Bytes 59-60: Pitch Euler Angle Bytes 61-62: Yaw Euler Angle |
57 | 62 | i | 2 | 3 | 3 | degrees | 3 |
| Spacecraft Altitude above Reference Ellipsoid | 63 | 64 | u | 2 | 1 | 1 | kilometers | |
| Earth Location (Geodetic subsatellite point normal to ellipsoid; North latitude and East longitude are positive) Bytes 65-68: Latitude Bytes 69-72: Longitude |
65 | 72 | i | 4 | 2 | 4 | degrees | |
| <Zero Fill> | 73 | 80 | i | 4 | 2 | 0 | ||
| SEM MINOR FRAME | ||||||||
| Missing Data Bit Flags (20 entries each for TIP words 20 and 21; used for instances when data from TIP
words 20 and 21 could not be recovered because of bit sync loss and the data padded with value 000.
This information is important to the further processing of SEM-2 data.) bits 8-1, byte 81: <Zero Fill> bits 8-1, byte 82: <Zero Fill> bits 8-1, byte 83: <Zero Fill> bit 1 (LSB of byte 83): if 1, TIP word 21, minor frame +19 is padded bit 8 (MSB of byte 84): if 1, TIP word 20, minor frame +19 is padded bit 7: if 1, TIP word 21, minor frame +18 is padded bit 6: if 1, TIP word 20, minor frame +18 is padded bit 5: if 1, TIP word 21, minor frame +17 is padded bit 4: if 1, TIP word 20, minor frame +17 is padded bit 3: if 1, TIP word 21, minor frame +16 is padded bit 2: if 1, TIP word 20, minor frame +16 is padded bit 1 (LSB of byte 84): if 1, TIP word 21, minor frame +15 is padded bit 8 (MSB of byte 85): if 1, TIP word 20, minor frame +15 is padded bit 7: if 1, TIP word 21, minor frame +14 is padded bit 6: if 1, TIP word 20, minor frame +14 is padded bit 5: if 1, TIP word 21, minor frame +13 is padded bit 4: if 1, TIP word 20, minor frame +13 is padded bit 3: if 1, TIP word 21, minor frame +12 is padded bit 2: if 1, TIP word 20, minor frame +12 is padded bit 1 (LSB of byte 85): if 1, TIP word 21, minor frame +11 is padded bit 8 (MSB of byte 86): if 1, TIP word 20, minor frame +11 is padded bit 7: if 1, TIP word 21, minor frame +10 is padded bit 6: if 1, TIP word 20, minor frame +10 is padded bit 5: if 1, TIP word 21, minor frame +09 is padded bit 4: if 1, TIP word 20, minor frame +09 is padded bit 3: if 1, TIP word 21, minor frame +08 is padded bit 2: if 1, TIP word 20, minor frame +08 is padded bit 1 (LSB of byte 86): if 1, TIP word 21, minor frame +07 is padded bit 8 (MSB of byte 87): if 1, TIP word 20, minor frame +07 is padded bit 7: if 1, TIP word 21, minor frame +06 is padded bit 6: if 1, TIP word 20, minor frame +06 is padded bit 5: if 1, TIP word 21, minor frame +05 is padded bit 4: if 1, TIP word 20, minor frame +05 is padded bit 3: if 1, TIP word 21, minor frame +04 is padded bit 2: if 1, TIP word 20, minor frame +04 is padded bit 1 (LSB of byte 87): if 1, TIP word 21, minor frame +03 is padded bit 8 (MSB of byte 88): if 1, TIP word 20, minor frame +03 is padded bit 7: if 1, TIP word 21, minor frame +02 is padded bit 6: if 1, TIP word 20, minor frame +02 is padded bit 5: if 1, TIP word 21, minor frame +01 is padded bit 4: if 1, TIP word 20, minor frame +01 is padded bit 3: if 1, TIP word 21, minor frame +00 is padded bit 2: if 1, TIP word 20, minor frame +00 is padded bit 1 (LSB of byte 88): <Zero Fill> |
81 | 88 | u | 4 | 2 | 0 | ||
| TIP word 20, start TIP minor frame plus 00 | 89 | 89 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 00 | 90 | 90 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 01 | 91 | 91 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 01 | 92 | 92 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 02 | 93 | 93 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 02 | 94 | 94 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 03 | 95 | 95 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 03 | 96 | 96 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 04 | 97 | 97 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 04 | 98 | 98 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 05 | 99 | 99 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 05 | 100 | 100 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 06 | 101 | 101 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 06 | 102 | 102 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 07 | 103 | 103 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 07 | 104 | 104 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 08 | 105 | 105 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 08 | 106 | 106 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 09 | 107 | 107 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 09 | 108 | 108 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 10 | 109 | 109 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 10 | 110 | 110 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 11 | 111 | 111 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 11 | 112 | 112 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 12 | 113 | 113 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 12 | 114 | 114 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 13 | 115 | 115 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 13 | 116 | 116 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 14 | 117 | 117 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 14 | 118 | 118 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 15 | 119 | 119 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 15 | 120 | 120 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 16 | 121 | 121 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 16 | 122 | 122 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 17 | 123 | 123 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 17 | 124 | 124 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 18 | 125 | 125 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 18 | 126 | 126 | u | 1 | 1 | 0 | ||
| TIP word 20, start TIP minor frame plus 19 | 127 | 127 | u | 1 | 1 | 0 | ||
| TIP word 21, start TIP minor frame plus 19 | 128 | 128 | u | 1 | 1 | 0 | ||
| <Zero Fill> | 129 | 132 | i | 4 | 1 | 0 | ||
| DIGITAL B TELEMETRY | ||||||||
| Invalid Word Bit Flags (Indicates whether updated instrument status data from TIP word 8 is in
this minor frame.) bit 8, MSB of byte 133: if 0, update of microprocessor System ID occurred bit 7: if 0, update of TED IFC status occurred bit 6: if 0, update of MEPED IFC status occurred bit 5: if 0, update of TED electron PHD level occurred, MSB bit 4: if 0, update of TED electron PHD level occurred, LSB bits 3-1: <zero fill> bit 8, MSB of byte 134: if 0, update of microprocessor A Watchdog occurred bit 7: if 0, update of microprocessor B Watchdog occurred bit 6: if 0, update of TED proton PHD level occurred, MSB bit 5: if 0, update of TED proton PHD level occurred, LSB bits 4-1: <zero fill> |
133 | 134 | u | 2 | 1 | 0 | ||
| Digital B Telemetry (contain the actual instrument status bits) bit 8, MSB of byte 135: Microprocessor System ID, 0 for processor A bit 7: TED IFC (0 = off; 1 = on) bit 6: MEPED IFC (0 = off; 1 = on) bit 5: TED electron PHD level, MSB bit 4: TED electron PHD level, LSB bits 3-1: <zero fill> bit 8, MSB of byte 136: microprocessor A watchdog, 0=normal bit 7: microprocessor B watchdog, 0=normal bit 6: TED proton PHD level, MSB bit 5: TED proton PHD level, LSB bits 4-1: <zero fill> |
135 | 136 | u | 2 | 1 | 0 | ||
| <Zero Fill> | 137 | 140 | i | 4 | 1 | 0 | ||
| ANALOG HOUSEKEEPING DATA (TIP) | ||||||||
| Invalid Word Bit Flags (TIP word 09 and 10 housekeeping availability flags. These indicate whether updated instrument analog housekeeping data from TIP words 9 and 10 are in this minor frame.) byte 141: <zero fill> bit 8, MSB of byte 142: <zero fill> bit 7: if 0, update of primary bus voltage monitor bit 6: if 0, update of backup pitch coil driver monitor (attitude control) bit 5: if 0, update of primary pitch coil driver monitor (attitude control) bit 4: if 0, update of backup roll/yaw coil driver bit 3: if 0, update of primary roll/yaw coil driver bit 2: if 0, update of Z axis gyro torque current monitor bit 1, LSB of byte 142: if 0, update of Y axis gyro torque current monitor bit 8, MSB of byte 143: if 0, update of X axis gryo torque current monitor bit 7: if 0, update of S gyro torque current monitor bit 6: if 0, update of DPU temperature monitor bit 5: if 0, update of TED temperature monitor bit 4: if 0, update MEPED proton telescope temperature monitor bit 3: if 0, update of MEPED circuit temperature monitor bit 2: if 0, update of Omni detector bias voltage monitor bit 1, LSB of byte 143: if 0, update of TED proton CEM high voltage monitor bit 8, MSB of byte 144: if 0, update of TED electron CEM high voltage monitor bit 7: if 0, update of TED sweep voltage monitor bit 6: if 0, update of TED +5V monitor bit 5: if 0, update of MEPED +5V monitor bit 4: if 0, update of DPU +5V monitor bit 3: if 0, update of microprocessor B +5V monitor bit 2: if 0, update of microprocessor A +5V monitor bit 1, LSB of byte 144: <zero fill> |
141 | 144 | u | 4 | 1 | 0 | ||
| Analog Telemetry (Actual values of TIP analog housekeeping words 09 and 10 refreshed only when
the corresponding bit in bytes 142-144 is set to 0.) byte 145: microprocessor A +5V monitor byte 146: microprocessor B +5V monitor byte 147: DPU +5V Monitor byte 148: MEPED +5V Monitor byte 149: TED +5V Monitor byte 150: TED Sweep Voltage monitor byte 151: TED electron CEM High Voltage monitor byte 152: TED proton CEM High Voltage monitor byte 153: MEPED Omni detector Bias Voltage monitor byte 154: MEPED electronics circuit temperature monitor byte 155: MEPED proton telescope temperature monitor byte 156: TED Temperature monitor byte 157: DPU Temperature monitor byte 158: S Gyro Torque Current monitor byte 159: X Gyro Torque Current monitor byte 160: Y Gyro Torque Current monitor byte 161: Z Gyro Torque Current monitor byte 162: Primary Roll/Yaw Coil Driver current monitor byte 163: Backup Roll/Yaw Coil Driver current monitor byte 164: Primary Pitch Coil Driver current monitor byte 165: Backup Pitch Coil Driver current monitor byte 166: Primary Bus Voltage monitor |
145 | 166 | u | 1 | 22 | 0 | ||
| FILLER | ||||||||
| <Zero Fill> | 167 | 512 | i | 2 | 173 | 0 | ||
|
NOTES: 1) The direction of satellite travel is required for calculation of sensor look angles with respect to the geomagnetic field. 2) A survey of the data in the incremental files shows that bytes 49-52 are always zero and it seems that satellite attitude quality flags are not introduced in the SEM-2 incremental data file. 3) A survey of the data in the incremental files shows that bytes 53-62 are always zero and it seems that satellite attitude status data are not introduced in the SEM-2 incremental data file. | ||||||||
An extensive survey of SEM incremental data files was done to verify this documentation. Of the bytes between 29 and 62 inclusive, that include navigation error flags and information about the Euler angles, only bytes 29, 34, and 36, ever show values other than 000. The conclusion is that navigation/attitude status flags (bytes 49-52) and Euler angle information (bytes 53-62) are not provided.
Moreover, certain bits in bytes 29, 34 and 36, that are defined as providing status, never seem to be used. Specifically, bit 3 in byte 29 (first good time following a spacecraft clock update) is never set to 1; bit 8 in byte 34 (time is bad but probably can be inferred from previous time) nor bit 5 in byte 34 (this time starts a sequence that duplicates previous times) are never set to 1; bit 6 in byte 36 (earth location questionable - marginal agreement with reasonableness check) nor bit 5 in byte 36 (earth location questionable - fails reasonableness check) are never set to 1.
The study did confirm that bit 2 in byte 29 (SEM instrument status changed beginning this frame) is a reliable indicator of when the TED or MEPED are undergoing IFC. The combination of bit 8 in byte 29 (this 2-second frame is not valid) set to 1, bit 7 in byte 29 (time sequence error in this 2-second frame) set to 1, bit 4 in byte 29 (earth location data not available) set to 1, and bit 8 in byte 36 (no earth location because of bad time) set to 1 proves to be a reliable indicator of zero fill in the earth location field (bytes 65 to 72).
Information about when the magnetic torque coils were energized, a procedure required to maintain spacecraft attitude control, was introduced into the SEM data record. This was done because of concern that when the coils were energized the measurement of low energy particles by the TED would be compromised. The analysis to determine whether or not the TED observations are influenced by the torque coils has not been done. However, it was verified that data in bytes 162-165 do reflect those times when the roll/yaw and pitch coils are energized and so that analysis of any impact on TED can be done.
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