NOAA KLM User's Guide

Section 8.3.1.3.3

Introduction Page, NOAA KLM TOC, Acronyms
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8.3.1.3.3 Data Records

The Data Records for LAC and HRPT data sets are archived in packed format to reduce storage requirements. Three 10-bit sensor samples are stored in a 32-bit word using the Band Interleaved by Pixel (BIP) method. The format for packed data sets is documented in Table 8.3.1.3.3-1. However, this format is inconvenient for data processing.

Table 8.3.1.3.3-1. Format of packed LAC/HRPT Data Sets.

Start Octet

End Octet

DT

Word Size

SF

Number of Words

SCAN LINE INFORMATION

1 2 u 2 0 1 Scan Line Number (cumulative, starting with 1)
3 4 u 2 0 1 Scan Line Year (e.g., 1999)
5 6 u 2 0 1 Scan Line Day of Year (e.g., 365)
7 8 i 2 0 1 Satellite Clock Drift Delta in milliseconds
9 12 u 4 0 1 Scan Line UTC Time of Day in milliseconds
13 14 u 2 0 1 Scan Line Bit Field
bit 15: 0 = northbound data; 1 = southbound data
bit 14: 1 = scan time corrected for clock drift
bits 13-2: <zero fill>
bits 1-0: channel 3 select (0 = 3b; 1 = 3a; 2 = transition)
15 24 i 2 0 5 <Zero Fill>
. . . . . .

QUALITY INDICATORS

25 28 u 4 0 1 Quality Indicator Bit Field
If a bit is on (=1) then the statement is true.
bit 31: do not use scan for product generation
bit 30: time sequence error detected within this scan (see below)
bit 29: data gap precedes this scan
bit 28: insufficient data for calibration (see below)
bit 27: earth location data not available (see below)
bit 26: first good time following a clock update (nominally 0)
bit 25: instrument status changed with this scan
bit 24: sync lock dropped during this frame
bit 23: frame sync word error greater than zero
bit 22: frame sync previously dropped lock
bit 21: flywheeling detected during this frame
bit 20: bit slippage detected during this frame
bits 19-9: <zero fill>
bit 8: TIP parity error detected
bits 7-6: reflected sunlight detected ch 3b (0 = no anomaly; 1 = anomaly; 3 = unsure)
bits 5-4: reflected sunlight detected ch 4 (0 = no anomaly; 1 = anomaly; 3 = unsure)
bits 3-2: reflected sunlight detected ch 5 (0 = no anomaly; 1 = anomaly; 3 = unsure)
bit 1: resync occurred on this frame
bit 0: pseudo noise occurred on this frame
29 32 u 4 0 1 Scan Line Quality Flags
If a bit is on (=1) then the statement is true.
Time Problem Code
(All bits off implies the scan time is as expected.)
bits 31-24: <zero fill>
bit 23: time field is bad but can probably be inferred from the previous good time.
bit 22: time field is bad and can't be inferred from the previous good time.
bit 21: this record starts a sequence that is inconsistent with previous times (i.e., there is a time discontinuity). This may or may not be associated with a spacecraft clock update. (See bit 26, Quality Indicator Bit Field)
bit 20: start of a sequence that apparently repeats scan times that have been previously accepted.
bits 19-16: <zero fill>
Calibration Problem Code
(Note these bits complement the channel indicators; all bits set to 0 indicates normal calibration.)
bit 15: scan line was not calibrated because of bad time.
bit 14: scan line was calibrated using fewer than the preferred number of scan lines because of proximity to start or end of data set or to a data gap.
bit 13: scan line was not calibrated because of bad or insufficient PRT data.
bit 12: scan line was calibrated but with marginal PRT data.
bit 11: some uncalibrated channels on this scan (see channel indicators)
bits 10-8: <zero fill>
Earth Location Problem Code
(all bits set to 0 implies the earth location was normal)
bit 7: not earth located because of bad time; earth location fields zero filled.
bit 6: earth location questionable because of questionable time code. (See time problem flags above).
bit 5: earth location questionable -- only marginal agreement with reasonableness check.
bit 4: earth location questionable -- fails reasonableness check.
bits 3-0: <zero fill>
33 38 u 2 0 3 Calibration Quality Flags
(all bits off implies a good calibration)
Word 1: Channel 3b
bits 15 - 8: <zero fill>
bit 7: this channel is not calibrated
bit 6: this channel is calibrated but questionable
bit 5: all bad blackbody counts for scan line
bit 4: all bad space view counts for scan line
bit 3: <zero fill>
bit 2: marginal blackbody view counts for this line
bit 1: marginal space view counts for this line
bit 0: <zero fill>
Word 2: Channel 4
Word 3: Channel 5
39 40 u 2 0 1 Count of Bit Errors in Frame Sync
41 48 i 4 0 2 <Zero Fill>
. . . . . .

CALIBRATION COEFFICIENTS

49 52 i 4 7 1 Visible Operational Cal Ch 1 Slope 1
53 56 i 4 6 1 Visible Operational Cal Ch 1 Intercept 1
57 60 i 4 7 1 Visible Operational Cal Ch 1 Slope 2
61 64 i 4 6 1 Visible Operational Cal Ch 1 Intercept 2
65 68 i 4 0 1 Visible Operational Cal Ch 1 Intersection
69 72 i 4 7 1 Visible Test Cal Ch 1 Slope 1
73 76 i 4 6 1 Visible Test Cal Ch 1 Intercept 1
77 80 i 4 7 1 Visible Test Cal Ch 1 Slope 2
81 84 i 4 6 1 Visible Test Cal Ch 1 Intercept 2
85 88 i 4 0 1 Visible Test Cal Ch 1 Intersection
89 92 i 4 7 1 Visible Prelaunch Cal Ch 1 Slope 1
93 96 i 4 6 1 Visible Prelaunch Cal Ch 1 Intercept 1
97 100 i 4 7 1 Visible Prelaunch Cal Ch 1 Slope 2
101 104 i 4 6 1 Visible Prelaunch Cal Ch 1 Intercept 2
105 108 i 4 0 1 Visible Prelaunch Cal Ch 1 Intersection
109 112 i 4 7 1 Visible Operational Cal Ch 2 Slope 1
113 116 i 4 6 1 Visible Operational Cal Ch 2 Intercept 1
117 120 i 4 7 1 Visible Operational Cal Ch 2 Slope 2
121 124 i 4 6 1 Visible Operational Cal Ch 2 Intercept 2
125 128 i 4 0 1 Visible Operational Cal Ch 2 Intersection
129 132 i 4 7 1 Visible Test Cal Ch 2 Slope 1
133 136 i 4 6 1 Visible Test Cal Ch 2 Intercept 1
137 140 i 4 7 1 Visible Test Cal Ch 2 Slope 2
141 144 i 4 6 1 Visible Test Cal Ch 2 Intercept 2
145 148 i 4 0 1 Visible Test Cal Ch 2 Intersection
149 152 i 4 7 1 Visible Prelaunch Cal Ch 2 Slope 1
153 156 i 4 6 1 Visible Prelaunch Cal Ch 2 Intercept 1
157 160 i 4 7 1 Visible Prelaunch Cal Ch 2 Slope 2
161 164 i 4 6 1 Visible Prelaunch Cal Ch 2 Intercept 2
165 168 i 4 0 1 Visible Prelaunch Cal Ch 2 Intersection
169 172 i 4 7 1 Visible Operational Cal Ch 3a Slope 1
173 176 i 4 6 1 Visible Operational Cal Ch 3a Intercept 1
177 180 i 4 7 1 Visible Operational Cal Ch 3a Slope 2
181 184 i 4 6 1 Visible Operational Cal Ch 3a Intercept 2
185 188 i 4 0 1 Visible Operational Cal Ch 3a Intersection
189 192 i 4 7 1 Visible Test Cal Ch 3a Slope 1
193 196 i 4 6 1 Visible Test Cal Ch 3a Intercept 1
197 200 i 4 7 1 Visible Test Cal Ch 3a Slope 2
201 204 i 4 6 1 Visible Test Cal Ch 3a Intercept 2
205 208 i 4 0 1 Visible Test Cal Ch 3a Intersection
209 212 i 4 7 1 Visible Prelaunch Cal Ch 3a Slope 1
213 216 i 4 6 1 Visible Prelaunch Cal Ch 3a Intercept 1
217 220 i 4 7 1 Visible Prelaunch Cal Ch 3a Slope 2
221 224 i 4 6 1 Visible Prelaunch Cal Ch 3a Intercept 2
225 228 i 4 0 1 Visible Prelaunch Cal Ch 3a Intersection
229 232 i 4 6 1 IR Operational Cal Ch 3b Coefficient 1
233 236 i 4 6 1 IR Operational Cal Ch 3b Coefficient 2
237 240 i 4 6 1 IR Operational Cal Ch 3b Coefficient 3
241 244 i 4 6 1 IR Test Cal Ch 3b Coefficient 1
245 248 i 4 6 1 IR Test Cal Ch 3b Coefficient 2
249 252 i 4 6 1 IR Test Cal Ch 3b Coefficient 3
253 256 i 4 6 1 IR Operational Cal Ch 4 Coefficient 1
257 260 i 4 6 1 IR Operational Cal Ch 4 Coefficient 2
261 264 i 4 6 1 IR Operational Cal Ch 4 Coefficient 3
265 268 i 4 6 1 IR Test Cal Ch 4 Coefficient 1
269 272 i 4 6 1 IR Test Cal Ch 4 Coefficient 2
273 276 i 4 6 1 IR Test Cal Ch 4 Coefficient 3
277 280 i 4 6 1 IR Operational Cal Ch 5 Coefficient 1
281 284 i 4 6 1 IR Operational Cal Ch 5 Coefficient 2
285 288 i 4 6 1 IR Operational Cal Ch 5 Coefficient 3
289 292 i 4 6 1 IR Test Cal Ch 5 Coefficient 1
293 296 i 4 6 1 IR Test Cal Ch 5 Coefficient 2
297 300 i 4 6 1 IR Test Cal Ch 5 Coefficient 3
301 312 i 4 0 3 <Zero Fill>
. . . . . .

NAVIGATION

313 316 u 4 0 1 Navigation Status Bit Field
bits 31-17: <zero fill>
bit 16: 1 = earth location corrected for TIP Euler angles
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)
317 320 u 4 0 1 Time Associated with TIP Euler Angles (Seconds)
321 326 i 2 3 3 TIP Euler Angles in Degrees
Word 1: Roll
Word 2: Pitch
Word 3: Yaw
327 328 u 2 1 1 Spacecraft Altitude above Reference Ellipsoid in km
329 634 i 2 2 153 Angular Relationships
(relative azimuth range +/- 180.00 degrees)
Word 1: Solar Zenith Angle, Point 25
Word 2: Satellite Zenith Angle, Point 25
Word 3: Relative Azimuth Angle, Point 25
Word 4: Solar Zenith Angle, Point 65
...
(set of 3 angles every 40 points)
...
Word 153: Relative Azimuth Angle, Point 2025
635 640 i 2 0 3 <Zero Fill>
641 1048 i 4 4 102 Earth Location
(North latitude and East longitude are positive)
Word 1: Latitude in Degrees, Point 25
Word 2: Longitude in Degrees, Point 25
Word 3: Latitude in Degrees, Point 65
...
(lat/lon word pair every 40 points)
...
Word 102: Longitude in Degrees, Point 2025
1049 1056 i 4 0 2 <Zero Fill>
. . . . . .

HRPT MINOR FRAME TELEMETRY

1057 1068 u 2 0 6 Frame Sync
The first sixty bits (six 10-bit values: 644, 367, 860, 413, 527, 149) from a 63 bit pseudonoise generator starting in the all 1's state. The generator polynomial is:
x6 + x5 + x2 + 1
1069 1072 u 2 0 2 ID
Word 1
bits 15-10: <zero fill>
bit 9: 0 = internal sync; 1 = AVHRR sync
bits 8-7: 0 = not an HRPT frame but a GAC frame; 1 = minor frame 1; 2 = minor frame 2; 3 = minor frame 3
bits 6-3: spacecraft address
bit 2: 0 = frame stable; 1 = frame resync occurred
bit 1: 0 = pseudonoise AVHRR input; 1 = normal AVHRR input
bit 0: 0 = AVHRR Ch 3b; 1 = AVHRR Ch 3a
Word 2
bits 15-10: <zero fill>
bits 9-0: <undefined>
1073 1080 u 2 0 4 Time Code
Word 1
bits 15-10: <zero fill>
bits 9-1: binary day count
bit 0 = 0
Word 2
bits 15-10: <zero fill>
bit 9 = 1
bit 8 = 0
bit 7 = 1
bits 6-0: most significant part of binary millisecond of day count
Word 3
bits 15-10: <zero fill>
bits 9-0: part of binary millisecond of day count
Word 4
bits 15-10: <zero fill>
bits 9-0: least significant part of binary millisecond of day count
1081 1100 u 2 0 10 Telemetry
Word 1: Ramp Calibration AVHRR Channel 1
Word 2: Ramp Calibration AVHRR Channel 2
Word 3: Ramp Calibration AVHRR Channel 3
Word 4: Ramp Calibration AVHRR Channel 4
Word 5: Ramp Calibration AVHRR Channel 5
Words 6-9
AVHRR Internal Target Temperature Data
Three readings from one of the four platinum resistance thermometers (PRT). A different PRT is sampled for each scan; every fifth scan will contain a reference value of 0 in place of each reading.
Word 6: PRT Reading 1
Word 7: PRT Reading 2
Word 8: PRT Reading 3
Word 9: Patch Temperature
Word 10: <undefined>
1101 1160 u 2 0 30 Back Scan
Ten words of calibration target view data from each AVHRR channel 3, 4, 5.
Word 1: Channel 3, Word 1
...
Word 3: Channel 5, Word 1
Word 4: Channel 3, Word 2
...
Word 30: Channel 5, Word 10
1161 1260 u 2 0 50 Space Data
Ten words of space view data from each AVHRR channel 1, 2, 3, 4, 5
Word 1: Channel 1, Word 1
...
Word 5: Channel 5, Word 1
Word 6: Channel 1, Word 2
...
Word 50: Channel 5, Word 10
1261 1262 u 2 0 1 Sync Delta
bits 15-10: <zero fill>
bit 9: 0 = AVHRR sync early; 1 = AVHRR sync late
bits 8-0: 9-bit binary count of 0.9984 MHz periods
1263 1264 i 2 0 1 <Zero Fill>
. . . . . .

AVHRR SENSOR DATA

1265 14920 u 4 0 3414 Sensor Data, Band Interleaved by Pixel (BIP)
Word 1
bits 31-30: <zero fill>
bits 29-20: Channel 1, Point 1
bits 19-10: Channel 2, Point 1
bits 9-0: Channel 3, Point 1
Word 2
bits 31-30: <zero fill>
bits 29-20: Channel 4, Point 1
bits 19-10: Channel 5, Point 1
bits 9-0: Channel 1, Point 2
...
Word 3414
bits 31-30: <zero fill>
bits 29-20: Channel 5, Point 2048
14921 14928 i 4 0 2 <Zero Fill>
. . . . . .

DIGITAL B TELEMETRY

14929 14930 u 2 0 1 Invalid Word Bit Flags
(if bit = 1, associated telemetry bit was not updated during most recent minor frame cycle - possibly due to lost frame)
bit 15: motor/telemetry
bit 14: electronics/telemetry
bit 13: channel 1 status
bit 12: channel 2 status
bit 11: channel 3a status
bit 10: channel 3b status
bit 9: channel 4 status
bit 8: channel 5 status
bit 7: channel 3a/3b select status
bit 6: voltage calibrate status
bit 5: cooler heat
bit 4: scan motor
bit 3: telemetry lock
bit 2: earth shield
bit 1: patch control
bit 0: <zero fill>
14931 14932 u 2 0 1 AVHRR Digital B Data
bit 15: motor/telemetry (0 = off; 1 = on)
bit 14: electronics/telemetry (0 = off; 1 = on)
bit 13: channel 1 status (0 = disable; 1 = enable)
bit 12: channel 2 status (0 = disable; 1 = enable)
bit 11: channel 3a status (0 = disable; 1 = enable)
bit 10: channel 3b status (0 = disable; 1 = enable)
bit 9: channel 4 status (0 = disable; 1 = enable)
bit 8: channel 5 status (0 = disable; 1 = enable)
bit 7: channel 3a/3b select status (0 = 3b; 1 = 3a)
bit 6: voltage calibrate status (0 = off; 1 = on)
bit 5: cooler heat (0 = off; 1 = on)
bit 4: scan motor (0 = low; 1 = high)
bit 3: telemetry lock (0 = off; 1 = lock)
bit 2: earth shield (0 = disable; 1 = deploy)
bit 1: patch control (0 = off; 1 = on)
bit 0: <zero fill>
14933 14944 i 4 0 3 <Zero Fill>
. . . . . .

ANALOG HOUSEKEEPING DATA (TIP)

14945 14948 u 4 0 1 Invalid Word Bit Flags
(if bit = 1, associated telemetry word was not updated during most recent minor frame cycle - possibly due to lost frame)
bits 31 - 23: <zero fill>
bit 22: reference voltage (word 22)
bits 21-2: words 21 through 2 (in order)
bit 1: patch temperature (word 1)
bit 0: <zero fill>
14949 14970 u 1 0 22 Word 1: Patch Temperature
Word 2: Patch Temperature Extended
Word 3: Patch Power
Word 4: Radiator Temperature
Word 5: Black Body Temperature 1
Word 6: Black Body Temperature 2
Word 7: Black Body Temperature 3
Word 8: Black Body Temperature 4
Word 9: Electronics Current
Word 10: Motor Current
Word 11: Earth Shield Position
Word 12: Electronics Temperature
Word 13: Cooler Housing Temperature
Word 14: Baseplate Temperature
Word 15: Motor Housing Temperature
Word 16: A/D Converter Temperature
Word 17: Detector #4 Bias Voltage
Word 18: Detector #5 Bias Voltage
Word 19: Channel 3b Blackbody View
Word 20: Channel 4 Blackbody View
Word 21: Channel 5 Blackbody View
Word 22: Reference Voltage
14971 14976 i 2 0 3 <Zero Fill>
. . . . . .

CLOUDS FROM AVHRR (CLAVR)

14977 14980 u 4 0 1 <Reserved>
CLAVR Status Bit Field 1
bits 31 - 1: <undefined>
bit 0: CLAVR status (0 = disable, CCM codes zero-filled; 1 = enable)
14981 14984 u 4 0 1 <Reserved>
14985 15496 u 2 0 256 <Reserved>
CCM (Clear/Cloudy/Mixed) Codes
(0 = unknown; 1 = clear; 2 = cloudy; 3 = partly cloudy)
Word 1
bits 15-14: CCM Point 1
...
bits 1-0: CCM Point 8
...
(set of 8 CCM Codes per word)
...
Word 256
bits 15-14: CCM Point 2041
...
bits 1-0: CCM Point 2048
. . . . . .

FILLER

15497 15872 i 4 0 94 <Zero Fill> 1
Notes (Revision History):
1 13Nov1998: Redefine reserved CLAVR section to include CLAVR Status Bit Field (Fagan, 24Sep1998); adjust trailing zero-fill

NESDIS archive systems support the selection of any combination of one to five channels, and sensor data word sizes of 8 or 16 bits (this is known as the unpacked format). The unpacking process stores each (10-bit) sensor data value in a separate eight or sixteen bit word. When 8-bit words are selected, the sensor data is reduced from ten to eight bits by removing the least significant two bits. When 16-bit words are selected, the sensor data is stored in the least significant ten bits and the six most significant bits are zero-filled. If a customer does not require all five channels from the AVHRR instrument, the unpacked format can also be reduced to any subset of active channels. At this time, however, the archive extraction programs do not differentiate between channels 3A and 3B. Channel selected data sets are not available in packed format. In all cases, the sensor data is stored in BIP order.

Tables 8.3.1.3.3-2 and 8.3.1.3.3-3 (containing the 8 and 16-bit unpacked structure, respectively) summarize how the selection of channel and sensor data word size affects the data set structure documented in Table 8.3.1.3.3-1. While the alignment of data words on eight octet boundaries is maintained by adding binary zero-fill after the sensor data section, in the interests of minimizing data set size the record lengths are no longer restricted to multiples of 512 octets.

Table 8.3.1.3.3-2. LAC/HRPT 8-bit Extract Structure.
Number of Channels 1 2 3 4 5
Pre-Data 1 - 1264 1 - 1264 1 - 1264 1 - 1264 1 - 1264
Sensor Data 1265 - 3312 1265 - 5360 1265 - 7408 1265 - 9456 1265 - 11504
Alignment Zero-Fill 3313-3320 5361-5368 7409-7416 9457-9464 11505-11512
Post-Data 3321-3880 5369-5928 7417-7976 9465-10024 11513-12072
Trailing Zero-Fill 3881-4096 5929-6144 7977-8192 10025-10240 12073-12288
Record Length 4096 6144 8192 10240 12288

Table 8.3.1.3.3-3. LAC/HRPT 16-bit Extract Structure.
Number of Channels 1 2 3 4 5
Pre-Data 1 - 1264 1 - 1264 1 - 1264 1 - 1264 1 - 1264
Sensor Data 1265 - 5360 1265 - 9456 1265 - 13552 1265 - 17648 1265 - 21744
Alignment Zero-Fill 5361-5368 9457-9464 13553-13560 17649-17656 21745-21752
Post-Data 5369-5928 9465-10024 13561-14120 17657-18216 21753-22312
Trailing Zero-Fill 5929-6144 10025-10240 14121-14336 18217-18432 22313-22528
Record Length 6144 10240 14336 18432 22528


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