NOAA KLM User's Guide

Section 4.1

Introduction Page, NOAA KLM TOC, Acronyms
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4.1 HRPT System

4.1.1 General

The High Resolution Picture Transmission (HRPT) system provides data from all spacecraft instruments at a rate of 665,400 bps. The S-band realtime transmission consists of the digitized unprocessed output of five AVHRR/3 channels, plus the TIP (HIRS/3, SBUV/2, SEM, DCS/2) data and AMSU data. All information necessary to calibrate the instrument outputs is included in the data stream.

During NOAA-K activation and evaluation, it was determined that AMSU-A channels 7 and 15 were switched. Direct readout users should be aware of this problem, although the switch should be transparent to Level 1b users as the channels were corrected (switched back) by the ingest software. Only the radiometric data was affected. The housekeeping temperatures, antenna patterns, beam efficiency and beam widths of channels 15 and 7 oscillators are correct as they are now and were not affected by the switch. Band pass for channels 7 and 15 was also not affected due to extremely broad rf-detectors.

4.1.2 Transmission Characteristics

The S-band transmission of time multiplexed, digital data is in a split phase format. Split phase data "0" is defined as being +68 degrees phase during the first half of the bit period and -68 degrees during the second half of the bit period. The split phase data "1" is defined as being -68 degrees phase during the first half of the bit period and +68 degrees phase during the second half of the bit period. Table 4.1.2-1 shows the general characteristics of the HRPT transmission system, while the general HRPT parameters are shown in Table 4.1.2-2.

Table 4.1.2-1. HRPT Transmission Characteristics.

Line Rate 360 lines/minute
Data Channels 5 transmitted, 6 available
Data Resolution 1.1 km
Carrier Modulation Digital split phase, phase modulated
Transmitter Frequency (MHz) 1698.0 or 1707.0
Transmitter Power (EOL) 6.35 W (38.03 dBm)
Radiated Power (dBm, @ 63 degrees) 40.13
Polarization RCP

Table 4.1.2-2. HRPT Parameters.

Major Frame

Rate 2 major frames/sec
Minor Frames/Major Frame 3

Minor Frame

Rate 6 minor frames/sec
Number of words 11090
Format SeeTable 4.1.3-1
Word Parameters
Rate 66,540 words/sec
Number of bits/word 10
Order Bit 1=MSB, Bit 10=LSB

Bit Parameters

Rate 665,400 bits/sec
Format Split phase
Data "0" +68/-68 degrees
Data "1" -68/+68 degrees

4.1.3 HRPT Minor Frame Format

The MIRP outputs the HRPT format simultaneously with the Automatic Picture Transmission (APT), Global Area Coverage (GAC) and Local Area Coverage (LAC) formats. GAC and LAC data are not considered real time, as these data are stored on the spacecraft digital recorders for readout by the CDA stations. The HRPT data format consists of a major frame which is subdivided into three minor frames. On NOAA KLM, TIP and AMSU data are updated at the major frame rate. That is, the three minor frames which make up the major frame will contain TIP data in the first minor frame, backfill in the second minor frame, and AMSU data from the AIP, in the third minor frame. In the previous series of satellites (NOAA E-J), the major frame consisted of three minor frames of only the TIP data. The details of the minor frame formats are shown in Table 4.1.3-1 and Figure 4.1.3-1.

Table 4.1.3-1. HRPT Minor Frame Format.

Function No. of Words Word
Position
Bit No. 1 2 3 4 5 6 7 8 9 10
Plus Word Code & Meaning
Frame Sync 6 1 1 0 1 0 0 0 0 1 0 0
2 0 1 0 1 1 0 1 1 1 1
3 1 1 0 1 0 1 1 1 0 0 See Note 1
4 0 1 1 0 0 1 1 1 0 1
5 1 0 0 0 0 0 1 1 1 1
6 0 0 1 0 0 1 0 1 0 1
ID 2 7 Bit 1; 0=Internal Sync; 1=AVHRR Sync
Bits 2 & 3; 00=Not an HRPT frame but a GAC frame; 01=Minor Frame #1; 10=Minor Frame #2; 11=Minor Frame #3
Bits 4-7; Spacecraft Addresses; Bit 4=MSB, BIT 7=LSB
Bit 8; 0=Frame Stable; 1=Frame Resync Occurred
Bit 9; 1=Normal AVHRR input, 0=PN AVHRR Input
Bit 10; 0=AVHRR Ch3B, 1=AVHRR Ch3A
8 Bits 1-10; undefined Spare
Time Code 4 9 Bits 1-9; Binary day count; Bit 1 = MSB; Bit 9 = LSB
Bit 10; 0; spare
10 Bit 1-3; 101, spare Bits 4-10; Part of Binary msec of day
count; Bit 4=MSB

11

Bit 1-10; Part of Binary msec of day count;
12 Bit 1-10; Remainder of Binary msec of day count; Bit 10=LSB
Telemetry 10 13 Ramp Calibration AVHRR Channel #1
14 Ramp Calibration AVHRR Channel #2
15 Ramp Calibration AVHRR Channel #3
16 Ramp Calibration AVHRR Channel #4
17 Ramp Calibration AVHRR Channel #5
18 PRT Reading 1
19 PRT Reading 2
20 PRT Reading 3 See Note 2
21 Channel 3 patch Temp.
22 Spare - Undefined
Calibration Target View 30 23
thru
52
10 words of calibration target view data from each AVHRR channel 3, 4, and 5. These data are time multiplexed as chan 3 (word 1), chan 4 (word 1), chan 5 ( word 1), chan 3 (word 2), chan 4 (word 2), chan 5 (word 2), etc.
Space Data 50 53
thru
102
10 words of space scan data from each AVHRR channel 1, 2, 3, 4, and 5. These data are time multiplexed as chan 1 (word 1), chan 2 (word 1), chan 3 (word 1), chan 4 (word 1) chan 5 (word 1), chan 1 (word 2), chan 2 (word 2), chan 3 (word 2), chan 4 (word 2), chan 5 (word 2), etc.
Sync Data 1 103 Bit 1; 0 = AVHRR sync early; 1 = AVHRR sync late, Bits 2-10; 9 bit binary count of 0.9984 MHz periods; Bit 2 = MSB, Bit 10=LSB
Data Words 520 104
thru
623
3 sets of data corresponding to three HRPT minor frames per HRPT major frame.
First HRPT minor frame: The 520 words contain 5 TIP minor frames of TIP data (104 TIP data words per TIP minor frame) Bits 1-8: Exact format as generated by TIP. Bit 9: Even parity check over Bits 1-8. Bit 10: Inverted Bit 1.
Second HRPT minor frame: The 520 words shall consist of five frames (104 words per frame) of spare data in the same form as spare words 624-750.
Third HRPT minor frame: The 520 words shall consist of five frames (104 words per frame-see Note 3)of AMSU data from the AIP. Bits 1-8: Exact format as generated by AIP.
Bit 9: Even parity check over Bits 1-8.
Bit 10: Inverted Bit 1.
Spare Words 127 624 1 0 1 0 0 0 1 1 1 0
625 1 1 1 0 0 0 1 0 1 1
626 0 0 0 0 1 0 1 1 1 1
627 1 0 1 1 0 0 0 1 1 1
628 1 1 0 1 0 1 0 0 1 0
... ... See Note 4
748 1 0 0 1 0 1 1 0 1 0
749 1 1 0 0 1 0 0 0 1 0
750 1 0 0 0 0 0 0 0 0 0
Earth Data 10,240 751 Chan 1 - Sample 1
752 Chan 2 - Sample 1
753 Chan 3 - Sample 1
754 Chan 4 - Sample 1
755 Chan 5 - Sample 1
756 Chan 1 - Sample 2
... ... See Note 5
10,985 Chan 5 - Sample 2047
10,986 Chan 1 - Sample 2048
10,987 Chan 2 - Sample 2048
10,988 Chan 3 - Sample 2048
10,989 Chan 4 - Sample 2048
10,990 Chan 5 - Sample 2048
Auxiliary Sync 100 10,991 1 1 1 1 1 0 0 0 1 0
10,992 1 1 1 1 1 1 0 0 1 1
10,993 0 1 1 0 1 1 0 1 0 1
10,994 1 0 1 0 1 1 1 1 0 1
... ... See Note 6
11,089 0 1 1 1 1 1 0 0 0 0
11,090 1 1 1 1 0 0 1 1 0 0
Notes:
  1. First 60 bits from 63 bit PN generator started in the all 1's state. The generator polynomial is X6+X5+X2+X+1
  2. 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.
  3. 104 words includes 103 words of the AMSU frame plus the first word of TIP
  4. Derived by inverting the output of a 1023 bit PN sequence provided by a feedback shift register generating the polynomial: X10+X5+X2+X+1. The generator is started in all 1's state at the beginning of word 7 of each minor frame.
  5. Each minor frame contains the data obtained during one Earth scan of the AVHRR sensor. The data from the five sensor channels of the AVHRR are time multiplexed as indicated.
  6. Derived from the non-inverted output of a 1023 bit PN sequence provided by a feedback shift register generating the polynomial: X10+X5+X2+X+1. The generator is started in the all 1's state at the beginning of word 10,991.

Of special note here is the flag in the telemetry (Word 7, Bit 10) which will indicate which of AVHRR/3 channel 3 sensors (3A or 3B) is operating. When channel 3B is selected, the patch temperature data is output every scan line (during the backscan), and every other scan line when channel 3A is selected. The data output will switch instantaneously between 3A or 3B upon command, even if the scan is in the middle of a line. However, the way the flag operates there is one scan line of uncertainty when switching from 3B to 3A, and two lines of uncertainty when switching from 3A to 3B.

Figure 4.1.3-1. AIP Output Format.
0-1-2
22-Bit Sync
3
////////
4
MFC
5
1)
6-7
////////////////
8-23
AMSU-A1 (Words 8 through 33)
24-33
AMSU-A1
34-47
AMSU-A2 (Words 34 through 47)
48-71
AMSU-B (Words 48 through 97)
72--95
AMSU-B (Words 48 through 97)
96-97
AMSU-B
98-101
///// Spare /////
102
2)
103-105
20-Bit Sync
SC ID
106
1), 3)
107
3), 4)
108
4)
109-110
CMMD VER
111
5)
112-114
Analog SUBCOM
32/16/1 Seconds
115 5) 116
6)
117
DAU
1
118
DAU 2
119
HIRS/3
120
HIRS/3
121-122 DCS-2 123-124
SEM
125-126 HIRS/3 127-128
DCS-2
129-130
HIRS/3
131-132 DCS-2 133-134
HIRS/3
135-136
DCS-2
137-138
HIRS/3
139-140
SBUV/2
141-142
HIRS/3
143
DCS-2
144
DCS-2
145-146
HIRS/3
147-148
DCS-2
149-154
CPU Telemetry
155-156
DCS-2
157-158
HIRS/3
159-160
DCS-2
161-162
HIRS/3
163-164
DCS-2
165-166
HIRS/3
167
DCS-2
168
DCS-2
169-170
HIRS/3
171-172
DCS-2
173-174 HIRS/3 175-176 DCS-2 177-178
HIRS/3
179-180
DCS-2
181-182 HIRS/3 183-184 SBUV/2 185-186
HIRS/3
187-188 HIRS/3 189-190
DCS-2
191
HIRS/3
192
HIRS/3
193-194
DCS-2
195-196
HIRS/3
197-198 DCS-2 199-204
CPU Telemetry
205
////////
206-207
7)
///// Indicates "Spare" and Reads 010101 etc.
Notes:
  1. Words 5 and 106: Bit 1 Command Verification Status, Bits 2&3-TIP status, Bits 4,5 & 6-Major Frame Counter.
  2. Word 102: Bits 1&2 spare, followed by 6 bits AMSU parity.
  3. Words 106 and 107: 9 Bit Dwell address.
  4. Words 107 and 108: 9 Bit Subcommutation counter.
  5. Digital-B Subcommutation (32 second).
  6. Analog Subcommutation.
  7. Word 206: 2 bits CPU data status followed by 6 bits TIP parity; word 207: 2 bits spare followed by 6 bits TIP parity calculated by AIP.

4.1.4 Digital "A" Telemetry

4.1.4.1 AMSU-A1

The AMSU-A1 Digital "A" telemetry incorporates all of the radiometric data taken during one scan. It also includes the data from the on-orbit calibrations. In the Full Scan Mode, the AMSU-A1 has 1,244 Digital "A" telemetry points, as identified in Table 4.1.4.1-1.

Table 4.1.4.1-1. AMSU-A1 Digital "A" Data Format - Full Scan Mode.

A1 Frame Byte Number Parameter
1-3 Sync. Sequence (FF Hex)
4 Unit Identification and Serial Number
5 Digital Housekeeping Data 1
6 Digital Housekeeping Data 2
7 Digital Housekeeping Data 3
8 Digital Housekeeping Data 4
9 Reflector 1, Position 1, MSP, First reading
10 Reflector 1, Position 1, LSP, First reading
11 Reflector 2, Position 1, MSP, First reading
12 Reflector 2, Position 1, LSP, First reading
13 Reflector 1, Position 1, MSP, Second reading
14 Reflector 1, Position 1, LSP, Second reading
15 Reflector 2, Position 1, MSP, Second reading
16 Reflector 2, Position 1, LSP, Second reading
17 Scene Position 1, Channel 3, MSP
18 Scene Position 1, Channel 3, LSP
19 Scene Position 1, Channel 4, MSP
20 Scene Position 1, Channel 4, LSP
... ...
41 Scene Position 1, Channel 15, MSP
42 Scene Position 1, Channel 15, LSP
43 Reflector 1, Position 2, MSP, First reading
44 Reflector 1, Position 2, LSP, First reading
45 Reflector 2, Position 2, MSP, First reading
46 Reflector 2, Position 2, LSP, First reading
47 Reflector 1, Position 2, MSP, Second reading
48 Reflector 1, Position 2, LSP, Second reading
49 Reflector 2, Position 2, MSP, Second reading
50 Reflector 2, Position 2, LSP, Second reading
51 Scene Position 2, Channel 3, MSP
52 Scene Position 2, Channel 3, LSP
... ...
75 Scene Position 2, Channel 15, MSP
76 Scene Position 2, Channel 15, LSP
77 Reflector 1, Position 3, MSP, First reading
78 Reflector 1, Position 3, LSP, First reading
79 Reflector 2, Position 3, MSP, First reading
80 Reflector 2, Position 3, LSP, First reading
81 Reflector 1, Position 3, MSP, Second reading
82 Reflector 1, Position 3, LSP, Second reading
83 Reflector 2, Position 3, MSP, Second reading
84 Reflector 2, Position 3, LSP, Second reading
85 Scene Position 3, Channel 3, MSP
86 Scene Position 3, Channel 3, LSP
... ...
1027 Scene Position 30, Channel 15, MSP
1028 Scene Position 30, Channel 15, LSP
1029 Reflector 1, Cold Cal. Position, MSP, First reading
1030 Reflector 1, Cold Cal. Position, LSP, First reading
1031 Reflector 2, Cold Cal. Position, MSP, First reading
1032 Reflector 2, Cold Cal. Position, LSP, First reading
1033 Reflector 1, Cold Cal. Position, MSP, Second reading
1034 Reflector 1, Cold Cal. Position, LSP, Second reading
1035 Reflector 2, Cold Cal. Position, MSP, Second reading
1036 Reflector 2, Cold Cal. Position, LSP, Second reading
1037 Cold Calibration 1, Channel 3, MSP
1038 Cold Calibration 1, Channel 3, LSP
1039 Cold Calibration 1, Channel 4, MSP
1040 Cold Calibration 1, Channel 4, LSP
... ...
1061 Cold Calibration 1, Channel 15, MSP
1062 Cold Calibration 1, Channel 15, LSP
1063 Cold Calibration 2, Channel 3, MSP
1064 Cold Calibration 2, Channel 3, LSP
1065 Cold Calibration 2, Channel 4, MSP
1066 Cold Calibration 2, Channel 4, LSP
... ...
1087 Cold Calibration 2, Channel 15, MSP
1088 Cold Calibration 2, Channel 15, LSP
1089 Temp Sensor 1, MSP
1090 Temp Sensor 1, LSP
1091 Temp Sensor 2, MSP
1092 Temp Sensor 2, LSP
... ...
1177 Temp Sensor 45, MSP
1178 Temp Sensor 45, LSP
1179 Temp Sensor Reference Voltage, MSP
1180 Temp Sensor Reference Voltage, LSP
1181 Reflector 1 Warm Cal. Position, MSP, First reading
1182 Reflector 1 Warm Cal. Position, LSP, First reading
1183 Reflector 2 Warm Cal. Position, MSP, First reading
1184 Reflector 2 Warm Cal. Position, LSP, First reading
1185 Reflector 1 Warm Cal. Position, MSP, Second reading
1186 Reflector 1 Warm Cal. Position, LSP, Second reading
1187 Reflector 2 Warm Cal. Position, MSP, Second reading
1188 Reflector 2 Warm Cal. Position, LSP, Second reading
1189 Warm Calibration 1, Channel 3, MSP
1190 Warm Calibration 1, Channel 3, LSP
... ...
1213 Warm Calibration 1, Channel 15, MSP
1214 Warm Calibration 1, Channel 15, LSP
1215 Warm Calibration 2, Channel 3, MSP
1216 Warm Calibration 2, Channel 3, LSP
... ...
1239 Warm Calibration 2, Channel 15, MSP
1240 Warm Calibration 2, Channel 15, LSP
... ...
1241-1243 Sync. Sequence (FF Hex)
1244 Unit Identification and Serial Number
Notes:
  1. The MSP is the most significant portion of a particular measurement; the LSP is the least significant portion of the particular measurement.
  2. The first set of readings for a particular reflector position are made prior to the integration interval; the second set of readings are made approximately ½ way through the integration period.
  3. Digital "A" data as read by the spacecraft shall contain an undetermined number of "fill words". These fill words shall be 0001H and will be intermingled with valid data. The Digital "A" data as sent by the instrument shall be such that no valid data of 0001H shall be included.
  4. Format of Position data is: DDDDDDDDDDDDDDE0, where:
    D = Data
    E = Error bit: 0=not in spec, 1=spec.
    0 = Zero
  5. Format of Radiometer data is: DDDDDDDDDDDDDDD0, where:
    D = Data
    0 = Zero
  6. Temperature Sensor Reference Voltage utilized for temperature sensors 36-45 only.

4.1.4.2 AMSU-A2

The AMSU-A2 Digital "A" telemetry incorporates all of the radiometric data taken during one scan. It also includes the data from the on-orbit calibrations. The AMSU-A2 has 316 Digital "A" telemetry points, as described in Table 4.1.4.2-1, in the Full Scan Mode.

Table 4.1.4.2-1. AMSU-A2 Digital "A" Format - Full Scan Mode.
A2 Frame Byte Number Parameter

1-3

Sync. Sequence (FF Hex)
4 Unit Identification and Serial Number
5 Digital Housekeeping Data 1
6 Digital Housekeeping Data 2
7 Digital Housekeeping Data 3
8 Digital Housekeeping Data 4
9 Reflector, Position 1, MSP, First reading
10 Reflector, Position 1, LSP, First reading
11 Reflector, Position 1, MSP, Second reading
12 Reflector, Position 1, LSP, Second reading
13 Scene Position 1, Channel 1, MSP
14 Scene Position 1, Channel 1, LSP
15 Scene Position 1, Channel 2, MSP
16 Scene Position 1, Channel 2, LSP
17 Reflector, Position 2, MSP, First reading
18 Reflector, Position 2, LSP, First reading
19 Reflector, Position 2, MSP, Second reading
20 Reflector, Position 2, LSP, Second reading
21 Scene Position 2, Channel 1, MSP
22 Scene Position 2, Channel 1, LSP
23 Scene Position 2, Channel 2, MSP
24 Scene Position 2, Channel 2, LSP
25 Reflector, Position 3, MSP, First reading
26 Reflector, Position 3, LSP, First reading
27 Reflector, Position 3, MSP, Second reading
28 Reflector, Position 3, LSP, Second reading

29

Scene Position 3, Channel 1, MSP

30

Scene Position 3, Channel 1, LSP
... ...
247 Scene Position 30, Channel 2, MSP
248 Scene Position 30, Channel 2, LSP
249 Reflector, Cold Calibration Position, MSP, First reading
250 Reflector, Cold Calibration Position, LSP, First reading
251 Reflector, Cold Calibration Position, MSP, Second reading
252 Reflector, Cold Calibration Position, LSP, Second reading
253 Cold Calibration 1, Channel 1, MSP
254 Cold Calibration 1, Channel 1, LSP
255 Cold Calibration 1, Channel 2, MSP
256 Cold Calibration 1, Channel 2, LSP
257 Cold Calibration 2, Channel 1, MSP
258 Cold Calibration 2, Channel 1, LSP
259 Cold Calibration 2, Channel 2, MSP
260 Cold Calibration 2, Channel 2, LSP
261 Temperature Sensor 1, MSP
262 Temperature Sensor 1, LSP
263 Temperature Sensor 2, MSP
264 Temperature Sensor 2, LSP
... ...
297 Temperature Sensor 19, MSP
298 Temperature Sensor 19, LSP
299 Temperature Sensor Reference Voltage, MSP
300 Temperature Sensor Reference Voltage, LSP
301 Reflector Warm Calibration Position, MSP, First reading
302 Reflector Warm Calibration Position, LSP, First reading
303 Reflector Warm Calibration Position, MSP, Second reading
304 Reflector Warm Calibration Position, LSP, Second reading
305 Warm Calibration 1, Channel 1, MSP
306 Warm Calibration 1, Channel 1, LSP
307 Warm Calibration 1, Channel 2, MSP
308 Warm Calibration 1, Channel 2, LSP
309 Warm Calibration 2, Channel 1, MSP
310 Warm Calibration 2, Channel 1, LSP
311 Warm Calibration 2, Channel 2, MSP
312 Warm Calibration 2, Channel 2, LSP
313-315 Synchronization Sequence (FF Hex)
316 Unit Identification and Serial Number
Notes:
  1. MSP is the most significant portion of a particular measurement while the LSP is the least significant portion of the particular measurement.
  2. The first set of readings for a particular reflector position are made prior to the integration interval; the second set of readings are made approximately half way through the integration period.
  3. Digital "A" data as read by the spacecraft shall contain an undetermined number of "fill words". These fill words shall be 0001H and will be intermingled with valid data. The Digital "A" data as sent by the instrument shall be such that no valid data of 0001H shall be included.
  4. Format of Position data is
    DDDDDDDDDDDDDDE0
    D=Data
    E=Error bit: 0=not in spec, 1=spec.
    0=Zero
  5. Format of Radiometer data is:
    DDDDDDDDDDDDDDD0
    D=Data
    0=Zero
  6. Temperature sensor reference voltage is utilized for temperature sensors 13 through 19 only.

4.1.4.3 AMSU-B

Digital "A" Data is clocked into the spacecraft AIP at a 16.64 kbps rate by the shift pulse whenever the Data Enable Pulse is presented to the instrument. The AMSU-B data is in the AIP minor frame words 48 through 97. The AIP reads the digital data output from the AMSU-B in 16 bit words.

The AMSU-B telemetry format consists of 78 minor frames of data. Minor frames 1 and 80 in each 8 second cycle are blank: i.e. no data is available in the PEU digital data FIFO during the first and last minor frames of each 8 second format. The 78 minor frames are organized as three blocks of 650 words as follows (representing one scan of the instrument):