Structure of MSU-MR instrument data transmitted via UHF band in direct broadcast mode


This section describes the structure of a signal that contains data from MSU-MR scanner and is received from "Meteor-M" №1 satellite via UHF band in direct broadcast mode (developed by RSS Corp. http://rniikp.ru). Signal is transmitted as a continuous sequence of phase-shift keyed “Manchester” code at 665.4 Kbit/s rate (transport rate is 1330.8 Kbit/s). Logical "1" is represented by symbol “10”, and logical "0" - by symbol "01".

Time-division multiplexing is used for transfer of data from scanner and from telemetry sensors. Data is packed into frames that are sent continuously one after another without intervals. One frame consists of 256 octets. Most significant bit of each octet comes first. The structure of a transport frame is given in Table 1.

Signals containing satellite clock data are included in the telemetry data stream. The structure of telemetry data stream is given in Table 2. Telemetry string length is 74 bytes. Telemetry data is contained in 2 bytes of a data frame (bytes 5 and 6), so to obtain a full string of telemetry data ground receiving station should accumulate telemetry data from an uninterrupted sequence of 37 data frames.

Data from MSU-MR scanner has its own structure, that is given in Table 3. Frames and strings of MSU-MR data are transmitted one after another without intervals.


Table 1.
Structure of a transport frame

Byte number Information Byte value Comments
1 Frame start marker
(32 bit PN sequence)
h  
2 CFh  
3 FCh  
4 1Dh  
5,6 Telemetry data 00...FFh  
7...22 Auxiliary information 00...FFh  
23...254 MSU-MR data 00...FFh  
255…256 Reserved 00...FFh  


Table 2.
Telemetry data string structure

Byte number Information Byte value Comments
1 Sync-word (64 bit PN sequence) 02h  
2 18h  
3 A7h  
4 A3h  
5 92h  
6 DDh  
7 09Ah  
8 BFh  
9...11 Special information 00…FFh  
12 Satellite clock data - hours 0...23 decimal value
13 Satellite clock data - minutes 0...59
14 Satellite clock data - seconds 0...59
15 Sync-word delay in reference to seconds of the satellite clock.
Sampling interval – 24.03846 microseconds
00...FFh most significant word
16 00...FFh least significant word
17...74 Special information 00...FFh  


Table 3.
Structure of MSU-MR data string

Byte number Value Comments
1...8 02h Sync-word
(64 bit PN sequence)
18h
A7h
A3h
92h
DDh
9Ah
BFh
 
Bits
 
27 26 25 24 23 22 21 20
9 0 0 0 17thbit 16thbit 15thbit 14thbit 13thbit hours
10 0 0 12thbit 11thbit 10thbit 9thbit 8thbit 7thbit minutes
11 0 0 6thbit 5thbit 4thbit 3rdbit 2ndbit 1stbit seconds
12 Delay of the string beginning in reference to seconds of satellite clock (lower bit value – 4 milliseconds)  
13 Number of MSU-MR unit  
14…35 Special data  
36 29WL1ch 28WL1ch 27WL1ch 26WL1ch 25WL1ch 24WL1ch 23WL1ch 22WL1ch Calibration signals brightness values
(10-bit encoding)
37 21WL1ch 20WL1ch 29BL1ch 28BL1ch 27BL1ch 26BL1ch 25BL1ch 24BL1ch
38 23BL1ch 22BL1ch 21BL1ch 20BL1ch 29WL2ch 28WL2ch 27WL2ch 26WL2ch
39 25WL2ch 24WL2ch 23WL2ch 22WL2ch 21WL2ch 20WL2ch 29BL2ch 28BL2ch
40 27BL2ch 26BL2ch 25BL2ch 24BL2ch 23BL2ch 22BL2ch 21BL2ch 20BL2ch
41 29WL3ch 28WL3ch 27WL3ch 26WL3ch 25WL3ch 24WL3ch 23WL3ch 22WL3ch
42 21WL3ch 20WL3ch 29BL3ch 28BL3ch 27BL3ch 26BL3ch 25BL3ch 24BL3ch
43 23BL3ch 22BL3ch 21BL3ch 20BL3ch 29CL4ch 28CL4ch 27CL4ch 26CL4ch
44 25CL4ch 24CL4ch 23CL4ch 22CL4ch 21CL4ch 20CL4ch 29HL4ch 28HL4ch
45 27HL4ch 26HL4ch 25HL4ch 24HL4ch 23HL4ch 22HL4ch 21HL4ch 20HL4ch
46 29CL5ch 28CL5ch 27CL5ch 26CL5ch 25CL5ch 24CL5ch 23CL5ch 22CL5ch
47 21CL5ch 20CL5ch 29HL5ch 28HL5ch 27HL5ch 26HL5ch 25HL5ch 24HL5ch
48 23HL5ch 22HL5ch 21HL5ch 20HL5ch 29CL6ch 28CL6ch 27CL6ch 26CL6ch
49 25CL6ch 24CL6ch 23CL6ch 22CL6ch 21CL6ch 20CL6ch 29HL6ch 28HL6ch
50 27HL6ch 26HL6ch 25HL6ch 24HL6ch 23HL6ch 22HL6ch 21HL6ch 20HL6ch
51 291p1ch 281p1ch 271p1ch 261p1ch 251p1ch 241p1ch 231p1ch 221p1ch Video-data
52 211p1ch 201p1ch 292p1ch 282p1ch 272p1ch 262p1ch 252p1ch 242p1ch
53 232p1ch 222p1ch 212p1ch 202p1ch 293p1ch 283p1ch 273p1ch 263p1ch
54 253p1ch 243p1ch 233p1ch 223p1ch 213p1ch 203p1ch 294p1ch 284p1ch
55 274p1ch 264p1ch 254p1ch 244p1ch 234p1ch 224p1ch 214p1ch 204p1ch
56 291p2ch 281p2ch 271p2ch 261p2ch 251p2ch 241p2ch 231p2ch 221p2ch
57 211p2ch 201p2ch 292p2ch 282p2ch 272p2ch 262p2ch 252p2ch 242p2ch
58 232p2ch 222p2ch 212p2ch 202p2ch 293p2ch 283p2ch 273p2ch 263p2ch
59 253p2ch 243p2ch 233p2ch 223p2ch 213p2ch 203p2ch 294p2ch 284p2ch
60 274p2ch 264p2ch 254p2ch 244p2ch 234p2ch 224p2ch 214p2ch 204p2ch
61
…
11600
... ... ... ... ... ... ... ...


Comments:

  1. Most significant bits come first.
  2. Number of MSU-MR unit: 00h - main, 0Fh - auxiliary.
  3. Channels 1, 2, 3 are visible range and channels 4, 5, 6 are IR range.
  4. Each channel has 1540 10-bit pixels of the earth surface image.
  5. 2NWLLch – Channel L white level, Nth bit, where 1≤L≤3 and 0≤N≤9.
  6. 2NBLLch – Channel L black level, Nth bit, where 1≤L≤3 and 0≤N≤9.
  7. 2NCLMch – Channel M Cold Black Body Level, Nth bit, where 4≤M≤6 and 0≤N≤9.
  8. 2NHLMch – Channel M Hot Black Body Level, Nth bit, where 4≤M≤6 and 0≤N≤9.
  9. 2NXPYch – Xth pixel of channel Y image, Nth bit, where 1≤X≤1540, 1≤Y≤6 and 0≤N≤9.
  10. Video-information is transmitted in the following order:
    • 5 octets (4 pixels, 10 bits each) of channel 1
    • 5 octets (4 pixels, 10 bits each) of channel 2
    • 5 octets (4 pixels, 10 bits each) of channel 3
    • 5 octets (4 pixels, 10 bits each) of channel 4
    • 5 octets (4 pixels, 10 bits each) of channel 5
    • 5 octets (4 pixels, 10 bits each) of channel 6
    • next 5 octets (4 pixels, 10 bits each) of channel 1,
      etc.
  11. String length remains constant (11600 octets), strings come one after another, without intervals.
  12. Satellite clock data is transmitted as a 17-bit binary data.



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