Fundamental Technologies

Voyager LECP Pages

Appendix B

Voyager LECP Master Rate Tape Format for CR-5A/UV-5A

Figure B-1

Physical Tape Organization for CR-5A

MRT Record 1
MRT Record 2
 
 
 
MRT Record n
ENG Record 1
MRT Record n+1
 
 
 
ENG Record m
EOF
EOF

 

Figure B-2

MRT Record Structure for CR-5A

MRT Header
38 16-bit words
1 -- 39
MRT Data
366 words
39 -- 405
MPT Data
80 words
405 -- 485

MRT Data Expanded

R3(3,32)
96 Real*4
192 16-bit words
39 -- 231
R1(26)
26 Real*4
52 words
231 -- 283
QR3(3,32)

96 words
283 -- 379
QR1(26)

26 words
379 -- 405

Table B-1

MRT Record Contents for CR-5A

Words Contents
1-38 MRT Header, defined by Table B-2 (below).
39-282 RS(122) Real*4 rates, consisting of R3(3,32) and R1(26).
Individual logics are defined in Table B-3.
283-404 QRS(122) Integer*2 quality words for rates above,
consisting of QR3(3,32) and QR1(26). Quality words are
defined in Table B-4.
405-484 PA(5,32) Logical*1, 32PHA data points of 5 bytes each,
Table B-5.

 

Table B-2

MRT Record Header (CR5A)
(Compare to
MRT original.)

Integer Byte Variable Description
1 1 MRID SCID Spacecraft ID
1=Voyager 1
0=Voyager 2
1 2 MRMOD SCDMSpacecraft telemetry mode
1-6 Cruise 2-7
7 Cruise 1
8 Near Encounter
10 (OAH) Far Encounter
24 (18H) Cruise 5A
19 (1DH) UV-5A
      Spacecraft Event Time - contains the Greenwich Mean
Time (GMT) of the first PN bit of the first minor
frame (MF) used in this LECP major frame.
2 3-4 MRETH SCETH Spacecraft Event Time, Hour -
Binary hours since the beginning of the current year.
3 5-6 MRETS SCETS Spacecraft Event Time, Seconds-
Binary seconds since the beginning of the current hour.
4 7-8 MRETMS SCETMS Spacecraft Event Time, Binary -
Binary milliseconds.
5 9-10 MRETYR SCETYR Spacecraft Event Time, Year-
Two least significant digits of year, e.g. 78
6 11 MRFLAG SCEF*16+FDSCFF where
SCEF is Spacecraft Event Time Flag
0000 input by NORT file
1111 input by EDRPROC
FDSCFF is FDSC Correction Flag which
indicates that the FDSC has been corrected.
(1=corrected, 0=OK)
Bit 3 Spare
Bit 2 MOD216
Bit 1 MOD60
Bit 0 Line Count
6 12 MRG181 Group 18 ID
7 13-14 MRM216 Mod2**16 counter from the Flight Data System (FDS).
Increments each 48 minutes.
8 15-16 MRM60 Mod60 counter from the FDS.
Increments each 48 seconds
9 17-18 MRLINE Line counter from the FDS.
Increment every 60 ms.
10 19-20 MRS1 S1 LECP Status Word 1, MSB=1 if missing.
11 21-22 MRS2 S2 LECP Status Word 2, MSB=1 if missing
12 23-24 MRS3 S3 LECP Status Word 3, MSB=1 if missing
13 25-26 MRS4 S4 LECP Status Word 4, MSB=1 if missing
14 27-28 MRS5 S5 LECP Status Word 5, MSB=1 if missing
15 29-30 MRS6 S6 LECP Status Word 6, MSB=1 if missing
16 31-32 MRMOT LECP Motor Position - contains the motor
position at the end of the current record.
= 1 if unknown, otherwise
Bits 3-1 Motor position (0-7) for sector (1-8)
Bit 0 Centered flag, =1 if centered.
17 33-34 MRNMOV Number of motor steps. Turn arounds in sectors 8
and 1 or 2 are considered to be 2 steps. = -1 if unknown.
18 35-36 MRLOGT Log. Amp. Temperature in Deg C*128.
=-9999 if unknown
20 39-40 MRMSI Basic accumulation interval in .01 sec.
21 41-42 MRQ Quality of frame = number of good groups
22 43-44 MRRT Record type
1 MRT
2 MPT Header
4 SEDR
10 Eng
11 Cal
23 45-46 MRVER Version number of S1P program used to
process this data.
24 47-48 MRALT LEPT/LEMPA - In GS-3 alternating mode this word
indicates which logics are being read out in the
current record:
-1 = unknown
0 LEPT
1 LEMPA
25 49-50 MRRAB Redundancy A/B - indicates which of the
LECP redundant data systems is being used.
-1 unknown
0 A
1 B
26 51-52 MRPRO Processing status
0 S1P
1 S2P, motor corrections applied
27 53-54 MRMOR Motor period in seconds with some special cases:
-1 Not known
0 Not decoded
9000 Encounter Stow (Vgr 2 Jupiter enc)
10000 Stowed or commanded to position
Values implemented in software include
5, 6, 24, 48, 144, 192, 360 (6 min), 384
28-36 55-72 MRS5S Nine S5's for Near Encounter only
37-38 73-76   Spare

Appendix B continued:

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Last modified 4/27/05, Tizby Hunt-Ward
tizby@ftecs.com
Original page by I. Robertson