IMP-8 Counts File Format
IMP-8 counts file consists data records of one 4-day interval, with the
last record indicated by a negative interval number.
Data records are fixed-blocked by a factor of 3. Physical records are
3564 bytes in length. Logical records are 1188 bytes(297 words) in
length and represent one album of data.
WORD CONTENT
1 Universal time at start of album(tenths of seconds of year)
2 S/C clock at start of album
right justified(low order 6 bits zero)
3 Pseudo-sequence count, negative at 400 BPS, positive at 1600 BPS
4 Halfword 1 Day of year
Halfword 2 Perigee count
5 Milliseconds of day
6 Longitude geocentric(degrees)
7 Latitude "
8 Longitude geomagnetic(degrees)
9 Latitude "
10 Ro(earth radii) (C.U.L.)
11 Radial distance from center of earth(km)
12 GSEx Satellite position in geocentric solar ecliptic coordinates(km)
13 GSEy " "
14 GSEz " "
15 GSMx Satellite position in geocentric magnetospheric coordinates(km)
16 GsMy " "
17 GSMz " "
18 GEIx Sun position in geocentric equatorial inertial coordinates(AU)
19 GEIy " "
20 GEIz " "
21 L McIlwain parameter(earth radii)
22 B Magnetic field strength(gamma)
23 Lsep Satellite earth sun angle(degrees)
24 Year of recording
25 Halfword 1 Data quality flag
Halfword 2 Time quality flag
26 Halfword 1 Number of 4-day period(negative, last record of
this period)
Halfword 2 Day of next perigee
27 Milliseconds of day of next perigee
28 Right ascension spin vector in celestial inertial coordinates(deg.)
29 Declination " "
30 Halfword 1 Year Time of orbit data
Halfword 2 Day of year
31 Milliseconds of day
32-35 Spare
WORD TYPE OF EVENT ACCUM.# LEVELS
36-43 (8) DI.E.-F.-G MED-R1 0,2,4,6,8,10,12,14
44-51 (8) DI.E.F.-G MED-R2 0,2,4,6,8,10,12,14
52-55 (4) DI.-D2.E.-F.-G MED-R3 0,4,8,12
56-59 (4) DI.-(DI+EI)l.E.-F.-G MED-R3 2,6,10,14
60-63 (4) ID1 MED-R4 0,4,8,12
64-67 (4) ID2 MED-R4 2,6,10,14
68-71 (4) DI.(DII+EII)R.E.-F.-G MED-R5 1,5,9,13
72-75 (4) DI.E.F MED-R5 3,7,11,15
76-79 (4) DI.(DI+EI)2.-(DII+EII)R.E.F.-G MED-R6 0,4,8,12
80-83 (4) DI.(DII+EII)R.E.F.-G MED-R6 2,6,10,14
84-87 (4) DI MED-R7 1,5,9,13
88-91 (4) E MED-R7 3,7,11,l5
92-95 (4) F MED-R8 0,4,8,12
96-99 (4) G MED-R8 2,6,10,14
100-103 (4) DI.(DI+EI)l.E.-F.-G MED-R9 1,5,9,13
104-107 (4) (DI+EI)2.E.-F.-G MED-R9 3,7,11,15
108-115 (8) (A+B)l.B.-C LED-R1 1,3,5,7,9,11,13,15
116-123 (8) A.B.-C LED-R2 0,2,4,6,8,10,12,14
124 Al LED-R3 0
125 (A+B)l.-B.-C LED-R3 2
126 B LED-R3 4
127 (A&B)2.A.B.-C LED-R3 6
128 (A&B)2.A.-B.-C LED-R3 8
129 Al.B LED-R3 10
130 A1.-B.-C LED-R3 12
131 C LED-R3 14
132-179 (48) VLET PHA DATA:
16 3-word groups(one per snapshot) as follows:
Word 1: DI(VLET-R1)
Sign bit contains event type:
0 = DI.DII.Sum(2)D.-F
1 = DI.DII.Sum(1)D.-F
Word 2: DII(VLET-R2)
Sign bit indicates undetermined event type if one
Word 3: E(VLET-R3)
If any of the three values was padded or negative as a
result of offset subtraction for a snapshot, all three
values for that snapshot will be set to -1
180-181 (2) DI 4 VLET-R4 1,9
182-183 (2) DI 3 VLET-R4 2,10
184-185 (2) DI 2 VLET-R4 3,11
186-187 (2) DI 1 VLET-R4 4,12
188-189 (2) F VLET-R4 5,13
190-191 (2) E VLET-R4 6,14
192-193 (2) DII VLET-R4 7,15
194-195 (2) DI VLET-R4 0,8
196-203 (8) DI.DII.Sum(1)D.-F VLET-R5 Even
204-211 (8) DI.DII.Sum(2)D.-F VLET-R5 Odd
WORD TYPE OF EVENT
212 Sectored data information
Halfword 1: OA/TM Slave flag
0 IF OA Slave mode
1 IF TM Slave mode during any portion of album
Halfword 2: Analog transmitter ON/OFF flag
0 = off
1 = On during any portion of album
213-220 (8) MED sectors 1-8, Page 0 DI.E.F.-G
221-228 (8) MED sectors 1-8, Page 1 DI.-D2.E.-F.-G
229-230 (8) MED sectors 1-8, Page 2 (DI+EI)1.E.-F.-G
237-244 (8) MED sectors 1-8, Page 3 DI.-(DI+EI)1.E.-F.-G
245 Halfword 1: 20 = 1 if a corrected LED sectored rate was
< 0 in Page 0
21 = 1 if a corrected LED sectored rate was
< 0 in Page 3
Halfword 2: 20 = 1 if a corrected sun time was used for
Page 0
21 = 1 if a corrected sun time was used for
Page 3
= 4 if no OA data was available. No
corrections made
246-253 (8) LED sectors 1-8, Page 0 Al.-B.-C
254-261 (8) VLET sectors 1-8, Page 1 DI.DII.-F
262-269 (8) VLET sectors 1-8, Page 2 DI.DII.Sum(1)D.-F
270-277 (8) LED sectors 1-8, Page 3 A1.B.-C
278 DP a2-17 (VLET event type)
Byte 1: 2 redundant readouts for each of snapshots 0-3 of page 0
Byte 2: Same as above for Page 1
Byte 3: Same as above for Page 2
Byte 4: Same as above for Page 3
(Note: These correspond to the sign bits of the DI words of
132-179. If the two redundant readouts are different for any
snapshot, the sign bit for the DII word of that snapshot will
be set to 1 and the sign bit of DI will be set to 1)
279 Halfword 1 APP-6 Leakage current, Page 0
Halfword 2 " " " , Page 1
280 Halfword 1 APP-6 Leakage current, Page 2
Halfword 2 " " " , Page 3
281 Halfword 1 APP-36 MED temp, Page 1
Halfword 2 " " " , Page 3
WORD CONTENT
282 Sun time
283 Earth width Page 0
284 Earth time (S.S. 1)
285 Spin period
286-289 (4) Same as above Page 1
290-293 (4) Same as above Page 2
294-297 (4) Same as above Page 3
NON-SECTORED RATES
The trend check for each rate will be right-justified in the lst byte
of the word. The last 3 bytes will contain the rate value. If the
rate is padded, the entire 4 byte word will contain l's (-l).
SECTORED RATES
The trend check for each sectored rate will be performed on the sum of
the sector values, and the resulting flag will be stored in the lst
byte of that word for SECTOR 1 in the same manner as for non-sectored
rates.