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The SP3 Enhanced Format used by the NGA St. Louis GPS Division (Geodesy & Geophysics):
The SP3 format is presented here in both the position (P) mode and the velocity (V) mode.
We will be using the format finalized by the National Geodetic Survey. The SP3 format is
precise to 1mm and 1 picosecond. If velocity is included, its precision is 10E-4 mm/sec
and 10E-4 picoseconds/s.
The following four modifications were made to the SP3 format upon completion of a one year
open period for customer feedback.
1. Version Identification:
On line one, character two, there is now a single version identification character. The
first released version has been designated version 'a'. Subsequent versions will use the
lower case letters in alphabetical order.
2. Position/Velocity Mode Flag:
The proposed formats did not accommodate velocity data on the theory that it can be derived
from the positional data. Although it is true that velocity data can be computed from positional
data--accurate to a few microns per second or better--there are arguments why velocity will be
needed, explicitly, in some situations. On line one, character three, there is now a single flag
to indicate if the SP3 file will comprise only positional data (P) or both position and velocity
data (V).
III. Position/Velocity Mode P:
In the proposal, the first character on the lines containing the x, y, z, and clock correction
values was 'V' for "vehicle". Now the first character will be 'P' for position.
IV. Position/Velocity Mode V:
When the position/velocity mode flag is set to 'V' each position line for a given satellite is
followed by a velocity line for the same satellite. The velocity components are given in
decimeters/s and have a precision of 10E-14 mm/sec. The last column of a velocity line is the
rate of change of clock correction given in units of 10E-4 microsec/s. The precision of this
parameter is 10E-16 s/s.
In addition to the above four changes, we have added a marker to designate the locations of clock
events. This marker is an 'E' located in column 75 of the position line for a satellite. This
field will normally be blank.
*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*
The following is the format for the "enhanced" SP3:
123456789012345678901234567890123456789012345678901234567890
1 #aV2006 5 28 0 0 .00000000 96 DD+AD WGS84 FIT NGA
2 ## 1377 .00000000 900.00000000 53883 .0000000000000
3 + 29 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16 17 18
4 + 19 20 21 22 23 24 25 26 27 28 29 30 0 0 0 0 0
5 + 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
6 + 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
7 + 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
8 ++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
9 ++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
10 ++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
11 ++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
12 ++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
13 %c cc cc ccc ccc cccc cccc cccc cccc ccccc ccccc ccccc ccccc
14 %c cc cc ccc ccc cccc cccc cccc cccc ccccc ccccc ccccc ccccc
15 %f 0.0000000 0.000000000 0.00000000000 0.000000000000000
16 %f 0.0000000 0.000000000 0.00000000000 0.000000000000000
17 %i 0 0 0 0 0 0 0 0 0
18 %i 0 0 0 0 0 0 0 0 0
19 /* NGA, ST. LOUIS,MO.
20 /* EPHEMERIS COMPUTED FROM 3 DAYS OF DATA
21 /* CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
22 /* CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
23 * 2006 5 28 0 0 .00000000
24 P 1 13752.206309 -20369.024073 10204.025024 55.610230
25 V 1 10790.304814 -6827.236053 -28761.711131 .025297
26 P 2 -4207.781938 14727.204491 21440.989691 .356215
27 V 2 -26576.583126 -8421.718506 356.729184 .028568
28 . . . .
29 . . . .
30 . . . .
31 . . . .
32 . . . .
33 . . . .
34 * 2006 5 28 23 45 .00000000
35 P 1 12973.835241 -19889.736391 12041.421093 55.838782
36 V 1 12878.846997 -7784.945215 -27217.727966 .025432
37 . . . .
38 . . . .
39 . . . .
40 . . . .
41 . . . .
42 . . . .
43 P 30 15849.387414 9776.120258 18703.529651 265.656142
44 V 30 3338.217385 24174.222185 -15120.093763 .139144
*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*
SP3(Enhanced) Format:
Line One:
('#aV',i4,4i3,f12.8,6x,'96 DD+AD WGS84 FIT NGA')
Column1 Symbol #
2 Version Identifier a
3 Pos/Vel Mode Flag P or V
4-7 Year Start 2006
8 Unused _
9-10 Month Start _5
11 Unused _
12-13 Day of Month Start _28
14 Unused _
15-16 Hour Start _0
17 Unused _
18-19 Minute Start _0
20 Unused _
21-31 Second Start _.00000000
32 Unused _
33-39 Number of Epochs _____96
40 Unused _
41-45 Data Used DD+AD
46 Unused _
47-51 Coordinate System WGS84
52 Unused _
53-55 Orbit Type FIT
56 Unused _
57-60 Agency NGA
Line Two:
('##',i5,f16.8,f15.8,i6,f16.13)
Column1-2 Symbols ##
3 Unused _
4-7 GPS Week _1377
8 Unused _
9-23 Seconds of Week _.00000000
24 Unused _
25-38 Epoch Interval __900.00000000
39 Unused _
40-44 Mod Julian Day Start 53883
45 Unused _
46-60 Fractional Day _.0000000000000
Line Three:
('+',i5,3x,17i3)
Column1-2 Symbols +_
3-4 Unused __
5-6 Number of Sats 29
7-9 Unused ___
10-12 Sat #1 Id __1
13-15 Sat #2 Id __2
* * *
* * *
* * *
58-60 Sat #17 Id _18
Line Four:
('+',8x,17i3)
Column1-2 Symbols +_
3-9 Unused _______
10-12 Sat #18 Id _19
13-15 Sat #19 Id _20
* * *
43-45 Sat #29 Id _30
* * *
* * *
58-60 Sat #34 Id __0
Line Five:
('+',8x,17i3)
(Same as Line Four for Sats 35 to 51)
Line Six:
('+',8x,17i3)
(Same as Line Four for Sats 52 to 68)
Line Seven:
('+',8x,17i3)
(Same as Line Four for Sats 69 to 85)
Line Eight:
('++',7x,17i3)
Column1-2 Symbols ++
3-9 Unused _______
10-12 Sat #1 Accuracy __0
13-15 Sat #2 Accuracy __0
* * *
* * *
* * *
58-60 Sat #17 Accuracy __0
Line Nine:
('++',7x,17i3)
(Same as Line Eight for Sats 18 to 34)
Line Ten:
('++',7x,17i3)
(Same as Line Eight for Sats 35 to 51)
Line Eleven:
('++',7x,17i3)
(Same as Line Eight for Sats 52 to 68)
Line Twelve:
('++',7x,17i3)
(Same as Line Eight for Sats 69 to 85)
Lines Thirteen and Fourteen:
('%c cc cc ccc ccc cccc cccc cccc cccc ccccc ccccc ccccc ccccc')
Column1-2 Symbols %c
3 Unused _
4-5 2 characters cc
6 Unused _
7-8 2 characters cc
9 Unused _
10-12 3 characters ccc
13 Unused _
14-16 3 characters ccc
17 Unused _
18-21 4 characters cccc
22 Unused _
23-26 4 characters cccc
27 Unused _
28-31 4 characters cccc
32 Unused _
33-36 4 characters cccc
37 Unused _
38-42 5 characters ccccc
43 Unused _
44-48 5 characters ccccc
49 Unused _
50-54 5 characters ccccc
55 Unused _
56-60 5 characters ccccc
Lines Fifteen and Sixteen:
('%f 0.0000000 0.000000000 0.00000000000 0.000000000000000')
Column1-2 Symbols %f
3 Unused _
4-13 10 column float _0.0000000
14 Unused _
15-26 12 column float _0.000000000
27 Unused _
28-41 14 column float _0.00000000000
42 Unused _
43-60 18 column float _0.000000000000000
Lines Seventeen and Eighteen:
('%i 0 0 0 0 0 0 0 0 0')
Column1-2 Symbols %i
3 Unused _
4-7 4 column integer ___0
8 Unused _
9-12 4 column integer ___0
13 Unused _
14-17 4 column integer ___0
18 Unused _
19-22 4 column integer ___0
23 Unused _
24-29 6 column integer _____0
30 Unused _
31-36 6 column integer _____0
37 Unused _
38-43 6 column integer _____0
44 Unused _
45-50 6 column integer _____0
51 Unused _
52-60 9 column integer ________0
Lines Nineteen to Twenty-two:
('/* CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC')
Column1-2 Symbols /*
3 Unused _
4-60 Comments CC...CC
Line Twenty-three (The Epoch Header Record):
('*',i6,4i3,f12.8)
Column1-2 Symbol *_
3 Unused _
4-7 Year Start 2006
8 Unused _
9-10 Month Start _5
11 Unused _
12-13 Day of Month Start _28
14 Unused _
15-16 Hour Start _0
17 Unused _
18-19 Minute Start _0
20 Unused _
21-31 Second Start _.00000000
Line Twenty-four (The Position and Clock Record):
('P',i3,4f14.6)
Column1 Position P
2-4 Vehicle Id __1
5-18 x coordinate (km) ___13752.206309
19-32 y coordinate (km) _-20369.024073
33-46 z coordinate (km) __10204.025024
47-60 clock (microseconds) _____55.610230
Line Twenty-five (The Velocity Record):
('V',i3,4f14.6)
Column1 Velocity V
2-4 Vehicle Id __1
5-18 x coordinate (dm/sec) __10790.304814
19-32 y coordinate (dm/sec) __-6827.236053
33-46 z coordinate (dm/sec) _-28761.711131
47-60 Rate of change of _______.025297
Clock Correction (0.0001 microsec/sec)
(Line Twenty-four will include an 'E' in column 75 to designate an Event in
the Position and Clock Record.) ('P',i3,4f14.6,14x,'E')
(Lines Twenty-four and Twenty-five repeat for each vehicle in the epoch.)
(Epoch Headers in Line Twenty-three repeat for each new epoch with vehicle
position and velocity records following.)
(Last line in file) EOF
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