rob, here is some info complied by george lewis,
see utility.txt \IOD
if you are not already reporting in the otwg format,
then it is suggested you use IOD format. Russell
has a slightly different format that is also explained
in utility.txt. george's app will convert all to IOD.
OTWG2IOD is used to convert observations reported using the Optical
Tracking Working Group (OTWG) format to the IOD format. Current users of this
format are David Brierley, Peter Wakelin and, with some departures from the
format definition, Rainer Kracht. I used it myself when reporting my
observations to the RGO during 1992-1997. After the OTWG ceased to exist
in March 1997--thereby requiring the format to stand on its own merit--I
concluded that the format was not worth continued support in view of its
limitations.
An example of visual satellite observations reported using the OTWG
format is the following:
8406503987697070622352907 01 12200054 +28239 01 4 +60+70 R
8406503987697070622353151 01 12195728 +27210 01 4 6 7 R
8406503987697070922261699 01 12194904 +10114 01 4 +60+80 0121R
9506601987697070923295348 01 12022498 +38388 01 4 -20+30 I
8204103987697071321341505 01 12215863 +39184 01 4 +60INV 0061F
8204103987697071321344828 01 12225397 +49310 01 4 +60INV F
7806401987697071321521988 01 12155067 -24270 01 4 +40 S
9605102987697071322024366 01 12020449 +64470 01 4 +40+70 0169R
9607201987697071322272203 01 12125823 +18392 01 4 +40+70 I
8406503987697071322433271 01 12231279 +73585 01 4 +7 INV F
8807801987697071323065989 01 12230253 +14515 02 4 +5 +7 F
Two format descriptions are given below. The first was received from the
Royal Greenwich Observatory in 1992. The second was posted by David Brierley to
the Seesat-L Internet forum in 1998. The two definitions don't agree in regard
to how the magnitude fields are defined. They also don't agree in regard to the
use of letter designations in columns 6 and 7. They don't agree on the use of
"INV" in columns 72-74, which the RGO description makes no mention of. The RGO
version has an additional optical characteristics code (X). Finally, Brierley's
version doesn't mention AZ/EL observations (format types 4-6).
OTWG2IOD is based on a combination of these format descriptions. Letter
designations in columns 6 and 7 are accommodated. "INV" in columns 72-74 is
accommodated. The magnitude fields as given in Brierley's definition allow xMm
or Mmm, where "x" denotes a sign (+ or -), "M" denotes 0-9, "m" denotes .0-.9,
and "mm" denotes .00 to .99. As it makes no sense for visual observers to
claim an accuracy of 1/100 of a magnitude, the "Mmm" usage is not recognized by
OTWG2IOD. Columns 69 and 72 must be either "+", "-" or " " (blank). This
prohibits reporting of magnitudes of 10.0 or greater. The two digits that
follow are interpreted as magnitudes of X.Y, where X and Y are both in the
range 0-9.
Format numbers 1-6 for positional observations, as given in the RGO
description, are accommodated.
Since the OTWG format is based on strict column assignment of data, it
is possible to perform a check of each column prior to conversion of each
observation. If OTWG2IOD encounters an unexpected value in any column, it
reports the column number containing the questionable value and the complete
observation line in OTWGLIST.OUT and goes on to the next observation without
attempting to convert the observation with the unexpected value. The slant
range and slant range uncertainty fields are not included in the check of each
observation.
As the OTWG format does not include the object number, the object number
is acquired from SSR.ID or DECAYED.ID as in RDE2IOD.
The main difference between the OTWG format and Russell Eberst's format
is that observations reported using the OTWG format are complete within each
line. Any observation reported in the OTWG format may be taken out of context
without losing anything in terms of the information needed for analysis, e.g.,
date, coordinate frame, observation uncertainty, etc. This is an essential
feature of a complete observation report format and it has been retained in the
IOD format.
==========================================================
OTWG Format Description From RGO (1992):
---------------------------------------
01 y Satellite number as yynnncc
02 y
03 n Unidentified sats are labelled 9900000
04 n
05 n
06 c cc =1 for A 2 for B etc
07 c
08 s Site number
09 s
10 s
11 s
12 y time of obs
13 y
14 m
15 m
16 d
17 d
18 h
19 h
20 m
21 m
22 S
23 S
24 s decimal point is implied between 23 and 24
25 s
26 s 24-27 should be left blank unless zero is significant
27 s
28 A
29 a implied decimal point between 28 and 29
30 a Timing accuracy in seconds
31 a
32 a
33 t timing standard 1 = UTC 2 = speaking clock 3 = BBC pips
34 c code for position type
35 p
36 p c=1-3 positions are in HMS and DMS
37 p c = 1 pppppppp = HHMMSSss qqqqqqq = DDMMSSs
38 p
39 p c = 2 HHMMmmmm DDMMmmm
40 p
41 p c = 3 HHMMmmmm DDddddd
42 p
43 s (sign + or 1 or blank)
44 q c=4-6 positions are in azimuth and elevation
45 q c = 4 DDDMMSSs DDMMSSs
46 q
47 q c = 5 DDDMMmmm DDMMmmm
48 q
49 q c = 6 DDDddddd DDddddd
50 q
51 a
52 a c = 1,4 aaaa is seconds of arc SSSs
53 a c = 2,5 minutes " MMmm
54 a c = 3,6 degrees " Dddd
55 e Epoch 0=date of obs 1=1855 2=1875 3=1900 4=1950 5=2000
56 R
57 R
58 R Slant range in Kilometres
59 R
60 R
61 r
62 r
63 r
64 A
66 A
66 a Slant range accuracy in kilometers
67 a
68 a
69 M (+ or -)
70 M Maximum magnitude
71 M
72 m (+ or -)
73 m minimum magnitude
74 m
75 S
76 S
77 S Flash period in seconds
78 s
79 s
80 F S=steady I=irregular R=regular variations F=constant flash period
X= Irregular flash period E unusually faint because of eclipse
=========================================================
OTWG Format Description From David Brierley (1998):
--------------------------------------------------
CODING FOR "RGO" POSITIONAL REPORTS
Decimal points are omitted.
x=sign (+ is optional).
Bytes:
1-7 COSPAR International Designator in numerical form,
e.g. 6710402. Use letters for fragments >99.
8-11 COSPAR Site number
12-17 Date (YYMMDD)
18-27 Time UT (HHMMSSssss)
28-32 Time accuracy (Sssss)
33 Time standard used: 1=radio, 2=phone
34 Coordinate system used in bytes 35-54
If byte 34=1
35-42 RA (HHMMSSss)
43-50 Dec (xDDMMSSs)
51-54 Angular accuracy (SSSs)
If byte 34=2
35-42 RA (HHMMmmmm)
43-50 Dec (xDDMMmmm)
51-54 Angular accuracy (MMmm)
If byte 34=3
35-42 RA (HHMMmmmm)
43-50 Dec (xDDddddd)
51-54 Angular accuracy (Dddd)
55 Epoch: 4=1950.0, 5=2000.0
56-63 Range (for radar observations)
64-68 Range accuracy (ditto)
69-71 Max brightness (xMm or Mmm) during a period of
about a minute centred on the observation
72-74 Min brightness (xMm, Mmm or "INV" if invisible)
75-79 Flash period or period of regular variation (SSSss)
80 Appearance: S=steady, I=irregular, R=Regular variation
F=Flashing, E=in Eclipse
Extracted from "The Reporting of Satellite Observations"
(1973), Radio and Space Research Station, Slough, England.
David Brierley
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