NOAA KLM User's Guide

Appendix A.3

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APPENDIX A.3: Explanation of Code Symbols

Table A.3-1 contains an explanation of the code symbols used for all parts of the TBUS-1 and TBUS-2 Predict messages.

Table A.3-1. Explanation of Code Symbols.
Symbol Explanation
TBUS-1 (or TBUS-2) APT Bulletin originating in the United States: TBUS-1 is North to South (descending) daylight orbit. TBUS-2 is South to North (ascending) daylight orbit.
KWBC Traffic entered at Washington, D.C.
APT PREDICT Identifies message content.
MMDDSS Message serial number
MM - Month
DD - Day of Month
SS - Number of spacecraft to which predict applies (See Table A-2).
PART I - Equator crossing reference information follows:
0 Code group indicator for first three groups
NrNrNrNr Number of reference orbit. (Note: Information in Parts II and III also are related to this reference orbit.)
DrDrHrHrmrmrsrsr Reference orbit equator crossing time (GMT), satellite northbound:
DrDr - Day of Month
HrHr - Hour
mrmr - Minute
srsr - Second
Note: In TBUS-1, northbound equator crossing takes place on NIGHT side of orbit. In TBUS-2, northbound equator crossing takes place on DAY side of orbit.
Qr Octant satellite is entering after crossing equator on reference orbit (See Figure A.3-1).
LoLoLoLo Reference orbit equator crossing longitude in degrees and hundredths.
T Indicator: nodal period follows (will always be shown as "T").
mm Nodal period, minutes
ss Nodal period, seconds. (Note: Hundreds group will not be included. Example: 100 minutes 13 seconds will be coded as 0013.)
L Indicator, nodal longitude increment follows (always shown as "L").
LoLoLoLo Degrees and hundredths of degrees longitude between successive equator crossings.
N4N4N4N4 Orbit number of fourth orbit following reference orbit.
H4H4 Hour of northbound satellite equator crossing four orbits after reference orbit.
m4m4 Minute
s4s4 Second
Q4 Octant satellite is entering after crossing equator on fourth orbit after reference orbit.
LoLoLoLo Equator crossing longitude of fourth orbit after reference orbit.
Above information is repeated for eighth (N8N8N8N8) and twelfth (N12N12N12N12) orbits following reference orbit.
NIGHT PART II (TBUS-1) or DAY PART II (TBUS-2): Contains satellite altitude and subpoint coordinates at two-minute intervals after time of equator crossing; satellite northbound.
02 Indicator; satellite altitude and subpoint coordinates at two minutes after time of equator crossing.
a02a02 Altitude, in hundreds and tens of kilometers, attwo minutes after equator crossing. Thousands figure understood; hence 1440 km is encoded as 44.)
Q02 Octant of globe at two minutes after equator crossing.
LaLala Latitude of satellite subpoint in degrees and tenths of degrees at two minutes after equator crossing.
LoLoLo Longitude of satellite subpoint in degrees and tenths of degrees at two minutes after equator crossing.
Above information is repeated at two-minute intervals over the NIGHT portion of the orbit north of the equator for TBUS-1, and DAY portion of the orbit north of the equator for TBUS-2.) Note: Should the time after ascending node become greater than 99, the hundreds will be assumed (example, minute 102 will be encoded as 02).
NIGHT PART III (TBUS-1) or DAY PART III (TBUS-2): Satellite altitude and subpoint coordinates at two-minute intervals south of equator on the ascending side of the orbit.
02 Indicator; satellite altitude and subpoint coordinates at two minutes after time of equator crossing follows.
a02a02 Satellite altitude in hundreds and tens of kilometers at two minutes after equator crossing.
Q02 Octant of globe at two minutes after equator crossing.
LaLala Latitude of satellite subpoint in degrees and tenths of degrees at two minutes after crossing.
LoLoLo Longitude of satellite subpoint in degrees and tenths of degrees at two minutes after equator crossing.
Above information is repeated at two-minute intervals over the night portion of the orbit south of the equator for TBUS-1, and sunlight portion of the orbit north of the equator for TBUS-2.
DAY PART II (TBUS-2) NIGHT PART II (TBUS-1): Satellite altitude and subpoint coordinates at two-minute intervals after time of equator crossing follows.
02 Information pertinent to 02 minutes after equator crossing follows.
a02a02 Satellite altitude in hundreds and tens of kilometers at 02 minutes after equator crossing.
Q02 Octant of globe at 02 minutes after equator crossing.
LaLala Latitude of satellite subpoint in degrees and tenths of degrees at 02 minutes after equator crossing.
LoLoLo Longitude of satellite subpoint in degrees and tenths of degrees at 02 minutes after equator crossing.
Above information is repeated at two-minutes intervals over the sunlit portion of the orbit north of the equator for TBUS-2, and night portion of the orbit north of the equator for TBUS-1.
DAY PART III (TBUS-1) or NIGHT PART III (TBUS-2): Satellite altitude and subpoint coordinates at two-minute intervals south of the equator on the descending side of the orbit.
02 Indicator: satellite altitude and subpoint coordinates at two minutes after time of equator crossing.
a02a02 Satellite altitude in tens of kilometers at two minutes after equator crossings.
Q02 Octant of globe at two minutes after equator crossing.
LaLala Latitude of satellite subpoint in degrees and tenths of degrees at two minutes after equator crossing.
LoLoLo Longitude of satellite subpoint in degrees and tenths of degrees at two minutes after equator crossing.
Above information is repeated at two-minute intervals over the sunlit portion of the orbit south of the equator for TBUS-1 and night portion of the orbit south of the equator for TBUS-2.

Note: Should the time after ascending node become greater than 99, the hundreds will be assumed (example, minute 102 will be encoded as 02).

PART IV: Contains high precision orbital elements transmission frequencies, and remarks - See Table A.3-2.

Figure showing global octant map

Part IV Code Symbols

In Table A.3-2, the classical elements (Keplerian) from MMMMMMMM to RRRRRRRR are Brouwer mean (BM) elements expressed in the form of Keplerian elements. The position and velocity components SSSSSSSSSS to XXXXXXXXX are instantaneous. The Greenwich Hour Angle is apparent sidereal time.

Table A.3-2. Part IV Code Symbols.
Symbol Explanation
AAAAAAAAA Spacecraft identification (International designator)
BBBBB Orbit number at epoch.
CCCCCCCCCCCC Time of the first ascending node, in days, from the beginning of the year, to nine decimal places.
DD Epoch year
EE Epoch month
FF Epoch day
GG Epoch hour
HH Epoch minute
IIIII Epoch second, to three decimal places
JJJJJJJ Apparent Greenwich Hour Angle at Aries at epoch, to four decimal places.
KKKKKKKK Anomalistic period (minutes), to four decimal places.
LLLLLLLL Nodal period (minutes), to four decimal places.
MMMMMMMM Brouwer Mean (BM) Eccentricity, eight decimal places.
NNNNNNNN BM Argument of perigee (degrees), five decimal places.
OOOOOOOO BM Right Ascension of the ascending node (degrees), five decimal places.
PPPPPPPP BM Inclination (degrees), five decimal places.
QQQQQQQQ BM Mean anomaly (degrees), five decimal places.
RRRRRRRR BM Semi-major axis (km), three decimal places.
SSSSSSSSSS Sign and epoch X position component (km), to four decimal places.
TTTTTTTTTT Sign and epoch Y position component (km), to four decimal places.
UUUUUUUUUU Sign and epoch Z position component (km), to four decimal places.
VVVVVVVVV Sign and epoch X velocity (Xdot) component (km/sec), to six decimal places.
WWWWWWWWW Sign and epoch Y velocity (Ydot) component (km/sec), to six decimal places.
XXXXXXXXX Sign and epoch Z velocity (Zdot) component(km/sec), to six decimal places.
YYYYYYYYY Ballistics coefficient CD-A/M (m2/kg), to eight decimal places.
ZZZ Daily solar flux value (10.7 cm) 10-7 W/m2.
aaa 90-day running mean of solar flux 10-7 W/m2.
bbb Planetary magnetic index (2x10-5 gauss).
cccc Drag modulation coefficient, to four decimal places.
dddddddddd Radiation pressure coefficient (m2/kg), to ten decimal places.
eeeeeeeee Sign and perigee motion (degrees/day), to five decimal places.
fffffffff Sign and motion of Right Ascension of the ascending node (degrees/day), to five decimal places.
ggggggggg Sign and rate of change of mean anomaly at epoch (degrees/day), to two decimal places.
hhhhhhhh Equator crossing longitude of the epoch reference orbit measure as East longitude, to five decimal places.
iiiiii Month, date and year (MMDDYY) of last TIP clock correction.
jjjjjj Sign and clock error after last correction measured in seconds, to three decimal places. (see Note 1)
kkkkkk Month, date and year (MMDDYY) of current clock error.
llllll Sign and current clock error measured in seconds, to three decimal places. (see Note 1)
mmmmmm Month, date and year (MMDDYY) of the measured clock error rate.
nnnnnn Sign and clock error rate expressed as milliseconds/day. (see Note 1)
oooooo Month, date and year (MMDDYY) of next TIP clock correction. (000000 if unknown.)
Notes: All signed values in Part IV are preceded by a "P" or "M" to denote a plus (+) or minus (-) value.

1. These will be set to 99999 if the value is unknown

APT TRANSMISSION FREQUENCY XXX.XX MHZ
HRPT TRANSMISSION FREQUENCY XXXX.XX MHZ
BEACON (DSB) TRANSMISSION FREQUENCY XXX.XX MHZ
APT DAY X/X APT NIGHT X/X
DCS CLK TIME YR/DA/TIM XXXX XXX XXXXX.XXX
(ADDITIONAL PLAIN LANGUAGE REMARKS WHEN NEEDED)

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