home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Ham Radio
/
Ham Radio CD-ROM (Emerald Software) (1995).ISO
/
satel
/
orbs141
/
orbs.doc
< prev
next >
Wrap
Text File
|
1988-05-07
|
31KB
|
612 lines
O R B S
Orbital Prediction Program
for
Earth Orbiting Satellites
Version 1.4
USER REFERENCE
11/16/87
Ron Dunbar, W0PN
=========
O R B S
=========
INTRODUCTION:
ORBS is a menu-driven system which produces printed listings showing
an earth-orbiting satellite's azimuth, elevation, range as well as
other approprate data at specified intervals of time as seen from an
observer's location. Perhaps the easiest way to give you an idea of
ORB's features is to start with the opening menu:
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
= =
= O R B S =
= =
= ORBITAL PREDICTION PROGRAM WITH TIME WINDOWS =
= 8/22/1987 =
= Ron Dunbar W0PN =
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
1. Generate orbital predictions.
2. Update Elements.
3. Modify beacon frequency file.
4. Modify station call/location file.
5. Exit to operating system.
Your choice..
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Let's investigate the menu items one at a time...
1. GENERATE ORBITAL PREDICTIONS:
If you choose this function, the next screen you'll see will look
something like this:
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
This program prints tracking data for earth-orbiting satellites
SATELLITE SELECTION MENU
1. oscar-9 ID = 12888 Set 1066 8/17/87
2. oscar-10 ID = 14129 Set 305 8/7/87
3. oscar-11 ID = 14781 Set 245 8/6/87
4. oscar-12 ID = 16909 Set 55 7/28/87
5. rs-5 ID = 12999 Set 426 8/13/87
6. rs-7 ID = 13001 Set 337 8/17/87
7. rs-10/11 ID = 18129 Set 60 8/17/87
8. meteor 2-14 ID = 16735 Set 126 5/31/87
9. meteor 2-15 ID = 17290 Set 87 8/16/87
10. meteor 3-1 ID = 16191 Set 689 8/16/87
11. noaa-9 ID = 15427 Set 186 8/7/87
12. noaa-10 ID = 16969 Set 70 8/14/87
13. mir ID = 16609 Set 782 8/17/87
14. salyut-7 ID = 13138 Set 732 8/17/87
15. ajisai ID = 16908 Set 50 8/8/87
SELECT SATELLITE?
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Now choose the satellite you're interested in, answer a few questions,
and the printed listing is produced in record speed, thanks to Turbo
BASIC's nimble compiled code and Tom Clark's QUICKSTEP algorithm
trickery (that's the infamous W3IWI, you know) which speeds up the
calculations when the satellite is below the horizon.
As you answer the questions mentioned above, you'll note that another
unique feature has been added; TIME WINDOWS. You have the option of
ignoring all satellite passes outside a selected timeframe.. after all,
there's little value in spending time calculating and producing a
listing covering times when you can't be there to see/hear/work that
satellite, is there?
TIME WINDOWS will allow you to span 2400 UTC with your window time;
you can specify a window such as 2200 to 0400, and it will be handled
properly.
The TIME WINDOW feature is particularly useful for listing the 'good'
visual passes of MIR and COSMOS 1870, for instance, because you can
only see them during the period between local civil twilight and the
time when they are enveloped in the earth's shadow.
Now let's see what a typical listing looks like. We'll use Oscar-9:
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
*** O R B S ***
OSCAR-9 Orbital Predictions Page # 1
for W0PN at Lat: 46.860 Lon: 92.459
Element set 1066 is 7.5 days old
Listing covers the period 237.0000 to 237.5000 or 12.00 hrs.
This listing run at 00:40:06 on 08-25-1987.
PARAMETER REFERENCE STARTING
--------- --------- --------
Catalog number 12888
Epoch 87229.50723967 87237.00000000
Inclination 97.6439 [ No change ]
R. A. A. N. 248.5757 256.2849
Eccentricity 0.00029260 [ No change ]
Arg. Perigee 33.8666 7.4516
Mean Anomaly 326.2793 195.4792
Mean Motion 15.29943109 15.29988380
Drag Correction 3.021E-005 [ No change ]
Orbit number 32611 32726
S.M.A.,(km) 6854.0761 6853.9409
Perigee Ht, km 473.9106 473.7754
Apogee Ht, km 477.9216 477.7863
Freq (MHz) 145.825 (F1) 435.025 (F2)
*************************************************************
Printing only the window between 0130:00 and 0500:00 UTC.
*************************************************************
U T C AZ EL 145.825 435.025 RANGE HEIGHT LAT LONG PHASE F2 TRACK
hhmm:ss deg deg DPLR Hz DPLR Hz km km deg deg <256> 435.025
- - - Orbit # 32728 - - - Day # 87237 - - - Tuesday, 8/25/87 - - -
0226:00 263 1 +1320 +3938 2417 474 40.6 119.5 24 435.021
0228:00 285 2 +206 +613 2366 474 48.1 122.0 29 435.024
0230:00 306 -1 -972 -2901 2606 474 55.6 125.2 35 435.028
End of OSCAR-9 listing.
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
As you can see by the information between the lines of asterisks, we
specified a 'time window' of 0130 to 0500 UTC, which is late enough for
most of us here in the Midwest, and prior to that time, we're probably
eating supper. You can further see (in the 5th printed line) that we
specified a 12 hour period, and only one pass was visible (and print-
ed) which occurred in that 12 hour period AND was within our specified
time window. You will also note from the ELevation column that it was
a marginal pass, just barely peeking up over the horizon to the west of
this QTH.
Note that two 'beacon' frequencies were present for Oscar-9 in the
FREQS.ORB file.. 145.825 and 435.025 MHz. The doppler associated with
each frequency is listed in the 4th and 5th columns of the printout...
the column heading shows the frequency the doppler is computed for.
The RANGE, HEIGHT, LAT and LONG all refer to the satellite. The LAT
and LONG are the point on the earth over which the satellite is
currently positioned (the Sub-Satellite Point, or SSP). The RANGE is
the distance from the observer in meters, and the HEIGHT is the
satellite's altitude above the earth in meters. LAT and LONG are in
degrees, of course.
Note the rightmost column labeled "F2 TRACK". The numbers in this
column represent the frequency you must transmit on to 'hit' the F2
TRACK frequency (435.025) as seen at the spacecraft.. this listed
frequency takes the doppler into consideration and is a handy feature
when you need to uplink at a specific frequency. One of the last
questions you are asked before the program goes off to compute all
this stuff is whether you would like to manually enter an alternate
frequency for F2. This lets you temporarily override the frequencies
contained in the FREQS.ORB default file. (More on that later).
Ok, now you've run your listing, and you've just downloaded the AMSAT
Orbital Data Bulletin and captured this week's latest Kepler elements
into your STUFF.LOG file. Use your favorite word processor in the NON-
DOCUMENT MODE (please) to edit STUFF.LOG and get rid of everything
except the elements. You can leave in all the carefully constructed
headers, asterisks, etc., but clean out all the stuff not relating to
the Bulletins.
Be sure to check the bulletin for typos.. sometimes the ':' following
the keywords gets lost, or 'e' (as in "1.687e-04") turns up missing.
The program will catch the first error, but not the second one. It
can show up as subsurface apogee and perigee heights in the parameter
listing on the first page.. that's why that listing is there! If you
come up with anything that looks weird, check and correct the ELEMENTS
file, then redo the update operation.
All bulletins should be combined into one file which MUST be named
ELEMENTS (no .EXTension, please). Now move that file into the same
directory that ORBS resides in (I call it \ORBS, for want of a better
name.. I have trouble remembering obscure names, birthdays, etc.).
If you spell ELEMENTS wrong or forget to move it into the \ORBS direc-
tory, you'll get a RUNTIME ERROR 53: which says you spelled ELEMENTS
wrong or forgot to move it to the \ORBS directory.. don't DO that!
(See HELPFUL HINTS at the end for a .BAT program to do the moving.)
2. UPDATE ELEMENTS:
Now, we're ready to choose item (2) on the ORBS menu.
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
= =
= ORBITAL ELEMENT UPDATE PROGRAM =
= =
= 8/23/1987 =
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Scanning input file... please wait.
Total number of satellites read from the ELEMENTS file = 16
Total number of satellites written to the KEPLER.ORB file = 16
The frequency data in FREQS.ORB will be inserted into the
records contained in KEPLER.ORB.
FREQS.ORB contains 5 records for input.
5 insertions completed.
End of update..
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Now, wasn't that a lot easier than typing in 14 numbers for 16 dif-
ferent satellites? You didn't have to do anything but sit there and
wonder what the computer was doing (especially when it was messing
around with your hard disk). You've just updated all the Keplerian
elements for all the satellites contained in the bulletin in about
one minute or less!
What actually happened was that (1) the program ORBUPDAT.TBC was called
by the menu program. (2) The file ELEMENTS was read in, (3) the beacon
frequency data from the file FREQS.ORB was merged with the ELEMENTS
data, and (4) the combined data was written to the KEPLER.ORB file
which is used by the tracking program ORBP.TBC.
KEPLER.ORB is the source of the data that is displayed as the list of
satellites from which you choose when you do menu item (1), "Generate
orbital predictions".
Let's suppose that a new satellite has been placed in orbit, and it
contains a beacon or two which you want to monitor. You're ready for
the next menu choice...
3. MODIFY BEACON FREQUENCY FILE:
When you make this choice from the menu, you'll see this....
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
= =
= Modify FREQS.ORB Entries =
= =
= 8/23/1987 =
= =
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Existing entries will be presented for possible modification, followed
by blank entry(s) to allow you to add to the list of satellite beacon
frequencies; the frequency specified can be any you wish to track; it
doesn't have to be strictly a beacon. Make certain you enter the
satellite's CATALOG number accurately.. the record is keyed on it.
Satellite name: Oscar-9
Catalog number: 12888
Frequency 1: 145.825
Frequency 2: 435.025
Accept, Delete, Modify this entry (A/d/m):
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note the prompt line.. the 'A' is in UPPER CASE. This is the
convention I use to indicate the DEFAULT you will get if you just hit
the ENTER key. You may also type an 'a' if you wish to follow
directions. If you Accept this entry, the next satellite contained in
the FREQS.ORB file will be presented in order, and so on until the
entries are exhausted.
If you choose to DELETE the entry, it goes away.. simple. If you
choose to MODIFY it, BE VERY CAREFUL that you get the "Catalog number"
right! You can misspell the name, but the catalog number is the key to
matching this data up with it's counterpart contained in the ELEMENTS
file.
If you choose MODIFY, the cursor moves to the field following
"Satellite name:" and waits for your action. If you merely hit ENTER,
the data in that field remains unchanged and the cursor moves on to the
next field.
If you modify a field, any data remaining in the field beyond the cursor
is erased before the cursor advances to the next field. When you ENTER
following the last field (enter '0' if you don't want one of the beacon
frequencies anymore), you are asked "Is data correct (Y/n):". If you
made an error, you can redo it by answering 'n', otherwise, a 'y' or an
ENTER will accept the modifications.èWhen you have responded to the last entry and hit the ENTER key to
accept the data, the following appears:
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
= =
= Modify FREQS.ORB Entries =
= =
= 8/23/1987 =
= =
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Existing entries will be presented for possible modification, followed
by blank entry(s) to allow you to add to the list of satellite beacon
frequencies; the frequency specified can be any you wish to track. It
does not have to be strictly a beacon. Make certain you enter the
satellite's CATALOG number accurately.. the record is keyed on it.
Satellite name:
Catalog number:
Frequency 1:
Frequency 2:
Make an entry (y/N):
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
You have noticed, of course, that all the fields are empty, and the
prompt is asking whether you wish to make a new entry. Remember to get
that "Catalog number" right!
I suppose that you'd like to get your call letters and location stuck
in here somewhere.. that brings us to the next main menu function..(4):
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
= =
= Modify ORB.CFG Entries =
= =
= 8/24/1987 =
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
The ORBS.CFG file contains 'observer specific' data used by the prediction
program. The existing entry will be displayed for possible modification.
Latitude is entered as decimal degrees (nn.nnn); South latitudes are
preceeded by a '-' (-nn.nnn). Longitude is entered as decimal degrees
West longitude. Observer Altitude is entered in meters, not feet.
Minimum elevation is that elevation (in degrees) above which you wish the
printout to commence (usually 0 or -1).
Observer name/call: W0PN
Observer latitude: 46.860
Observer W. longitude: 92.459
Observer altitude: 435
Min sat elevation (deg): -1
Accept or Modify this entry (A/m):
Most of the fields are pretty self-explanatory. The Station latitude
and longitude must be in decimal degrees, not degrees, minutes, etc.
The longitude is specified as WEST longitude.. none of that '-179.999'
stuff allowed. The altitude is in METERS, not feet or furlongs.
If you don't want to forever run listings with my call and coordinates
on them, I suggest you choose to MODIFY this entry. When you have
completed your task (operates the same as the previous function), you
will receive this screen:
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
= =
= Modify ORB.CFG Entries =
= =
= 8/24/1987 =
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
The ORBS.CFG file contains 'observer specific' data used by the prediction
program. The existing entry will be displayed for possible modification.
Latitude is entered as decimal degrees (nn.nnn); South latitudes are
preceeded by a '-' (-nn.nnn). Longitude is entered as decimal degrees
West longitude. Observer Altitude is entered in meters, not feet.
Minimum elevation is that elevation (in degrees) above which you wish the
printout to commence (usually 0 or -1).
Observer name/call: W3IWII
Observer latitude: 66.871
Observer W. longitude: 74.103
Observer altitude: 250
Min sat elevation (deg): -1
Is data correct (Y/n):
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Again, you have a chance to correct any typos.
The only remaining main menu function is (5) Exit to operating system.
That one ALWAYS works exactly as it's supposed to, even after extensive
and rigorous testing conditions (read: exiting to fix another bug!).
Please forward your comments, suggestions and abuse to me via AMSAT
Telemail (RDUNBAR), or you can try to reach me where I now live (but I
don't expect to be here long.. hi!):
Ron Dunbar, W0PN (Res) 218-729-6355
4696 Hwy 33 N. (Bus) 218-720-2093
Saginaw, MN 55779
..and I thank you for your support!
Supplemental:
The ARChived file of which this document file is a part, contains
the following files:
ELEMENTS ORBP .TBC
FREQS .ORB ORBS .CFG
KEPLER .ORB ORBS .DOC
MODCFG .TBC ORBS .EXE
MODFREQ .TBC ORBUPDAT.TBC
ELEMENTS:
Contains a recent version of the AMSAT Orbital Data Bulletin which
is prepared weekly for AMSAT NA by Ralph Wallio, W0RPK. This file is
normally captured directly from a bulletin board system (BBS). ORBS
allows you to input this unedited data file directly, thereby
avoiding the formidable task of entering the data manually. You can
also download current Bulletins by calling W0RPK's BBS at 515-961-
3325. This service is also being provided by others; just ask
around, or leave a query on Ralph's BBS when you call in.
A sample of the first few lines of a typical Orbital Data Bulletin:
*******************************************************************
* A M S A T O R B I T A L D A T A B U L L E T I N *
* ORBS227O 15AUG87 *
* Prepared for AMSAT-NA by W0RPK *
*******************************************************************
Orbital Elements for OSCARs
SAT. UO-9 AO-10 UO-11 FO-12 RS-5 RS-7 RS-10/11
SET# 62 305 245 55 425 335 52
NEW? Y Y Y N N Y Y
Satellite: oscar-9 |Yes, you can create a file
Catalog number: 12888 |with your favorite word pro-
Epoch time: 87218.25756376 |cessor in NON-DOCUMENT mode
Element set: 1062 |IF you take particular care
Inclination: 97.6454 deg |to duplicate the KEYWORDS
RA of node: 237.0035 deg |exactly as shown at left;
Eccentricity: 0.0003676 |the upper-case letters MUST
Arg of perigee: 58.3920 deg |be upper-case and the colons
Mean anomaly: 301.7665 deg |MUST be positioned as shown.
Mean motion: 15.29888737 rev/day |There MUST be at least one
Decay rate: 2.007e-05 rev/day^2 |space between the keyword
Epoch rev: 32439 |and the value following.
|The words following the value
Satellite: oscar-10 |are NOT required; i.e.; 'deg',
Catalog number: 14129 |'rev/day', etc.
.....etc.................
FREQS.ORB:
Contains user defined beacon frequencies for selected satellites.
When you choose "Update Elements." from the ORBS menu, the ORBUPDAT
routine merges the data from the FREQS.ORB file with the data from
the ELEMENTS file to produce the file KEPLER.ORB, which is used
directly by the ORBS tracking program, ORBP.TBC.
As supplied, FREQS.ORB contains the following data:
"Oscar-9", 12888,145.825,435.025
"Oscar-10",14129,145.810,145.987
"Oscar-11",14781,145.826,435.026
"Oscar-12",16909,435.795,145.850
"rs-10/11",12999,145.857,145.907
Each line (or record) is terminated in a <CR/LF> to indicate the end
of the record. You need not worry about constructing this file
yourself, because ORBS provides you with a menu selection which does
the hard work for you.
ORBS.CFG:
Contains observer specific data. As supplied, ORB.CFG contains the
following:
"W0PN",46.860,92.459,435,-1
This entry is followed by a <CR/LF> to indicate the end of the record.
LATE NOTES & HELPFUL HINTS:
--------------------------
Julian search time:
When you're running a listing, you will notice a highlighted 6 digit
number spinning in the upper right corner of your screen.. the 6 digit
number is followed by a single '0' or '1' which appears to change
randomly. The label to the left of the number says "Julian search
time:". This is the instantaneous day of the year and fractional part
of the day that is being used in the determination of the satellite's
position. The 0/1 following indicates whether the satellite is below
or above the observer's horizon. It's just a 'fuzzy blanket' to let
you know the computer is actually doing something between printouts.
Sidereal Time table:
I neglected to mention that the sidereal time tables have been
eliminated because that figure is now calculated internally by ORBP.TBC.
Moving the ELEMENTS file from your communications subdirectory to the
ORBS subdirectory:
I use the following batch file to perform the relocation of the ELEMENTS
file from my communication subdirectory over to the ORBS subdirectory.
Note that the previous ELEMENTS file is renamed ELEMENTS.OLD, just in case
something is drastically wrong with the new data and I want to get the old
stuff back (simply a matter of deleting the defective ELEMENTS file and
renaming ELEMENTS.OLD to ELEMENTS).
= = = = = =
REM Move ELEMENTS to \ORBS directory from \PROCOMM
echo off
cd\procomm
if NOT EXIST ELEMENTS goto nofile
cd\orbs
del elements.old
ren elements elements.old
cd\procomm
copy elements \orbs\elements
del elements
goto exit
REM
:nofile
echo No ELEMENTS file found.. update aborted.
pause
REM
:exit
echo on
= = = = = =
