home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Cream of the Crop 1
/
Cream of the Crop 1.iso
/
EDUCATE
/
SATEQ74.ARJ
/
SATEQ.DOC
< prev
next >
Wrap
Text File
|
1990-04-03
|
11KB
|
189 lines
┌─────────┐
│ PREFACE │
└─────────┘
This writeup is by no means a complete manual, it is intended however to give
all the information needed to run the program. Some advice given sounds like
motherhood, problems that have led to assistance calls in the past are the
background for the advice given in this short document. SATEQ is a new
program, it is a migration from SATG, the keplerian elements and groundstation
data are represented in IEEE-binary format. The calculations are a somewhat
more accurate with this new format.
NOTE: The files SATKEP and SATBOD (SATGRD) used with previous versions, will
not produce correct results with this program, because of the number format
change, consequently the new files have been given different names, they are
now named SATKEPN.DAT and SATBODN.DAT. SATEQ is written in QUICKBASIC 4.5
and compiled, it has been tested with IBM-PC, XT, AT, PS/2 Mod 30,50,60,70 and
80. Any problems should be reported to the author, whereby the two numbers
displayed on the screen above the text "STOP in LINE 10000" are most essential
to pin down the cause of a problem.
Activation of CTRL-BREAK as an inherent feature to abort a QUICKBASIC program,
should always terminate the program execution if pressed as an answer to a
prompt. It may be necessary to hit CR after CTL-BREAK.
++ OE1HSI ++
┌──────────────────────────────────────────────────────────┐
│ Instructions for SATEQ.EXE Version 7.4 of April 3rd 1990 │
└──────────────────────────────────────────────────────────┘
Hardware requirements: IBM-PC or PS2.Mod.30-80 minimum. 256k
CGA,MCGA,EGA or VGA-adapter with COLOR-display
optional: printer if printouts of predictions are requested.
NOTE: some options of the program can run on a system with
a monochrome adapter, however the graphic display mode
may not be selected.
Software requirements : DOS 2.0 or higher, GRAFTABL (and if the PRTSCREEN
function is to be used also GRAPHICS) have to be
loaded prior to the invocation of this program.
Other files required : SATBODN.DAT .. binary file holding geogr. data of the
groundstation (observer).
SATMAP.DAT ... binary file with worldmap.
SATKEPN.DAT .. binary file holding the keplerian
elements of the satellites.
If SATKEPN.DAT AND SATBODN.DAT are not present, this files can be easily
created. All one has to do is to create a short files (just a few bytes) with
an EDITOR or with DEBUG, that have this names. The options to update the data
of this files may then be used to build up the files with correct data. The
"PREDICTION" option can handle up to 20 satellites, however the
"REALTIMETRACKING" option will not work correctly if called with more then 15
entries. The last entry in the SATKEPN file shoud be named "END" with all
data set to zero, this will accelerate the calculation. Satellite names
should contain only capital letters and no spaces, starting with version 7.0
all names entered with the utility options are converted to capital letters.
If files with satellite names from other sources are to be used, the names
should be edited to this rules with a fileeditor, otherwise it will not be
possible to call this satellites or delete them from within the utility
options of this program.
To invoke the program just enter "SATEQ", the files SATKEPN.DAT, SATBODN.DAT
and SATMAP.DAT have to be in the default drive, otherwise the program will
terminate with an error message.
┌───────────────────────────┐
│ Change groundstation data │
└───────────────────────────┘
With this option the geographical data of the groundstation may be updated, in
the graphic display option, the groundstation is represented by a small circle
on the screen. Antenna azimuth and eleveation are calculated for the ground
position. Name and callsign of the groundstation may be 10 characters long,
20 characters are available for the location. Spaces and some special
charcters may be used but no commas (BASIC convention). Any changes made are
saved in the file "SATBODN.DAT" (remove the writeprotect tab from the
diskette).
┌──────────────────────────────────┐
│ Option UPDATE satellite elements │
└──────────────────────────────────┘
With this option the keplerian elements may be updated. It is most essential
to work always with the most recent data available, otherwise the calculations
will produce incorrect results. Up to date data is available from AMSAT
publications, it is available on many HAM bulletin boards and packet radio
mailboxes. The program has an internal check for the age of the reference
element data, if old reference data is encountered in SATKEPN.DAT, the program
will abort with an error message. If for any reason valid data is not
obtainable for a certain satellite, this entry should be removed from the file
to avoid error conditions. Note that the name of the satellite may not
contain mor then 10 charcters and no commas. Any changes made are saved in
the file "SATKEPN.DAT" (remove the writeprotect tab from the diskette).
┌────────────────────────────┐
│ Option "REALTIME TRACKING" │
└────────────────────────────┘
Immediately after the start of this option, a chance to change the time and
date is offered, since the calculations are based on UTC. Depending on the
hardware and softwareversion used, any changes may also affect the system
clock and even realtime clock. You will have to determine the effects on your
own system and eventually take corrective action to set your loacl time after
the program has terminated. Next the satellite positions will be displayed in
a table, satellites above the horizon are displayed in red, satellites just
rising or going below the horizon will be redblinking and activate a beep.
The program execution can be terminated at any time by pressing ESC. With F9
the program will switch into and out of the graphics mode. While running in
graphics mode the keys F10, F9, F8 and F7 may be activated. "PHASE"
calculation and display has been added to this option, in order to enable the
determination of the operating modes of the Radio Amateur Satellites.
"F10" will permit selection of a single satellite, if a CR (or the ENTER key)
is pressed at the satellite name prompt, the program will display all
satellites. The selection of a satellite has to be made with the exact name
including any special characters.
"F7" will control the speed of the display, this option has been built into
the program to adopt to the different clock speed of various systems. Ten
speeds are available, the aktive speed is displayed in the top line of the
display. Every activation of F7 switches to a higher speed, the start
defaultvalue is "3". After the fastest gear (0) the program switches to
lowest speed (9) upon the next activation of F7.
With "F8" pressed, the program will toggle a "sound" mode on and off, a beep
will be generated with every display of a next satellite. This option is
most helpfull to adjust to a suitable speed for observation.
┌──────────────────────┐
│ Option "PREDICTION" │
└──────────────────────┘
With this option, a prediction of satellite orbits may be produced. A listing
can be displayed on the screen, routed to the printer or routed to a file. If
routing to a file is selected, the listing will be saved in a file named
SATDATA.TXT in straightforward ASCII-text format. The drive identifier on
which this file is to be saved will be prompted. If the file "SATDATA.TXT
already exists on the specified drive, the new data will be appended to the
existing file. Output to the printer is always routed to LPT1:, error
detection routines prevent operation with an inactive printer, an out of paper
condition or no printer on LPT1, if the printer option was selected. The
starting time, duration and timestep for the listing have to be selected as
well as a minimum antenna elevation. However, if a minimum elevation angle of
10 or 15 degrees is choosen, this will not reduce calculation time, it will
only shorten the output listing. If no minimum elevation angle is selcted the
programm defaults to 0 degrees. Listings of the satellite positions below the
horizon may be obtained by selection of a negative elevation, entering -360
will produce a full listing of the orbits. The "day of the year" is
calculated from the year of the reference elements, numbers higher then 365
(or 366) indicate previous years reference elements. Calculation may be
timeconsuming, depending on the power of the system and the selected timestep,
quite substantial times may pass without any visible option while the
satellite is below the horizon of the observing station.
"PHASE", also called MA in AMSAT bulletins is the 256th part of an orbit,
every new orbit starts with a perigee, that is a phase of 0, apogee is at
phase 128 of an orbit. Operating modes are switched on some satellites in
dependence of the phase.
┌─────────┐
│ GENERAL │
└─────────┘
The program has evolved from calculations and code published in the AMSAT
JOURNAL "ORBIT" published in 1981 and written by W3IWI, W0SL has adopted the
program for the IBM-PC and added the graphics display features. DB6ZH has
contributed improved features to the element updating utility, the autor of
this version (OE1HSI) has added numerous features, the user interface the
groundstation utilities and has finally compiled the programs to one neat
package. The current version 7.4 (April 3rd 1990) is written in and
compiled with QUICKBASIC 4.5 (TM MICROSOFT), with the objective to produce a
PS/2 compatible version. The sideral timetables stored in this version have
been provided by friends at NASA and are good until the year 1999. Quite some
time could still be invested in further enhancements and more complete error
handling, however this version is a good compromise between time spent and
runtime comfort. Other derivates of the basic programms are available from
AMSAT in the US. This package does not contain basic source code, negative
experience with previous versions have influenced this limitation. Anyone
interested in the (little and german language commented) QUICKBASIC source may
drop a line to the author at the address given below.
┌──────────────────────────────────────┐
│ Author: │
│ OE1HSI Ing. Herbert F. STRASSER └───────────────────┐
│ Slatingasse 6-B-5 A1130 VIENNA/AUSTRIA │
│ or via Packetradio @OE1XIB.WIEN.AUT.EU │
└──────────────────────────────────────────────────────────┘