home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Tech Arsenal 1
/
Tech Arsenal (Arsenal Computer).ISO
/
tek-20
/
satrak.zip
/
SATRAK.DOC
< prev
next >
Wrap
Text File
|
1990-01-16
|
11KB
|
240 lines
SATRAK.DOC PC Version 5.38 Page 1 of 4
======================================================================
SATRAK is a major modification of `USAT' to provide a program that is
user friendly and will function for the rest of the 20th century and
possibly into the early 21st century. This program is intended for use
by all Amateur Radio Operators and others interested in the functions
it performs in Non-Commercial applications.
System Requirements: IBM PC, XT, AT, or compatible computer with 256 K
of memory, a Color Graphics Adapter with either a color or monchrome
monitor and any combination of drives. All SATRAK files must reside on
the default drive in the default directory.
Files required for SATRAK operation are:
---------------------------------------
SATRAK.BAS - GW Basic Ver. 2.12 Source Code
or
SATRAK.EXE - Compiled Version
and
SATRAK.DAT - Database of Satellite Records Available
SATRAK.GSD - Ground Station Data
SATRAK.MAP - World Map for Realtime Tracking Screen
SATRAK.DEF - User Default Definitions
SATRAK.DOC - Program Description
SATRAK - MAIN MENU OPTIONS :
============================
(P) Orbital Prediction Listing
(R) Realtime Tracking On High Resolution Sreeen
(C) Change, Add, Delete Satellite Records
(G) Change Ground Station Data
(S) Set User Defaults: Blink, Delay And Tweak
(N) Convert Day Of Year Number To Date And Time
(D) Return To DOS
Enter Selection (P,R,C,G,S,N,D)-->
(will accept UPPER or lower case)
This program is capable of making orbit predication lists output to the
screen or printer for any satellite in the database for a user defined
time period, time step and minimum elevation angle. On screen
simulation of realtime tracking of satellites in orbit or table type
listing starting with the selected satellite and up to seven (7)
additional satellites for a maximum of eight (8) with current valid
data in the database.
If the listing is blinking on and off it could be visible from your
Ground Station location depending on your minimum Elevation Angle
required to clear local obstructions. On a color monitor in addition
to blinking these listings will be in red. Data contained in the .DAT,
.GSD and .DEF files can be altered from within the program.
(continued on Page 2)
SATRAK.DOC PC Version 5.38 Page 2 of 4
======================================================================
It provides you with a user friendly interface to the program and no
longer depends on specialized internal time dependent data .
The original version of `USAT' program does not explain how you can
obtain or generate the sidereal time table matrix data yourself.
SATRAK now generates the data required. Sometime after the year 2000
this method may not be adequate. SATRAK has a method for tweaking this
data if necessary as explained later in this document.
SATRAK contains program sections by each of the following individuals.
I have made some changes in the current wording and/or locations of
these sections in the modified program.
"USAT" program by Ing. H. F. Strasser - OE1HSI - Jan. 1985 which
included the following programs by others.
Satellite Tracking By R. D. Welch - W0SL - May 1983
Orbital Prediction By Dr. Thomas A. Clark - W3IWI - May 1980
In order for the user to be better informed about the information
SATRAK uses I have provided screen displays of all the information
currently in the Ground Station Data file, User Default Definition file
and Satellite Database file. Changes or additions to any of these
files can be made by selecting the proper options from the Main Menu.
SATRAK.DAT - You will be required to keep the satellite data records on
file current. This means the Epoch Year, Epoch Day and other data for
each satellite must be from the current or preceding year. You can
update this data using information from local packet bulletin boards or
AMSAT nets held on various frequencies. The satellite listing will
inform you which satellite records contain "CURRENT" or "OLD" Data.
A maximum of eight (8) records with `CURRENT DATA' will be displayed
on the Realtime Tracking Screen when that option is selected.
SATRAK.GSD - Normally when you receive this program the data in the
file will be for some other Amateur Radio Operators QTH so you will
need to make changes in this file so that your station coordinates are
taken into account when using the `realtime tracking' or `orbital
predications' portions of the program. You need to furnish your Call,
QTH, Latitude and Longitude to 3 decimal places, and height above sea
level for your receiving antenna in Meters.
SATRAK.DEF contains the User Default values for BLINK, DELAY, TWEAK and
CAL variables. The Blink Delay for the Graphics Screen has a range of
10 to 10000 with a default value of 500. The Line Delay is for the
Status Line of the Graphics Screen and has a range of 10 to 20000 with
default value of 1000. These were made into variables the user can
a change because of the large range of speeds available with computers
past and present. Set BLINK for ~ 0.25 sec. and DELAY for ~ 1.0 sec.
(continued on Page 3)
SATRAK.DOC PC Version 5.38 Page 3 of 4
======================================================================
SATRAK.DEF (Tweak Cal. contiuned)
The Tweak Calibration is for adjustment of the internally calulated
sidereal time constant and can be either a plus or minus adjustment.
It is to be used to compensate for descrepancies in actual location and
time verus program predicted location and time.
TWEAK is an expression where one is equal to a 24 hour day. Therefore
when time is entered in seconds as a positive or negative number it
becomes a decimal number of from 4 to 7 places to the right of the
decimal point.
Example: 0.0000583 for positive correction of 5 seconds or -0.0000583
for a negative correction of 5 seconds. CAL is the conversion of TWEAK
to a decimal value of Plus or Minus Minutes to keep you informed.
Some Single Precision TWEAK Values For Time Are:
------------------------------------------------------
1 second = 0.0000116 30 seconds = 0.0003499
5 seconds = 0.0000583 60 seconds = 0.0006999
10 seconds = 0.0001166 300 seconds = 0.0034998
The average sidereal time constant for the years 1981 through 2019 is
0.2760026. This nineteen year average value then represents a time
span of 6 Hours, 37 Minutes and 26.6251 Seconds.
The deviation above this value was 1 Minute and 57.8524 Seconds.
The deviation below this value was 2 Minutes and 00.4234 Seconds.
As mentioned earlier if you are experiencing some timing problems
working the amatuer satellite some minor corrections can be made using
TWEAK to pad the internal calculated values up or down. When you do
this all satellite records must be current and in the same year. This
is because the year used for this internal calculation will be from the
satellite record selected.
TWEAK IS NOT A TOY FUNCTION TO PLAY WITH !! IF YOU DO NOT NEED OR
UNDERSTAND ITS FUNCTION LEAVE THE DEFAULT VALUE SET TO ZERO !!
Unless you have precise methods to test and verify that the changes you
make using TWEAK are improving your operations I recommend not using
the function.
SATRAK.MAP Contains the graphic information to draw a flat map of the
world on your monitor in High Resolution Black And White Graphics Mode
and must be keep in tack as received. It is used by the Realtime
Tracking option.
The above information explains how the files that SATRAK uses fit into
the overall picture.
The Orbitial Prediction section can output the data to screen or
(continued on Page 4)
SATRAK.DOC PC Version 5.38 Page 4 of 4
======================================================================
printer. You define the starting and stopping point for this function
along with a step rate and minimum elevation angle for your particular
antenna system.
The program then prints out a set of parameter changes which are used
for this current set of listings on the first sheet of paper followed
by as many other sheets as required to list the occasions when the
satellite is in view of your receiving antenna for the period
requested. Ability to work an "in view" satellite will depend upon the
combination of "Range" and "Height" variables matched against your
station capabilities.
The Realtime Tracking section will place a cross on the Map Screen for
up to eight satellite's with `Current Data' in its database record.
These location crosses will be updated approximatly every two seconds
times the number of satellites being displayed. You may toggle between
the Table listing and Map Screen using the <F9> function key. The
program will display each satellites current location information on
the bottom line of the display or you can request continuos listing of
just one particular satellite using the <F10> function key. Enter the
satellite name at the prompt or just <ENTER> to return to listing up to
eight satellites.
The Convert Day of Year Number To Date and Time section is a useful
utility when you need to know what calendar date and time corresponds
to the day of year number stored as each satellite's Epoch date. This
section saves a lot of time and effort figuring that out for you.
If you are going to use this program for show purposes only using just
the realtime tracking section then you can tolerate the use of data
classified as `CURRENT' even though it is one or almost two years old.
You can even update your database with the data using internal
calculated values from the Orbital Prediction Section since accuracy is
not really all that important for that type of operation.
For the serious user I suggest obtaining AMSAT data every sixty days or
sooner. For satellites that average six or less orbits per day try 60
day updates. For those that average seven to thirteen orbits per day
try 45 day updates. Then for those that average over thirteen try 30
day updates.
The `USAT' program's database file `ELEMENTS.DAT' is not compatible with SATRAK's database file `SATRAK.DAT'.
It has been a very interesting experience finding out how all the
pieces should fit together and operate. Then formulate soulutions for
fixing each fault. I admit to a lot of remodeling along the way to
make the program look and feel as I felt it should have been from the
start. The real point to make is that it did not work right when I
received it and now it will work right for many years to come.
73's
H.A.Jones, WB8AMI
SATRAK.DOC / Rev. G / 01-16-1990 /