Monster Media 1996 #15/Monster Media Number 15 (Monster Media)(July 1996).ISO/ham/sop9615a.zip/STSPLUS.NEW

Text File | 1996-04-04 | 14KB | 248 lines

STSORBIT PLUS Revision History
------------------------------

     Each released version of STSPLUS uses a four digit revision code such
as 9614. The first two digits indicate the year and the second two digits
indicate the week of the year. In some cases, an additional letter suffix
is added to distinguish changes occurring within the same week or to
identify special versions. A partial week at the beginning or end of the
year is counted as a full week. Using this method, a year will typically
have 53 weeks although it is possible to have 54 weeks in a leap year (1972
is an example). The current year-week revision code is shown on the Julian
Date display, Display Mode 7, in my program ASTROCLK.
     This file records the revision history of program STSPLUS through all
of the minor twists and turns that usually accompany the evolution of such
a complex program. It illustrates the tortuous process of maintaining and
refining a program as ideas and problems are reported from every quarter.
These notes may also be helpful to users who are upgrading from one version
to another to find out what has changed.

                                              David H. Ransom, Jr.


Version 9615 -- April 1996
--------------------------
-This is a MAINTENANCE UPDATE, incorporating several significant
enhancements and repairing several minor bugs.
-In response to several inquiries, processing times for STSPLUS have
increased for current versions due to improved accuracy and complexity, as
well as added features. These improvements have been implemented, in part,
because of the much greater processing power and speed of current systems.
Delays will be more apparent on older systems with 386 and slower 486
processors.

                         ** IMPORTANT NOTE **

     Users are reminded that for most DOS and Windows 3.1
     systems, a "vanilla" system (configured without a memory
     manager) will execute MUCH faster; computation times for
     Visible Pass Predictions, for example, are FOUR TIMES faster
     with the "vanilla" configuration on a typical Pentium
     system. The standard "MS-DOS Prompt" configuration for
     Windows 95 does not include a memory manager and will
     execute at high speed.

-With widespread availability of TLEs on the Internet, many users are now
receiving TLEs via these sources. Unfortunately, many Internet systems use
UNIX servers and the TLE files are often reformatted with LF-only line
termination which causes most DOS programs to fail. STSPLUS has now been
modified to test TLE files and, if UNIX or MAC format is detected, to
automatically convert the file to DOS format. During file processing (F2
from the Main Menu), the following message is displayed while this
conversion is being performed:

     UNIX.TLE is in UNIX/MAC format and is being converted!

     Please wait ...

The original UNIX/MAC file ("UNIX.TLE" in the example above) is replaced by
the new DOS file and the original file is deleted. Normal operation of
STSPLUS then resumes.
-The Visible Pass Prediction code has been optimized for speed. Calculation
times have been improved by 20% to 30% and time resolution has been
slightly decreased. Minor differences in data may be observed when compared
to prior versions.
-Prompted by the re-entry of the Chinese spy satellite (#22870) in early
March of 1996, I have changed the code used to detect possible orbital
decay. STSPLUS now calculates the perigee at Epoch and displays a warning
message if the perigee is less than 75 nautical miles. The user may press
ENTER to return to the Main Menu or may press ESC to proceed with orbital
calculations. Once a satellite's orbital altitude decays to below about 70
nautical miles (130 kilometers), re-entry may have occurred or will occur
very soon thereafter. NOTE: The calculations may fail with a BASIC Error if
the satellite has already decayed.
-Added data for Perigee and Apogee to that shown using ALT-F1 from the Main
Menu. Data are calculated using the orbital data as of Epoch. Also repaired
a BASIC Error when using this feature when a launch date and time had not
been specified for the satellite.
-Corrected a bug with the Duration of Line-of-Sight passes when the Minimum
Horizon angle was set to zero degrees. STSPLUS generated inaccurate times,
sometimes by tens of hours. Thanks to Josh Willims for spotting the bug!
-In order to display a "reasonable" South Atlantic Anomaly when the Space
Shuttle is on the launch pad and during ascent phase, the SAA is forced to
use a minimum altitude of 75 nautical miles.
-Yet another COUNTRY CODE bug has surfaced, this time in file STSPLUS.OBS
which is written by STSPLUS for use by Kelso's program TRAKSTAR. In this
case, the decimal point in local latitude and longitude were automatically
replaced by commas (in spite of a FORMAT statement that explicitly used the
period!), causing TRAKSTAR to fail. The code has been rewritten. Thanks to
Arve Fager in Sweden for reporting the problem!
-Modified automatic map redrawing in rectangular projections so that the
map will not be redrawn when AUTO REDRAW is enabled ("A" displayed at upper
right, press TAB key with map displayed to enable/disable AUTO MAP REDRAW)
until the current map has been displayed for at least 90 seconds. Thanks to
Les Putnam for the reminders on this annoying bug!
-Added local station latitude (degrees), longitude (degrees), and elevation
(meters) to Pass Prediction data output header section.
-Some lakes and rivers still slipped through in the orthographic projection
when RIVERS were disabled. Thanks to Ed Toomey for spotting them!
-Various minor cosmetic changes.
-A pre-release of this update, Version 9614, included most changes EXCEPT
the automatic conversion of TLE files to DOS format.


Version 9610 -- March 1996
--------------------------
-This is a MAINTENANCE UPDATE, correcting several minor bugs and one major
problem primarily affecting users outside the United States.
-For users with non-US COUNTRY CODE, corrected a problem with Pass
Predictions (F3 from the Main Menu) which caused a BASIC Error when the
output was sent anywhere except the screen. Pass Prediction data sent to
file STSPLUS.LOG or LPT1/COM1/COM2 now no longer includes the day of the
week in the header but does include the local time zone. The problem was
related to a non-US COUNTRY CODE, a remnant of an earlier COUNTRY CODE
problem which I thought I had eliminated. Thanks to Arve Fager at Volvo in
Sweden for providing the necessary clue!
-Added the next date and time at which pass predictions will be tested to
the elapsed time calculation:

     Elapsed time =  27.1 seconds, Next test at 05 MAR 96  06:40:26

Several users complained that for visible passes when no passes were found,
they lost track of the date; I found I had the same problem and fixed it.
-Corrected a minor problem which prevented display of the South Atlantic
Anomaly when attempting to automatically upgrade from Version 9602 or
earlier using an old STSPLUS.INI file. Although the menu item (F10+F3+F7)
would switch from ON to OFF and back to ON, the SAA would never be drawn
because the color inadvertently was set to the color BLACK. (If the SAA
color was manually set or the file STSPLUS.INI from the Version 9607
release was used, the SAA would be drawn correctly.)
-Corrected a minor bug which caused several rivers in northern Russia to be
displayed on the World Map. (Rivers are always disabled for the full world
in the rectangular projection to avoid cluttering the screen.)
-Added the Target Satellite Label to the data block for range and velocity
calculations. The label used is the label entered when setting up the
Target Satellite using F6+F1 from the Main Menu. Thanks to Ridge Tolbert!
-Added preliminary usage notes for Windows 95 and Windows NT to this
documentation.
-In response to several complaints from LCD laptop users about "invisible
text", I have adjusted the colors used for filename lists and one prompt
for F2 and F6+F2/F3 from the Main Menu. Comments invited ...
-Various minor cosmetic changes.


Version 9607 -- February 1996
-----------------------------

     IN MEMORIAM

     This release of STSORBIT PLUS is dedicated to the memory of
     my good friend Joel Runes who passed away unexpectedly on
     January 11, 1996, hours after covering the launch of STS-72
     for radio station WMEL in Melbourne, Florida. A true expert
     in the space field, Joel's many contributions to STSORBIT
     PLUS and to the RPV Astronomy BBS, along with all his other
     activities far and wide, will be greatly missed by his
     friends around the world.

-This is a MAINTENANCE UPDATE to enhance several features and correct
various minor bugs.
-CAUTION: In order to accommodate new and planned features, the structure
of file STSPLUS.INI has been changed. This means that while you may upgrade
from a prior version without difficulty, you MUST delete file STSPLUS.INI
IF YOU RETURN TO AN OLDER VERSION! As a precaution or if you plan to return
to an older version, save the old STSPLUS.INI file for later use.
-In response to many user requests, I have rewritten the Pass Prediction
code (F3 from the Main Menu) to add Line-of-Sight and Visible passes, both
with settable minimum pass altitude (maximum pass elevation above the
horizon) and minimum horizon threshold (minimum elevation above the
horizon). The times and other data for Line-of-Sight and Visible passes now
take into account the visibility and horizon criteria, as appropriate,
eliminating all passes which do not meet those criteria. The "All Passes"
mode is essentially identical to the pass prediction feature in prior
versions. Note that users with slow computers and especially those without
a math coprocessor may find that calculation times are painfully slow!
-Corrected a long-standing cosmetic bug [thanks for the reminders on this
bug from Don Nicholson] which caused certain islands in the north of Canada
to display as lakes. Lakes and rivers are still disabled in the full world
rectangular projection, as before, so as to avoid unnecessarily cluttering
the display. In this process, the four map database index files were also
found to have errors which have been corrected and are included with this
update:

     EARTH4.MCX
     EARTH3.MCX
     EARTH2.MCX
     EARTH1.MCX

.cp 3
                               *************
                               ** CAUTION **
                               *************

     Users MUST replace ALL their existing EARTH*.MCX files with the
     new versions supplied with this update or unpredictable results
     may occur when drawing the maps. Users who do not use the higher
     detail map database files (EARTH3 through EARTH1) may discard the
     unneeded files, retaining only those which correspond to the map
     database files present on their system. The corresponding map
     vector files, EARTH*.MCP and EARTH*.XYZ, have not been changed
     from prior releases.

-After years of procrastination, I have finally modeled the South Atlantic
Anomaly zone (SAA) using NASA Mission Maps, unfortunately now long out of
print, for spacecraft altitudes from 140 nm to 330 nm. The current SAA
model corresponds to the SAA as shown on the NASA Mission Maps for 140 nm
and 330 nm with non-linear interpolation used at intermediate altitudes;
the accuracy of the model used is unknown for altitudes greater than 330 nm
although the SAA is drawn for altitudes up to 1000 nm. The SAA is disabled
for satellite altitudes above 1000 nm. In this process, I have coded both
the rectangular projection (shown as a simple ellipse in prior versions)
and the orthographic projection (which was disabled in prior versions). The
SAA data is contained in file STSPLUS.SAA which must be present in the
default directory. Users are cautioned NOT to alter file STSPLUS.SAA or
results may be unpredictable.
-The color used to draw the South Atlantic Anomaly has been added to the
User-Definable Map Colors using F10+F9 from the Main Menu. The default
color is white as in prior versions.
-Corrected a minor bug which sometimes caused the Orbit Number in the
Descending Node Display (F10+F5 from the Main Menu) to be one high.
-Modified the Ascending/Descending Node data display (F10+F5 from the Main
Menu) so that it is now active in both rectangular and orthographic
projections including the Motion Map. In prior versions it was only active
in rectangular projection. Repaired a number of minor cosmetic bugs related
to this feature.
-Improved a minor cosmetic bug that caused stray terminator pixels to
occasionally be left behind, usually at the southern-most or northern-most
points of the terminator. The bug was a subtle timing problem related to
when the Sun's position was calculated. The changes reduce but do not
completely eliminate the problem. Completely eliminating the problem IS
possible but would substantially slow map update times by requiring that
the solar terminator be completely redrawn every ten seconds. In view of
the relatively few complaints, I have elected to make a partial fix which
reduces the incidence of the problem and does not materially affect the map
update times.
-Repaired a minor cosmetic bug that re-used old saved pixels behind the
satellite icon when the map was redrawn and the pixels should have been
discarded. This caused stray ground track and map features to appear at the
prior location of the satellite each time the map display was redrawn. The
problem was most apparent at higher zoom factors.
-I have increased the minimum donation for program registration from
US$10.00 to US$15.00. My costs and the time required have increased
steadily since I first offered my software for US$10.00 in the late 1980s.
I have also added US$5.00 for foreign air mail postage to help cover the
additional costs and handling. I still think it's one of the best software
bargains around ...
-Beta Test Version 9604X was released on a limited basis in January 1996
and included some but not all of the features of this release.