The Unsorted BBS Collection/thegreatunsorted.tar/thegreatunsorted/misc/stsplus.new

Text File | 1994-08-25 | 12KB | 210 lines

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

      Each released version of STSPLUS uses a four digit revision code such
as 9435. 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 9435A -- August 1994
----------------------------
-Version 9435A corrects a problem with certain country codes (such as those
which use the "YY-MM-DD" date format) which still caused "BASIC Error = 5"
in the orthographic mode for Version 9435. The program should now be
independent of the country code.
-Corrected a minor bug with amateur radio satellite frequencies. If the
primary satellite was changed with F6, the frequency file (STSPLUS.FRQ) was
not rescanned and the frequencies from the prior satellite remained.
STSPLUS will now always rescan file STSPLUS.FRQ if the primary satellite is
changed.


Version 9435 -- August 1994
---------------------------
-This release repairs an unfortunate bug which surfaced when I added the
NORAD-style date on the orthographic display. Only users who set DOS to
non-US-style date formats were affected. The problem occurred immediately
when drawing the orthographic map as "BASIC Error = 5" and returned the
user to DOS.
-Added satellite name cross-reference in file STSPLUS.XRF. When TLEs are
read and accepted, STSPLUS now checks for the cross-reference file and, if
the file is present in the current directory, checks for the NORAD Number
of the satellite and a cross-reference name. If found, the new name is
substituted for that found in the TLE file. The file is standard ASCII and
each entry consists of a SPACE, the five-digit NORAD Number, a SPACE, and
then the satellite name. A sample file:

 22920 HST Solar Array
 22076 Topex/Poseidon
 21225 Gamma Ray Observ
 20638 Rosat Observatory
 20580 Hubble Telescope
 16609 MIR Space Station

NOTE: The leading space is required for file compatibility with my program
ORBITEL (but is optional for STSPLUS). The NORAD Number MUST be 5 digits;
pad with leading zeroes if necessary. Only one entry is read per satellite.
If the satellite name is longer than 19 characters, only the left 19
characters will be used. This feature may be used to substitute any name
for that given in a TLE file (which is not always consistent from source to
source) or to specify a payload piggy-backed on another satellite (as is
frequently the case with amateur radio transponders). A number of XRF files
are posted on my RPV Astronomy BBS; such files must be renamed for use with
STSPLUS.
-Repaired a minor bug which caused the pass predictions (F3 from Main Menu
to repeat a pass indefinitely when that pass was a grazing pass with a
maximum elevation of less than one degree (0.14 degrees in the test case
reported by Ken Ernandes).
-Corrected a bug in read/save .SCF files (F6 from the Main Menu). If a
fileltype is entered (".SCF" or whatever), it is now ignored and ".SCF" is
automatically appended to the filename. Thanks to Paul Becker for reporting
the problem.
-In response to many requests, the date input routine has been modified to
permit entry in the European style "dd.mm.yyyy" in addition to the US style
"mm/dd/yyyy". The choice of delimiter ("." or "/") determines the method of
interpretation. In both cases, the year may be entered as the last two
digits only, "yy", if desired; "50" through "99" will be interpreted as
"1950" through "1999" and all others as 2000+yy. Dates are displayed as "dd
MMM yyyy" where "MMM" is the English abbreviation for the month.
-All current .SCF files are now displayed for both SAVE and READ functions
(F6+F2 and F6+F3 from the Main Menu).
-Improved backspace processing and error checking when entering TLE
filenames (F2 from the Main Menu).
-Corrected "West Latitude" to "West Longitude" in the data entry section
for local coordinates (F10+F2).
-Various minor cosmetic changes.

-Version 9434 was released as a Beta Version to selected users and included
all changes in Version 9435 EXCEPT the repair to the NORAD-style date bug.

Version 9432A -- August 1994
----------------------------
-As too often happens, a bug was discovered in Version 9432 just after it
was released. The elevation ("Elv") and azimuth ("Azm") in the rectangular
projections either remained at zeroes or at the last value calculated
during orthographic projection. There was no workaround. The problem has
been repaired. My apologies to those who received the defective version.


Version 9432 -- July 1994
-------------------------
-Version 9432 adds several new features and corrects a number of program
errors and/or "bugs". Several minor cosmetic changes were also made.
-Added Data Output Mode 8 to generate tabular output for Doppler Shift
calculations for a selected pass while the tracking map is displayed. Use
F3 from the Main Menu and select Mode 8; setup features are identical to
other modes (output device, interval, etc.). See text for details.
-Look angle calculations [elevation ("Elv") and azimuth ("Azm")] during the
tracking map display are more accurate thanks to an improved algorithm
supplied by Ken Ernandes. Users should note that near culmination (maximum
elevation) for passes near the user's zenith (approaching 90 degrees
elevation) there is some uncertainty and ambituity as to azimuth although
the angular error remains very small.
-Changed "Alt" to "Elv" as the label for satellite elevation (altitude)
above mean sea level to conform to standard satellite tracking convention.
-Because STSPLUS is used worldwide, I have reformatted all displayed dates
throughout the program to avoid confusion of the day versus the month. For
orthographic displays, the display now shows the current UTC date and time
("dd MMM hh:mm:ss UTC") and then the local time ("dd mmm hh:mm:ss PDT"
where "PDT" is replaced by the local time abbreviation). For both dates,
the year is implied. The MET/T+E is moved up one line. A typical time
display will show:
     15 JUL 19:57:36 UTC
     15 JUL 12:57:36 PDT
          7/03:14:36 MET
For the Main Menu and rectangular projections, the dates are all given as
"dd MMM yyyy". Data locations are unchanged. A typical date and time will
now be displayed as:
     15 JUL 1994  19:57:36 UTC
For all cases, "MMM" is the three letter English abbreviation for the
month, "JAN" for January, "FEB" for February, etc.

     IMPORTANT NOTE: Keyboard entry of dates is still in the American
     numeric format, "mm/dd/yyyy" or "mm/dd/yy".

-For orthographic projections, the current time using NORAD convention
("yyddd.dddddd") is displayed immediately beneath the current TLE filename:
        94196.831667
This provides an immediate method to identify the current year and day-of-
the-year, "94" and "196" respectively in the example above.
-Added an additional data line in orthographic display to show the current
orbital period ("Per'd" using the format "hh:mm:ss") for normal display OR,
for satellites with Eccentricity >= 0.005, satellite Phase, defined as Mean
Anomaly normalized to the range 0-256 ("Phase" using the format "nnn.n")
for use with the Doppler Shift mode [press F8 while the map is displayed]
and satellites which change transponder mode based upon phase. Although
Phase is technically defined as an integer value from 0 through 255,
STSPLUS displays it to one decimal place to alert users to upcoming
phase/transponder changes. Other users may also be interested in two
important Phase or Mean Anomaly angles: Phase=0.0 (Mean Anomaly is 0
degrees) corresponds to perigee and Phase=128.0 (Mean Anomaly is 180
degrees) corresponds to apogee.

     NOTE: Mean Anomaly (and therefore Phase) becomes undefined for a
     perfectly circular orbit. In practice, satellites with eccentricity
     less than 0.005 will display some ambiguity as to Mean Anomaly and
     Phase. Note also that the "Elv" is the geodetic elevation (altitude)
     of the satellite above Mean Sea Level and NOT the geocentric radius of
     the satellite's orbit, the paramter used to determine apogee and
     perigee; the difference due to the shape of the Earth is as much as
     21 km. See the section "Satellite Communications and Amateur Radio"
     for additional discussion!

-Repaired the Tracking Station color feature (F10+F9) so that it operates
correctly. Versions 9415/9414 caused the entire screen to turn light red
when the Tracking Station color was changed due to a careless coding error.
-Rewrote the local coordinates code and text (F10+F2) to improve clarity
and add several features. Now uses a function key menu to select action to
perform. Press ENTER to return to prior menu. When entering new
coordinates, an illegal latitude or longitude will cause that coordinate to
be set to zero. Longitude may be entered as East Longitude (0 to +360) or
West Longitude (0 to -180); the longitude is converted if necessary and
stored in the range from -180 to 0 to +180.
-The threshold for generating the "Satellite may have decayed!" message has
been increased to a Mean Motion of 16.4 revs/day to reduce the probability
of the message appearing during low shuttle flights.
-Added code to check for synchronization and data errors in the .INI file
between the "short form" satellite position data and the 2-line elements.
If the NORAD numbers do not agree, the "short form" data will be set to the
TLE NORAD number and the remaining data reset; if TLEs are not present,
dummy TLEs are inserted. Use F6 to verify and/or correct the secondary
satellites, then use F2+& to update data from TLE file(s).
-Adjusted the "trigger" for automatic redraw in orthographic modes with
higher zoom factors to compensate for high speed processors such as the
90MHz Pentium. (Under some circumstances, redraw was being triggered
continuously.)
-Repaired a minor bug that caused the TDRS and Sun AOS/LOS data to be
missing on the rectangular display when Doppler Shift mode had been
selected on the orthographic display.
-Corrected the conversion factor used to convert meters to feet. Thanks to
Steve Lenz for reporting the bug!
-Removed all references to the RPV HOTLINE BBS since that telephone line is
now in rotary with the main number, [phone].

-Versions 9424, 9429, and 9431 were beta test versions not released
publicly and included some of the features and changes in this release. For
Version 9424, the precision of Doppler shift frequencies was increased to 5
digits (10 Hz) to the right of the decimal point but this proved confusing
and has been restored to 4 digits (100 Hz).

Version 9415 -- April 1994
--------------------------
-This release repairs a problem in rectangular projections which caused the
Alt/Az calculations to be incorrect. (The data in orthographic projections
were alright.) The problem was traced to a duplicated variable name which
was added to shared common. Only file STSPLUS.EXE is changed.