predict.txt

一个预测卫星方位俯仰的软件

PREDICT (2.2.1d)                                 PREDICT (2.2.1d)



NAME
       predict  - Track and predict passes of satellites in Earth
       orbit

SYNOPSIS
       predict [-u tle_update_source] [-t tlefile]  [-q  qthfile]
       [-a  serial_port]  [-a1  serial_port]  [-f sat_name start-
       ing_date/time  ending_date/time]   [-p   sat_name   start-
       ing_date/time] [-o output_file]

LICENSING
       PREDICT  is  an easy-to-use satellite tracking and orbital
       prediction program written and created by John A.  Maglia-
       cane, KD2BD.

       PREDICT  is  free software. You can redistribute it and/or
       modify it under  the  terms  of  the  GNU  General  Public
       License  as  published  by  the  Free Software Foundation,
       either version 2 of the License or any later version.

       PREDICT is distributed in the hope that it will be useful,
       but  WITHOUT  ANY  WARRANTY, without even the implied war-
       ranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PUR-
       POSE. See the GNU General Public License for more details.

DESCRIPTION
       The DOS version of PREDICT is a derivative  of  the  full-
       featured  Linux  version  PREDICT.   It was compiled under
       Caldera's DR-DOS 7.02 operating  system  using  the  DJGPP
       version  2.03  32-bit  protected mode software development
       environment (gcc 3.2, PDCurses 2.4).

       PREDICT is 32-bit protected mode  software,  and  as  such
       requires  a  32-bit  processor (80386 or better).  Numeric
       co-processor emulation is available for environments lack-
       ing  a  co-processor,  but  the  emulation may not provide
       results as accurate as those possible when a physical  co-
       processor is present.

       The protected mode driver (CWSDPMI.EXE) packaged with this
       software is required for proper operation of PREDICT,  and
       needs  to  be  installed  either  in  your current working
       directory, or in a subdirectory  within  your  OSs  search
       path.   (Type  "path" on your command line to inspect your
       search path.)  Users of Windows 9.x and later versions  do
       not  need  to  install  the protected mode driver included
       with this software.

FIRST TIME USE
       PREDICT tracks and predicts passes of satellites based  on
       the  geographical location of the ground station, the cur-
       rent date and time as provided by  the  computer  system's
       clock,  and  Keplerian  orbital data for the satellites of
       interest to the ground station. First time users  of  PRE-
       DICT  are  provided  default  ground  station location and
       orbital data information files. These files are managed by
       the  program,  and  are  normally  located under PREDICT's
       installation directory.  First time users must supply PRE-
       DICT with their geographical location (the same as select-
       ing option [G] from the program's  main  menu)  the  first
       time  the  program  is run. Latitude is entered in decimal
       degrees north. Latitudes south of the equator are  entered
       as  negative  values.  Longitude  is  entered  as  decimal
       degrees west.  Eastern longitudes may be entered as  nega-
       tive  values. Station altitude is entered as the number of
       meters the ground station is located above sea level. This
       parameter is not very critical.  If unsure, make a realis-
       tic guess or simply enter 0.

       Users of PREDICT  need  Keplerian  orbital  data  for  the
       satellites  they wish to track that is preferably no older
       than one month. The default orbital data supplied with the
       program  is liable to be quite old, and so must be brought
       up to date if accurate results are to  be  expected.  This
       may be accomplished by selecting option [E] from PREDICT's
       main menu and manually entering Keplerian  data  for  each
       satellite  in  the  program's  database,  or  by selecting
       option [U] and specifying a file containing recent  2-line
       Keplerian  element data sets that correspond to the satel-
       lites in the program's database.  Keplerian  orbital  data
       is   available   from  a  variety  of  sources,  including
       http://www.celestrak.com/ and http://www.amsat.org/.

PROGRAM OPERATION
       The start-up screen of PREDICT lists  the  program's  main
       functions.   Several tracking and orbital prediction modes
       are available, as well as several utilities to manage  the
       program's orbital database.

PREDICTING SATELLITE PASSES
       Orbital  predictions are useful for determining in advance
       when a satellite is expected to come  within  range  of  a
       ground station. They can also be used to look back to pre-
       vious passes to help to confirm or identify past  observa-
       tions.

       PREDICT  includes  two orbital prediction modes to predict
       any pass above a ground station (main menu option [P]), or
       list  only  those passes that might be visible to a ground
       station through optical means (main menu option [V]).   In
       either  mode,  the  user is asked to select a satellite of
       interest from a menu, and then asked to enter the date and
       time  (in  UTC)  at  which  prediction calculations should
       start.

       The current date and time may be selected  by  default  by
       entering  nothing  and  hitting  simply the ENTER key when
       prompted to enter the starting date and time.

       Otherwise, the starting date and time should be entered in
       the form:

            DDMonYY HH:MM:SS

       Entering the time is optional.  If it is omitted, midnight
       (00:00:00) is assumed.  Once  complete,  orbital  calcula-
       tions  are started and prediction information is displayed
       on the screen.

       The date and time in UTC, along with the satellite's  ele-
       vation  above  ground, azimuth heading, modulo 256 orbital
       phase, sub-satellite point latitude and  longitude,  slant
       range  between  the  ground station and the satellite, and
       the satellite's orbit number are all displayed.  If space-
       craft  attitude  parameters  (ALAT,  ALON) are included in
       PREDICT's  transponder  database  file,  then   spacecraft
       antenna  squint angles are displayed instead of orbit num-
       bers in the orbital prediction output.

       An asterisk (*) displayed to the right of the orbit number
       or  squint angle means the satellite is in sunlight at the
       date and time listed on the line. A plus symbol (+)  means
       the  satellite  is in sunlight while the ground station is
       under the cover of darkness at the time and  date  listed.
       Under  good  viewing  conditions, large satellites such as
       the International Space Station (ISS), the US Space  Shut-
       tles, and Hubble Space Telescope, and the Upper Atmosphere
       Research Satellite (UARS) are visible to the naked eye. If
       no  symbol  appears  to  the  right of each line, then the
       satellite is in the Earth's shadow at the  time  and  date
       listed,  and  is  not  receiving any illumination from the
       sun.

       Pressing the ENTER key, the 'Y'  key,  or  the  space  bar
       advances  the  orbital predictions to a screen listing the
       next available passes.  Pressing the 'L'  key  allows  the
       currently  displayed screen plus any subsequent screens to
       be logged to a text file in your  current  working  direc-
       tory.  The  name  given  to  this  file is the name of the
       satellite plus a ".txt" extension.  Any slashes or  spaces
       appearing in the satellite name are replaced by the under-
       score (_) symbol. The logging feature may  be  toggled  on
       and  off  at any time by pressing the 'L' key. Exiting the
       orbital prediction mode by pressing  'N'  or  hitting  the
       ESCape key will also close the log file. The log file will
       be appended with additional information if additional pre-
       dictions  are  conducted  for  the same satellite with the
       logging feature turned on.

       Selecting [V] from  PREDICT's  main  menu  will  permit  a
       ground  station to only predict passes for satellites that
       are potentially visible through optical means.  Since  all
       other passes are filtered out in this mode, and since some
       satellites may never arrive over  a  ground  station  when
       optical  viewing conditions are possible, the program pro-
       vides the option of breaking out of visual orbital predic-
       tion mode by pressing the [ESC]ape key as calculations are
       made. A prompt is displayed at the bottom of the screen to
       alert the user of this option.

       In either orbital prediction mode, predictions will not be
       attempted for satellites that can  never  rise  above  the
       ground station's horizon, or for satellites in geostation-
       ary orbits. If a satellite is in  range  at  the  starting
       date  and time specified, PREDICT will adjust the starting
       date back in time until the point of AOS so that the  pre-
       diction  screen  displays  the  first pass in its entirety
       from start to finish.

SINGLE SATELLITE TRACKING MODE
       In addition to predicting satellite passes, PREDICT allows
       satellites to be tracked in real-time using PREDICT's Sin-
       gle Satellite Tracking Mode (main  menu  option  [T]),  or
       simultaneously as a group of 24 using the program's Multi-
       Satellite Tracking Mode (main menu option [M]).  The posi-
       tions of the Sun and Moon are also displayed when tracking
       satellites in real-time.

       Selecting option [T] from PREDICT's main menu  places  the
       program  in  Single Satellite Tracking Mode. The user will
       be prompted to select the  satellite  of  interest,  after
       which  a screen will appear and display tracking positions
       for the satellite selected.

       In Single Satellite Tracking Mode, a wealth of information
       related to tracking a spacecraft and communicating through
       its transponder is displayed.  The current date  and  time
       is  displayed  along  with  the  satellite's sub-satellite
       point, its orbital altitude in both kilometers and statute
       miles, the slant range distance between the ground station
       and the satellite in both kilometers  and  statute  miles,
       the  current  azimuth  and  elevation  headings toward the
       satellite, the orbital velocity of the satellite  in  both
       kilometers  per hour and statute miles per hour, the foot-
       print of the satellite  in  both  kilometers  and  statute
       miles,  the modulo 256 orbital phase of the satellite, the
       eclipse depth, the spacecraft antenna  squint  angle,  and