mirror of https://github.com/XEphem/XEphem.git
141 lines
4.6 KiB
Raku
Executable File
141 lines
4.6 KiB
Raku
Executable File
#!/usr/bin/perl -w
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# tle2edb.pl: perl script to convert NASA "2-line" geocentric orbital elements
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# to XEphem .edb. we crack everything that looks reasonable. we allow the TLE
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# to be embedded in other text, just so long as it stands on three successive
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# lines of their own. the idea is to keep rolling successive lines into l1,
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# l2 and l3 and crack whenever they all look correct.
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#
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# (c) 1993,1995,1998,2000 Elwood Charles Downey
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#
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# v2.2 9/22/00 add drag term
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# v2.1 12/8/98 change to perl. actually use the checksum. support Y2K.
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# v2: 6/26/95 allow names up to 22 chars long (official format change).
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# v1.3 10/26/93 looks even harder.
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# v1.2 9/12/93 fixes for NORAD-format (by bon@LTE.E-TECHNIK.uni-erlangen.de)
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# v1.1 9/8/93 change type code to E
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# v1.0 8/10/93 initial cut
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#
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# usage:
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# tle2edb.pl [file]
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#
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# Data for each satellite consists of three lines in the following format:
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#
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# AAAAAAAAAAAAAAAAAAAAAA
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# 1 NNNNNU NNNNNAAA NNNNN.NNNNNNNN +.NNNNNNNN +NNNNN-N +NNNNN-N N NNNNN
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# 2 NNNNN NNN.NNNN NNN.NNNN NNNNNNN NNN.NNNN NNN.NNNN NN.NNNNNNNNNNNNNN
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#
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# Line 0 is a 22-character name.
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#
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# Lines 1 and 2 are the standard Two-Line Orbital Element Set Format identical
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# to that used by NORAD and NASA. The format description is:
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#
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# Line 1
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# Column Description
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# 01-01 Line Number of Element Data
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# 03-07 Satellite Number
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# 10-11 International Designator (Last two digits of launch year)
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# 12-14 International Designator (Launch number of the year)
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# 15-17 International Designator (Piece of launch)
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# 19-20 Epoch Year (Last two digits of year). 2000+ if < 57.
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# 21-32 Epoch (Julian Day and fractional portion of the day)
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# 34-43 First Time Derivative of the Mean Motion
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# or Ballistic Coefficient (Depending on ephemeris type)
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# 45-52 Second Time Derivative of Mean Motion (decimal point assumed;
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# blank if N/A)
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# 54-61 BSTAR drag term if GP4 general perturbation theory was used.
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# Otherwise, radiation pressure coefficient. (Decimal point assumed)
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# 63-63 Ephemeris type
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# 65-68 Element number
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# 69-69 Check Sum (Modulo 10)
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# (Letters, blanks, periods, plus signs = 0; minus signs = 1)
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#
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# Line 2
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# Column Description
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# 01-01 Line Number of Element Data
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# 03-07 Satellite Number
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# 09-16 Inclination [Degrees]
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# 18-25 Right Ascension of the Ascending Node [Degrees]
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# 27-33 Eccentricity (decimal point assumed)
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# 35-42 Argument of Perigee [Degrees]
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# 44-51 Mean Anomaly [Degrees]
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# 53-63 Mean Motion [Revs per day]
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# 64-68 Revolution number at epoch [Revs]
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# 69-69 Check Sum (Modulo 10)
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#
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# All other columns are blank or fixed.
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#
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# Example:
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#
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# NOAA 6
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# 1 11416U 86 50.28438588 0.00000140 67960-4 0 5293
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# 2 11416 98.5105 69.3305 0012788 63.2828 296.9658 14.24899292346978
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#
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# shield yield:
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#
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# NOAA 6-529,E,1/ 50.28438588/1986, 98.5105, 69.3305,0.0012788, 63.2828,296.9658,14.24899292,0.00000140,34697
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#
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$[ = 1; # set array base to 1
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$l1 = "";
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$l2 = "";
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$l3 = "";
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while (<>) {
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chop; # discard newline
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s/^[\s]*//; # strip leading whitespace
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s/[\s]*$//; # strip trailing whitespace
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$l1 = $l2; # roll into place
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$l2 = $l3;
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$l3 = $_;
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# sanity checks
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next if (length($l1)>22 or $l2 !~ /^1 / or $l3 !~ /^2 /);
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next if (!&chksum ($l2));
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next if (!&chksum ($l3));
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# $l1 is just the satellite name
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$name = $l1;
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# pick out the goodies from l2, "line 1" of the TLE
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$year = substr($l2, 19, 2);
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if ($year >= 57) {$year += 1900;} else {$year += 2000;}
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$dayno = substr($l2, 21, 12);
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$decay = substr($l2, 34, 10);
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$drag = substr($l2,54,1) .
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substr($l2, 55, 5) * (10 ** substr($l2, 60, 2)) * 1e-5;
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$set = substr($l2, 65, 4);
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# pick out the goodies from l3, "line 2" of the TLE
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$inc = substr($l3, 9, 8);
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$ra = substr($l3, 18, 8);
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$e = substr($l3, 27, 7) * 1e-7;
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$ap = substr($l3, 35, 8);
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$anom = substr($l3, 44, 8);
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$n = substr($l3, 53, 11);
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$rev = substr($l3, 64, 5);
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# print in xephem format.
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printf "%s-%d,E,1/%s/%d,%s,%s,%s,%s,%s,%s,%s,%d,%s\n", $name, $set, $dayno,
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$year, $inc, $ra, $e, $ap, $anom, $n, $decay, $rev, $drag;
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}
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sub chksum
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{
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my $line = $_[0];
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my $len = length($line);
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my ($sum, $i, $c);
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$sum = 0;
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for ($i = 1; $i < $len; $i++) {
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$c = substr($line,$i,1);
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$sum += $c if ($c =~ /[\d]/);
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$sum += 1 if ($c eq "-");
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}
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$c = substr($line,$len,1);
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return (($sum % 10) == $c);
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}
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# For RCS Only -- Do Not Edit
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# @(#) $RCSfile: tle2edb.pl,v $ $Date: 2000/09/26 23:33:09 $ $Revision: 1.3 $ $Name: $
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