This program queries a Predict server on port 1210/UDP and returns values for satellite information, such as next acquisition of signal (AOS) and whether or not the satellite is in sunlight. Any suggestions for making it a bit more efficient? 
#!/usr/bin/perl -w

use strict;
use Socket;

my $port = 1210;
my ($predict_server, $satellite);

# Use defaults if no command line arguments given
if ($#ARGV eq 1) {
  $predict_server = $ARGV[0];
  $satellite = $ARGV[1];
}
else {
  print "WARNING: Use syntax \"sat.pl hostname satellite\" (i.e., sat.
+pl localhost FO-20)\n";
  print "Substituting default arguments\n";
  $predict_server = "localhost";
  $satellite = "OSCAR-10";
}

# Setup for UDP socket commumnication
my ($d1, $d2, $d3, $d4, $rawserver) = gethostbyname($predict_server);
my $serveraddr = pack("Sna4x8", 2, $port, $rawserver);
my $prototype = getprotobyname('udp');
socket(SOCKET,2,SOCK_DGRAM,$prototype) || die("No Socket\n");
$| = 1;  # no buffering

# Setup timeout routine
$SIG{ALRM} = \&time_out;
alarm(10);  # Force exit if no response from server

# Send request to predict
send(SOCKET, "GET_SAT $satellite\0" , 0 , $serveraddr) or die("UDP sen
+d failed $!\n");

# Get response from predict
my $server_response = '';  # required by recv function
recv(SOCKET, $server_response, 100, 0) or die "UDP recv failed $!\n";

# Extract individual responses
my ($name, $lon, $lat, $az, $el, $aos_seconds, $foot) = split /\n/, $s
+erver_response;
my $aos_time_date = gmtime($aos_seconds);

# Output response
print "\nPREDICT returned the following string in response to GET_SAT 
+$satellite:\n\n$server_response\n";
print "Values are as follows:\nName: $name\nLong: $lon\nLat: $lat\nAz:
+ $az\nEl: $el\nNext AOS: $aos_seconds = $aos_time_date UTC\nFootprint
+: $foot\n\n";

close(SOCKET);


sub time_out {
  die "Server not responding for satellite $satellite\n";
}

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In reply to Satellite Tracking by tekniko

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