From 8183967eeef2d3fb13afa5e28859239613b33c6c Mon Sep 17 00:00:00 2001
From: Jogi Hofmüller <jogi@mur.at>
Date: Sat, 13 Aug 2011 09:55:41 +0000
Subject: - implemented downloading and parsing TLEs from
 http://www.celestrak.com/NORAD/elements/amateur.txt

git-svn-id: https://svn.spreadspace.org/mur.sat@140 7de4ea59-55d0-425e-a1af-a3118ea81d4c
---
 tools/mmd/MmdSatellite.py | 60 +++++++++++++++++++++++++++++++----------------
 1 file changed, 40 insertions(+), 20 deletions(-)

(limited to 'tools/mmd/MmdSatellite.py')

diff --git a/tools/mmd/MmdSatellite.py b/tools/mmd/MmdSatellite.py
index e6a0c08..97f516a 100644
--- a/tools/mmd/MmdSatellite.py
+++ b/tools/mmd/MmdSatellite.py
@@ -4,28 +4,10 @@ import ephem
 import time
 import os
 import sys
+import urllib
 from MmdDb import Db
 from MmdLocation import Location
 
-# def createJavaArray (point_list, name):
-#   astring = '''var {0} = new Array (\n'''.format (name)
-#   astring = '{0}\tnew Array ('.format (astring)
-#   last = 'west'
-# 
-#   for point in point_list:
-#     if point[0][0] == '-':
-#       if last == 'east':
-#         astring = astring[:-1]
-#         astring = '{0}\n\t\t),\n\tnew Array ('.format (astring)
-#       last = 'west'
-#     else:
-#       last = 'east'
-#     astring = '{0}\n\t\tnew OpenLayers.LonLat ({1}, {2}).transform (from, to),'.format (astring, point[0], point[1])
-#   if astring[-1] == ',':
-#     astring = astring[:-1]
-#   astring = '{0}\n\t\t)\n\t);'.format (astring)
-#   return astring
-
 def dms2degdec (lonlat):
   '''
   convert a position argument from Deg:Min:Sec.Frac to
@@ -44,7 +26,8 @@ def dms2degdec (lonlat):
 class Satellite:
 
   def __init__ (self, location = False):
-    self.name = 'RADIOSCAF-B/ARISSAT-1'
+    self.name = 'RADIOSCAF-B'
+    self.nickname = 'ARISSAT-1'
     self.tle_filename = '/usr/local/mmd/tles/current'
     self.db = Db ()
     self.initSatellite (location)
@@ -150,14 +133,51 @@ class Satellite:
     return self._computeTrajectory ()
 
   def _updateTLEFile (self):
+    '''
+    store new TLE data in file with format
+    YYYYMMDDhhmmss (Year Month Day hour minute second)
+    and make symlink to self.tle_filename
+    '''
+    if not self._getTLEFileFromNetwork ():
+      return False
+    filename = '/usr/local/mmd/tles/{0}'.format (time.strftime ('%Y%m%d%H%M%S'))
+    for line in self.tle_data:
+      if line.startswith (self.name):
+        tle = open (filename, 'w')
+        tle.write (line)
+        tle.write (self.tle_data.next ())
+        tle.write (self.tle_data.next ())
+        tle.close ()
+        return self._compareAndLinkNewTLEFile (filename)
     return False
 
+  def _compareAndLinkNewTLEFile (self, filename):
+    old_data = open (self.tle_filename).read ()
+    new_data = open (filename).read ()
+    if old_data == new_data:
+      os.unlink (filename)
+      return False
+    os.unlink (self.tle_filename)
+    os.symlink (filename, self.tle_filename)
+    return True
+
   def _updateTrajectory (self):
     self.db.satelliteDeleteObsoleteSSPs (time.strftime ('%s'))
 
   def getLatestSSP (self):
     return self.db.satelliteGetLatestSSP ()
 
+  def _getTLEFileFromNetwork (self):
+    '''
+    retreive TLE update from NORAD
+    '''
+    networkfile = 'http://www.celestrak.com/NORAD/elements/amateur.txt'
+    try:
+      self.tle_data = urllib.urlopen (networkfile)
+    except IOError:
+      return False
+    return True
+
 if __name__ == "__main__":
   satellite = Satellite ()
   # print satellite.longitude, satellite.latitude
-- 
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