from datetime import datetime, timedelta
# Root URL from which data files are retrieved
source = "http://celestrak.com/NORAD/elements/"
# Yeah, I know what TLE stands for :-) Still, entries are comprised of three lines, one being occupied by the sat.name
linecount = 3
def parseDT(buffer):
yearPos, yearLen = 18, 2
floatDayPos, floatDayLen = 20, 13
secondsInDay = 24*60*60
buff = buffer.split("\n")
if len(buff) < linecount:
logging.error("TLE file too short.\n" + buffer)
return None
if len(buff[1]) < floatDayPos + floatDayLen:
logging.error("Corrupted datetime entry.\n" + buffer)
return None
try:
year = buff[1][yearPos : yearPos + yearLen]
dt = datetime.strptime(year, "%y")
except ValueError:
logging.error("Cannot extract year value from %s" % year)
return None
day = buff[1][floatDayPos : floatDayPos + floatDayLen]
if len(day.split(".")) != 2:
logging.error("Cannot extract day value from %s" % day)
return None
try:
dayOfYear, partOfDay = day.split(".")
dayOfYear = int(dayOfYear)
partOfDay = float("0." + partOfDay)
except ValueError:
logging.error("Cannot parse day value: %s is not a float" % day)
return None
dt += timedelta(days = dayOfYear - 1) + timedelta(seconds = int(secondsInDay * partOfDay))
return dt
def parseTLE(tleLines):
name = tleLines[0].strip()
noradid = int(tleLines[2].split()[1])
body = "\n".join([tleLines[0].strip(), tleLines[1], tleLines[2]]) + "\n"
timestamp = parseDT(body)
return noradid, name, body, timestamp