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Bring current with 7 dec 15 vallado CPP version #35

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merged 4 commits into from
Dec 2, 2019
Merged

Bring current with 7 dec 15 vallado CPP version #35

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1f62192
Bring current with 7 dec 15 vallado CPP version
interplanetarychris Jul 29, 2019
fd53dad
Handle deprecated assertRaisesRegexp
interplanetarychris Oct 13, 2019
e64fef9
Use assertRaisesRegexp for Python 2.6/2.7
interplanetarychris Oct 13, 2019
db9686c
Fix initialization of averaged mean elements
interplanetarychris Oct 14, 2019
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31 changes: 15 additions & 16 deletions sgp4/io.py
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Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,7 @@
* typerun - type of run verification 'v', catalog 'c',
* manual 'm'
* typeinput - type of manual input mfe 'm', epoch 'e', dayofyr 'd'
* afspc_mode - True for afspc calculations, False for 'improved' mode
* opsmode - mode of operation afspc or improved 'a', 'i'
* whichconst - which set of constants to use 72, 84
*
* outputs :
Expand All @@ -99,7 +99,7 @@
--------------------------------------------------------------------------- */
"""

def twoline2rv(longstr1, longstr2, whichconst, afspc_mode=False):
def twoline2rv(longstr1, longstr2, whichconst, opsmode='i'):
"""Return a Satellite imported from two lines of TLE data.

Provide the two TLE lines as strings `longstr1` and `longstr2`,
Expand All @@ -112,7 +112,7 @@ def twoline2rv(longstr1, longstr2, whichconst, afspc_mode=False):

Normally, computations are made using various recent improvements
to the algorithm. If you want to turn some of these off and go
back into "afspc" mode, then set `afspc_mode` to `True`.
back into "opsmode" mode, then set `opsmode` to `a`.

"""

Expand All @@ -139,17 +139,18 @@ def twoline2rv(longstr1, longstr2, whichconst, afspc_mode=False):
line[63] == ' '):

_saved_satnum = satrec.satnum = int(line[2:7])
# classification = line[7] or 'U'
# intldesg = line[9:17]
satrec.line1 = line
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Was this debugging code, or an idea for a new feature? Vallado's routines don't save the lines, and here in Python there may be a danger: will users do things like take a satellite, adjust a parameter, and expect .line1 to now reflect the new parameter? It might be safer to not cache this data since the source library does not.

satrec.classification = line[7] or 'U'
satrec.intldesg = line[9:17]
two_digit_year = int(line[18:20])
satrec.epochdays = float(line[20:32])
satrec.ndot = float(line[33:43])
satrec.nddot = float(line[44] + '.' + line[45:50])
nexp = int(line[50:52])
satrec.bstar = float(line[53] + '.' + line[54:59])
ibexp = int(line[59:61])
# numb = int(line[62])
# elnum = int(line[64:68])
satrec.ephtype = line[62]
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If I'm reading Vallado's code correctly, it takes satrec.ephtype and satrec.elnum from line2 instead of line1. Can we switch to do the same, for compatibility in case the lines disagree?

satrec.elnum = int(line[64:68])
else:
raise ValueError(error_message.format(1, LINE1, line))

Expand All @@ -171,24 +172,24 @@ def twoline2rv(longstr1, longstr2, whichconst, afspc_mode=False):
if _saved_satnum != satrec.satnum:
raise ValueError('Object numbers in lines 1 and 2 do not match')

satrec.line2 = line
satrec.inclo = float(line[8:16])
satrec.nodeo = float(line[17:25])
satrec.ecco = float('0.' + line[26:33].replace(' ', '0'))
satrec.argpo = float(line[34:42])
satrec.mo = float(line[43:51])
satrec.no = float(line[52:63])
#revnum = line[63:68]
satrec.no_kozai = float(line[52:63])
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Well, drat. This creates an incompatible change that will crash Python programs that looked at the .no attribute previously. After merging this, I might add a .no property that returns this value, to prevent breakage. But I agree that we should follow Vallado, as a higher priority.

satrec.revnum = line[63:68]
#except (AssertionError, IndexError, ValueError):
else:
raise ValueError(error_message.format(2, LINE2, line))

# ---- find no, ndot, nddot ----
satrec.no = satrec.no / xpdotp; # rad/min
satrec.no_kozai = satrec.no_kozai / xpdotp; # rad/min
satrec.nddot= satrec.nddot * pow(10.0, nexp);
satrec.bstar= satrec.bstar * pow(10.0, ibexp);

# ---- convert to sgp4 units ----
satrec.a = pow( satrec.no*tumin , (-2.0/3.0) );
satrec.ndot = satrec.ndot / (xpdotp*1440.0); # ? * minperday
satrec.nddot= satrec.nddot / (xpdotp*1440.0*1440);

Expand All @@ -198,8 +199,6 @@ def twoline2rv(longstr1, longstr2, whichconst, afspc_mode=False):
satrec.argpo = satrec.argpo * deg2rad;
satrec.mo = satrec.mo * deg2rad;

satrec.alta = satrec.a*(1.0 + satrec.ecco) - 1.0;
satrec.altp = satrec.a*(1.0 - satrec.ecco) - 1.0;

"""
// ----------------------------------------------------------------
Expand All @@ -225,9 +224,9 @@ def twoline2rv(longstr1, longstr2, whichconst, afspc_mode=False):
int(sec_fraction * 1000000.0 // 1.0))

# ---------------- initialize the orbit at sgp4epoch -------------------
sgp4init(whichconst, afspc_mode, satrec.satnum, satrec.jdsatepoch-2433281.5, satrec.bstar,
satrec.ecco, satrec.argpo, satrec.inclo, satrec.mo, satrec.no,
satrec.nodeo, satrec)
sgp4init(whichconst, opsmode, satrec.satnum, satrec.jdsatepoch-2433281.5, satrec.bstar,
satrec.ndot, satrec.nddot, satrec.ecco, satrec.argpo, satrec.inclo, satrec.mo,
satrec.no_kozai, satrec.nodeo, satrec)

return satrec

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