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Improve doc for surface position decoding

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wrobell 2020-03-11 21:08:04 +00:00 committed by GitHub
parent ed18352c0c
commit db57d7419f
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1 changed files with 11 additions and 7 deletions
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18
pyModeS/decoder/adsb.py
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@ -49,14 +49,19 @@ def typecode(msg):
def position(msg0, msg1, t0, t1, lat_ref=None, lon_ref=None): def position(msg0, msg1, t0, t1, lat_ref=None, lon_ref=None):
"""Decode position from a pair of even and odd position message """Decode surface or airborne position from a pair of even and odd
(works with both airborne and surface position messages) position messages.
Note, that to decode surface position using the position message pair,
the reference position has to be provided.
Args: Args:
msg0 (string): even message (28 bytes hexadecimal string) msg0 (string): even message (28 bytes hexadecimal string)
msg1 (string): odd message (28 bytes hexadecimal string) msg1 (string): odd message (28 bytes hexadecimal string)
t0 (int): timestamps for the even message t0 (int): timestamps for the even message
t1 (int): timestamps for the odd message t1 (int): timestamps for the odd message
lat_ref (float): latitude of reference position
lon_ref (float): longitude of reference position
Returns: Returns:
(float, float): (latitude, longitude) of the aircraft (float, float): (latitude, longitude) of the aircraft
@ -65,11 +70,10 @@ def position(msg0, msg1, t0, t1, lat_ref=None, lon_ref=None):
tc1 = typecode(msg1) tc1 = typecode(msg1)
if 5 <= tc0 <= 8 and 5 <= tc1 <= 8: if 5 <= tc0 <= 8 and 5 <= tc1 <= 8:
if (not lat_ref) or (not lon_ref): if lat_ref is None or lon_ref is None:
raise RuntimeError( raise RuntimeError(
"Surface position encountered, a reference \ "Surface position encountered, a reference position"
position lat/lon required. Location of \ " lat/lon required. Location of receiver can be used."
receiver can be used."
) )
else: else:
return surface_position(msg0, msg1, t0, t1, lat_ref, lon_ref) return surface_position(msg0, msg1, t0, t1, lat_ref, lon_ref)
@ -83,7 +87,7 @@ def position(msg0, msg1, t0, t1, lat_ref=None, lon_ref=None):
return airborne_position(msg0, msg1, t0, t1) return airborne_position(msg0, msg1, t0, t1)
else: else:
raise RuntimeError("incorrect or inconsistent message types") raise RuntimeError("Incorrect or inconsistent message types")
def position_with_ref(msg, lat_ref, lon_ref): def position_with_ref(msg, lat_ref, lon_ref):