def position(msg0, msg1, t0, t1, lat_ref=None, lon_ref=None):
"""Decode position from a pair of even and odd position message
(works with both airborne and surface position messages)
Args:
msg0 (string): even message (28 bytes hexadecimal string)
msg1 (string): odd message (28 bytes hexadecimal string)
t0 (int): timestamps for the even message
t1 (int): timestamps for the odd message
Returns:
(float, float): (latitude, longitude) of the aircraft
"""
tc0 = typecode(msg0)
tc1 = typecode(msg1)
if 5 <= tc0 <= 8 and 5 <= tc1 <= 8:
if (not lat_ref) or (not lon_ref):
raise RuntimeError("Surface position encountered, a reference \
position lat/lon required. Location of \
receiver can be used.")
else:
return surface_position(msg0, msg1, t0, t1, lat_ref, lon_ref)
elif 9 <= tc0 <= 18 and 9 <= tc1 <= 18:
# Airborne position with barometric height
return airborne_position(msg0, msg1, t0, t1)
elif 20 <= tc0 <= 22 and 20 <= tc1 <= 22:
# Airborne position with GNSS height
return airborne_position(msg0, msg1, t0, t1)
else:
raise RuntimeError("incorrect or inconsistant message types")
def position(msg0, msg1, t0, t1, lat_ref=None, lon_ref=None):
"""Decode surface or airborne position from a pair of even and odd
position messages.
Note, that to decode surface position using the position message pair,
the reference position has to be provided.
Args:
msg0 (string): even message (28 hexdigits)
msg1 (string): odd message (28 hexdigits)
t0 (int): timestamps for the even message
t1 (int): timestamps for the odd message
lat_ref (float): latitude of reference position
lon_ref (float): longitude of reference position
Returns:
(float, float): (latitude, longitude) of the aircraft
"""
tc0 = typecode(msg0)
tc1 = typecode(msg1)
if 5 <= tc0 <= 8 and 5 <= tc1 <= 8:
if lat_ref is None or lon_ref is None:
raise RuntimeError(
"Surface position encountered, a reference position"
" lat/lon required. Location of receiver can be used."
)
else:
return surface_position(msg0, msg1, t0, t1, lat_ref, lon_ref)
elif 9 <= tc0 <= 18 and 9 <= tc1 <= 18:
# Airborne position with barometric height
return airborne_position(msg0, msg1, t0, t1)
elif 20 <= tc0 <= 22 and 20 <= tc1 <= 22:
# Airborne position with GNSS height
return airborne_position(msg0, msg1, t0, t1)
else:
raise RuntimeError("Incorrect or inconsistent message types")
