184 lines
3.7 KiB
Python
184 lines
3.7 KiB
Python
# ------------------------------------------
|
|
# BDS 6,0
|
|
# Heading and speed report
|
|
# ------------------------------------------
|
|
|
|
from pyModeS import common
|
|
from pyModeS.extra import aero
|
|
|
|
|
|
def is60(msg):
|
|
"""Check if a message is likely to be BDS code 6,0
|
|
|
|
Args:
|
|
msg (str): 28 hexdigits string
|
|
|
|
Returns:
|
|
bool: True or False
|
|
"""
|
|
|
|
if common.allzeros(msg):
|
|
return False
|
|
|
|
d = common.hex2bin(common.data(msg))
|
|
|
|
# status bit 1, 13, 24, 35, 46
|
|
|
|
if common.wrongstatus(d, 1, 2, 12):
|
|
return False
|
|
|
|
if common.wrongstatus(d, 13, 14, 23):
|
|
return False
|
|
|
|
if common.wrongstatus(d, 24, 25, 34):
|
|
return False
|
|
|
|
if common.wrongstatus(d, 35, 36, 45):
|
|
return False
|
|
|
|
if common.wrongstatus(d, 46, 47, 56):
|
|
return False
|
|
|
|
ias = ias60(msg)
|
|
if ias is not None and ias > 500:
|
|
return False
|
|
|
|
mach = mach60(msg)
|
|
if mach is not None and mach > 1:
|
|
return False
|
|
|
|
vr_baro = vr60baro(msg)
|
|
if vr_baro is not None and abs(vr_baro) > 6000:
|
|
return False
|
|
|
|
vr_ins = vr60ins(msg)
|
|
if vr_ins is not None and abs(vr_ins) > 6000:
|
|
return False
|
|
|
|
# additional check knowing altitude
|
|
if (mach is not None) and (ias is not None) and (common.df(msg) == 20):
|
|
alt = common.altcode(msg)
|
|
if alt is not None:
|
|
ias_ = aero.mach2cas(mach, alt * aero.ft) / aero.kts
|
|
if abs(ias - ias_) > 20:
|
|
return False
|
|
|
|
return True
|
|
|
|
|
|
def hdg60(msg):
|
|
"""Megnetic heading of aircraft
|
|
|
|
Args:
|
|
msg (str): 28 hexdigits string
|
|
|
|
Returns:
|
|
float: heading in degrees to megnetic north (from 0 to 360)
|
|
"""
|
|
d = common.hex2bin(common.data(msg))
|
|
|
|
if d[0] == "0":
|
|
return None
|
|
|
|
sign = int(d[1]) # 1 -> west
|
|
value = common.bin2int(d[2:12])
|
|
|
|
if sign:
|
|
value = value - 1024
|
|
|
|
hdg = value * 90 / 512 # degree
|
|
|
|
# convert from [-180, 180] to [0, 360]
|
|
if hdg < 0:
|
|
hdg = 360 + hdg
|
|
|
|
return round(hdg, 3)
|
|
|
|
|
|
def ias60(msg):
|
|
"""Indicated airspeed
|
|
|
|
Args:
|
|
msg (str): 28 hexdigits string
|
|
|
|
Returns:
|
|
int: indicated airspeed in knots
|
|
"""
|
|
d = common.hex2bin(common.data(msg))
|
|
|
|
if d[12] == "0":
|
|
return None
|
|
|
|
ias = common.bin2int(d[13:23]) # kts
|
|
return ias
|
|
|
|
|
|
def mach60(msg):
|
|
"""Aircraft MACH number
|
|
|
|
Args:
|
|
msg (str): 28 hexdigits string
|
|
|
|
Returns:
|
|
float: MACH number
|
|
"""
|
|
d = common.hex2bin(common.data(msg))
|
|
|
|
if d[23] == "0":
|
|
return None
|
|
|
|
mach = common.bin2int(d[24:34]) * 2.048 / 512.0
|
|
return round(mach, 3)
|
|
|
|
|
|
def vr60baro(msg):
|
|
"""Vertical rate from barometric measurement, this value may be very noisy.
|
|
|
|
Args:
|
|
msg (str): 28 hexdigits string
|
|
|
|
Returns:
|
|
int: vertical rate in feet/minutes
|
|
"""
|
|
d = common.hex2bin(common.data(msg))
|
|
|
|
if d[34] == "0":
|
|
return None
|
|
|
|
sign = int(d[35]) # 1 -> negative value, two's complement
|
|
value = common.bin2int(d[36:45])
|
|
|
|
if value == 0 or value == 511: # all zeros or all ones
|
|
return 0
|
|
|
|
value = value - 512 if sign else value
|
|
|
|
roc = value * 32 # feet/min
|
|
return roc
|
|
|
|
|
|
def vr60ins(msg):
|
|
"""Vertical rate measured by onboard equipment (IRS, AHRS)
|
|
|
|
Args:
|
|
msg (str): 28 hexdigits string
|
|
|
|
Returns:
|
|
int: vertical rate in feet/minutes
|
|
"""
|
|
d = common.hex2bin(common.data(msg))
|
|
|
|
if d[45] == "0":
|
|
return None
|
|
|
|
sign = int(d[46]) # 1 -> negative value, two's complement
|
|
value = common.bin2int(d[47:56])
|
|
|
|
if value == 0 or value == 511: # all zeros or all ones
|
|
return 0
|
|
|
|
value = value - 512 if sign else value
|
|
|
|
roc = value * 32 # feet/min
|
|
return roc
|