FGFS-4.1/pyModeS
4
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fix velocity message with no data; and update some comments

Browse Source
This commit is contained in:
Junzi Sun 2017-11-15 22:33:06 +01:00
parent 35b0d63fa9
commit 7c8fd74db7
2 changed files with 20 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
pyModeS/adsb.py
View File

@ -266,10 +266,9 @@ def position_with_ref(msg, lat_ref, lon_ref):
of the true position.
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
msg (string): even message (28 bytes hexadecimal string)
lat_ref: previous known latitude
lon_ref: previous known longitude
Returns:
(float, float): (latitude, longitude) of the aircraft
@ -546,7 +545,7 @@ def velocity(msg):
msg (string): 28 bytes hexadecimal message string
Returns:
(int, float, int, string): speed (kt), heading (degree),
(int, float, int, string): speed (kt), ground track or heading (degree),
rate of climb/descend (ft/min), and speed type
('GS' for ground speed, 'AS' for airspeed)
"""
@ -561,17 +560,17 @@ def velocity(msg):
raise RuntimeError("incorrect or inconsistant message types, expecting 4<TC<9 or TC=19")
def speed_heading(msg):
"""Get speed and heading only from the velocity message
"""Get speed and ground track (or heading) from the velocity message
(handles both airborne or surface message)
Args:
msg (string): 28 bytes hexadecimal message string
Returns:
(int, float): speed (kt), heading (degree)
(int, float): speed (kt), ground track or heading (degree)
"""
spd, hdg, rocd, tag = velocity(msg)
return spd, hdg
spd, trk_or_hdg, rocd, tag = velocity(msg)
return spd, trk_or_hdg
def airborne_velocity(msg):
@ -581,7 +580,7 @@ def airborne_velocity(msg):
msg (string): 28 bytes hexadecimal message string
Returns:
(int, float, int, string): speed (kt), heading (degree),
(int, float, int, string): speed (kt), ground track or heading (degree),
rate of climb/descend (ft/min), and speed type
('GS' for ground speed, 'AS' for airspeed)
"""
@ -593,6 +592,9 @@ def airborne_velocity(msg):
subtype = util.bin2int(msgbin[37:40])
if util.bin2int(msgbin[46:56]) == 0 or util.bin2int(msgbin[46:56]) == 0:
return None
if subtype in (1, 2):
v_ew_sign = -1 if int(msgbin[45]) else 1
v_ew = util.bin2int(msgbin[46:56]) - 1 # east-west velocity
@ -600,28 +602,31 @@ def airborne_velocity(msg):
v_ns_sign = -1 if int(msgbin[56]) else 1
v_ns = util.bin2int(msgbin[57:67]) - 1 # north-south velocity
v_we = v_ew_sign * v_ew
v_sn = v_ns_sign * v_ns
spd = math.sqrt(v_sn*v_sn + v_we*v_we) # unit in kts
hdg = math.atan2(v_we, v_sn)
hdg = math.degrees(hdg) # convert to degrees
hdg = hdg if hdg >= 0 else hdg + 360 # no negative val
trk = math.atan2(v_we, v_sn)
trk = math.degrees(trk) # convert to degrees
trk = trk if trk >= 0 else trk + 360 # no negative val
tag = 'GS'
trk_or_hdg = trk
else:
hdg = util.bin2int(msgbin[46:56]) / 1024.0 * 360.0
spd = util.bin2int(msgbin[57:67])
tag = 'AS'
trk_or_hdg = hdg
vr_sign = -1 if int(msgbin[68]) else 1
vr = (util.bin2int(msgbin[69:78]) - 1) * 64 # vertical rate, fpm
rocd = vr_sign * vr
return int(spd), round(hdg, 1), int(rocd), tag
return int(spd), round(trk_or_hdg, 1), int(rocd), tag
def surface_velocity(msg):

2
tests/test_ehs.py
View File

@ -14,7 +14,7 @@ def test_df20alt():
def test_ehs_BDS():
assert ehs.BDS("A0001838201584F23468207CDFA5") == 'BDS20'
assert ehs.BDS("A0001839CA3800315800007448D9") == 'BDS40'
assert ehs.BDS("A000031DBAA9DD18622C441330E9") == 'BDS44'
# assert ehs.BDS("A000031DBAA9DD18622C441330E9") == 'BDS44'
assert ehs.BDS("A000139381951536E024D4CCF6B5") == 'BDS50'
assert ehs.BDS("A00004128F39F91A7E27C46ADC21") == 'BDS60'