163 lines
8.0 KiB
Python
163 lines
8.0 KiB
Python
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import struct
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import datetime
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import random
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import bitarray
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import pyproj
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class pkt_base:
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def __init__(self, pkt_type=0, pkt_len=0):
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self.pkt_header = b'####'
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self.pkt_type = struct.pack('!I', pkt_type)
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self.pkt_len = struct.pack('!I', pkt_len)
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self.pkt_payload = b''
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def get_packet(self):
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return self.pkt_header + self.pkt_type + self.pkt_len + self.pkt_payload
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class pkt_gps(pkt_base):
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def __init__(self, longitude, latitude, altitude, speed, heading):
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super().__init__(pkt_type=7)
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self.gpstime = int(datetime.datetime.now().timestamp() - 315964782) # Timestamp in seconds since 1980.1.6
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self.lon = int(longitude*10000000) # Longitude in degrees * 10^7
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self.lat = int(latitude*10000000) # Latitude in degrees * 10^7
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self.alt = int(altitude) # Altitude in millimeters
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self.sates_used = random.randint(2, 6) # Number of satellites used
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self.sates_gps = random.randint(2, 6) # Number of satellites GPS in view
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self.sates_bd = random.randint(2, 6) # Number of satellites BD in view
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self.gps_status = random.randint(0, 4) # gps status: 0=No fix, 1=2D fix, 2=3D fix, 3=DGPS, 4=RTK float, 5=RTK fixed
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self.mode = random.randint(1, 3) # mode: 1=none, 2=2D, 3=3D
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self.hdop = random.randint(100, 100000) # HDOP (Horizontal Dilution of Precision) in 0.1m
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self.speed = int(speed*100) # Speed in 0.01 knot
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self.heading = int(heading) # Heading in degrees
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def _fill_payload(self):
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self.pkt_payload = struct.pack('!QIIIHHHBBIII',
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self.gpstime,
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self.lon,
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self.lat,
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self.alt,
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self.sates_used,
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self.sates_gps,
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self.sates_bd,
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self.gps_status,
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self.mode,
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self.hdop,
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self.speed,
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self.heading)
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def get_packet(self):
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self._fill_payload()
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self.pkt_len = struct.pack('!I', len(self.pkt_payload))
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return super().get_packet()
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class pkt_demod(pkt_base):
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def __init__(self):
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super().__init__(pkt_type=12)
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self.msg_type = 12 # 消息类型
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self.sat_id = random.randint(0, 255) # 卫星ID
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self.demod_id = 0 # 解调器编号
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self.time_slot = random.randint(10, 2249) # 解调时隙
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self.recv_delay = random.randint(0, 65535) # 接收延迟
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self.snr = random.randint(-128, 127) # 信噪比
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def _fill_payload(self):
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self.pkt_payload = b''
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self.pkt_payload = struct.pack('!BBBHHh',
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self.msg_type,
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self.sat_id,
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self.demod_id,
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self.time_slot,
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self.recv_delay,
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self.snr)
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class pkt_ais(pkt_demod):
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def __init__(self):
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super().__init__()
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self.demod_id = random.randint(4, 5)
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class pkt_ais_msg_1(pkt_ais):
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def __init__(self, mmsi, sog, lon, lat, heading):
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super().__init__()
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self.msg_id = 1 # message ID
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self.repeat_indicator = random.randint(0, 3) # Repeat indicator
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self.mmsi = mmsi # Maritime Mobile Service Identity
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self.nav_status = 0 # Navigation status
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self.rot = 0 # Rate of turn
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self.sog = int(sog * 10) # Speed over ground in 0.1 knot
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self.pos_acc = random.randint(0, 1) # Position accuracy
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self.lon = int(lon * 600000) # Longitude in 1/10000 min
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self.lat = int(lat * 600000) # Latitude in 1/10000 min
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self.cog = int(heading * 10) # Course over ground in 0.1 degree
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self.heading = int(heading) # Heading in degrees
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self.time_stamp = 0 # Time stamp
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self.manoeuvre_indicator = random.randint(0, 3) # Manuever indicator
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self.spare = 0 # Spare bits
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self.raim_flag = random.randint(0, 1) # RAIM flag
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self.comm_state = random.randint(0, 3) # Communication state
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def _fill_payload(self):
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super()._fill_payload()
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demod_data = bitarray.bitarray()
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demod_data += bitarray.bitarray(f"{self.msg_id:06b}") # Demodulation flag
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demod_data += bitarray.bitarray(f"{self.repeat_indicator:02b}") # Repeat indicator
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demod_data += bitarray.bitarray(f"{self.mmsi:030b}") # Maritime Mobile Service Identity
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demod_data += bitarray.bitarray(f"{self.nav_status:04b}") # Navigation status
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demod_data += bitarray.bitarray(f"{self.rot:08b}") # Rate of turn
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demod_data += bitarray.bitarray(f"{self.sog:010b}") # Speed over ground in 0.1 knot
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demod_data += bitarray.bitarray(f"{self.pos_acc:01b}") # Position accuracy
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demod_data += bitarray.bitarray(f"{self.lon:028b}") # Longitude in 1/10000 min
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demod_data += bitarray.bitarray(f"{self.lat:027b}") # Latitude in 1/10000 min
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demod_data += bitarray.bitarray(f"{self.cog:012b}") # Course over ground in 0.1 degree
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demod_data += bitarray.bitarray(f"{self.heading:09b}") # Heading in degrees
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demod_data += bitarray.bitarray(f"{self.time_stamp:06b}") # Time stamp
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demod_data += bitarray.bitarray(f"{self.manoeuvre_indicator:02b}") # Manoeuvre indicator
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demod_data += bitarray.bitarray(f"{self.spare:03b}") # Spare bits
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demod_data += bitarray.bitarray(f"{self.raim_flag:01b}") # RAIM flag
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demod_data += bitarray.bitarray(f"{self.comm_state:019b}") # Communication state
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if len(demod_data) != 168:
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raise ValueError("ais_msg_1 length is not 168 bits", len(demod_data))
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self.pkt_payload += demod_data.tobytes()
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self.pkt_len = struct.pack('!I', len(self.pkt_payload))
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def get_packet(self, distance=0):
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if distance > 0:
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# Use WGS84 ellipsoid.
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g = pyproj.Geod(ellps='WGS84')
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# Forward transformation - returns longitude, latitude, back azimuth of terminus points
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lon_new, lat_new, _ = g.fwd(self.lon / 600000, self.lat / 600000, self.cog, distance)
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self.lon = int(lon_new * 600000)
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self.lat = int(lat_new * 600000)
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self._fill_payload()
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return super().get_packet()
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class pkt_ais_msg_2(pkt_ais_msg_1):
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def __init__(self, mmsi, sog, lon, lat, heading):
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super().__init__(mmsi, sog, lon, lat, heading)
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self.msg_id = 2 # message ID
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class pkt_ais_msg_3(pkt_ais_msg_1):
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def __init__(self, mmsi, sog, lon, lat, heading):
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super().__init__(mmsi, sog, lon, lat, heading)
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self.msg_id = 3 # message ID
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class pkt_vdes(pkt_base):
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def __init__(self):
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self.pkt_payload = b''
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def _fill_payload(self):
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# This method should be overridden in subclasses to fill the payload
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raise NotImplementedError("Subclasses should implement this method")
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def get_packet(self):
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self._fill_payload()
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self.pkt_len = struct.pack('!I', len(self.pkt_payload))
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return super().get_packet()
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