125 lines
4.6 KiB
Python
125 lines
4.6 KiB
Python
import struct
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def create_tcp_packet(packet_type, content):
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"""创建符合VDES TCP协议的报文"""
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# 报文帧头 (4字节)
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header = b'####'
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# 报文类型 (4字节，大端)
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type_field = struct.pack('>I', packet_type)
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# 报文长度 (4字节，大端，内容长度)
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length = len(content)
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length_field = struct.pack('>I', length)
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# 构建完整报文
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packet = header + type_field + length_field + content
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return packet
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def create_gps_packet():
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"""创建GPS解析数据报文(类型7)的内容"""
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# 模拟GPS数据 (表11定义)
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utc_time = 1680000000 # UTC时间 (8字节)
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longitude = 1205000000 # 经度 (4字节，东经120.5度)
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latitude = 305000000 # 纬度 (4字节，北纬30.5度)
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altitude = 50 # 海拔高度 (4字节，50米)
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used_sats = 10 # 定位使用的卫星数 (2字节)
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gps_sats = 8 # GPS卫星数 (2字节)
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beidou_sats = 7 # 北斗卫星数 (2字节)
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gps_status = 1 # GPS状态 (1字节，单点定位)
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position_mode = 3 # 定位模式 (1字节，3D定位)
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hdop = 2550 # 水平精度因子 (4字节，25.5米)
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speed = 1024 # 运动速度 (4字节，10.24节)
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direction = 359 # 运动方向 (4字节，359度)
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# 打包为二进制 (大端字节序)
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content = struct.pack(
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'>QiiiHHHBBIII', # 格式: Q(8),i(4),i(4),i(4),H(2),H(2),H(2),B(1),B(1),I(4),I(4),I(4)
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utc_time,
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longitude,
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latitude,
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altitude,
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used_sats,
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gps_sats,
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beidou_sats,
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gps_status,
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position_mode,
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hdop,
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speed,
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direction
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)
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return content
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def build_demod_message():
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"""创建AIS解调数据报文(类型8)的内容"""
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# 模拟AIS数据
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message_id = 1 # 消息ID (6 bits)
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repeat_indicator = 0 # 转发指示符 (2 bits)
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user_id = 123456789 # 用户ID/MMSI (30 bits)
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nav_status = 8 # 导航状态 (4 bits)
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rot = -128 # 旋转速率 (8 bits)
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sog = 102 # 地面航速 (10 bits)
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pos_acc = 1 # 位置准确度 (1 bit)
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longitude = 120500000 # 经度 (28 bits)
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latitude = 30500000 # 纬度 (27 bits)
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cog = 900 # 地面航线 (12 bits)
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true_heading = 90 # 实际航向 (9 bits)
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timestamp = 30 # 时戳 (6 bits)
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spare = 0 # 备用 (3 bits)
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raim = 0 # RAIM标志 (1 bit)
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comm_state = 0 # 通信状态 (19 bits)
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# 总比特数 168 (上面字段总和)
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# 打包为二进制 (大端字节序)
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content = struct.pack(
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'>Q', # 使用8字节无符号长整型打包所有位字段
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(message_id & 0x3F) << 58 |
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(repeat_indicator & 0x3) << 56 |
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(user_id & 0x3FFFFFFF) << 26 |
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(nav_status & 0xF) << 22 |
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(rot & 0xFF) << 14 |
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(sog & 0x3FF) << 4 |
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(pos_acc & 0x1) << 3 |
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((longitude >> 4) & 0xFFFFFFF) << 31 |
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(latitude & 0x7FFFFFF) << 4 |
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(cog & 0xFFF) << 19 |
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(true_heading & 0x1FF) << 10 |
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(timestamp & 0x3F) << 4 |
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(spare & 0x7) << 1 |
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(raim & 0x1)
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)
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return content
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ais_c = build_demod_message()
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print(len(ais_c)) # 应该输出21
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print(ais_c)
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# # 生成GPS报文
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# gps_content = create_gps_packet()
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# gps_packet = create_tcp_packet(7, gps_content)
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# # 打印二进制报文
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# print("完整报文字节长度:", len(gps_packet))
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# print("二进制表示:")
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# print(gps_packet)
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# print(' '.join(f'{b:02x}' for b in gps_packet))
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# # 打印字段解释
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# print("\n报文结构解析:")
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# print(f"帧头: {gps_packet[:4].decode('ascii')}")
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# print(f"报文类型: {struct.unpack('>I', gps_packet[4:8])[0]} (7=GPS解析数据)")
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# print(f"内容长度: {struct.unpack('>I', gps_packet[8:12])[0]} 字节")
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# # 解析内容部分
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# fields = struct.unpack('>QiiiHHHBBIII', gps_packet[12:])
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# print("\nGPS内容解析:")
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# print(f"UTC时间: {fields[0]} (自1980-01-06的秒数)")
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# print(f"经度: {fields[1]/10000000:.5f}° (东经)")
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# print(f"纬度: {fields[2]/10000000:.5f}° (北纬)")
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# print(f"海拔: {fields[3]} 米")
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# print(f"使用卫星: GPS={fields[5]}, 北斗={fields[6]}, 总计={fields[4]}")
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# print(f"定位状态: {fields[7]}(单点定位), 模式: {fields[8]}(3D)")
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# print(f"水平精度: {fields[9]/10:.1f} 米")
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# print(f"速度: {fields[10]/100:.2f} 节")
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# print(f"方向: {fields[11]}°") |