07 树莓派5 GPS数据解析
硬件连接与配置
1. 物理连接
GPS模块 树莓派5 =================== VCC -> 5V (Pin 1) GND -> GND (Pin 6) RX -> TX (GPIO14, Pin 8) TX -> RX (GPIO15, Pin 10)
2.安装解析 NMEA 格式 GPS 数据的常用库
pip install pynmea2
Python GPS数据解析程序
一定要注意自己的GPS模块的串口波特率，一般是9600，但是我的这个正点原子家的gps串口波特率是38400。
import serial
import pynmea2
import time
import json
import socket
import math
from datetime import datetime, timezone
class GPSParser:
def __init__(self, port='/dev/ttyAMA0', baudrate=38400):
self.port = port
self.baudrate = baudrate
self.serial_conn = None
self.udp_socket = None
self.udp_target = ('127.0.0.1', 5000)
self.last_position = None
self.data = {
'timestamp': None,
'latitude': None,
'longitude': None,
'altitude': None,
'speed': None, # 单位：米/秒
'course': None, # 航向（度）
'satellites': None, # 使用卫星数量
'hdop': None, # 水平精度因子（float）
'fix_quality': None, # 定位质量
'pdop': None, # 位置精度因子
'vdop': None, # 垂直精度因子
'distance': 0.0, # 累计距离（米）
'total_distance': 0.0 # 总距离（米）
}
def connect_serial(self):
"""连接串口设备"""
try:
self.serial_conn = serial.Serial(
port=self.port,
baudrate=self.baudrate,
parity=serial.PARITY_NONE,
stopbits=serial.STOPBITS_ONE,
bytesize=serial.EIGHTBITS,
timeout=1.0
)
print(f"成功连接到 {self.port} @ {self.baudrate} bps")
return True
except serial.SerialException as e:
print(f"串口连接失败: {e}")
return False
def connect_udp(self, ip='127.0.0.1', port=5000):
"""配置UDP连接"""
try:
self.udp_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self.udp_target = (ip, port)
print(f"UDP目标: {ip}:{port}")
return True
except socket.error as e:
print(f"UDP配置失败: {e}")
return False
def parse_nmea(self, nmea_string):
"""解析NMEA语句"""
try:
msg = pynmea2.parse(nmea_string)
if isinstance(msg, pynmea2.GGA): # 全球定位系统定位数据
self.data['timestamp'] = datetime.combine(
datetime.utcnow().date(),
msg.timestamp
).replace(tzinfo=timezone.utc).isoformat()
self.data['latitude'] = msg.latitude
self.data['longitude'] = msg.longitude
self.data['altitude'] = msg.altitude
self.data['satellites'] = msg.num_sats
self.data['hdop'] = float(msg.horizontal_dil) if msg.horizontal_dil else None # 确保是float
self.data['fix_quality'] = msg.gps_qual
return 'GGA'
elif isinstance(msg, pynmea2.RMC): # 推荐最小定位信息
if msg.status == 'A': # 有效定位
self.data['speed'] = msg.spd_over_grnd * 0.51444 # 节转米/秒
self.data['course'] = msg.true_course
self._calculate_distance()
return 'RMC'
return None
elif isinstance(msg, pynmea2.GSA): # 当前卫星信息
self.data['pdop'] = float(msg.pdop) if msg.pdop else None
self.data['hdop'] = float(msg.hdop) if msg.hdop else None
self.data['vdop'] = float(msg.vdop) if msg.vdop else None
return 'GSA'
elif isinstance(msg, pynmea2.GSV): # 可见卫星信息
return 'GSV'
except pynmea2.ParseError:
return None
except Exception as e:
print(f"解析错误: {e}")
return None
def _calculate_distance(self):
"""计算距离（使用Haversine公式）"""
if None in (self.data['latitude'], self.data['longitude']):
return
if self.last_position is None:
self.last_position = (self.data['latitude'], self.data['longitude'])
return
lat1, lon1 = self.last_position
lat2, lon2 = self.data['latitude'], self.data['longitude']
# 将角度转换为弧度
lat1_rad = math.radians(lat1)
lon1_rad = math.radians(lon1)
lat2_rad = math.radians(lat2)
lon2_rad = math.radians(lon2)
# 地球半径（米）
R = 6371000
# 计算差值
dlat = lat2_rad - lat1_rad
dlon = lon2_rad - lon1_rad
# Haversine公式
a = math.sin(dlat/2)**2 + math.cos(lat1_rad) * math.cos(lat2_rad) * math.sin(dlon/2)**2
c = 2 * math.atan2(math.sqrt(a), math.sqrt(1-a))
distance = R * c
self.data['distance'] = distance
self.data['total_distance'] += distance
self.last_position = (lat2, lon2)
def send_data(self):
"""通过UDP发送JSON格式数据"""
if not self.udp_socket:
return False
try:
json_data = json.dumps(self.data, ensure_ascii=False)
self.udp_socket.sendto(json_data.encode('utf-8'), self.udp_target)
return True
except Exception as e:
print(f"UDP发送失败: {e}")
return False
def get_status(self):
"""获取GPS状态信息"""
status = {
'connected': self.serial_conn is not None and self.serial_conn.is_open,
'valid_fix': self.data['fix_quality'] is not None and self.data['fix_quality'] > 0,
'satellites': self.data['satellites'],
'hdop': self.data['hdop'],
'position_accuracy': "未知"
}
if isinstance(status['hdop'], (int, float)):
# 根据HDOP估算精度
if status['hdop'] <= 1:
status['position_accuracy'] = "极佳 (<2.5m)"
elif status['hdop'] <= 2:
status['position_accuracy'] = "良好 (2.5-5m)"
elif status['hdop'] <= 5:
status['position_accuracy'] = "一般 (5-10m)"
else:
status['position_accuracy'] = "较差 (>10m)"
return status
def run(self, udp_ip='127.0.0.1', udp_port=5000, output_interval=1.0):
"""主运行循环"""
if not self.connect_serial():
return False
if not self.connect_udp(udp_ip, udp_port):
return False
print("开始接收GPS数据...")
print("按Ctrl+C退出")
last_output = time.time()
last_status = time.time()
try:
while True:
# 读取串口数据
try:
raw_data = self.serial_conn.readline().decode('utf-8', errors='ignore').strip()
except serial.SerialException as e:
print(f"串口读取错误: {e}")
time.sleep(1)
continue
# 解析NMEA语句
if raw_data.startswith('$'):
sentence_type = self.parse_nmea(raw_data)
# 每秒输出一次状态
current_time = time.time()
if current_time - last_status >= 1.0:
status = self.get_status()
if status['valid_fix']:
fix_status = (
f"定位有效 | 卫星: {status['satellites']} | "
f"HDOP: {status['hdop']:.1f} | "
f"精度: {status['position_accuracy']}"
)
else:
fix_status = "等待定位..."
print(f"\r状态: {fix_status}", end='', flush=True)
last_status = current_time
# 定时发送数据
current_time = time.time()
if current_time - last_output >= output_interval:
if self.send_data():
last_output = current_time
except KeyboardInterrupt:
print("\n程序已终止")
finally:
if self.serial_conn and self.serial_conn.is_open:
self.serial_conn.close()
if self.udp_socket:
self.udp_socket.close()
def main():
# 创建GPS解析器
gps = GPSParser()
# 配置参数
udp_ip = '127.0.0.1' # 目标IP地址
udp_port = 5000 # 目标端口
output_interval = 0.5 # 数据发送间隔(秒)
# 启动主循环
gps.run(udp_ip, udp_port, output_interval)
if __name__ == "__main__":
main()成果验证
#端口监听 nc -ul 5000
由于在室内收不到星,无法解析出经纬度，但是可以看到时间已经解析出来了。
将gps移到窗户旁，成功搜到星。
可以看到已经成功解析出经纬度。
STM32
MCU
通讯及无线技术
物联网技术
电子DIY
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