1 前言
本文简单介绍下如何从air551G提取经度纬度数据。
2 硬件连接
3 获取uart数据
- tag_uart = "test5_uart"
- id = 1
- len = 1024
- date_longitude = "" -- 经度
- date_latitude = "" -- 纬度
- date_GGA = ""
- function init_uart_air551()
- log.info(tag_uart,"init_uart_air551")
- uart.setup(1, 115200)
- -- func1: 接收数据,只要收到就接收
- uart.on(id, "receive",uart_air551_receive)
- end
- function uart_air551_receive()
- log.info("uart_air551_receive")
- local s = ""
- s = uart.read(id, len)
- if #s > 0 then -- #s 是取字符串的长度
- -- 如果传输二进制/十六进制数据, 部分字符不可见, 不代表没收到
- -- 关于收发hex值,请查阅 https://doc.openluat.com/article/583
- log.info("uart", "receive", id, #s, s) -- 这句将接收的都打印出来
- -- log.info("uart", "receive", id, #s, s:toHex())
- end
- end
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4 下发PGK命令
- tag_uart = "test5_uart"
- id = 1
- len = 1024
- date_longitude = "" -- 经度
- date_latitude = "" -- 纬度
- date_GGA = ""
- function init_uart_air551()
- log.info(tag_uart,"init_uart_air551")
- uart.setup(1, 115200)
- uart_air551_NMEA_set()
- end
- function uart_air551_NMEA_set()
- log.info("uart_air551_NMEA_set")
- uart.write(id, "$PGKC242,0,0,0,1*2Arn") --只接收GGA数据。注意需要传入回车符
- end
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5 提取经度纬度坐标
5.1 GGA数据结构
建议看下GGA的数据结构
5.2 从uart接收中提取一组
- function test_string_get()
- string_temp = "xxxxx$GNGGA,000004.811,XXX,N,XXX,E,0,0,,143.01,M,6.99,M,,*6Dr$GNGGA,000003.811,*6A"
- temp_start = string.find(string_temp,'$GNGGA',1)
- temp_end = string.find(string_temp,'r',1)
- temp_gga = string.sub(string_temp,temp_start,temp_end-1)
- log.info("temp_x:",temp_start,temp_end,temp_gga)
- end
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先执行该函数,了解一下string的两个函数find和sub。
https://www.runoob.com/lua/lua-strings.html
5.3 从一组数据中提取纬度和经度
完整代码如下
- tag_uart = "test5_uart"
- id = 1
- len = 1024
- get_gga_time = 10000
- date_longitude = "" -- 经度
- date_latitude = "" -- 纬度
- date_GGA = ""
- function init_uart_air551()
- log.info(tag_uart,"init_uart_air551")
- uart.setup(1, 115200)
- uart_air551_NMEA_set()
- -- 定时发送数据
- -- timex = sys.timerLoopStart(uart_air551_send,1000)
- -- log.info(tag_uart,"time:",timex)
- sys.wait(1000)
- -- func1: 接收数据,只要收到就接收
- -- uart.on(id, "receive",uart_air551_receive)
- -- func2: 定时接收
- timex = sys.timerLoopStart(uart_air551_receive,get_gga_time)
- log.info(tag_uart,"time:",timex)
- end
- function uart_air551_send()
- -- log.info("uart_air551_send")
- uart.write(id, "test")
- end
- -- 下发命令
- function uart_air551_NMEA_set()
- log.info("uart_air551_NMEA_set")
- uart.write(id, "$PGKC242,0,0,0,1*2Arn") --只接收GGA数据。注意需要传入回车符
- end
- -- 获取串口数据
- function uart_air551_receive()
- log.info("uart_air551_receive")
- local s = ""
- s = uart.read(id, len)
- if #s > 0 then -- #s 是取字符串的长度
- -- 如果传输二进制/十六进制数据, 部分字符不可见, 不代表没收到
- -- 关于收发hex值,请查阅 https://doc.openluat.com/article/583
- -- log.info("uart", "receive", id, #s, s) -- 这句将接收的都打印出来
- log.info("get air551","uart", "receive", id, #s)
- -- log.info("uart", "receive", id, #s, s:toHex())
- end
- --提取一组数据
- date_GGA = get_gga(s)
- log.info("date_GGA",date_GGA)
- --提取xy
- get_gga_longitude_latitude(date_GGA)
- end
- --测试数据提取
- function test_string_get()
- string_temp = "xxxxx$GNGGA,000004.811,XXX,N,XXX,E,0,0,,143.01,M,6.99,M,,*6Dr$GNGGA,000003.811,*6A"
- temp_start = string.find(string_temp,'$GNGGA',1)
- temp_end = string.find(string_temp,'r',1)
- temp_gga = string.sub(string_temp,temp_start,temp_end-1)
- log.info("temp_x:",temp_start,temp_end,temp_gga)
- end
- -- 提取一组数据
- function get_gga(value)
- temp_start = string.find(value,'$GNGGA',1)
- temp_end = string.find(value,'r',1)
- temp_gga = string.sub(value,temp_start,temp_end-1)
- -- log.info("temp_value:",temp_start,temp_end,temp_gga)
- return temp_gga
- end
- function get_gga_longitude_latitude(value_gga)
- -- log.info(type(value_gga))
- if value_gga == "" then --数据第一次异常
- return -1
- end
- L2_temp = string.sub(value_gga,8) -- +8是因为"$gngga"
- log.info("L2_temp",L2_temp)
- L2_temp_x_start = string.find(L2_temp,',',1)+1
- L2_temp_x_end = string.find(L2_temp,',N',1)-1
- date_longitude = string.sub(L2_temp,L2_temp_x_start,L2_temp_x_end)
- L2_temp_y_start = L2_temp_x_end+4
- L2_temp_y_end = string.find(L2_temp,',E',1)-1
- date_latitude = string.sub(L2_temp,L2_temp_y_start,L2_temp_y_end) -- +3是因为"time,xxx,N,yyy,E",",N"后面三个才是y开始
- log.info("L2_temp_gga",date_longitude,date_latitude)
- -- log.info("temp_value:",temp_start,temp_end,temp_gga)
- return temp_gga
- end
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5.4 结果
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