【Luat-air551G】4 air551G连接esp32获取GGA数据

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

连接方式如图。

3 获取uart数据

tag_uart = "test5_uart"id = 1
len = 1024date_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)
endfunction 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/583log.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

4 下发PGK命令

tag_uart = "test5_uart"id = 1
len = 1024date_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()
endfunction uart_air551_NMEA_set()log.info("uart_air551_NMEA_set")uart.write(id, "$PGKC242,0,0,0,1*2A\r\n")       --只接收GGA数据。注意需要传入回车符
end

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$GNGGA,000004.811,XXX,N,XXX,E,0,0,,143.01,M,6.99,M,,*6D\r$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

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 = 10000date_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)
endfunction 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, "$PGKC242,0,0,0,1*2A\r\n")       --只接收GGA数据。注意需要传入回车符
end-- 获取串口数据
function uart_air551_receive()log.info("uart_air551_receive")local s = ""s = uart.read(id, len)if #s > 0 then -- #s 是取字符串的长度-- 如果传输二进制/十六进制数据, 部分字符不可见, 不代表没收到-- 关于收发hex值,请查阅 https://doc.openluat.com/article/583-- log.info("uart", "receive", id, #s, s) -- 这句将接收的都打印出来log.info("get air551","uart", "receive", id, #s)-- log.info("uart", "receive", id, #s, s:toHex())end--提取一组数据date_GGA = get_gga(s)log.info("date_GGA",date_GGA)--提取xyget_gga_longitude_latitude(date_GGA)
end--测试数据提取
function test_string_get()string_temp = "xxxxx$GNGGA,000004.811,XXX,N,XXX,E,0,0,,143.01,M,6.99,M,,*6D\r$GNGGA,000003.811,*6A"temp_start = string.find(string_temp,'$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,'$GNGGA',1)temp_end = string.find(value,'\r',1)temp_gga = string.sub(value,temp_start,temp_end-1)-- log.info("temp_value:",temp_start,temp_end,temp_gga)return temp_gga
endfunction get_gga_longitude_latitude(value_gga)-- log.info(type(value_gga))if value_gga == "" then	 --数据第一次异常return -1endL2_temp = string.sub(value_gga,8)	 -- +8是因为"$gngga"log.info("L2_temp",L2_temp)L2_temp_x_start = string.find(L2_temp,',',1)+1L2_temp_x_end = string.find(L2_temp,',N',1)-1date_longitude = string.sub(L2_temp,L2_temp_x_start,L2_temp_x_end)L2_temp_y_start = L2_temp_x_end+4L2_temp_y_end = string.find(L2_temp,',E',1)-1date_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

5.4 结果

6 小结

提取经度纬度数据成功，后续再结合lvgl显示。