#include "API_Gps.h"
#include <SoftwareSerial.h>
SoftwareSerial Serial_Gps(4, 5);
#define GNRMC_TERM "$GNRMC," //定义要解析的指令，因为这条指令包含定位和时间信息
char nmeaSentence[68];
String latitude; //纬度
String longitude; //经度
String lndSpeed; //速度
String gpsTime; //UTC时间，本初子午线经度0度的时间，和北京时间差8小时
String beiJingTime; //北京时间
void Get_Gps(){
// For one second we parse GPS data and report some key values
for (unsigned long start = millis(); millis() - start < 1000;) //一秒钟内不停扫描GPS信息
{
while (Serial_Gps.available()) //串口获取到数据开始解析
{
char c = Serial_Gps.read(); //读取一个字节获取的数据
switch(c) //判断该字节的值
{
case '$': //若是$，则说明是一帧数据的开始
Serial_Gps.readBytesUntil('*', nmeaSentence, 67); //读取接下来的数据，存放在nmeaSentence字符数组中，最大存放67个字节
//Serial_Gps.println(nmeaSentence);
latitude = parseGNRMcLat(nmeaSentence); //获取纬度值
longitude = parseGNRMcLon(nmeaSentence);//获取经度值
lndSpeed = parseGNRMcSpeed(nmeaSentence);//获取速度值
gpsTime = parseGNRMcTime(nmeaSentence);//获取GPS时间
if(latitude > "") //当不是空时候打印输出
{
Serial.println("------------------------------------");
Serial.println("latitude: " + latitude);
}
if(longitude > "") //当不是空时候打印输出
{
Serial.println("longitude: " + longitude);
}
if(lndSpeed > "") //当不是空时候打印输出
{
Serial.println("Speed (knots): " + lndSpeed);
}
if(gpsTime > "") //当不是空时候打印输出
{
Serial.println("gpsTime: " + gpsTime);
beiJingTime = getBeiJingTime(gpsTime); //获取北京时间
Serial.println("beiJingTime: " + beiJingTime);
}
}//switch(c)
}// while
}//for
}
void setup() //初始化内容
{
Serial.begin(9600);
Serial_Gps.begin(9600); //定义波特率9600，
}
void loop() //主循环
{
Get_Gps();
}//loop()
API_Gps.h
String getBeiJingTime(String s)
{
int hour = s.substring(0,2).toInt();
int minute = s.substring(2,4).toInt();
int second = s.substring(4,6).toInt();
hour += 8;
if(hour > 24)
hour -= 24;
s = String(hour) + String(minute) + String(second);
return s;
}
//Parse GNRMC NMEA sentence data from String
//String must be GNRMC or no data will be parsed
//Return Latitude
String parseGNRMcLat(String s)
{
int pLoc = 0; //paramater location pointer
int lEndLoc = 0; //lat parameter end location
int dEndLoc = 0; //direction parameter end location
String lat;
/*make sure that we are parsing the GNRMC string.
Found that setting s.substring(0,5) == "GNRMC" caused a FALSE.
There seemed to be a 0x0D and 0x00 character at the end. */
if(s.substring(0,4) == "GNRM")
{
//Serial.println(s);
for(int i = 0; i < 5; i++)
{
if(i < 3)
{
pLoc = s.indexOf(',', pLoc+1);
/*Serial.print("i < 3, pLoc: ");
Serial.print(pLoc);
Serial.print(", ");
Serial.println(i);*/
}
if(i == 3)
{
lEndLoc = s.indexOf(',', pLoc+1);
lat = s.substring(pLoc+1, lEndLoc);
/*Serial.print("i = 3, pLoc: ");
Serial.println(pLoc);
Serial.print("lEndLoc: ");
Serial.println(lEndLoc);*/
}
else
{
dEndLoc = s.indexOf(',', lEndLoc+1);
lat = lat + " " + s.substring(lEndLoc+1, dEndLoc);
/*Serial.print("i = 4, lEndLoc: ");
Serial.println(lEndLoc);
Serial.print("dEndLoc: ");
Serial.println(dEndLoc);*/
}
}
return lat;
}
//}
//}
}
//Parse GNRMC NMEA sentence data from String
//String must be GNRMC or no data will be parsed
//Return Longitude
String parseGNRMcLon(String s)
{
int pLoc = 0; //paramater location pointer
int lEndLoc = 0; //lat parameter end location
int dEndLoc = 0; //direction parameter end location
String lon;
/*make sure that we are parsing the GNRMC string.
Found that setting s.substring(0,5) == "GNRMC" caused a FALSE.
There seemed to be a 0x0D and 0x00 character at the end. */
if(s.substring(0,4) == "GNRM")
{
//Serial.println(s);
for(int i = 0; i < 7; i++)
{
if(i < 5)
{
pLoc = s.indexOf(',', pLoc+1);
/*Serial.print("i < 3, pLoc: ");
Serial.print(pLoc);
Serial.print(", ");
Serial.println(i);*/
}
if(i == 5)
{
lEndLoc = s.indexOf(',', pLoc+1);
lon = s.substring(pLoc+1, lEndLoc);
/*Serial.print("i = 3, pLoc: ");
Serial.println(pLoc);
Serial.print("lEndLoc: ");
Serial.println(lEndLoc);*/
}
else
{
dEndLoc = s.indexOf(',', lEndLoc+1);
lon = lon + " " + s.substring(lEndLoc+1, dEndLoc);
/*Serial.print("i = 4, lEndLoc: ");
Serial.println(lEndLoc);
Serial.print("dEndLoc: ");
Serial.println(dEndLoc);*/
}
}
return lon;
}
}
//Parse GNRMC NMEA sentence data from String
//String must be GNRMC or no data will be parsed
//Return Longitude
String parseGNRMcSpeed(String s)
{
int pLoc = 0; //paramater location pointer
int lEndLoc = 0; //lat parameter end location
int dEndLoc = 0; //direction parameter end location
String lndSpeed;
/*make sure that we are parsing the GNRMC string.
Found that setting s.substring(0,5) == "GNRMC" caused a FALSE.
There seemed to be a 0x0D and 0x00 character at the end. */
if(s.substring(0,4) == "GNRM")
{
//Serial.println(s);
for(int i = 0; i < 8; i++)
{
if(i < 7)
{
pLoc = s.indexOf(',', pLoc+1);
/*Serial.print("i < 8, pLoc: ");
Serial.print(pLoc);
Serial.print(", ");
Serial.println(i);*/
}
else
{
lEndLoc = s.indexOf(',', pLoc+1);
lndSpeed = s.substring(pLoc+1, lEndLoc);
/*Serial.print("i = 8, pLoc: ");
Serial.println(pLoc);
Serial.print("lEndLoc: ");
Serial.println(lEndLoc);*/
}
}
return lndSpeed;
}
}
//Parse GNRMC NMEA sentence data from String
//String must be GNRMC or no data will be parsed
//Return Longitude
String parseGNRMcTime(String s)
{
int pLoc = 0; //paramater location pointer
int lEndLoc = 0; //lat parameter end location
int dEndLoc = 0; //direction parameter end location
String gpsTime;
/*make sure that we are parsing the GNRMC string.
Found that setting s.substring(0,5) == "GNRMC" caused a FALSE.
There seemed to be a 0x0D and 0x00 character at the end. */
if(s.substring(0,4) == "GNRM")
{
//Serial.println(s);
for(int i = 0; i < 2; i++)
{
if(i < 1)
{
pLoc = s.indexOf(',', pLoc+1);
/*Serial.print("i < 8, pLoc: ");
Serial.print(pLoc);
Serial.print(", ");
Serial.println(i);*/
}
else
{
lEndLoc = s.indexOf(',', pLoc+1);
gpsTime = s.substring(pLoc+1, lEndLoc);
/*Serial.print("i = 8, pLoc: ");
Serial.println(pLoc);
Serial.print("lEndLoc: ");
Serial.println(lEndLoc);*/
}
}
return gpsTime;
}
}
// Turn char[] array into String object
String charToString(char *c)
{
String val = "";
for(int i = 0; i <= sizeof(c); i++)
{
val = val + c;
}
return val;
}