Linkit ONE开发板实验03-串口打印GPS数据

来源：互联网发布：java安装在d盘教程编辑：程序博客网时间：2024/05/22 00:35

Linkit ONE开发板GPS相关的API官方文档请自行查阅，这里只是简单解析下GPRMC中的数据。

读取GPS并进行简易解析的代码如下所示：

#include <string.h>#include <LGPS.h>#define LED_GPIO_PIN  13struct gps_info {  long longitude;  long latitude;  int  moveDirection;  int  speed;  int  satNum;};void setup() {  // initialize LED pin as an output.  pinMode(LED_GPIO_PIN, OUTPUT);  //Setup Serial Port.  Serial.begin(9600);  Serial.println("Linkit ONE Board"); //print with line change.  gpsPowerOn();}void ledOn() {  digitalWrite(LED_GPIO_PIN, HIGH);   // turn the LED on (HIGH is the voltage level)}void ledOff() {  digitalWrite(LED_GPIO_PIN, LOW);    // turn the LED off by making the voltage LOW}void gpsPowerOn() {  LGPS.powerOn();}void gpsPowerOff() {  LGPS.powerOff();}void gpsGetData() {  gpsSentenceInfoStruct info;  LGPS.getData(&info);  Serial.print((char*)info.GPGGA);  Serial.print((char*)info.GPGSA);  Serial.print((char*)info.GPRMC);  Serial.print((char*)info.GPVTG);  Serial.print((char*)info.GPGSV);  Serial.print((char*)info.GLGSV);  Serial.print((char*)info.BDGSV);  Serial.print((char*)info.BDGSA);  Serial.println(" ");  parseGPRMC((char*)info.GPRMC);}/*RPRMC(Recommended Minimum Specific GPS/TRANSIT Data)  Format:$GPRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>*hh<CR><LF>  字段 0：$GPRMC，语句ID，表明该语句为Recommended Minimum Specific GPS/TRANSIT Data（RMC）推荐最小定位信息  字段 1：UTC时间，hhmmss.sss格式  字段 2：状态，A=定位，V=未定位  字段 3：纬度ddmm.mmmm，度分格式（前导位数不足则补0）  字段 4：纬度N（北纬）或S（南纬）  字段 5：经度dddmm.mmmm，度分格式（前导位数不足则补0）  字段 6：经度E（东经）或W（西经）  字段 7：速度，节，Knots（一节也是1.852千米／小时）  字段 8：方位角，度（二维方向指向，相当于二维罗盘）  字段 9：UTC日期，DDMMYY格式  字段10：磁偏角，（000 - 180）度（前导位数不足则补0）  字段11：磁偏角方向，E=东，W=西  字段12：模式，A=自动，D=差分，E=估测，N=数据无效（3.0协议内容）  字段13：校验值*/void parseGPRMC(char* gprmcStr) {  char* p = NULL;  char* pData = gprmcStr;  char* spliter = ",";  int  spliterPos[12];  char* headStr = "$GPRMC";  //  p = strstr(gprmcStr, headStr);  if (NULL == p) {    Serial.println("No $GPRMC");    return;  }  //  int i = 0;  for( i = 0; i < 12; i++) {    p = strstr(pData, spliter);    spliterPos[i] = p - gprmcStr;    pData = p + 1;    //Serial.println(p);  }  //01.UTC Time.  char utcTime[16] = {0};  memcpy(utcTime, gprmcStr + 1 + spliterPos[0], spliterPos[1] - spliterPos[0] - 1);  Serial.print("utctime:");  Serial.println(utcTime);  //02.Locate Status  char gpsAvailable = 'V';  if (0 == strncmp(gprmcStr + 1 + spliterPos[1], "A", 1)) {    gpsAvailable = 'A';  }  Serial.print("gpsAvailable:");  Serial.println(gpsAvailable);  //03~04. GPS Latitude  char gpsLat[16] = {0};    memcpy(gpsLat, gprmcStr + 1 + spliterPos[2], spliterPos[3] - spliterPos[2] - 1);  if (0 == strncmp(gprmcStr + 1 + spliterPos[3], "N", 1)) {    Serial.println("N");  } else {    Serial.println("S");  }  Serial.print("Latitude:");  Serial.println(gpsLat);  //05~06. GPS Longitude  char gpsLon[16] = {0};  memcpy(gpsLon, gprmcStr + 1 + spliterPos[4], spliterPos[5] - spliterPos[4] - 1);  if (0 == strncmp(gprmcStr + 1 + spliterPos[5], "E", 1)) {    Serial.println("E");  } else {    Serial.println("W");  }  Serial.print("Longitude:");  Serial.println(gpsLon);  //07. Speed  char gpsSpd[16] = {0};  memcpy(gpsSpd, gprmcStr + 1 + spliterPos[6], spliterPos[7] - spliterPos[6] - 1);  Serial.print("Speed:");  Serial.println(gpsSpd);    //08. Direction  char gpsDir[16] = {0};  memcpy(gpsDir, gprmcStr + 1 + spliterPos[7], spliterPos[8] - spliterPos[7] - 1);  Serial.print("Direction:");  Serial.println(gpsDir);  //09. UTC date  char gpsDate[16] = {0};  memcpy(gpsDate, gprmcStr + 1 + spliterPos[8], spliterPos[9] - spliterPos[8] - 1);  Serial.print("UTC Date:");  Serial.println(gpsDate);  Serial.println(" ");}void loop() {  gpsGetData();  delay(200);  ledOn();  delay(800);  ledOff();}

其中GPS模块的开启和关闭由函数gpsPowerOn()和函数gpsPowerOff()控制。

一旦开启了GPS，则可以通过gpsGetDate()函数来获取GPS数据了。Linkit ONE SDK自己定义了一个GPS袁术数据的数据结构：

typedef struct {  unsigned char GPGGA[GPS_MAX_GPGGA_SENTENCE_LENGTH+1];  unsigned char GPGSA[GPS_MAX_GPGSA_SENTENCE_LENGTH+1];  unsigned char GPRMC[GPS_MAX_GPRMC_SENTENCE_LENGTH+1];  unsigned char GPVTG[GPS_MAX_GPVTG_SENTENCE_LENGTH+1];  unsigned char GPGSV[GPS_MAX_GPGSV_SENTENCE_LENGTH+1];  unsigned char GLGSV[GPS_MAX_GLGSV_SENTENCE_LENGTH+1];  unsigned char GLGSA[GPS_MAX_GLGSA_SENTENCE_LENGTH+1];  unsigned char BDGSV[GPS_MAX_BDGSV_SENTENCE_LENGTH+1];  unsigned char BDGSA[GPS_MAX_BDGSA_SENTENCE_LENGTH+1];} gpsSentenceInfoStruct;

我们通过API函数LGPS.getData()函数获取到的GPS数据则为上面的结构体。

获取到这个结构体后我们就可以通过解析其中的数据来获取我们需要的GPS信息了，上面的例子以解析GPRMC数据为例。解析的思路为：找出字符串中的所有分隔符（','）的位置，然后根据NMEA-0183文档的定义来把其中的各个字段读出来。根据自己定义个GPS的数据结构可能要对获取到的字符串做一些数据类型转换。

最后这里给出本例子的一个运行结果：

Linkit ONE Board No $GPRMC No $GPRMC$GPGGA,093351.319,2232.3497,N,11354.7916,E,0,0,,316.4,M,-2.7,M,,*5E$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,1.00*01$GPRMC,093351.319,V,2232.3497,N,11354.7916,E,0.000,0.00,221017,,,N*44$GPVTG,0.00,T,,M,0.000,N,0.000,K,N*32$GPGSV,2,1,5,21,57,235,,18,56,343,,32,18,275,,14,07,262,*48$GPGSV,2,2,5,193,,,*77$GLGSV,1,1,1*54 utctime:093351.319gpsAvailable:VNLatitude:2232.3497ELongitude:11354.7916Speed:0.000Direction:0.00UTC Date:221017

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