前段时间写的那个主要是根据位数来定位信息，不具有通用性，而且容易出错，现在这个根据逗号定位，通用性，准确性都有很大提高（ :-)，卖瓜了）。主要是参考一个外国人的代码，vc版本的，我把它移植到arm开发板上。
程序如下：
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "serial.h"
//some define
#define UInt32 unsigned int
#define Int16 short
#define UInt16 unsigned short
#define UInt8 unsigned char
#define Boolean int
#define false 0
#define true 1
#define DEBUG
#ifdef DEBUG
#define TRACE(str, args...) printf(str, ## args)
#else
#define TRACE(str, args...)
#endif
#define GPS_RECV_CMD_MAX_BUF 128 //the buffer size
#define RMC_MAX_BUF 16 //the buffer size of rmc field
#if ! defined( CARRIAGE_RETURN )
#define CARRIAGE_RETURN 0x0D
#endif
#if ! defined( LINE_FEED )
#define LINE_FEED 0x0A
#endif
//the rmc info struct
typedef struct RMCINFO{
int bIsGPRMC;
UInt8 hour, bjhour, min, sec, secFrac;
double latitude;
UInt8 latNS;
double longitude;
UInt8 lgtEW;
UInt8 date, day, month, year;
double course;
double speed;
}RMCINFO;
char buffer[GPS_RECV_CMD_MAX_BUF] = "GPRMC,161229.487,A,3723.2475,N,12158.3416,W,0.13,309.62,120598,,*10";
double FieldDouble( int field_number );
int main(void)
{
int fd;
int i;
RMCINFO rmcinfo;
char Latitude[RMC_MAX_BUF];
char Longitude[RMC_MAX_BUF];
char Degree[4];
char Minute[8];
char Time[RMC_MAX_BUF];
char Hour[4];
char Minu[4];
char Second[4];
char Date[RMC_MAX_BUF];
char Day[4];
char Month[4];
char Year[4];
int no = 0;
//open the COM
if((fd=open_port(fd,1))<0)
{
perror("open_port error");
return;
}
TRACE("fd=%d\n",fd);
//set the COM
if((i=set_opt(fd,9600,8,'N',1))<0)
{
perror("set_opt error");
return;
}
//
while(1)
{
while(!Is_startGP(fd));
TRACE("start to receive\n");
//receive the info
for(i = 0; i {
read(fd,&buffer[i],1);
TRACE("%c",buffer[i]);
if(buffer[i]=='\n')break;
}
TRACE("\n");
//proc the RMC info
if( (Is_RMC(buffer)) && (IsValid(2)) )
{
/*
** First we check the checksum...
*/
Boolean check = IsChecksumBad( 12 );
if ( check == true )
{
printf( "Invalid Checksum" );
continue;
}
TRACE("Valid checksum\n");
rmcinfo.bIsGPRMC = 1;
//Time:6-15
memset(Time, 0, RMC_MAX_BUF);
Field(1, Time);
TRACE("Time= %s\n",Time);
for(i = 0;i < 4;i++)
Hour[i]=0;
Hour[0]=Time[0];
Hour[1]=Time[1];
for(i = 0;i < 4;i++)
Minu[i]=0;
Minu[0]=Time[2];
Minu[1]=Time[3];
for(i = 0;i < 4;i++)
Second[i]=0;
Second[0]=Time[4];
Second[1]=Time[5];
rmcinfo.hour = atoi(Hour);
rmcinfo.min = atoi(Minu);
rmcinfo.sec = atoi(Second);
rmcinfo.secFrac = 0;
rmcinfo.bjhour = rmcinfo.hour + 8;
if(rmcinfo.bjhour >= 24)
rmcinfo.bjhour -= 24;
//Latitude:19-27
memset(Latitude, 0, RMC_MAX_BUF);
Field(3, Latitude);
TRACE("Latitude= %s\n",Latitude);
for(i = 0;i < 4;i++)
Degree[i]=0;
Degree[0]=Latitude[0];
Degree[1]=Latitude[1];
no = 2;
for(i=0;i<8;i++)
Minute[i]=0;
for(i=0;i<7;i++)
Minute[i]=Latitude[no+i];
rmcinfo.latitude=(atof(Minute)) / 60.0 + atoi(Degree);
//NS:29
Field(4, &rmcinfo.latNS );
//Longitude:31-40
memset(Longitude, 0, RMC_MAX_BUF);
Field(5, Longitude);
TRACE("Longitude= %s\n",Longitude);
for(i=0;i<4;i++)
Degree[i]=0;
Degree[0]=Longitude[0];
Degree[1]=Longitude[1];
Degree[2]=Longitude[2];
no=3;
for(i=0;i<8;i++)
Minute[i]=0;
for(i=0;i<7;i++)
Minute[i]=Longitude[no+i];
rmcinfo.longitude=(atof(Minute)) / 60.0 + atoi(Degree);
//WE:42
Field(6, &rmcinfo.lgtEW);
// speed:44
rmcinfo.speed = FieldDouble(7);
// course
rmcinfo.course = FieldDouble(8);
//Date:
memset(Date, 0, RMC_MAX_BUF);
Field(9, Date);
TRACE("Date = %s\n",Date);
for(i = 0;i < 4;i++)
Day[i]=0;
Day[0]=Date[0];
Day[1]=Date[1];
for(i = 0;i < 4;i++)
Month[i]=0;
Month[0]=Date[2];
Month[1]=Date[3];
for(i = 0;i < 4;i++)
Year[i]=0;
Year[0]=Date[4];
Year[1]=Date[5];
rmcinfo.day = atoi(Day);
rmcinfo.month = atoi(Month);
rmcinfo.year = atoi(Year);
printf("UTC Time:%d h %d m %d s\n",rmcinfo.hour,rmcinfo.min,rmcinfo.sec);
printf("BJ Time:%d h %d m %d s\n",rmcinfo.bjhour,rmcinfo.min,rmcinfo.sec);
printf("Date:%d y %d m %d d\n",rmcinfo.year,rmcinfo.month,rmcinfo.day);
printf("Latitude:%c wei %f \n",rmcinfo.latNS,rmcinfo.latitude);
printf("Longitude:%c jing %f \n",rmcinfo.lgtEW,rmcinfo.longitude);
printf("Speed:%f \n",rmcinfo.speed);
printf("Course:%f \n",rmcinfo.course);
printf("\n");
}//end Is_RMC
else continue;
sleep(1);
}//end while 1
close(fd);
return 0;
}//end main
/*
** RMC - Recommended Minimum Navigation Information
** 12
** 1 2 3 4 5 6 7 8 9 10 11|
** | | | | | | | | | | | |
** $--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxx,x.x,a*hh
**
** Field Number:
** 1) UTC Time
** 2) Status, V = Navigation receiver warning
** 3) Latitude
** 4) N or S
** 5) Longitude
** 6) E or W
** 7) Speed over ground, knots
** 8) Track made good, degrees true
** 9) Date, ddmmyy
** 10) Magnetic Variation, degrees
** 11) E or W
** 12) Checksum
*/
int Is_startGP(int fp)
{
int status=0;
char cc;
read(fp,&cc,1);
if(cc == '$')status=1;
return status;
}
int Is_RMC(char p[GPS_RECV_CMD_MAX_BUF])
{
int status=0;
if(p[2] == 'R' && p[3] == 'M' && p[4] == 'C')
status=1;
return status;
}
int Field( int desired_field_number, char rmc_field[] )
{
char return_string[RMC_MAX_BUF];
int i;
int index = 0;
int current_field_number = 0;
int string_length = 0;
memset(return_string, 0, RMC_MAX_BUF);
memset(rmc_field, 0, RMC_MAX_BUF);
string_length = GPS_RECV_CMD_MAX_BUF;
while( current_field_number < desired_field_number && index < string_length )
{
if ( buffer[ index ] == ',' || buffer[ index ] == '*' )
{
current_field_number++;
}
index++;
}
if ( current_field_number == desired_field_number )
{
i = 0;
while( index < string_length &&
buffer[ index ] != ',' &&
buffer[ index ] != '*' &&
buffer[ index ] != 0x00 )
{
return_string[i] = buffer[ index ];
index++;
i++;
}
}
for(index = 0; index < i; index++)
rmc_field[index] = return_string[index];
TRACE("rmc_field: %s \n",rmc_field);
return 0;
}
char ComputeChecksum( void )
{
char checksum_value = 0;
int string_length = GPS_RECV_CMD_MAX_BUF;
int index = 0;
while( index < string_length &&
buffer[ index ] != '*' &&
buffer[ index ] != CARRIAGE_RETURN &&
buffer[ index ] != LINE_FEED )
{
checksum_value ^= buffer[ index ];
index++;
}
TRACE("checksum_value = %x\n",checksum_value);
return( checksum_value );
}
int HexValue( const char *hex_string )
{
int return_value = 0;
sscanf( hex_string, "%x", (int *) &return_value );
TRACE("hex_string = %s\n",hex_string);
TRACE("return_value = %x\n",return_value);
return( return_value );
}
Boolean IsChecksumBad( int checksum_field_number )
{
/*
** Checksums are optional, return TRUE if an existing checksum is known to be bad
*/
char checksum_in_sentence[RMC_MAX_BUF] ;
memset(checksum_in_sentence, 0, RMC_MAX_BUF);
Field( checksum_field_number, checksum_in_sentence);
TRACE("checksum_in_sentence = %s\n",checksum_in_sentence);
if ( checksum_in_sentence == "" )
{
return( true );
}
if ( ComputeChecksum() != HexValue( checksum_in_sentence ) )
{
return( true );
}
return( false );
}
Boolean IsValid( int field_number )
{
char field_data[RMC_MAX_BUF];
memset(field_data, 0, RMC_MAX_BUF);
Field( field_number, field_data );
TRACE("field_data = %s\n",field_data);
if ( *field_data == 'A' )
{
return( true );
}
else
{
return( false );
}
}
double FieldDouble( int field_number )
{
double tmp;
char field_data[RMC_MAX_BUF];
memset(field_data, 0, RMC_MAX_BUF);
Field( field_number, field_data );
TRACE("field_data = %s\n",field_data);
tmp =atof(field_data);
TRACE("tmp = %f\n",tmp);
return tmp;
}
 |
| 文件: |
NMEA0183源代码.zip |
| 大小: |
70KB |
| 下载: |
下载 | |
