Revision 0:67f22e813b74, committed 2016-05-18

Comitter:

quicksand

Date:

Wed May 18 14:47:17 2016 +0000

Commit message:

Version for NMEA message parsing on the QW boards

Changed in this revision

diff -r 000000000000 -r 67f22e813b74 GPS.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/GPS.cpp	Wed May 18 14:47:17 2016 +0000
@@ -0,0 +1,302 @@
+#include "GPS.h"
+#include "math.h"
+#include "inttypes.h"
+Serial debug(USBTX, USBRX);
+GPS::GPS(PinName tx, PinName rx) : _gps(tx, rx) {
+    _gps.baud(9600);
+    nmea_longitude = 0.0;
+    nmea_latitude = 0.0;
+    utc_time = 0;
+    ns = ' ';
+    ew = ' ';
+    lock = 0;
+    satelites = 0;
+    msl_altitude = 0.0;
+    msl_units = ' ';
+    satellites[0] = 0;
+    satellites[1] = 0;
+    satellites[2] = 0;
+    satellites[3] = 0;
+    satellites[4] = 0;
+    satellites[5] = 0;
+    satellites[6] = 0;
+    satellites[7] = 0;
+    satellites[8] = 0;
+    satellites[9] = 0;
+    satellites[10] = 0;
+    satellites[11] = 0;    
+    pdop = 0.0;
+    hdop = 0.0;
+    vdop = 0.0;
+    navigation_mode = 1;
+    gprmc_status = 'V';
+    tdformat[0] = 0;
+    
+
+    rmc_status = ' ';
+    speed_k = 0.0;
+    course_d = 0.0;
+    date = 0;
+
+    dec_longitude = 0.0;
+    dec_latitude = 0.0;
+
+    gll_status = ' ';
+
+    course_t = 0.0; // ground speed true
+    course_t_unit = ' ';
+    course_m = 0.0; // magnetic
+    course_m_unit = ' ';
+    speed_k_unit = ' ';
+    speed_km = 0.0; // speed km/hr
+    speed_km_unit = ' ';
+
+    altitude_ft = 0.0;
+}
+
+float GPS::nmea_to_dec(float deg_coord, char nsew) {
+    int degree = (int)(deg_coord/100);
+    float minutes = deg_coord - degree*100;
+    float dec_deg = minutes / 60;
+    float decimal = degree + dec_deg;
+    if (nsew == 'S' || nsew == 'W') { // return negative
+        decimal *= -1;
+    }
+    return decimal;
+}
+
+char * GPS::get_nmea_to_td() {
+    int lat_degree = (int)(nmea_latitude/100);
+    float lat_minutes = (rint((nmea_latitude - lat_degree*100)*1000)/1000.0); // round to 3 digits 
+    uint8_t lat_sign = 0;
+    if (ns == 'S' )lat_sign = 0x40;
+    int lng_degree = (int)(nmea_longitude/100);
+    float lng_minutes = rint((nmea_longitude - lng_degree*100)*1000)/1000.0; // round to 3 digits
+    uint8_t lng_sign = 0;
+    if (ew == 'W' )lng_sign = 0x80;
+    uint32_t height = rint(msl_altitude/2.0);
+    debug.printf("lng degree: %d, lng min %f,lat degree: %d, lat min %f" , lng_degree, lng_minutes,lat_degree, lat_minutes);
+    char temp[32];
+    sprintf(temp, "%d%05.0f%d%05.0f",lng_degree, lng_minutes*1000,lat_degree, lat_minutes*1000);
+    unsigned long long ret;
+    ret = strtoull(temp, NULL, 10);   
+    //debug.printf("the string: %s\r\n",temp);
+    //debug.printf("the long variable: %llu\r\n",ret);
+    //debug.printf("the long variable in hex: %012llx",ret);
+    sprintf(tdformat, "01010%012llx%03x%02x",ret,height&0xfff,(lng_sign+lat_sign)&0xff); // to do: add sattelites in view, altiude sign and horizontal dillution
+    //debug.printf("Formatted string:%s \r\n", tdformat);
+    return tdformat;
+}
+
+int GPS::sample() {
+    int line_parsed = 0;
+
+    if (_gps.readable()) {
+        getline();
+        debug.printf("%s\r\n",msg);
+        // Check if it is a GPGGA msg (matches both locked and non-locked msg)
+        // $xxGGA,time,lat,NS,long,EW,quality,numSV,HDOP,alt,M,sep,M,diffAge,diffStation*cs<CR><LF>
+        if (sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d,%d,%f,%f,%c", &utc_time, &nmea_latitude, &ns, &nmea_longitude, &ew, &lock, &satelites, &hdop, &msl_altitude, &msl_units) >= 1) {
+            line_parsed = GGA;
+        }
+        // Check if it is a GPSA msg (navigational mode)
+        // $xxGSA,opMode,navMode{,sv},PDOP,HDOP,VDOP*cs<CR><LF>
+        else if (sscanf(msg, "GPGSA,%c,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%f,%f,%f", &operating_mode, &navigation_mode, &satellites[0], &satellites[1], &satellites[2], &satellites[3], &satellites[4], &satellites[5], &satellites[6], &satellites[7], &satellites[8], &satellites[9], &satellites[10], &satellites[11],&pdop,&hdop,&vdop) >= 1) {
+            line_parsed = GSA;
+        }
+        // Check if it is a GPRMC msg
+        // $xxRMC,time,status,lat,NS,long,EW,spd,cog,date,mv,mvEW,posMode*cs<CR><LF>
+        else if (sscanf(msg, "GPRMC,%f,%c,%f,%c,%f,%c,%f,%f,%d", &utc_time, &gprmc_status, &nmea_latitude, &ns, &nmea_longitude,&ew,&speed_k,&course_d,&date) >= 1) {
+            line_parsed = RMC;
+        }
+        // GLL - Geographic Position-Lat/Lon
+        // $xxGLL,lat,NS,long,EW,time,status,posMode*cs<CR><LF>
+        else if (sscanf(msg, "GPGLL,%f,%c,%f,%c,%f,%c", &nmea_latitude, &ns, &nmea_longitude, &ew, &utc_time, &gll_status) >= 1) {
+            line_parsed = GLL;
+        }
+        // VTG-Course Over Ground and Ground Speed
+        else if (sscanf(msg, "GPVTG,%f,%c,%f,%c,%f,%c,%f,%c", &course_t, &course_t_unit, &course_m, &course_m_unit, &speed_k, &speed_k_unit, &speed_km, &speed_km_unit) >= 1) {
+            line_parsed = VTG;
+        }
+        
+        /*if(satelites == 0) {
+            lock = 0;
+        }*/
+        if(gprmc_status == 'A'|| satelites > 0 || navigation_mode > 1) lock = 1;
+        else lock = 0;
+    }
+    if (!lock) {
+        return NO_LOCK;
+    } else if (line_parsed) {
+        return line_parsed;
+    } else {
+        return NOT_PARSED;
+    }
+}
+
+
+// INTERNAL FUNCTINS ////////////////////////////////////////////////////////////
+float GPS::trunc(float v) {
+    if (v < 0.0) {
+        v*= -1.0;
+        v = floor(v);
+        v*=-1.0;
+    } else {
+        v = floor(v);
+    }
+    return v;
+}
+
+void GPS::getline() {
+    while (_gps.getc() != '$');   // wait for the start of a line
+    for (int i=0; i<1022; i++) {
+        msg[i] = _gps.getc();
+        if (msg[i] == '\r') {
+            msg[i] = 0;
+            return;
+        }
+    }
+    error("Overflow in getline");
+}
+
+// GET FUNCTIONS /////////////////////////////////////////////////////////////////
+float GPS::get_msl_altitude() {
+    if (!lock)
+        return 0.0;
+    else
+        return msl_altitude;
+}
+
+int GPS::get_satelites() {
+    if (!lock)
+        return 0;
+    else
+        return satelites;
+}
+
+float GPS::get_nmea_longitude() {
+    if (!lock)
+        return 0.0;
+    else
+        return nmea_longitude;
+}
+
+float GPS::get_dec_longitude() {
+    dec_longitude = nmea_to_dec(nmea_longitude, ew);
+    if (!lock)
+        return 0.0;
+    else
+        return dec_longitude;
+}
+
+float GPS::get_nmea_latitude() {
+    if (!lock)
+        return 0.0;
+    else
+        return nmea_latitude;
+}
+
+float GPS::get_dec_latitude() {
+    dec_latitude = nmea_to_dec(nmea_latitude, ns);
+    if (!lock)
+        return 0.0;
+    else
+        return dec_latitude;
+}
+
+float GPS::get_course_t() {
+    if (!lock)
+        return 0.0;
+    else
+        return course_t;
+}
+
+float GPS::get_course_m() {
+    if (!lock)
+        return 0.0;
+    else
+        return course_m;
+}
+
+float GPS::get_speed_k() {
+    if (!lock)
+        return 0.0;
+    else
+        return speed_k;
+}
+
+float GPS::get_speed_km() {
+    if (!lock)
+        return 0.0;
+    else
+        return speed_km;
+}
+
+float GPS::get_altitude_ft() {
+    if (!lock)
+        return 0.0;
+    else
+        return 3.280839895*msl_altitude;
+}
+
+// NAVIGATION FUNCTIONS ////////////////////////////////////////////////////////////
+float GPS::calc_course_to(float pointLat, float pontLong) {
+    const double d2r = PI / 180.0;
+    const double r2d = 180.0 / PI;
+    double dlat = abs(pointLat - get_dec_latitude()) * d2r;
+    double dlong = abs(pontLong - get_dec_longitude()) * d2r;
+    double y = sin(dlong) * cos(pointLat * d2r);
+    double x = cos(get_dec_latitude()*d2r)*sin(pointLat*d2r) - sin(get_dec_latitude()*d2r)*cos(pointLat*d2r)*cos(dlong);
+    return atan2(y,x)*r2d;
+}    
+
+/*
+var y = Math.sin(dLon) * Math.cos(lat2);
+var x = Math.cos(lat1)*Math.sin(lat2) -
+        Math.sin(lat1)*Math.cos(lat2)*Math.cos(dLon);
+var brng = Math.atan2(y, x).toDeg();
+*/
+
+/*
+            The Haversine formula according to Dr. Math.
+            http://mathforum.org/library/drmath/view/51879.html
+                
+            dlon = lon2 - lon1
+            dlat = lat2 - lat1
+            a = (sin(dlat/2))^2 + cos(lat1) * cos(lat2) * (sin(dlon/2))^2
+            c = 2 * atan2(sqrt(a), sqrt(1-a)) 
+            d = R * c
+                
+            Where
+                * dlon is the change in longitude
+                * dlat is the change in latitude
+                * c is the great circle distance in Radians.
+                * R is the radius of a spherical Earth.
+                * The locations of the two points in 
+                    spherical coordinates (longitude and 
+                    latitude) are lon1,lat1 and lon2, lat2.
+*/
+double GPS::calc_dist_to_mi(float pointLat, float pontLong) {
+    const double d2r = PI / 180.0;
+    double dlat = pointLat - get_dec_latitude();
+    double dlong = pontLong - get_dec_longitude();
+    double a = pow(sin(dlat/2.0),2.0) + cos(get_dec_latitude()*d2r) * cos(pointLat*d2r) * pow(sin(dlong/2.0),2.0);
+    double c = 2.0 * asin(sqrt(abs(a)));
+    double d = 63.765 * c;
+    
+    return d;
+}
+
+double GPS::calc_dist_to_ft(float pointLat, float pontLong) {
+    return calc_dist_to_mi(pointLat, pontLong)*5280.0;
+}
+
+double GPS::calc_dist_to_km(float pointLat, float pontLong) {
+    return calc_dist_to_mi(pointLat, pontLong)*1.609344;
+}
+
+double GPS::calc_dist_to_m(float pointLat, float pontLong) {
+    return calc_dist_to_mi(pointLat, pontLong)*1609.344;
+}
+
+    
\ No newline at end of file

diff -r 000000000000 -r 67f22e813b74 GPS.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/GPS.h	Wed May 18 14:47:17 2016 +0000
@@ -0,0 +1,103 @@
+#include "mbed.h"
+
+#ifndef MBED_GPS_H
+#define MBED_GPS_H
+
+#define NO_LOCK     1
+#define NOT_PARSED  2
+#define GGA         3
+#define GLL         4
+#define RMC         5
+#define VTG         6
+#define ESTIMATE    7
+#define GSA         8
+
+#define PI (3.141592653589793)
+
+/**  A GPS interface for reading from a Globalsat EM-406 GPS Module */
+class GPS {
+public:
+
+    /** Create the GPS interface, connected to the specified serial port
+     */    
+    GPS(PinName tx, PinName rx);
+    
+    /** Sample the incoming GPS data, returning whether there is a lock
+     * 
+     * @return 1 if there was a lock when the sample was taken (and therefore .longitude and .latitude are valid), else 0
+     */
+    int sample();
+    char operating_mode;
+    int navigation_mode;
+    int satellites[12];
+    float pdop;
+    float hdop;
+    float vdop;
+    char gprmc_status;
+    
+    float get_nmea_longitude();
+    float get_nmea_latitude();
+    float get_dec_longitude();
+    float get_dec_latitude();
+    float get_msl_altitude();
+    float get_course_t();
+    float get_course_m();
+    float get_speed_k();
+    float get_speed_km();
+    int get_satelites();
+    float get_altitude_ft();
+    char * get_nmea_to_td();
+    char tdformat[32];
+    
+    // navigational functions
+    float calc_course_to(float, float);
+    double calc_dist_to_mi(float, float);
+    double calc_dist_to_ft(float, float);
+    double calc_dist_to_km(float, float);
+    double calc_dist_to_m(float, float); 
+    
+private:
+    float nmea_to_dec(float, char);
+    float trunc(float v);
+    void getline();
+    void format_for_log(void);
+    
+    Serial _gps;
+    char msg[1024];
+    char bfr[1030];
+
+    // calculated values
+    float dec_longitude;
+    float dec_latitude;
+    float altitude_ft;
+    
+    // GGA - Global Positioning System Fixed Data
+    float nmea_longitude;
+    float nmea_latitude;    
+    float utc_time;
+    char ns, ew;
+    int lock;
+    int satelites;
+    float msl_altitude;
+    char msl_units;
+    
+    // RMC - Recommended Minimmum Specific GNS Data
+    char rmc_status;
+    float speed_k;
+    float course_d;
+    int date;
+    
+    // GLL
+    char gll_status;
+    
+    // VTG - Course over ground, ground speed
+    float course_t; // ground speed true
+    char course_t_unit;
+    float course_m; // magnetic
+    char course_m_unit;
+    char speed_k_unit;
+    float speed_km; // speek km/hr
+    char speed_km_unit;
+};
+
+#endif