Diff: SerialGPS.cpp

Revision:

0:1a8299deb917

Child:

1:214714f54773

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SerialGPS.cpp	Fri Feb 12 12:39:46 2021 +0100
@@ -0,0 +1,108 @@
+/* mbed GPS Module Library
+ * Copyright (c) 2008-2010, sford
+ * Copyright (c) 2013, B.Adryan
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+ 
+#include "SerialGPS.h"
+
+SerialGPS::SerialGPS(PinName tx, PinName rx, int Baud) : _gps(tx, rx) {
+    _gps.set_baud(Baud);    
+    longitude   = 0.0;
+    latitude    = 0.0;        
+}
+
+int SerialGPS::sample() {
+    char ns, ew, unit;
+    int lock;
+
+    while(1) {        
+        getline();
+
+        // Check if it is a GPGGA msg (matches both locked and non-locked msg)
+        if(sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d,%d,%f,%f,%c,%f", &time, &latitude, &ns, &longitude, &ew, &lock, &sats, &hdop, &alt, &unit, &geoid) >= 1) 
+        { 
+            if(!lock) 
+            {
+                time        = 0.0;
+                longitude   = 0.0;
+                latitude    = 0.0;
+                sats        = 0;
+                hdop        = 0.0;
+                alt         = 0.0;
+                geoid       = 0.0;
+
+                return 0;
+            } 
+            else 
+            {
+                //GPGGA format according http://aprs.gids.nl/nmea/#gga
+                // time (float), lat (f), (N/S) (c), long (f), (E/W) (c), fix (d), sats (d),
+                // hdop (float), altitude (float), M, geoid (float), M, , ,  
+                //GPGGA,092010.000,5210.9546,N,00008.8913,E,1,07,1.3,9.7,M,47.0,M,,0000*5D
+                
+                if(ns == 'S') { latitude  *= -1.0;  }
+                if(ew == 'W') { longitude *= -1.0;  }
+
+                float degrees   = trunc(latitude / 100.0f);
+                float minutes   = latitude - (degrees * 100.0f);
+
+                latitude        = degrees + minutes / 60.0f;    
+                degrees         = trunc(longitude / 100.0f * 0.01f);
+                minutes         = longitude - (degrees * 100.0f);
+                longitude       = degrees + minutes / 60.0f;
+
+                return 1;
+            }
+        }
+    }
+}
+
+float SerialGPS::trunc(float v) 
+{
+    if(v < 0.0) 
+    {
+        v*= -1.0;
+        v = floor(v);
+        v*=-1.0;
+    } 
+    else 
+    {
+        v = floor(v);
+    }
+    return v;
+}
+
+void SerialGPS::getline() 
+{
+    while(_gps.getc() != '$');    // wait for the start of a line
+
+    for(int i = 0; i < 256; i++) 
+    {
+        msg[i] = _gps.getc();
+        if(msg[i] == '\r') 
+        {
+            msg[i] = 0;
+            return;
+        }
+    }
+
+    error("Overflowed message limit");
+}
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