Diff: GPS/GPS.cpp

Revision:

61:2b30d8e75fe7

Child:

62:35d41c8b9419

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/GPS/GPS.cpp	Thu Nov 28 15:44:17 2019 +0000
@@ -0,0 +1,93 @@
+/* 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 "GPS.h"
+ 
+GPS::GPS(PinName tx, PinName rx, int Baud) : _gps(tx, rx)
+{
+    _gps.baud(Baud);
+    longitude = 0.0;
+    latitude = 0.0;
+}
+ 
+int GPS::sample()
+{
+ 
+    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
+ 
+                //format utc time to beijing time,add 8 time zone
+                time = time + 80000.00f;
+                hour = int(time) / 10000;
+                minute = (int(time) % 10000) / 100;
+                seconed = int(time) % 100;
+            
+                return 1;
+            }
+        }
+    }
+}
+ 
+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<256; i++) {
+        msg[i] = _gps.getc();
+        if(msg[i] == '\r') {
+            msg[i] = 0;
+            return;
+        }
+    }
+    error("Overflowed message limit");
+}
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