diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
index 817684f..b1bd0ee 100644
--- a/.idea/inspectionProfiles/Project_Default.xml
+++ b/.idea/inspectionProfiles/Project_Default.xml
@@ -36,5 +36,13 @@
     <inspection_tool class="StringBufferReplaceableByString" enabled="false" level="WARNING" enabled_by_default="false" />
     <inspection_tool class="TrivialIf" enabled="false" level="WARNING" enabled_by_default="false" />
     <inspection_tool class="TryWithIdenticalCatches" enabled="false" level="WARNING" enabled_by_default="false" />
+    <inspection_tool class="UNUSED_SYMBOL" enabled="false" level="WARNING" enabled_by_default="false">
+      <option name="LOCAL_VARIABLE" value="true" />
+      <option name="FIELD" value="true" />
+      <option name="METHOD" value="true" />
+      <option name="CLASS" value="true" />
+      <option name="PARAMETER" value="true" />
+      <option name="REPORT_PARAMETER_FOR_PUBLIC_METHODS" value="true" />
+    </inspection_tool>
   </profile>
 </component>
\ No newline at end of file
diff --git a/app/src/main/java/github/luv/mockgeofix/CommandDispatcher.java b/app/src/main/java/github/luv/mockgeofix/CommandDispatcher.java
index 18b1d90..3d01f1b 100644
--- a/app/src/main/java/github/luv/mockgeofix/CommandDispatcher.java
+++ b/app/src/main/java/github/luv/mockgeofix/CommandDispatcher.java
@@ -50,7 +50,12 @@ protected void _dispatch(SocketChannel client, String command) {
             if ( passwordCommand.passwordRequired() && (! passwordCommand.loggedIn(client)) ) {
                 ResponseWriter.notLoggedIn(client);
             } else {
-                geoCommand.execute(client, command);
+                try {
+                    geoCommand.execute(client, command);
+                } catch (Throwable ex) {
+                    // anything goes wrong, just ignore this command
+                    Log.e(TAG, "error during executing geo command: "+ex.toString());
+                }
             }
         } else if (cmd.equals("help")) {
             helpCommand.execute(client, command);
diff --git a/app/src/main/java/github/luv/mockgeofix/MockLocationProvider.java b/app/src/main/java/github/luv/mockgeofix/MockLocationProvider.java
index fa44fee..947d850 100644
--- a/app/src/main/java/github/luv/mockgeofix/MockLocationProvider.java
+++ b/app/src/main/java/github/luv/mockgeofix/MockLocationProvider.java
@@ -46,12 +46,15 @@ static public void simulate(double longitude, double latitude, double altitude,
         getInstance()._simulate(longitude, latitude, altitude, satellites);
     }
 
-    @SuppressWarnings("UnusedDeclaration")
     static public void simulate(Location location) {
         getInstance()._verifyInitiated();
         getInstance()._simulate(location);
     }
 
+    static public Location getLocation() {
+        return new Location(locationProviderName);
+    }
+
     protected void _init(Context context) {
         if (mContext != null) {
             throw new AssertionError(TAG+".init called twice!");
@@ -93,6 +96,12 @@ protected void _simulate(double longitude, double latitude, double altitude, int
     }
 
     protected void _simulate(Location location) {
+        if (!location.hasAccuracy()) {
+            location.setAccuracy(accuracy);
+        }
+        if (!location.hasAltitude()) {
+            location.setAltitude(0);
+        }
         try {
             Method locationJellyBeanFixMethod = Location.class.getMethod("makeComplete");
             if (locationJellyBeanFixMethod != null) {
diff --git a/app/src/main/java/github/luv/mockgeofix/command/GeoNmeaCommand.java b/app/src/main/java/github/luv/mockgeofix/command/GeoNmeaCommand.java
index 75f0ade..0d2c3ab 100644
--- a/app/src/main/java/github/luv/mockgeofix/command/GeoNmeaCommand.java
+++ b/app/src/main/java/github/luv/mockgeofix/command/GeoNmeaCommand.java
@@ -1,17 +1,202 @@
 package github.luv.mockgeofix.command;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
+import android.location.Location;
+import android.util.Log;
 
 import java.nio.channels.SocketChannel;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.TimeZone;
+
+import github.luv.mockgeofix.MockLocationProvider;
+import github.luv.mockgeofix.util.ResponseWriter;
 
 public class GeoNmeaCommand implements Command {
     Context mContext;
+    String TAG = "GeoNmeaCommand";
+
     GeoNmeaCommand(Context context) {
         mContext = context;
     }
 
     @Override
     public void execute(SocketChannel client, String command) {
+        String[] args = command.split(" ");
+        String[] nmeaFields;
+
+        try {
+            nmeaFields = args[2].split(",");
+        } catch (IndexOutOfBoundsException ex) {
+            ResponseWriter.writeLine(client,
+                    "KO: NMEA sentence missing, try 'help geo nmea'");
+            return;
+        }
+
+        String type;
+        try {
+            type = nmeaFields[0];
+        } catch (IndexOutOfBoundsException ex) {
+            // ok because that's what the emulator does as well
+            ResponseWriter.ok(client);
+            return;
+        }
+
+        if (type.equals("$GPRMC")) {
+            processGPRMC(client, nmeaFields, command);
+        } else if (type.equals("$GPGGA")) {
+            processGPGGA(client, nmeaFields, command);
+        } else {
+            // ok because that's what the emulator does as well
+            ResponseWriter.ok(client);
+        }
+    }
+
+    public void processGPRMC(SocketChannel client, String[] nmeaFields, String command) {
+        // example: $GPRMC,081836,A,3751.65,S,14507.36,E,000.0,360.0,130998,011.3,E*62
+        /* example fields:
+        225446       Time of fix 22:54:46 UTC
+        A            Status A=active or V=Void
+        4916.45,N    Latitude 49 deg. 16.45 min North
+        12311.12,W   Longitude 123 deg. 11.12 min West
+        000.5        Speed over ground, Knots
+        054.7        Track angle in degrees, True
+        191194       Date of fix  19 November 1994
+        020.3,E      Magnetic variation 20.3 deg East
+        optional field:  mode indicator
+                (can be A=autonomous, D=differential, E=Estimated, N=not valid, S=Simulator)
+        *68          mandatory checksum
+        */
+
+        String strTime, strStatus, strLatitude, strLatitudeQual, strLongitude, strLongitudeQual,
+                strSpeed, strTrackAngle, strDate;
+        try {
+            strTime = nmeaFields[1];
+            strStatus = nmeaFields[2];
+            strLatitude = nmeaFields[3];
+            strLatitudeQual = nmeaFields[4];
+            strLongitude = nmeaFields[5];
+            strLongitudeQual = nmeaFields[6];
+            strSpeed = nmeaFields[7];
+            strTrackAngle = nmeaFields[8];
+            strDate = nmeaFields[9];
+        } catch (IndexOutOfBoundsException ex) {
+            // ok because that's what the emulator does as well
+            Log.i(TAG, "Ignoring Nmea sentence: too few fields: "+command);
+            ResponseWriter.ok(client);
+            return;
+        }
+
+        if (!checkChecksum(command)) {
+            ResponseWriter.ok(client);
+            Log.i(TAG, "Ignoring Nmea sentence: invalid checksum: "+command);
+            return;
+        }
+
+        if (strStatus.toLowerCase().equals("v")) {
+            ResponseWriter.ok(client);
+            Log.i(TAG, "Ignoring Nmea sentence: Status is 'V' (void): "+command);
+            return;
+        }
+
+        long timestamp;
+        double latitude;
+        double longitude;
+        float speed;
+        float bearing;
+        try {
+            timestamp = convertTimeAndDate(strTime, strDate);
+        } catch(ParseException ex) {
+            ResponseWriter.ok(client);
+            Log.i(TAG, "Ignoring Nmea sentence: Can't parse date or time: "+command);
+            return;
+        }
+
+        try {
+            latitude = convertLatitude(strLatitude, strLatitudeQual);
+            longitude = convertLongitude(strLongitude, strLongitudeQual);
+        } catch(NumberFormatException ex) {
+            ResponseWriter.ok(client);
+            Log.i(TAG, "Ignoring Nmea sentence: Can't parse latitude or longitude: "+command);
+            return;
+        }
+
+        try {
+            speed = Float.valueOf(strSpeed) * (float)0.51444;
+        } catch(NumberFormatException ex) {
+            ResponseWriter.ok(client);
+            Log.i(TAG, "Ignoring Nmea sentence: Can't parse speed: "+command);
+            return;
+        }
+
+        try {
+            // this might be completely wrong
+            bearing = Float.valueOf(strTrackAngle);
+        } catch(NumberFormatException ex) {
+            ResponseWriter.ok(client);
+            Log.i(TAG, "Ignoring Nmea sentence: Can't parse track angle: "+command);
+            return;
+        }
+
+        Location location = MockLocationProvider.getLocation();
+        location.setTime(timestamp);
+        location.setLatitude(latitude);
+        location.setLongitude(longitude);
+        location.setSpeed(speed);
+        location.setBearing(bearing);
+
+        MockLocationProvider.simulate(location);
+        Log.d(TAG, "nmea sentence processed (lat, long: "+String.valueOf(latitude)+
+                " , "+String.valueOf(longitude)+")");
+
+        ResponseWriter.ok(client);
+    }
+
+    public void processGPGGA(SocketChannel client, String[] nmeaFields, String command) {
+        ResponseWriter.writeLine(client, "KO: Not Implemented Yet");
+    }
+
+    public boolean checkChecksum(String command) {
+        int from = command.indexOf("$");
+        int to = command.indexOf("*");
+        if (from == -1 || to == -1) {
+            return false;
+        }
+        String checkString = command.substring(from+1,to);
+        String checksum = command.substring(to+1);
+        int sum = 0;
+        for (int i=0; i<checkString.length(); i++) {
+            sum ^= (int)( checkString.charAt(i) );
+        }
+        String hexsum = Integer.toHexString(sum);
+        return hexsum.toLowerCase().equals(checksum.toLowerCase());
+    }
+
+    public long convertTimeAndDate(String time, String date) throws ParseException {
+        //  UTC time, in milliseconds since January 1, 1970.
+
+        // suppressed because we set the timezone using setTimeZone in next step
+        @SuppressLint("SimpleDateFormat") SimpleDateFormat sf = new SimpleDateFormat("HHmmss ddMMyy");
+        sf.setTimeZone(TimeZone.getTimeZone("UTC"));
+        Date d = sf.parse(time+" "+date);
+        return d.getTime();
+    }
+
+    public double convertLatitude(String strLatitude, String qual) throws NumberFormatException {
+        double lat = Double.valueOf(strLatitude) / 100;
+        if (qual.equals("S")) {
+            lat *= -1;
+        }
+        return lat;
+    }
 
+    public double convertLongitude(String strLongitude, String qual) throws NumberFormatException {
+        double longitude = Double.valueOf(strLongitude) / 100;
+        if (qual.equals("W")) {
+            longitude *= -1;
+        }
+        return longitude;
     }
-}
+}
\ No newline at end of file