diff --git a/libraries/AP_Compass/AP_Compass.cpp b/libraries/AP_Compass/AP_Compass.cpp
index e2a0ed5acd..837ac69a41 100644
--- a/libraries/AP_Compass/AP_Compass.cpp
+++ b/libraries/AP_Compass/AP_Compass.cpp
@@ -14,9 +14,9 @@
 		heading : Magnetic heading
 		heading_X : Magnetic heading X component
 		heading_Y : Magnetic heading Y component
-		mag_X : Raw X axis magnetometer data
-		mag_Y : Raw Y axis magnetometer data
-		mag_Z : Raw Z axis magnetometer data		
+		mag_x : Raw X axis magnetometer data
+		mag_y : Raw Y axis magnetometer data
+		mag_z : Raw Z axis magnetometer data		
 	
 	Methods:
 		init() : initialization of I2C and sensor
@@ -78,13 +78,13 @@ AP_Compass::update()
 	// All bytes received?
 	if (i == 6)	{
 		// MSB byte first, then LSB, X,Y,Z
-		mag_X = -((((int)buff[0]) << 8) | buff[1]);		// X axis
-		mag_Y =  ((((int)buff[2]) << 8) | buff[3]);		// Y axis
-		mag_Z = -((((int)buff[4]) << 8) | buff[5]);		// Z axis
+		mag_x = -((((int)buff[0]) << 8) | buff[1]);		// X axis
+		mag_y =  ((((int)buff[2]) << 8) | buff[3]);		// Y axis
+		mag_z = -((((int)buff[4]) << 8) | buff[5]);		// Z axis
 	}
-	mag.x = mag_X;
-	mag.y = mag_Y;
-	mag.z = mag_Z
+	mag.x = mag_x;
+	mag.y = mag_y;
+	mag.z = mag_z
 }
 
 void
@@ -103,10 +103,10 @@ AP_Compass::calculate(float roll, float pitch)
 	sin_pitch = sin(pitch);
 	
 	// Tilt compensated Magnetic field X component:
-	head_X = mag_X * cos_pitch + mag_Y * sin_roll * sin_pitch + mag_Z * cos_roll * sin_pitch;
+	head_X = mag_x * cos_pitch + mag_y * sin_roll * sin_pitch + mag_z * cos_roll * sin_pitch;
 	
 	// Tilt compensated Magnetic field Y component:
-	head_Y = mag_Y * cos_roll - mag_Z * sin_roll;
+	head_Y = mag_y * cos_roll - mag_z * sin_roll;
 	
 	// Magnetic heading
 	heading = atan2(-head_Y, head_X);
diff --git a/libraries/AP_Compass/AP_Compass_HIL.cpp b/libraries/AP_Compass/AP_Compass_HIL.cpp
index 46f8a71605..8b5fc13e68 100644
--- a/libraries/AP_Compass/AP_Compass_HIL.cpp
+++ b/libraries/AP_Compass/AP_Compass_HIL.cpp
@@ -20,11 +20,11 @@ AP_Compass_HIL::AP_Compass_HIL() : orientation(0), declination(0.0)
   offset[2] = 0;
   
   // initialise orientation matrix
-  orientationMatrix = ROTATION_NONE;
+  orientation_matrix = ROTATION_NONE;
 }
 
 // Public Methods //////////////////////////////////////////////////////////////
-bool AP_Compass_HIL::init(int initialiseWireLib)
+bool AP_Compass_HIL::init(int initialise_wire_lib)
 {
   unsigned long currentTime = millis();  // record current time
   int numAttempts = 0;
@@ -83,7 +83,7 @@ void AP_Compass_HIL::calculate(float roll, float pitch)
   if( orientation == 0 )
       rotMagVec = Vector3f(magX+offset[0],magY+offset[1],magZ+offset[2]);  
   else
-      rotMagVec = orientationMatrix*Vector3f(magX+offset[0],magY+offset[1],magZ+offset[2]); 
+      rotMagVec = orientation_matrix*Vector3f(magX+offset[0],magY+offset[1],magZ+offset[2]); 
   
   // Tilt compensated Magnetic field X component:
   headX = rotMagVec.x*cos_pitch+rotMagVec.y*sin_roll*sin_pitch+rotMagVec.z*cos_roll*sin_pitch;
@@ -103,27 +103,27 @@ void AP_Compass_HIL::calculate(float roll, float pitch)
   }
         
   // Optimization for external DCM use. Calculate normalized components
-  headingX = cos(heading);
-  headingY = sin(heading);
+  heading_x = cos(heading);
+  heading_y = sin(heading);
 }
 
-void AP_Compass_HIL::setOrientation(const Matrix3f &rotationMatrix)
+void AP_Compass_HIL::set_orientation(const Matrix3f &rotation_matrix)
 {
-    orientationMatrix = rotationMatrix;
-        if( orientationMatrix == ROTATION_NONE )
+    orientation_matrix = rotation_matrix;
+        if( orientation_matrix == ROTATION_NONE )
             orientation = 0;
         else
             orientation = 1;
 }
 
-void AP_Compass_HIL::setOffsets(int x, int y, int z)
+void AP_Compass_HIL::set_offsets(int x, int y, int z)
 {
     offset[0] = x;
         offset[1] = y;
         offset[2] = z;
 }
 
-void AP_Compass_HIL::setDeclination(float radians)
+void AP_Compass_HIL::set_declination(float radians)
 {
     declination = radians;
 }
diff --git a/libraries/AP_Compass/AP_Compass_HIL.h b/libraries/AP_Compass/AP_Compass_HIL.h
index b22e6dbfc2..67a13c0545 100644
--- a/libraries/AP_Compass/AP_Compass_HIL.h
+++ b/libraries/AP_Compass/AP_Compass_HIL.h
@@ -7,21 +7,23 @@
 
 class AP_Compass_HIL : public Compass
 {
-  private:
-	int orientation;
-	Matrix3f orientationMatrix;
-	float calibration[3];
-	int offset[3];
-	float declination;
   public:
 	AP_Compass_HIL();  // Constructor
-	bool init(int initialiseWireLib = 1);
-	void read();
-	void calculate(float roll, float pitch);
-	void setOrientation(const Matrix3f &rotationMatrix);
-	void setOffsets(int x, int y, int z);
-	void setDeclination(float radians);
-    void setHIL(float Mag_X, float Mag_Y, float Mag_Z);
+	
+	bool 		init(int initialise_wire_lib = 1);
+	void 		read();
+	void 		calculate(float roll, float pitch);
+	void 		set_orientation(const Matrix3f &rotation_matrix);
+	void 		set_offsets(int x, int y, int z);
+	void 		set_declination(float radians);
+    void 		setHIL(float Mag_X, float Mag_Y, float Mag_Z);
+
+  private:
+	int 		orientation;
+	Matrix3f 	orientation_matrix;
+	float 		calibration[3];
+	int 		offset[3];
+	float 		declination;
 };
 
 #endif
diff --git a/libraries/AP_Compass/AP_Compass_HMC5843.cpp b/libraries/AP_Compass/AP_Compass_HMC5843.cpp
index f901222628..24220acc51 100644
--- a/libraries/AP_Compass/AP_Compass_HMC5843.cpp
+++ b/libraries/AP_Compass/AP_Compass_HMC5843.cpp
@@ -13,20 +13,20 @@
 	
 	Variables:
 		heading : magnetic heading
-		headingX : magnetic heading X component
-		headingY : magnetic heading Y component
+		heading_x : magnetic heading X component
+		heading_y : magnetic heading Y component
 		magX : Raw X axis magnetometer data
 		magY : Raw Y axis magnetometer data
 		magZ : Raw Z axis magnetometer data		
-		lastUpdate : the time of the last successful reading		
+		last_update : the time of the last successful reading		
 	
 	Methods:
 		init() : Initialization of I2C and sensor
 		read() : Read Sensor data	
 		calculate(float roll, float pitch) : Calculate tilt adjusted heading
-		setOrientation(const Matrix3f &rotationMatrix) : Set orientation of compass
-		setOffsets(int x, int y, int z) : Set adjustments for HardIron disturbances
-		setDeclination(float radians) : Set heading adjustment between true north and magnetic north
+		set_orientation(const Matrix3f &rotation_matrix) : Set orientation of compass
+		set_offsets(int x, int y, int z) : Set adjustments for HardIron disturbances
+		set_declination(float radians) : Set heading adjustment between true north and magnetic north
 
 	To do : code optimization
 	Mount position : UPDATED
@@ -41,7 +41,7 @@
 #include <Wire.h>
 #include "AP_Compass_HMC5843.h"
 
-#define CompassAddress       0x1E
+#define COMPASS_ADDRESS       0x1E
 #define ConfigRegA           0x00
 #define ConfigRegB           0x01
 #define magGain              0x20
@@ -61,11 +61,11 @@ AP_Compass_HMC5843::AP_Compass_HMC5843() : orientation(0), declination(0.0)
   offset[2] = 0;
   
   // initialise orientation matrix
-  orientationMatrix = ROTATION_NONE;
+  orientation_matrix = ROTATION_NONE;
 }
 
 // Public Methods //////////////////////////////////////////////////////////////
-bool AP_Compass_HMC5843::init(int initialiseWireLib)
+bool AP_Compass_HMC5843::init(int initialise_wire_lib)
 {
   unsigned long currentTime = millis();  // record current time
   int numAttempts = 0;
@@ -87,7 +87,7 @@ bool AP_Compass_HMC5843::init(int initialiseWireLib)
 	  numAttempts++;
   
 	  // force positiveBias (compass should return 715 for all channels)
-	  Wire.beginTransmission(CompassAddress);
+	  Wire.beginTransmission(COMPASS_ADDRESS);
 	  Wire.send(ConfigRegA);
 	  Wire.send(PositiveBiasConfig);
 	  if (0 != Wire.endTransmission())
@@ -95,13 +95,13 @@ bool AP_Compass_HMC5843::init(int initialiseWireLib)
 	  delay(50);
 	  
 	  // set gains
-	  Wire.beginTransmission(CompassAddress);
+	  Wire.beginTransmission(COMPASS_ADDRESS);
 	  Wire.send(ConfigRegB);
 	  Wire.send(magGain);
 	  Wire.endTransmission();
 	  delay(10);  
 
-	  Wire.beginTransmission(CompassAddress);
+	  Wire.beginTransmission(COMPASS_ADDRESS);
 	  Wire.send(ModeRegister);
 	  Wire.send(SingleConversion);
 	  Wire.endTransmission();
@@ -123,13 +123,13 @@ bool AP_Compass_HMC5843::init(int initialiseWireLib)
 	  }
 		
 	  // leave test mode
-	  Wire.beginTransmission(CompassAddress);
+	  Wire.beginTransmission(COMPASS_ADDRESS);
 	  Wire.send(ConfigRegA);
 	  Wire.send(NormalOperation);
 	  Wire.endTransmission();
 	  delay(50);
 
-	  Wire.beginTransmission(CompassAddress);
+	  Wire.beginTransmission(COMPASS_ADDRESS);
 	  Wire.send(ModeRegister);
 	  Wire.send(ContinuousConversion);        // Set continuous mode (default to 10Hz)
 	  Wire.endTransmission();                 // End transmission
@@ -144,12 +144,12 @@ void AP_Compass_HMC5843::read()
   int i = 0;
   byte buff[6];
  
-  Wire.beginTransmission(CompassAddress); 
+  Wire.beginTransmission(COMPASS_ADDRESS); 
   Wire.send(0x03);        //sends address to read from
   Wire.endTransmission(); //end transmission
   
-  //Wire.beginTransmission(CompassAddress); 
-  Wire.requestFrom(CompassAddress, 6);    // request 6 bytes from device
+  //Wire.beginTransmission(COMPASS_ADDRESS); 
+  Wire.requestFrom(COMPASS_ADDRESS, 6);    // request 6 bytes from device
   while(Wire.available())     
   { 
     buff[i] = Wire.receive();  // receive one byte
@@ -163,7 +163,7 @@ void AP_Compass_HMC5843::read()
     magX = -((((int)buff[0]) << 8) | buff[1]) * calibration[0];    // X axis
     magY = ((((int)buff[2]) << 8) | buff[3]) * calibration[1];    // Y axis
     magZ = -((((int)buff[4]) << 8) | buff[5]) * calibration[2];    // Z axis
-    lastUpdate = millis();  // record time of update
+    last_update = millis();  // record time of update
   }
 }
 
@@ -186,7 +186,7 @@ void AP_Compass_HMC5843::calculate(float roll, float pitch)
   if( orientation == 0 )
       rotmagVec = Vector3f(magX+offset[0],magY+offset[1],magZ+offset[2]);  
   else
-      rotmagVec = orientationMatrix*Vector3f(magX+offset[0],magY+offset[1],magZ+offset[2]); 
+      rotmagVec = orientation_matrix*Vector3f(magX+offset[0],magY+offset[1],magZ+offset[2]); 
   
   // Tilt compensated magnetic field X component:
   headX = rotmagVec.x*cos_pitch+rotmagVec.y*sin_roll*sin_pitch+rotmagVec.z*cos_roll*sin_pitch;
@@ -206,27 +206,27 @@ void AP_Compass_HMC5843::calculate(float roll, float pitch)
   }
 	
   // Optimization for external DCM use. Calculate normalized components
-  headingX = cos(heading);
-  headingY = sin(heading);
+  heading_x = cos(heading);
+  heading_y = sin(heading);
 }
 
-void AP_Compass_HMC5843::setOrientation(const Matrix3f &rotationMatrix)
+void AP_Compass_HMC5843::set_orientation(const Matrix3f &rotation_matrix)
 {
-    orientationMatrix = rotationMatrix;
-	if( orientationMatrix == ROTATION_NONE )
+    orientation_matrix = rotation_matrix;
+	if( orientation_matrix == ROTATION_NONE )
 	    orientation = 0;
 	else
 	    orientation = 1;
 }
 
-void AP_Compass_HMC5843::setOffsets(int x, int y, int z)
+void AP_Compass_HMC5843::set_offsets(int x, int y, int z)
 {
     offset[0] = x;
 	offset[1] = y;
 	offset[2] = z;
 }
 
-void AP_Compass_HMC5843::setDeclination(float radians)
+void AP_Compass_HMC5843::set_declination(float radians)
 {
     declination = radians;
 }
diff --git a/libraries/AP_Compass/AP_Compass_HMC5843.h b/libraries/AP_Compass/AP_Compass_HMC5843.h
index 346fac394d..0364b5c5a4 100644
--- a/libraries/AP_Compass/AP_Compass_HMC5843.h
+++ b/libraries/AP_Compass/AP_Compass_HMC5843.h
@@ -62,7 +62,7 @@ class AP_Compass_HMC5843 : public Compass
 {
   private:
 	int orientation;
-	Matrix3f orientationMatrix;
+	Matrix3f orientation_matrix;
 	float calibration[3];
 	int offset[3];
 	float declination;
@@ -71,8 +71,8 @@ class AP_Compass_HMC5843 : public Compass
 	bool init(int initialiseWireLib = 1);
 	void read();
 	void calculate(float roll, float pitch);
-	void setOrientation(const Matrix3f &rotationMatrix);
-	void setOffsets(int x, int y, int z);
-	void setDeclination(float radians);
+	void set_orientation(const Matrix3f &rotation_matrix);
+	void set_offsets(int x, int y, int z);
+	void set_declination(float radians);
 };
 #endif
diff --git a/libraries/AP_Compass/Compass.h b/libraries/AP_Compass/Compass.h
index 5098a7088c..a09354638a 100644
--- a/libraries/AP_Compass/Compass.h
+++ b/libraries/AP_Compass/Compass.h
@@ -7,20 +7,19 @@
 class Compass
 {
   public:
-	int magX;
-	int magY;
-	int magZ;
+	int mag_x;
+	int mag_y;
+	int mag_z;
 	float heading;
-	float headingX;
-	float headingY;
-	unsigned long lastUpdate;	
+	float heading_x;
+	float heading_y;
+	unsigned long last_update;	
 	
-	// 
-	virtual bool init(int initialiseWireLib = 1);
+	virtual bool init(int initialise_wire_lib = 1);
 	virtual void read();
 	virtual void calculate(float roll, float pitch);
-	virtual void setOrientation(const Matrix3f &rotationMatrix);
-	virtual void setOffsets(int x, int y, int z);
-	virtual void setDeclination(float radians);
+	virtual void set_orientation(const Matrix3f &rotation_matrix);
+	virtual void set_offsets(int x, int y, int z);
+	virtual void set_declination(float radians);
 };
 #endif
diff --git a/libraries/AP_Compass/examples/AP_Compass_test/AP_Compass_test.pde b/libraries/AP_Compass/examples/AP_Compass_test/AP_Compass_test.pde
index 1a69883789..cd1bd031e7 100644
--- a/libraries/AP_Compass/examples/AP_Compass_test/AP_Compass_test.pde
+++ b/libraries/AP_Compass/examples/AP_Compass_test/AP_Compass_test.pde
@@ -4,9 +4,9 @@
 */
 
 #include <Wire.h>
-#include <AP_Compass.h> // Compass Library
+#include <AP_Compass_HMC5843.h> // Compass Library
 
-AP_Compass compass;
+AP_Compass_HMC5843 compass;
 
 unsigned long timer;
 
@@ -14,7 +14,7 @@ void setup()
 {	
 	compass.init();	 // Initialization
 	Serial.begin(38400);
-  Serial.println("AP Compass library test (HMC5843)");
+	Serial.println("AP Compass library test (HMC5843)");
 	delay(1000);
 	timer = millis();
 }
@@ -25,16 +25,16 @@ void loop()
 	
 	if((millis()- timer) > 100){
 		timer = millis();
-		compass.update();
+		compass.read();
 		compass.calculate(0, 0);	// roll = 0, pitch = 0 for this example
 	    Serial.print("Heading:");
-		Serial.print(compass.ground_course,DEC);
+		Serial.print(compass.heading, DEC);
     	Serial.print("  (");
-		Serial.print(compass.mag_X);
+		Serial.print(compass.mag_x);
 	    Serial.print(",");
-		Serial.print(compass.mag_Y);
+		Serial.print(compass.mag_y);
     	Serial.print(",");
-		Serial.print(compass.mag_Z);
+		Serial.print(compass.mag_z);
    		Serial.println(" )");
 	}
 }
\ No newline at end of file
diff --git a/libraries/AP_Compass/keywords.txt b/libraries/AP_Compass/keywords.txt
index c53c5c878c..5741e14ca2 100644
--- a/libraries/AP_Compass/keywords.txt
+++ b/libraries/AP_Compass/keywords.txt
@@ -7,9 +7,9 @@ calculate	KEYWORD2
 heading	KEYWORD2
 heading_X	KEYWORD2
 heading_Y	KEYWORD2
-mag_X	KEYWORD2
-mag_Y	KEYWORD2
-mag_Z	KEYWORD2
+mag_x	KEYWORD2
+mag_y	KEYWORD2
+mag_z	KEYWORD2