diff --git a/libraries/PID/PID.h b/libraries/PID/PID.h
index 9b0fbd5b52..7a440ea384 100644
--- a/libraries/PID/PID.h
+++ b/libraries/PID/PID.h
@@ -7,95 +7,113 @@
 #define PID_h
 
 #include <AP_Common.h>
-#include <math.h>		// for fabs()
+#include <math.h>               // for fabs()
 
 /// @class	PID
 /// @brief	Object managing one PID control
 class PID {
 public:
 
-    PID(const float &initial_p = 0.0,
-        const float &initial_i = 0.0,
-        const float &initial_d = 0.0,
-        const int16_t &initial_imax = 0)
+    PID(const float &   initial_p = 0.0,
+        const float &   initial_i = 0.0,
+        const float &   initial_d = 0.0,
+        const int16_t & initial_imax = 0)
     {
-		_kp = initial_p;
-		_ki = initial_i;
-		_kd = initial_d;
-		_imax = initial_imax;
-	}
+        _kp = initial_p;
+        _ki = initial_i;
+        _kd = initial_d;
+        _imax = initial_imax;
+    }
 
-	/// Iterate the PID, return the new control value
-	///
-	/// Positive error produces positive output.
-	///
-	/// @param error	The measured error value
-	/// @param dt		The time delta in milliseconds (note
-	///					that update interval cannot be more
-	///					than 65.535 seconds due to limited range
-	///					of the data type).
-	/// @param scaler	An arbitrary scale factor
-	///
-	/// @returns		The updated control output.
-	///
-	int32_t	get_pid(int32_t error, float scaler = 1.0);
+    /// Iterate the PID, return the new control value
+    ///
+    /// Positive error produces positive output.
+    ///
+    /// @param error	The measured error value
+    /// @param dt		The time delta in milliseconds (note
+    ///					that update interval cannot be more
+    ///					than 65.535 seconds due to limited range
+    ///					of the data type).
+    /// @param scaler	An arbitrary scale factor
+    ///
+    /// @returns		The updated control output.
+    ///
+    int32_t        get_pid(int32_t error, float scaler = 1.0);
 
-	/// Reset the PID integrator
-	///
-	void	reset_I();
+    /// Reset the PID integrator
+    ///
+    void        reset_I();
 
-	/// Load gain properties
-	///
-	void 	load_gains();
+    /// Load gain properties
+    ///
+    void        load_gains();
 
-	/// Save gain properties
-	///
-	void 	save_gains();
+    /// Save gain properties
+    ///
+    void        save_gains();
 
-	/// @name	parameter accessors
-	//@{
+    /// @name	parameter accessors
+    //@{
 
-	/// Overload the function call operator to permit relatively easy initialisation
-	void operator() (const float p,
-	                 const float i,
-	                 const float d,
-	                 const int16_t imaxval) {
-		_kp = p; _ki = i; _kd = d; _imax = imaxval;
-	}
+    /// Overload the function call operator to permit relatively easy initialisation
+    void operator        () (const float    p,
+                             const float    i,
+                             const float    d,
+                             const int16_t  imaxval) {
+        _kp = p; _ki = i; _kd = d; _imax = imaxval;
+    }
 
-	float	kP() const				{ return _kp.get(); }
-	float	kI() const 				{ return _ki.get(); }
-	float	kD() const 				{ return _kd.get(); }
-	int16_t	imax() const			{ return _imax.get(); }
+    float        kP() const {
+        return _kp.get();
+    }
+    float        kI() const {
+        return _ki.get();
+    }
+    float        kD() const {
+        return _kd.get();
+    }
+    int16_t        imax() const {
+        return _imax.get();
+    }
 
-	void	kP(const float v)		{ _kp.set(v); }
-	void	kI(const float v)		{ _ki.set(v); }
-	void	kD(const float v)		{ _kd.set(v); }
-	void	imax(const int16_t v)	{ _imax.set(abs(v)); }
+    void        kP(const float v)               {
+        _kp.set(v);
+    }
+    void        kI(const float v)               {
+        _ki.set(v);
+    }
+    void        kD(const float v)               {
+        _kd.set(v);
+    }
+    void        imax(const int16_t v)   {
+        _imax.set(abs(v));
+    }
 
-	float	get_integrator() const	{ return _integrator; }
+    float        get_integrator() const {
+        return _integrator;
+    }
 
-    static const struct AP_Param::GroupInfo var_info[];
+    static const struct AP_Param::GroupInfo        var_info[];
 
 private:
-	AP_Float			_kp;
-	AP_Float			_ki;
-	AP_Float			_kd;
-	AP_Int16			_imax;
+    AP_Float        _kp;
+    AP_Float        _ki;
+    AP_Float        _kd;
+    AP_Int16        _imax;
 
-	float				_integrator;		///< integrator value
-	int32_t				_last_error;		///< last error for derivative
-	float				_last_derivative; 	///< last derivative for low-pass filter
-	uint32_t			_last_t;
+    float           _integrator;                                ///< integrator value
+    int32_t         _last_error;                                ///< last error for derivative
+    float           _last_derivative;                           ///< last derivative for low-pass filter
+    uint32_t        _last_t;
 
-	int32_t	_get_pid(int32_t error, uint16_t dt, float scaler);
+    int32_t         _get_pid(int32_t error, uint16_t dt, float scaler);
 
-	/// Low pass filter cut frequency for derivative calculation.
-	///
-	/// 20 Hz becasue anything over that is probably noise, see
-	/// http://en.wikipedia.org/wiki/Low-pass_filter.
-	///
-	static const uint8_t _fCut = 20;
+    /// Low pass filter cut frequency for derivative calculation.
+    ///
+    /// 20 Hz becasue anything over that is probably noise, see
+    /// http://en.wikipedia.org/wiki/Low-pass_filter.
+    ///
+    static const uint8_t        _fCut = 20;
 };
 
 #endif