diff --git a/libraries/AP_GPS/AP_GPS.h b/libraries/AP_GPS/AP_GPS.h
index 5410220bae..5f3a149ead 100644
--- a/libraries/AP_GPS/AP_GPS.h
+++ b/libraries/AP_GPS/AP_GPS.h
@@ -12,3 +12,4 @@
 #include "AP_GPS_None.h"
 #include "AP_GPS_Auto.h"
 #include "AP_GPS_HIL.h"
+#include "AP_GPS_Shim.h"	// obsoletes AP_GPS_HIL, use in preference
diff --git a/libraries/AP_GPS/AP_GPS_Shim.h b/libraries/AP_GPS/AP_GPS_Shim.h
new file mode 100644
index 0000000000..9e402698b6
--- /dev/null
+++ b/libraries/AP_GPS/AP_GPS_Shim.h
@@ -0,0 +1,29 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
+//
+//  Shim GPS driver, for use when the actual GPS data is coming from somewhere else.
+//  Code by Mike Smith
+//
+//	This library is free software; you can redistribute it and / or
+//	modify it under the terms of the GNU Lesser General Public
+//	License as published by the Free Software Foundation; either
+//	version 2.1 of the License, or (at your option) any later version.
+//
+//
+#ifndef AP_GPS_Shim_h
+#define AP_GPS_Shim_h
+
+#include <GPS.h>
+
+class AP_GPS_Shim : public GPS
{
+public:
+	AP_GPS_Shim() : GPS(NULL) {}
+	virtual void init(void) {};
+	virtual bool read(void) {
		bool updated = _updated;
		_updated = false;
		return _updated
	};
+
+	/// Set-and-mark-updated macro for the public member variables; each instance
+	/// defines a member function set_<variable>(<type>)
+	///
#define __GPS_SHIM_SET(__name) void set_##__name(typeof(GPS::__name) v) { __name = v; _updated = true; }
	__GPS_SHIM_SET(time);
	__GPS_SHIM_SET(latitude);
	__GPS_SHIM_SET(longitude);
	__GPS_SHIM_SET(altitude);
	__GPS_SHIM_SET(ground_speed);
	__GPS_SHIM_SET(ground_course);
	__GPS_SHIM_SET(speed_3d);
	__GPS_SHIM_SET(hdop);
#undef __GPS_SHIM_SET

private:
+	bool	_updated;		///< set anytime a member is updated, cleared when read() returns true
+};
+
+#endif	// AP_GPS_HIL_H