diff --git a/ArduCopter/GCS_Mavlink.pde b/ArduCopter/GCS_Mavlink.pde
index d119600849..7d5d74204f 100644
--- a/ArduCopter/GCS_Mavlink.pde
+++ b/ArduCopter/GCS_Mavlink.pde
@@ -1877,7 +1877,7 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
             mavlink_msg_gps_raw_decode(msg, &packet);
 
             // set gps hil sensor
-            g_gps->setHIL(packet.usec/1000.0,packet.lat,packet.lon,packet.alt,
+            g_gps->setHIL(packet.usec/1000,packet.lat,packet.lon,packet.alt,
                           packet.v,packet.hdg,0,0);
             if (gps_base_alt == 0) {
                 gps_base_alt = packet.alt*100;
@@ -1944,7 +1944,7 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
 			float cog = wrap_360(ToDeg(atan2(packet.vx, packet.vy)) * 100);
 
             // set gps hil sensor
-            g_gps->setHIL(packet.time_usec/1000.0,
+            g_gps->setHIL(packet.time_usec/1000,
                           packet.lat*1.0e-7, packet.lon*1.0e-7, packet.alt*1.0e-3,
                           vel*1.0e-2, cog*1.0e-2, 0, 10);
 
@@ -2006,7 +2006,7 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
 			mavlink_msg_gps_raw_decode(msg, &packet);
 
 			// set gps hil sensor
-			g_gps->setHIL(packet.usec/1000.0,packet.lat,packet.lon,packet.alt,
+			g_gps->setHIL(packet.usec/1000,packet.lat,packet.lon,packet.alt,
 			packet.v,packet.hdg,0,0);
 			break;
 		}
diff --git a/libraries/AP_GPS/AP_GPS_HIL.cpp b/libraries/AP_GPS/AP_GPS_HIL.cpp
index 66dc206332..1ffa45c992 100644
--- a/libraries/AP_GPS/AP_GPS_HIL.cpp
+++ b/libraries/AP_GPS/AP_GPS_HIL.cpp
@@ -38,7 +38,7 @@ bool AP_GPS_HIL::read(void)
     return result;
 }
 
-void AP_GPS_HIL::setHIL(long _time, float _latitude, float _longitude, float _altitude,
+void AP_GPS_HIL::setHIL(uint32_t _time, float _latitude, float _longitude, float _altitude,
                         float _ground_speed, float _ground_course, float _speed_3d, uint8_t _num_sats)
 {
     time 			= _time;
diff --git a/libraries/AP_GPS/AP_GPS_HIL.h b/libraries/AP_GPS/AP_GPS_HIL.h
index 939815d0d0..1b802c6ea4 100644
--- a/libraries/AP_GPS/AP_GPS_HIL.h
+++ b/libraries/AP_GPS/AP_GPS_HIL.h
@@ -30,7 +30,7 @@ public:
      * @param speed_3d - ground speed in meters/second
      * @param altitude - altitude in meters
      */
-    virtual void setHIL(long time, float latitude, float longitude, float altitude,
+    virtual void setHIL(uint32_t time, float latitude, float longitude, float altitude,
                         float ground_speed, float ground_course, float speed_3d, uint8_t num_sats);
 
 private:
diff --git a/libraries/AP_GPS/GPS.cpp b/libraries/AP_GPS/GPS.cpp
index 7df3b0d673..ea7e336153 100644
--- a/libraries/AP_GPS/GPS.cpp
+++ b/libraries/AP_GPS/GPS.cpp
@@ -70,7 +70,7 @@ GPS::update(void)
 }
 
 void
-GPS::setHIL(long _time, float _latitude, float _longitude, float _altitude,
+GPS::setHIL(uint32_t _time, float _latitude, float _longitude, float _altitude,
             float _ground_speed, float _ground_course, float _speed_3d, uint8_t _num_sats)
 {
 }
diff --git a/libraries/AP_GPS/GPS.h b/libraries/AP_GPS/GPS.h
index bd6410ce97..7cadcb8400 100644
--- a/libraries/AP_GPS/GPS.h
+++ b/libraries/AP_GPS/GPS.h
@@ -112,7 +112,7 @@ public:
     bool	print_errors; 	///< deprecated
 
     // HIL support
-    virtual void setHIL(long time, float latitude, float longitude, float altitude,
+    virtual void setHIL(uint32_t time, float latitude, float longitude, float altitude,
                         float ground_speed, float ground_course, float speed_3d, uint8_t num_sats);
 
     /// Time in milliseconds after which we will assume the GPS is no longer