APM: added LAND_FLARE_ALT and LAND_FLARE_SEC

these allow you to configure the altitude and time before touchdown to
flare the plane and lock the heading. Useful on larger planes.

ArduPlane/Parameters.h

@@ -71,6 +71,8 @@ public:
 		k_param_ins,
         k_param_stick_mixing,
         k_param_reset_mission_chan,
+		k_param_land_flare_alt,
+		k_param_land_flare_sec,
 
 		// 110: Telemetry control
 		//
@@ -297,6 +299,8 @@ public:
     AP_Int32    airspeed_cruise_cm;
     AP_Int32    RTL_altitude_cm;
 	AP_Int16	land_pitch_cd;
+	AP_Float	land_flare_alt;
+	AP_Float	land_flare_sec;
     AP_Int32    min_gndspeed_cm;
     AP_Int16    pitch_trim_cd;
     AP_Int16    FBWB_min_altitude_cm;

ArduPlane/Parameters.pde

@@ -79,6 +79,22 @@ const AP_Param::Info var_info[] PROGMEM = {
 	// @User: Advanced
 	GSCALAR(land_pitch_cd,          "LAND_PITCH_CD",  0),
 
+	// @Param: land_flare_alt
+	// @DisplayName: Landing flare altitude
+	// @Description: Altitude in autoland at which to lock heading and flare to the LAND_PITCH_CD pitch
+	// @Units: meters
+	// @Increment: 0.1
+	// @User: Advanced
+	GSCALAR(land_flare_alt,          "LAND_FLARE_ALT",  3.0),
+
+	// @Param: land_flare_sec
+	// @DisplayName: Landing flare time
+	// @Description: Time before landing point at which to lock heading and flare to the LAND_PITCH_CD pitch
+	// @Units: seconds
+	// @Increment: 0.1
+	// @User: Advanced
+	GSCALAR(land_flare_sec,          "LAND_FLARE_SEC",  2.0),	
+
     // @Param: XTRK_GAIN_SC
 	// @DisplayName: Crosstrack Gain
 	// @Description: The scale between distance off the line and angle to meet the line (in Degrees * 100)

ArduPlane/commands_logic.pde

@@ -317,14 +317,14 @@ static bool verify_land()
 
     // Set land_complete if we are within 2 seconds distance or within
     // 3 meters altitude of the landing point
-	if (((wp_distance > 0) && (wp_distance <= (2*g_gps->ground_speed/100)))
+	if (((wp_distance > 0) && (wp_distance <= (g.land_flare_sec*g_gps->ground_speed*0.01)))
-		|| (current_loc.alt <= next_WP.alt + 300)){
+		|| (current_loc.alt <= next_WP.alt + g.land_flare_alt*100)) {
 
 		land_complete = true;
 
 		if (hold_course == -1) {
-            // we have just reached the threshold of 2 seconds or 3
+            // we have just reached the threshold of to flare for landing.
-			// meters to landing. We now don't want to do any radical
+			// We now don't want to do any radical
 			// turns, as rolling could put the wings into the runway.
 			// To prevent further turns we set hold_course to the
 			// current heading. Previously we set this to
@@ -333,7 +333,7 @@ static bool verify_land()
 			// sudden large roll correction which is very nasty at
 			// this point in the landing.
 			hold_course = ahrs.yaw_sensor;
-            gcs_send_text_fmt(PSTR("Holding course %ld"), hold_course);
+            gcs_send_text_fmt(PSTR("Land Complete - Hold course %ld"), hold_course);
 		}
 
         // reload any airspeed or groundspeed parameters that may have