APM: Added RST_MISSION_CH option

this allows a pilot to reset the mission using a transmitter
switch. Very useful for repeating a mission during testing

ArduPlane/Parameters.h

@@ -70,6 +70,7 @@ public:
 		k_param_land_pitch_cd,
 		k_param_ins,
         k_param_stick_mixing,
+        k_param_reset_mission_chan,
 
 		// 110: Telemetry control
 		//
@@ -289,6 +290,7 @@ public:
     AP_Int16    num_resets;
     AP_Int16    log_bitmask;
     AP_Int8		reset_switch_chan;
+    AP_Int8		reset_mission_chan;
     AP_Int8		manual_level;
     AP_Int32    airspeed_cruise_cm;
     AP_Int32    RTL_altitude_cm;

ArduPlane/Parameters.pde

@@ -379,10 +379,16 @@ const AP_Param::Info var_info[] PROGMEM = {
 
     // @Param: RST_SWITCH_CH
 	// @DisplayName: Reset Switch Channel
-	// @Description: RC channel to use to reset to last flight mode after geofence takeover
+	// @Description: RC channel to use to reset to last flight mode	after geofence takeover.
 	// @User: Advanced
 	GSCALAR(reset_switch_chan,      "RST_SWITCH_CH",  0),
 
+    // @Param: RST_MISSION_CH
+	// @DisplayName: Reset Mission Channel
+	// @Description: RC channel to use to reset the mission to the first waypoint. When this channel goes above 1750 the mission is reset. Set RST_MISSION_CH to 0 to disable.
+	// @User: Advanced
+	GSCALAR(reset_mission_chan,      "RST_MISSION_CH",  0),
+
     // @Param: TRIM_ARSPD_CM
 	// @DisplayName: Target airspeed
 	// @Description: Airspeed in cm/s to aim for when airspeed is enabled in auto mode

ArduPlane/control_modes.pde

@@ -39,6 +39,13 @@ static void read_control_switch()
 		reset_I();
 	}
 
+    if (g.reset_mission_chan != 0 && 
+        APM_RC.InputCh(g.reset_mission_chan-1) > RESET_SWITCH_CHAN_PWM) {
+        // reset to first waypoint in mission
+		prev_WP = current_loc;
+        change_command(1);
+    }
+
     switch_debouncer = false;
 
     if (g.inverted_flight_ch != 0) {