diff --git a/msg/VehicleCommand.msg b/msg/VehicleCommand.msg
index b147bef092..4bce9173d7 100644
--- a/msg/VehicleCommand.msg
+++ b/msg/VehicleCommand.msg
@@ -165,7 +165,10 @@ int8 ARMING_ACTION_ARM = 1
 uint8 GRIPPER_ACTION_RELEASE = 0
 uint8 GRIPPER_ACTION_GRAB = 1
 
-uint8 ORB_QUEUE_LENGTH = 8
+uint8 frame                     # The coordinate system of the COMMAND.
+uint8 FRAME_UNKNOWN             = 0 # Not specified.
+uint8 FRAME_GLOBAL              = 1 # Global (WGS84) coordinate frame + MSL altitude.
+uint8 FRAME_GLOBAL_RELATIVE_ALT = 2 # Global (WGS84) coordinate frame + altitude relative to the home position.
 
 float32 param1			# Parameter 1, as defined by MAVLink uint16 VEHICLE_CMD enum.
 float32 param2			# Parameter 2, as defined by MAVLink uint16 VEHICLE_CMD enum.
@@ -184,4 +187,6 @@ bool from_external
 
 uint16 COMPONENT_MODE_EXECUTOR_START = 1000
 
+uint8 ORB_QUEUE_LENGTH = 8
+
 # TOPICS vehicle_command gimbal_v1_command vehicle_command_mode_executor
diff --git a/src/modules/mavlink/mavlink_receiver.cpp b/src/modules/mavlink/mavlink_receiver.cpp
index 0385c6a1eb..7667506d9a 100644
--- a/src/modules/mavlink/mavlink_receiver.cpp
+++ b/src/modules/mavlink/mavlink_receiver.cpp
@@ -469,6 +469,24 @@ MavlinkReceiver::handle_message_command_int(mavlink_message_t *msg)
 	vcmd.param3 = cmd_mavlink.param3;
 	vcmd.param4 = cmd_mavlink.param4;
 
+	switch (cmd_mavlink.frame) {
+	case MAV_FRAME_GLOBAL:
+
+	// FALLTHROUGH
+	case MAV_FRAME_GLOBAL_INT:
+		vcmd.frame = vehicle_command_s::FRAME_GLOBAL;
+		break;
+
+	case MAV_FRAME_GLOBAL_RELATIVE_ALT_INT:
+		vcmd.frame = vehicle_command_s::FRAME_GLOBAL_RELATIVE_ALT;
+		break;
+
+	default:
+		vcmd.frame = vehicle_command_s::FRAME_UNKNOWN;
+		PX4_WARN("invalid frame %" PRIu8 " for command %" PRIu16, cmd_mavlink.frame, cmd_mavlink.command);
+		break;
+	}
+
 	if (cmd_mavlink.x == INT32_MAX && cmd_mavlink.y == INT32_MAX) {
 		// INT32_MAX for x and y means to ignore it.
 		vcmd.param5 = (double)NAN;
diff --git a/src/modules/navigator/land.cpp b/src/modules/navigator/land.cpp
index b6a951d1b7..717090bf0a 100644
--- a/src/modules/navigator/land.cpp
+++ b/src/modules/navigator/land.cpp
@@ -108,6 +108,7 @@ Land::on_active()
 		vehicle_command_s vcmd = {};
 
 		vcmd.command = vehicle_command_s::VEHICLE_CMD_DO_REPOSITION;
+		vcmd.frame = vehicle_command_s::FRAME_GLOBAL;
 		vcmd.param1 = -1;
 		vcmd.param2 = 1;
 		vcmd.param5 = _navigator->get_global_position()->lat;
diff --git a/src/modules/navigator/mission_base.cpp b/src/modules/navigator/mission_base.cpp
index 595f548c83..8178203aee 100644
--- a/src/modules/navigator/mission_base.cpp
+++ b/src/modules/navigator/mission_base.cpp
@@ -855,6 +855,7 @@ MissionBase::do_abort_landing()
 	vehicle_command_s vcmd = {};
 
 	vcmd.command = vehicle_command_s::VEHICLE_CMD_DO_REPOSITION;
+	vcmd.frame = vehicle_command_s::FRAME_GLOBAL;
 	vcmd.param1 = -1;
 	vcmd.param2 = 1;
 	vcmd.param5 = _mission_item.lat;
diff --git a/src/modules/navigator/navigator_main.cpp b/src/modules/navigator/navigator_main.cpp
index d5ea7ac22d..280a84b92f 100644
--- a/src/modules/navigator/navigator_main.cpp
+++ b/src/modules/navigator/navigator_main.cpp
@@ -267,6 +267,7 @@ void Navigator::run()
 
 				vehicle_global_position_s position_setpoint{};
 
+				// latitude/longitude
 				if (PX4_ISFINITE(cmd.param5) && PX4_ISFINITE(cmd.param6)) {
 					position_setpoint.lat = cmd.param5;
 					position_setpoint.lon = cmd.param6;
@@ -276,7 +277,24 @@ void Navigator::run()
 					position_setpoint.lon = get_global_position()->lon;
 				}
 
-				position_setpoint.alt = PX4_ISFINITE(cmd.param7) ? cmd.param7 : get_global_position()->alt;
+				// altitude
+				if (PX4_ISFINITE(cmd.param7)) {
+					switch (cmd.frame) {
+					default:
+
+					// FALLTHROUGH
+					case vehicle_command_s::FRAME_GLOBAL:
+						position_setpoint.alt = cmd.param7;
+						break;
+
+					case vehicle_command_s::FRAME_GLOBAL_RELATIVE_ALT:
+						position_setpoint.alt = cmd.param7 + get_home_position()->alt;
+						break;
+					}
+
+				} else {
+					position_setpoint.alt = get_global_position()->alt;
+				}
 
 				if (geofence_allows_position(position_setpoint)) {
 					position_setpoint_triplet_s *rep = get_reposition_triplet();