feat(mavlink): ESTIMATOR_SENSOR_FUSION_STATUS stream

Add MAVLink stream that maps EstimatorFusionControl uORB message to
ESTIMATOR_SENSOR_FUSION_STATUS, exposing per-sensor intended/active
bitmasks to the GCS.

src/modules/ekf2/EKF2.cpp

@@ -2037,7 +2037,7 @@ void EKF2::PublishFusionControl(const hrt_abstime &timestamp)
 	msg.rng_active    = cs.rng_hgt;
 	msg.mag_active    = cs.mag;
 	msg.aspd_active   = cs.fuse_aspd;
-	// msg.rngbcn_active = cs.rngbcn_fusion; // waiting for RangeBeacon PR
+	msg.rngbcn_active = cs.rngbcn_fusion;
 
 #if defined(CONFIG_EKF2_AUX_GLOBAL_POSITION)
 	{

src/modules/mavlink/mavlink_main.cpp

@@ -1466,6 +1466,9 @@ Mavlink::configure_streams_to_default(const char *configure_single_stream)
 		configure_stream_local("ESC_EEPROM", unlimited_rate);
 #endif
 		configure_stream_local("ESTIMATOR_STATUS", 0.5f);
+#if defined(MAVLINK_MSG_ID_ESTIMATOR_SENSOR_FUSION_STATUS)
+		configure_stream_local("ESTIMATOR_SENSOR_FUSION_STATUS", 0.5f);
+#endif
 		configure_stream_local("EXTENDED_SYS_STATE", 1.0f);
 		configure_stream_local("GIMBAL_DEVICE_ATTITUDE_STATUS", 5.0f);
 		configure_stream_local("GIMBAL_DEVICE_SET_ATTITUDE", 5.0f);
@@ -1545,6 +1548,9 @@ Mavlink::configure_streams_to_default(const char *configure_single_stream)
 		configure_stream_local("CURRENT_MODE", 0.5f);
 		configure_stream_local("EFI_STATUS", 2.0f);
 		configure_stream_local("ESTIMATOR_STATUS", 1.0f);
+#if defined(MAVLINK_MSG_ID_ESTIMATOR_SENSOR_FUSION_STATUS)
+		configure_stream_local("ESTIMATOR_SENSOR_FUSION_STATUS", 1.0f);
+#endif
 		configure_stream_local("EXTENDED_SYS_STATE", 5.0f);
 		configure_stream_local("GIMBAL_DEVICE_ATTITUDE_STATUS", 5.0f);
 		configure_stream_local("GIMBAL_DEVICE_SET_ATTITUDE", 5.0f);
@@ -1714,6 +1720,9 @@ Mavlink::configure_streams_to_default(const char *configure_single_stream)
 		configure_stream_local("ESC_EEPROM", unlimited_rate);
 #endif
 		configure_stream_local("ESTIMATOR_STATUS", 5.0f);
+#if defined(MAVLINK_MSG_ID_ESTIMATOR_SENSOR_FUSION_STATUS)
+		configure_stream_local("ESTIMATOR_SENSOR_FUSION_STATUS", 1.0f);
+#endif
 		configure_stream_local("EXTENDED_SYS_STATE", 2.0f);
 		configure_stream_local("GLOBAL_POSITION_INT", 10.0f);
 #if defined(MAVLINK_MSG_ID_GNSS_INTEGRITY)

src/modules/mavlink/mavlink_messages.cpp

@@ -70,6 +70,9 @@
 #include "streams/COMPONENT_METADATA.hpp"
 #include "streams/DISTANCE_SENSOR.hpp"
 #include "streams/EFI_STATUS.hpp"
+#if defined(MAVLINK_MSG_ID_ESTIMATOR_SENSOR_FUSION_STATUS)
+#include "streams/ESTIMATOR_SENSOR_FUSION_STATUS.hpp"
+#endif
 #include "streams/ESC_INFO.hpp"
 #include "streams/ESC_STATUS.hpp"
 #include "streams/ESTIMATOR_STATUS.hpp"
@@ -340,6 +343,9 @@ static const StreamListItem streams_list[] = {
 #if defined(ESTIMATOR_STATUS_HPP)
 	create_stream_list_item<MavlinkStreamEstimatorStatus>(),
 #endif // ESTIMATOR_STATUS_HPP
+#if defined(ESTIMATOR_SENSOR_FUSION_STATUS_HPP)
+	create_stream_list_item<MavlinkStreamEstimatorSensorFusionStatus>(),
+#endif // ESTIMATOR_SENSOR_FUSION_STATUS_HPP
 #if defined(VIBRATION_HPP)
 	create_stream_list_item<MavlinkStreamVibration>(),
 #endif // VIBRATION_HPP

src/modules/mavlink/streams/ESTIMATOR_SENSOR_FUSION_STATUS.hpp

@@ -0,0 +1,132 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2026 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef ESTIMATOR_SENSOR_FUSION_STATUS_HPP
+#define ESTIMATOR_SENSOR_FUSION_STATUS_HPP
+
+#include <uORB/topics/estimator_fusion_control.h>
+#include <cmath>
+
+/**
+ * Array index = ESTIMATOR_SENSOR_FUSION_SOURCE - 1:
+ *   [0] GPS    [1] OF     [2] EV    [3] AGP
+ *   [4] BARO   [5] RNG    [6] MAG   [7] ASPD  [8] RNGBCN
+ *
+ * Each element is a per-instance bitmask (bit 0 = instance 0, etc.).
+ */
+
+class MavlinkStreamEstimatorSensorFusionStatus : public MavlinkStream
+{
+public:
+	static MavlinkStream *new_instance(Mavlink *mavlink) { return new MavlinkStreamEstimatorSensorFusionStatus(mavlink); }
+
+	static constexpr const char *get_name_static() { return "ESTIMATOR_SENSOR_FUSION_STATUS"; }
+	static constexpr uint16_t get_id_static() { return MAVLINK_MSG_ID_ESTIMATOR_SENSOR_FUSION_STATUS; }
+
+	const char *get_name() const override { return get_name_static(); }
+	uint16_t get_id() override { return get_id_static(); }
+
+	unsigned get_size() override
+	{
+		return _estimator_fusion_control_sub.advertised() ? MAVLINK_MSG_ID_ESTIMATOR_SENSOR_FUSION_STATUS_LEN + MAVLINK_NUM_NON_PAYLOAD_BYTES : 0;
+	}
+
+private:
+	// Array indices matching ESTIMATOR_SENSOR_FUSION_SOURCE - 1
+	static constexpr uint8_t IDX_GPS    = 0;
+	static constexpr uint8_t IDX_OF     = 1;
+	static constexpr uint8_t IDX_EV     = 2;
+	static constexpr uint8_t IDX_AGP    = 3;
+	static constexpr uint8_t IDX_BARO   = 4;
+	static constexpr uint8_t IDX_RNG    = 5;
+	static constexpr uint8_t IDX_MAG    = 6;
+	static constexpr uint8_t IDX_ASPD   = 7;
+	static constexpr uint8_t IDX_RNGBCN = 8;
+
+	explicit MavlinkStreamEstimatorSensorFusionStatus(Mavlink *mavlink) : MavlinkStream(mavlink) {}
+
+	uORB::Subscription _estimator_fusion_control_sub{ORB_ID(estimator_fusion_control)};
+
+	bool send() override
+	{
+		estimator_fusion_control_s fc;
+
+		if (_estimator_fusion_control_sub.update(&fc)) {
+			mavlink_estimator_sensor_fusion_status_t msg{};
+
+			for (int i = 0; i < 9; i++) { msg.test_ratio[i] = NAN; }
+
+			// intended: sensor enabled by user AND CTRL param not disabled
+			for (int i = 0; i < 2; i++) {
+				if (fc.gps_intended[i]) { msg.intended[IDX_GPS] |= (1u << i); }
+			}
+
+			msg.intended[IDX_OF]     = fc.of_intended;
+			msg.intended[IDX_EV]     = fc.ev_intended;
+			msg.intended[IDX_BARO]   = fc.baro_intended;
+			msg.intended[IDX_RNG]    = fc.rng_intended;
+			msg.intended[IDX_MAG]    = fc.mag_intended;
+			msg.intended[IDX_ASPD]   = fc.aspd_intended;
+			msg.intended[IDX_RNGBCN] = fc.rngbcn_intended;
+
+			for (int i = 0; i < 4; i++) {
+				if (fc.agp_intended[i]) { msg.intended[IDX_AGP] |= (1u << i); }
+			}
+
+			// active: estimator is actually fusing data from this source
+			for (int i = 0; i < 2; i++) {
+				if (fc.gps_active[i]) { msg.active[IDX_GPS] |= (1u << i); }
+			}
+
+			msg.active[IDX_OF]   = fc.of_active;
+			msg.active[IDX_EV]   = fc.ev_active;
+
+			for (int i = 0; i < 4; i++) {
+				if (fc.agp_active[i]) { msg.active[IDX_AGP] |= (1u << i); }
+			}
+
+			msg.active[IDX_BARO] = fc.baro_active;
+			msg.active[IDX_RNG]  = fc.rng_active;
+			msg.active[IDX_MAG]  = fc.mag_active;
+			msg.active[IDX_ASPD]   = fc.aspd_active;
+			msg.active[IDX_RNGBCN] = fc.rngbcn_active;
+
+			mavlink_msg_estimator_sensor_fusion_status_send_struct(_mavlink->get_channel(), &msg);
+			return true;
+		}
+
+		return false;
+	}
+};
+
+#endif // ESTIMATOR_SENSOR_FUSION_STATUS_HPP