update airspeed usage to airspeed_validated (#13710)

* Mavlink: subscribe to airspeed_validated instead of airspeed topic

	This e.g. changes the way QGC displays the airspeed in case of an
	airspeed failure (0 instead of the last valid airspeed). It will
	always display the airspeed that's used currently in the control
	modules.

* FW land detector: move to subscribe to airspeed_validated instead of airspeed topic
	- the land detector checks further if the airspeed is NAN, in which case
	it sets the airspeed to 0 (min groundspeed, vz  and accel checks still
	have to pass.

* Fixed-wing land detector use airspeed_vaidated: addressed review comments
	- replaced ternary by conditional
	- set airspeed to 0 if airspeed_validated stops publishing

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

src/modules/land_detector/FixedwingLandDetector.cpp

@@ -54,7 +54,7 @@ FixedwingLandDetector::FixedwingLandDetector()
 void FixedwingLandDetector::_update_topics()
 {
 	LandDetector::_update_topics();
-	_airspeed_sub.update(&_airspeed);
+	_airspeed_validated_sub.update(&_airspeed_validated);
 }
 
 bool FixedwingLandDetector::_get_landed_state()
@@ -83,7 +83,13 @@ bool FixedwingLandDetector::_get_landed_state()
 			_velocity_z_filtered = val;
 		}
 
-		_airspeed_filtered = 0.95f * _airspeed_filtered + 0.05f * _airspeed.true_airspeed_m_s;
+		// set _airspeed_filtered to 0 if airspeed data is invalid
+		if (!PX4_ISFINITE(_airspeed_validated.true_airspeed_m_s) || hrt_elapsed_time(&_airspeed_validated.timestamp) > 1_s) {
+			_airspeed_filtered = 0.0f;
+
+		} else {
+			_airspeed_filtered = 0.95f * _airspeed_filtered + 0.05f * _airspeed_validated.true_airspeed_m_s;
+		}
 
 		// A leaking lowpass prevents biases from building up, but
 		// gives a mostly correct response for short impulses.

src/modules/land_detector/FixedwingLandDetector.h

@@ -43,7 +43,7 @@
 #pragma once
 
 #include <matrix/math.hpp>
-#include <uORB/topics/airspeed.h>
+#include <uORB/topics/airspeed_validated.h>
 
 #include "LandDetector.h"
 
@@ -69,9 +69,9 @@ class FixedwingLandDetector final : public LandDetector
 	static constexpr hrt_abstime LANDED_TRIGGER_TIME_US = 2_s;
 	static constexpr hrt_abstime FLYING_TRIGGER_TIME_US = 0_us;
 
-	uORB::Subscription _airspeed_sub{ORB_ID(airspeed)};
+	uORB::Subscription _airspeed_validated_sub{ORB_ID(airspeed_validated)};
 
-	airspeed_s _airspeed{};
+	airspeed_validated_s _airspeed_validated{};
 
 	float _airspeed_filtered{0.0f};
 	float _velocity_xy_filtered{0.0f};

src/modules/mavlink/mavlink_messages.cpp

@@ -58,7 +58,7 @@
 #include <uORB/topics/actuator_armed.h>
 #include <uORB/topics/actuator_controls.h>
 #include <uORB/topics/actuator_outputs.h>
-#include <uORB/topics/airspeed.h>
+#include <uORB/topics/airspeed_validated.h>
 #include <uORB/topics/battery_status.h>
 #include <uORB/topics/camera_trigger.h>
 #include <uORB/topics/camera_capture.h>
@@ -1396,7 +1396,7 @@ class MavlinkStreamVFRHUD : public MavlinkStream
 	MavlinkOrbSubscription *_act0_sub;
 	MavlinkOrbSubscription *_act1_sub;
 
-	MavlinkOrbSubscription *_airspeed_sub;
+	MavlinkOrbSubscription *_airspeed_validated_sub;
 	uint64_t _airspeed_time;
 
 	MavlinkOrbSubscription *_air_data_sub;
@@ -1413,7 +1413,7 @@ class MavlinkStreamVFRHUD : public MavlinkStream
 		_armed_time(0),
 		_act0_sub(_mavlink->add_orb_subscription(ORB_ID(actuator_controls_0))),
 		_act1_sub(_mavlink->add_orb_subscription(ORB_ID(actuator_controls_1))),
-		_airspeed_sub(_mavlink->add_orb_subscription(ORB_ID(airspeed))),
+		_airspeed_validated_sub(_mavlink->add_orb_subscription(ORB_ID(airspeed_validated))),
 		_airspeed_time(0),
 		_air_data_sub(_mavlink->add_orb_subscription(ORB_ID(vehicle_air_data)))
 	{}
@@ -1422,16 +1422,16 @@ class MavlinkStreamVFRHUD : public MavlinkStream
 	{
 		vehicle_local_position_s pos = {};
 		actuator_armed_s armed = {};
-		airspeed_s airspeed = {};
+		airspeed_validated_s airspeed_validated = {};
 
 		bool updated = false;
 		updated |= _pos_sub->update(&_pos_time, &pos);
 		updated |= _armed_sub->update(&_armed_time, &armed);
-		updated |= _airspeed_sub->update(&_airspeed_time, &airspeed);
+		updated |= _airspeed_validated_sub->update(&_airspeed_time, &airspeed_validated);
 
 		if (updated) {
-			mavlink_vfr_hud_t msg = {};
-			msg.airspeed = airspeed.indicated_airspeed_m_s;
+			mavlink_vfr_hud_t msg{};
+			msg.airspeed = airspeed_validated.indicated_airspeed_m_s;
 			msg.groundspeed = sqrtf(pos.vx * pos.vx + pos.vy * pos.vy);
 			msg.heading = math::degrees(wrap_2pi(pos.yaw));