MCLandDetector: fix low thrust detection in stabilized mode

HTE runs based on the position controller so, even if we whish to use
the estimate, it is only available in altitude and position modes.
Therefore, we need to always initialize the hoverThrottle using the hover
thrust parameter in case we fly in stabilized

src/modules/land_detector/MulticopterLandDetector.cpp

@@ -118,8 +118,15 @@ void MulticopterLandDetector::_update_params()
 	param_get(_paramHandle.useHoverThrustEstimate, &use_hover_thrust_estimate);
 	_params.useHoverThrustEstimate = (use_hover_thrust_estimate == 1);
 
-	if (!_params.useHoverThrustEstimate) {
+	if (!_params.useHoverThrustEstimate || !_hover_thrust_initialized) {
 		param_get(_paramHandle.hoverThrottle, &_params.hoverThrottle);
+
+		// HTE runs based on the position controller so, even if we wish to use
+		// the estimate, it is only available in altitude and position modes.
+		// Therefore, we need to always initialize the hoverThrottle using the hover
+		// thrust parameter in case we fly in stabilized
+		// TODO: this can be removed once HTE runs in all modes
+		_hover_thrust_initialized = true;
 	}
 }
 

src/modules/land_detector/MulticopterLandDetector.h

@@ -129,6 +129,8 @@ class MulticopterLandDetector : public LandDetector
 	vehicle_control_mode_s            _vehicle_control_mode {};
 	vehicle_local_position_setpoint_s _vehicle_local_position_setpoint {};
 
+	bool _hover_thrust_initialized{false};
+
 	hrt_abstime _min_trust_start{0};	///< timestamp when minimum trust was applied first
 	hrt_abstime _landed_time{0};