drivers: Accept entire distance sensor signal strength range

src/drivers/distance_sensor/ll40ls/LidarLiteI2C.h

@@ -73,7 +73,7 @@ static constexpr uint8_t LL40LS_UNIT_ID_LOW           = 0x17;
 static constexpr uint8_t LL40LS_SIG_COUNT_VAL_REG     = 0x02; /* Maximum acquisition count register */
 static constexpr uint8_t LL40LS_SIG_COUNT_VAL_MAX     = 0xFF; /* Maximum acquisition count max value */
 
-static constexpr int LL40LS_SIGNAL_STRENGTH_MIN_V3HP  = 70;  /* Min signal strength for V3HP */
+static constexpr int LL40LS_SIGNAL_STRENGTH_MIN_V3HP  = 0;  /* Min signal strength for V3HP */
 static constexpr int LL40LS_SIGNAL_STRENGTH_MAX_V3HP  = 255; /* Max signal strength for V3HP */
 
 static constexpr int LL40LS_SIGNAL_STRENGTH_LOW       = 24;  /* Minimum signal strength for a valid measurement */

src/modules/ekf2/EKF/common.h

@@ -430,7 +430,8 @@ struct parameters {
 	float max_hagl_for_range_aid{5.0f};     ///< maximum height above ground for which we allow to use the range finder as height source (if rng_control == 1)
 	float max_vel_for_range_aid{1.0f};      ///< maximum ground velocity for which we allow to use the range finder as height source (if rng_control == 1)
 	float range_aid_innov_gate{1.0f};       ///< gate size used for innovation consistency checks for range aid fusion
-	float range_valid_quality_s{1.0f};      ///< minimum duration during which the reported range finder signal quality needs to be non-zero in order to be declared valid (s)
+	float range_valid_quality_s{1.0f};      ///< Minimum duration during which the reported range finder signal quality needs to be >= EKF2_RNG_QMIN in order to be declared valid (s)
+	float range_valid_quality_min{0.0f};	///< Range data will only be used in air if the sensor reports a quality metric >= EKF2_RNG_QMIN.
 	float range_cos_max_tilt{0.7071f};      ///< cosine of the maximum tilt angle from the vertical that permits use of range finder and flow data
 	float range_kin_consistency_gate{1.0f}; ///< gate size used by the range finder kinematic consistency check
 

src/modules/ekf2/EKF/ekf.cpp

@@ -76,6 +76,7 @@ void Ekf::reset()
 	_range_sensor.setPitchOffset(_params.rng_sens_pitch);
 	_range_sensor.setCosMaxTilt(_params.range_cos_max_tilt);
 	_range_sensor.setQualityHysteresis(_params.range_valid_quality_s);
+	_range_sensor.setQualityMinimum(_params.range_valid_quality_min);
 #endif // CONFIG_EKF2_RANGE_FINDER
 
 	_control_status.value = 0;

src/modules/ekf2/EKF/range_height_control.cpp

@@ -53,6 +53,7 @@ void Ekf::controlRangeHeightFusion()
 		_range_sensor.setPitchOffset(_params.rng_sens_pitch);
 		_range_sensor.setCosMaxTilt(_params.range_cos_max_tilt);
 		_range_sensor.setQualityHysteresis(_params.range_valid_quality_s);
+		_range_sensor.setQualityMinimum(_params.range_valid_quality_min);
 
 		_range_sensor.runChecks(_time_delayed_us, _R_to_earth);
 

src/modules/ekf2/EKF/sensor_range_finder.cpp

@@ -74,7 +74,7 @@ void SensorRangeFinder::updateValidity(uint64_t current_time_us)
 	if (_is_sample_ready) {
 		_is_sample_valid = false;
 
-		if (_sample.quality == 0) {
+		if (_sample.quality < _quality_minimum) {
 			_time_bad_quality_us = current_time_us;
 
 		} else if (current_time_us - _time_bad_quality_us > _quality_hyst_us) {

src/modules/ekf2/EKF/sensor_range_finder.hpp

@@ -94,6 +94,8 @@ class SensorRangeFinder : public Sensor
 		_quality_hyst_us = uint64_t(valid_quality_threshold_s * 1e6f);
 	}
 
+	void setQualityMinimum(float quality_minimum) { _quality_minimum = quality_minimum; }
+
 	float getCosTilt() const { return _cos_tilt_rng_to_earth; }
 
 	void setRange(float rng) { _sample.rng = rng; }
@@ -161,7 +163,8 @@ class SensorRangeFinder : public Sensor
 	 * Quality check
 	 */
 	uint64_t _time_bad_quality_us{};	///< timestamp at which range finder signal quality was 0 (used for hysteresis)
-	uint64_t _quality_hyst_us{};		///< minimum duration during which the reported range finder signal quality needs to be non-zero in order to be declared valid (us)
+	uint64_t _quality_hyst_us{};		///< minimum duration during which the reported range finder signal quality needs to be >= EKF2_RNG_QMIN in order to be declared valid (us)
+	float _quality_minimum{};		///< range data will only be used in air if the sensor reports a quality metric >= EKF2_RNG_QMIN.
 };
 
 } // namespace sensor

src/modules/ekf2/EKF2.cpp

@@ -159,6 +159,7 @@ EKF2::EKF2(bool multi_mode, const px4::wq_config_t &config, bool replay_mode):
 	_param_ekf2_rng_a_hmax(_params->max_hagl_for_range_aid),
 	_param_ekf2_rng_a_igate(_params->range_aid_innov_gate),
 	_param_ekf2_rng_qlty_t(_params->range_valid_quality_s),
+	_param_ekf2_rng_qmin(_params->range_valid_quality_min),
 	_param_ekf2_rng_k_gate(_params->range_kin_consistency_gate),
 	_param_ekf2_rng_pos_x(_params->rng_pos_body(0)),
 	_param_ekf2_rng_pos_y(_params->rng_pos_body(1)),

src/modules/ekf2/EKF2.hpp

@@ -654,6 +654,7 @@ class EKF2 final : public ModuleParams, public px4::ScheduledWorkItem
 		(ParamExtFloat<px4::params::EKF2_RNG_A_HMAX>) _param_ekf2_rng_a_hmax,
 		(ParamExtFloat<px4::params::EKF2_RNG_A_IGATE>) _param_ekf2_rng_a_igate,
 		(ParamExtFloat<px4::params::EKF2_RNG_QLTY_T>) _param_ekf2_rng_qlty_t,
+		(ParamExtFloat<px4::params::EKF2_RNG_QMIN>) _param_ekf2_rng_qmin,
 		(ParamExtFloat<px4::params::EKF2_RNG_K_GATE>) _param_ekf2_rng_k_gate,
 		(ParamExtFloat<px4::params::EKF2_RNG_POS_X>) _param_ekf2_rng_pos_x,
 		(ParamExtFloat<px4::params::EKF2_RNG_POS_Y>) _param_ekf2_rng_pos_y,

src/modules/ekf2/ekf2_params.c

@@ -1185,7 +1185,7 @@ PARAM_DEFINE_FLOAT(EKF2_RNG_A_HMAX, 5.0f);
 PARAM_DEFINE_FLOAT(EKF2_RNG_A_IGATE, 1.0f);
 
 /**
- * Minimum duration during which the reported range finder signal quality needs to be non-zero in order to be declared valid (s)
+ * Minimum duration during which the reported range finder signal quality needs to be >= EKF2_RNG_QMIN in order to be declared valid (s)
  *
  *
  * @group EKF2
@@ -1195,6 +1195,15 @@ PARAM_DEFINE_FLOAT(EKF2_RNG_A_IGATE, 1.0f);
 */
 PARAM_DEFINE_FLOAT(EKF2_RNG_QLTY_T, 1.0f);
 
+/**
+ * Range data will only be used in air if the sensor reports a quality metric >= EKF2_RNG_QMIN.
+ *
+ * @group EKF2
+ * @min 0
+ * @max 100
+*/
+PARAM_DEFINE_FLOAT(EKF2_RNG_QMIN, 27.0f);
+
 /**
  * Gate size used for range finder kinematic consistency check
  *