distance sensors: Improve variable naming / description

msg/distance_sensor.msg

@@ -5,7 +5,7 @@ float32 min_distance		# Minimum distance the sensor can measure (in m)
 float32 max_distance		# Maximum distance the sensor can measure (in m)
 float32 current_distance	# Current distance reading (in m)
 float32 covariance		# Measurement covariance (in m), 0 for unknown / invalid readings
-int8 signal_strength		# Signal strength in percent (0...100%) or -1 if unknown
+int8 signal_quality		# Signal quality in percent (0...100%), where 0 = invalid signal, 100 = perfect signal, and -1 = unknown signal quality.
 
 uint8 type			# Type from MAV_DISTANCE_SENSOR enum
 uint8 MAV_DISTANCE_SENSOR_LASER = 0

src/drivers/distance_sensor/leddar_one/leddar_one.cpp

@@ -411,7 +411,7 @@ void leddar_one::_publish(uint16_t distance_mm)
 	report.min_distance = MIN_DISTANCE;
 	report.max_distance = MAX_DISTANCE;
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 	report.id = 0;
 
 	_reports->force(&report);

src/drivers/distance_sensor/ll40ls/LidarLiteI2C.cpp

@@ -515,14 +515,14 @@ int LidarLiteI2C::collect()
 
 	/* Final data quality evaluation. This is based on the datasheet and simple heuristics retrieved from experiments*/
 	// Step 1: Normalize signal strength to 0...100 percent using the absolute signal peak strength.
-	uint8_t signal_strength = 100 * math::max(ll40ls_peak_strength - LL40LS_PEAK_STRENGTH_LOW,
-				  0) / (LL40LS_PEAK_STRENGTH_HIGH - LL40LS_PEAK_STRENGTH_LOW);
+	uint8_t signal_quality = 100 * math::max(ll40ls_peak_strength - LL40LS_PEAK_STRENGTH_LOW,
+				 0) / (LL40LS_PEAK_STRENGTH_HIGH - LL40LS_PEAK_STRENGTH_LOW);
 
 	// Step 2: Also use ll40ls_signal_strength (a relative measure, i.e. peak strength to noise!) to reject potentially ambiguous measurements
-	if (ll40ls_signal_strength <= LL40LS_SIGNAL_STRENGTH_LOW) { signal_strength = 0; }
+	if (ll40ls_signal_strength <= LL40LS_SIGNAL_STRENGTH_LOW) { signal_quality = 0; }
 
 	// Step 3: Filter physically impossible measurements, which removes some crazy outliers that appear on LL40LS.
-	if (distance_m < LL40LS_MIN_DISTANCE) { signal_strength = 0; }
+	if (distance_m < LL40LS_MIN_DISTANCE) { signal_quality = 0; }
 
 	/* this should be fairly close to the end of the measurement, so the best approximation of the time */
 	report.timestamp = hrt_absolute_time();
@@ -530,7 +530,7 @@ int LidarLiteI2C::collect()
 	report.min_distance = get_minimum_distance();
 	report.max_distance = get_maximum_distance();
 	report.covariance = 0.0f;
-	report.signal_strength = signal_strength;
+	report.signal_quality = signal_quality;
 	report.type =
 		distance_sensor_s::MAV_DISTANCE_SENSOR_LASER;		// the sensor is in fact a laser + sonar but there is no enum for this
 	report.orientation = _rotation;

src/drivers/distance_sensor/mb12xx/mb12xx.cpp

@@ -556,7 +556,7 @@ MB12XX::collect()
 	report.min_distance = get_minimum_distance();
 	report.max_distance = get_maximum_distance();
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 	/* TODO: set proper ID */
 	report.id = 0;
 

src/drivers/distance_sensor/sf0x/sf0x.cpp

@@ -616,7 +616,7 @@ SF0X::collect()
 	report.min_distance = get_minimum_distance();
 	report.max_distance = get_maximum_distance();
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 	/* TODO: set proper ID */
 	report.id = 0;
 

src/drivers/distance_sensor/sf1xx/sf1xx.cpp

@@ -552,7 +552,7 @@ SF1XX::collect()
 	report.min_distance = get_minimum_distance();
 	report.max_distance = get_maximum_distance();
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 	/* TODO: set proper ID */
 	report.id = 0;
 

src/drivers/distance_sensor/srf02/srf02.cpp

@@ -559,7 +559,7 @@ SRF02::collect()
 	report.min_distance = get_minimum_distance();
 	report.max_distance = get_maximum_distance();
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 	/* TODO: set proper ID */
 	report.id = 0;
 

src/drivers/distance_sensor/teraranger/teraranger.cpp

@@ -633,7 +633,7 @@ TERARANGER::collect()
 	report.min_distance = get_minimum_distance();
 	report.max_distance = get_maximum_distance();
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 	/* TODO: set proper ID */
 	report.id = 0;
 

src/drivers/distance_sensor/tfmini/tfmini.cpp

@@ -580,7 +580,7 @@ TFMINI::collect()
 	report.min_distance = get_minimum_distance();
 	report.max_distance = get_maximum_distance();
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 	/* TODO: set proper ID */
 	report.id = 0;
 

src/drivers/distance_sensor/vl53lxx/vl53lxx.cpp

@@ -675,7 +675,7 @@ VL53LXX::collect()
 	report.min_distance = VL53LXX_MIN_RANGING_DISTANCE;
 	report.max_distance = VL53LXX_MAX_RANGING_DISTANCE;
 	report.covariance = 0.0f;
-	report.signal_strength = -1;
+	report.signal_quality = -1;
 
 	/* TODO: set proper ID */
 	report.id = 0;

src/drivers/px4flow/px4flow.cpp

@@ -595,7 +595,7 @@ PX4FLOW::collect()
 	distance_report.max_distance = PX4FLOW_MAX_DISTANCE;
 	distance_report.current_distance = report.ground_distance_m;
 	distance_report.covariance = 0.0f;
-	distance_report.signal_strength = -1;
+	distance_report.signal_quality = -1;
 	distance_report.type = distance_sensor_s::MAV_DISTANCE_SENSOR_ULTRASOUND;
 	/* TODO: the ID needs to be properly set */
 	distance_report.id = 0;

src/modules/ekf2/ekf2_main.cpp

@@ -942,7 +942,7 @@ void Ekf2::run()
 					// check if distance sensor is within working boundaries
 					if (range_finder.min_distance >= range_finder.current_distance ||
 					    range_finder.max_distance <= range_finder.current_distance ||
-					    range_finder.signal_strength == 0) {
+					    range_finder.signal_quality == 0) {
 						// use rng_gnd_clearance if on ground
 						if (_ekf.get_in_air_status()) {
 							range_finder_updated = false;

src/modules/simulator/simulator_mavlink.cpp

@@ -1173,7 +1173,7 @@ int Simulator::publish_distance_topic(mavlink_distance_sensor_t *dist_mavlink)
 	dist.id = dist_mavlink->id;
 	dist.orientation = dist_mavlink->orientation;
 	dist.covariance = dist_mavlink->covariance / 100.0f;
-	dist.signal_strength = -1;
+	dist.signal_quality = -1;
 
 	int dist_multi;
 	orb_publish_auto(ORB_ID(distance_sensor), &_dist_pub, &dist, &dist_multi, ORB_PRIO_HIGH);

src/platforms/posix/drivers/df_bebop_rangefinder_wrapper/df_bebop_rangefinder_wrapper.cpp

@@ -162,7 +162,7 @@ int DfBebopRangeFinderWrapper::_publish(struct bebop_range &data)
 
 	distance_data.covariance = 1.0f; // TODO set correct value
 
-	distance_data.signal_strength = -1;
+	distance_data.signal_quality = -1;
 
 	if (_range_topic == nullptr) {
 		_range_topic = orb_advertise_multi(ORB_ID(distance_sensor), &distance_data,

src/platforms/posix/drivers/df_isl29501_wrapper/df_isl29501_wrapper.cpp

@@ -169,7 +169,7 @@ int DfISL29501Wrapper::_publish(struct range_sensor_data &data)
 
 	d.covariance = 0.0f;
 
-	d.signal_strength = -1;
+	d.signal_quality = -1;
 
 	if (_range_topic == nullptr) {
 		_range_topic = orb_advertise_multi(ORB_ID(distance_sensor), &d,

src/platforms/posix/drivers/df_trone_wrapper/df_trone_wrapper.cpp

@@ -175,7 +175,7 @@ int DfTROneWrapper::_publish(struct range_sensor_data &data)
 
 	d.covariance = 0.0f;
 
-	d.signal_strength = -1;
+	d.signal_quality = -1;
 
 	if (_range_topic == nullptr) {
 		_range_topic = orb_advertise_multi(ORB_ID(distance_sensor), &d,