From b7986e6fdd103064128d0933f7cb32ab4252159b Mon Sep 17 00:00:00 2001
From: Lorenz Meier <lm@inf.ethz.ch>
Date: Fri, 5 Jun 2015 12:43:45 +0200
Subject: [PATCH] land detector: Improve performance for fixed wing setups

---
 .../land_detector/FixedwingLandDetector.cpp   | 14 ++++++----
 src/modules/land_detector/LandDetector.h      |  2 +-
 .../land_detector/land_detector_params.c      | 27 ++++++++++++++++---
 3 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/src/modules/land_detector/FixedwingLandDetector.cpp b/src/modules/land_detector/FixedwingLandDetector.cpp
index e26954d1a6..6e8393617e 100644
--- a/src/modules/land_detector/FixedwingLandDetector.cpp
+++ b/src/modules/land_detector/FixedwingLandDetector.cpp
@@ -84,11 +84,15 @@ bool FixedwingLandDetector::update()
 	const uint64_t now = hrt_absolute_time();
 	bool landDetected = false;
 
-	// TODO: reset filtered values on arming?
-	_velocity_xy_filtered = 0.95f * _velocity_xy_filtered + 0.05f * sqrtf(_vehicleLocalPosition.vx *
-				_vehicleLocalPosition.vx + _vehicleLocalPosition.vy * _vehicleLocalPosition.vy);
-	_velocity_z_filtered = 0.95f * _velocity_z_filtered + 0.05f * fabsf(_vehicleLocalPosition.vz);
-	_airspeed_filtered = 0.95f * _airspeed_filtered + 0.05f * _airspeed.true_airspeed_m_s;
+	if (hrt_elapsed_time(&_vehicleLocalPosition.timestamp) < 500 * 1000) {
+		_velocity_xy_filtered = 0.95f * _velocity_xy_filtered + 0.05f * sqrtf(_vehicleLocalPosition.vx *
+					_vehicleLocalPosition.vx + _vehicleLocalPosition.vy * _vehicleLocalPosition.vy);
+		_velocity_z_filtered = 0.95f * _velocity_z_filtered + 0.05f * fabsf(_vehicleLocalPosition.vz);
+	}
+
+	if (hrt_elapsed_time(&_airspeed.timestamp) < 500 * 1000) {
+		_airspeed_filtered = 0.95f * _airspeed_filtered + 0.05f * _airspeed.true_airspeed_m_s;
+	}
 
 	// crude land detector for fixedwing
 	if (_velocity_xy_filtered < _params.maxVelocity
diff --git a/src/modules/land_detector/LandDetector.h b/src/modules/land_detector/LandDetector.h
index b2984003b9..68f96288cd 100644
--- a/src/modules/land_detector/LandDetector.h
+++ b/src/modules/land_detector/LandDetector.h
@@ -87,7 +87,7 @@ protected:
 	virtual void initialize() = 0;
 
 	/**
-	* @brief Convinience function for polling uORB subscriptions
+	* @brief Convenience function for polling uORB subscriptions
 	* @return true if there was new data and it was successfully copied
 	**/
 	bool orb_update(const struct orb_metadata *meta, int handle, void *buffer);
diff --git a/src/modules/land_detector/land_detector_params.c b/src/modules/land_detector/land_detector_params.c
index 9cf57b5fc9..b670dcc035 100644
--- a/src/modules/land_detector/land_detector_params.c
+++ b/src/modules/land_detector/land_detector_params.c
@@ -45,6 +45,8 @@
  *
  * Maximum vertical velocity allowed to trigger a land (m/s up and down)
  *
+ * @unit m/s
+ *
  * @group Land Detector
  */
 PARAM_DEFINE_FLOAT(LNDMC_Z_VEL_MAX, 0.30f);
@@ -54,6 +56,8 @@ PARAM_DEFINE_FLOAT(LNDMC_Z_VEL_MAX, 0.30f);
  *
  * Maximum horizontal velocity allowed to trigger a land (m/s)
  *
+ * @unit m/s
+ *
  * @group Land Detector
  */
 PARAM_DEFINE_FLOAT(LNDMC_XY_VEL_MAX, 1.00f);
@@ -63,6 +67,8 @@ PARAM_DEFINE_FLOAT(LNDMC_XY_VEL_MAX, 1.00f);
  *
  * Maximum allowed around each axis to trigger a land (degrees per second)
  *
+ * @unit deg/s
+ *
  * @group Land Detector
  */
 PARAM_DEFINE_FLOAT(LNDMC_ROT_MAX, 20.0f);
@@ -72,6 +78,9 @@ PARAM_DEFINE_FLOAT(LNDMC_ROT_MAX, 20.0f);
  *
  * Maximum actuator output on throttle before triggering a land
  *
+ * @min 0.1
+ * @max 0.5
+ *
  * @group Land Detector
  */
 PARAM_DEFINE_FLOAT(LNDMC_THR_MAX, 0.20f);
@@ -81,24 +90,36 @@ PARAM_DEFINE_FLOAT(LNDMC_THR_MAX, 0.20f);
  *
  * Maximum horizontal velocity allowed to trigger a land (m/s)
  *
+ * @min 0.5
+ * @max 10
+ * @unit m/s
+ *
  * @group Land Detector
  */
-PARAM_DEFINE_FLOAT(LNDFW_VEL_XY_MAX, 0.40f);
+PARAM_DEFINE_FLOAT(LNDFW_VEL_XY_MAX, 4.0f);
 
 /**
  * Fixedwing max climb rate
  *
  * Maximum vertical velocity allowed to trigger a land (m/s up and down)
  *
+ * @min 5
+ * @max 20
+ * @unit m/s
+ *
  * @group Land Detector
  */
-PARAM_DEFINE_FLOAT(LNDFW_VEL_Z_MAX, 10.00f);
+PARAM_DEFINE_FLOAT(LNDFW_VEL_Z_MAX, 10.0f);
 
 /**
  * Airspeed max
  *
  * Maximum airspeed allowed to trigger a land (m/s)
  *
+ * @min 4
+ * @max 20
+ * @unit m/s
+ *
  * @group Land Detector
  */
-PARAM_DEFINE_FLOAT(LNDFW_AIRSPD_MAX, 10.00f);
+PARAM_DEFINE_FLOAT(LNDFW_AIRSPD_MAX, 8.00f);