terrain_estimator: remove dead code. Since the terrain estimator is

constantly reset on ground, it is not necessary anymore to fuse fake
measurements on ground if the range measurements are bad.

EKF/terrain_estimator.cpp

@@ -90,7 +90,8 @@ void Ekf::runTerrainEstimator()
 	// Perform a continuity check on range finder data
 	checkRangeDataContinuity();
 
-	// Perform initialisation check
+	// Perform initialisation check and
+	// on ground, continuously reset the terrain estimator
 	if (!_terrain_initialised || !_control_status.flags.in_air) {
 		_terrain_initialised = initHagl();
 
@@ -108,15 +109,6 @@ void Ekf::runTerrainEstimator()
 		// limit the variance to prevent it becoming badly conditioned
 		_terrain_var = math::constrain(_terrain_var, 0.0f, 1e4f);
 
-		// if stationary on the ground and no or bad range data for over a second, fake a measurement
-		// to handle bad range finder data when on ground
-		if ((_rng_hgt_faulty || !_range_data_ready) && !_control_status.flags.in_air && _vehicle_at_rest &&
-			(_time_last_imu - _time_last_hagl_fuse) > (uint64_t)1E6) {
-			_range_data_ready = true;
-			_rng_hgt_faulty = false;
-			_range_sample_delayed.rng = _params.rng_gnd_clearance;
-		}
-
 		// Fuse range finder data if available
 		if (_range_data_ready && !_rng_hgt_faulty) {
 			fuseHagl();