Copter: increase read_rangefinder to 50hz

ArduCopter/Copter.cpp

@@ -104,7 +104,7 @@ const AP_Scheduler::Task Copter::scheduler_tasks[] = {
     SCHED_TASK(auto_disarm_check,     10,     50),
     SCHED_TASK(auto_trim,             10,     75),
 #if RANGEFINDER_ENABLED == ENABLED
-    SCHED_TASK(read_rangefinder,      20,    100),
+    SCHED_TASK(read_rangefinder,      50,    100),
 #endif
 #if PROXIMITY_ENABLED == ENABLED
     SCHED_TASK_CLASS(AP_Proximity,         &copter.g2.proximity,        update,         100,  50),

ArduCopter/sensors.cpp

@@ -47,7 +47,7 @@ void Copter::read_rangefinder(void)
             // reset filter if we haven't used it within the last second
             rangefinder_state.alt_cm_filt.reset(rangefinder_state.alt_cm);
         } else {
-            rangefinder_state.alt_cm_filt.apply(rangefinder_state.alt_cm, 0.05f);
+            rangefinder_state.alt_cm_filt.apply(rangefinder_state.alt_cm, 0.02f);
         }
         rangefinder_state.last_healthy_ms = now;
     }